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* [PATCH 0/2] pinctrl: Introduce support for iodelay module in TI SoCs
@ 2015-03-04  0:00 Nishanth Menon
  2015-03-04  0:00 ` [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration Nishanth Menon
  2015-03-04  0:00 ` [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver Nishanth Menon
  0 siblings, 2 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-04  0:00 UTC (permalink / raw)
  To: Tony Lindgren, Linus Walleij
  Cc: linux-gpio, linux-kernel, devicetree, linux-omap,
	linux-arm-kernel, Lokesh Vutla, Nishanth Menon

Hi,

SoCs such as DRA7 family from Texas Instruments also include a highly
configurable hardware block called the IOdelay block. This block
allows very specific custom fine tuning for electrical characteristics
of IO pins that are necessary for functionality and device lifetime
requirements.

IODelay module exists on it's own register space with registers
allocated for various pins. A set of values (derived from either
automated tools OR from device datasheet) is then computed on a
per-chip basis(to account for die specific variations) to generate a
set of delay parameters that are programmed to one or more registers
for the delay path of the io line. This is used in specific instances
such as MMC to achieve high-throughput modes, and most pins dont
usually need tweaking functionality provided by this driver.

Even though this kind of operates similar to a pinctrl model,
functionally, it is a characteristics tuning which does not completely
fit the standard pinconf model either.

In addition to the regular pin muxing modes supported by the
pinctrl-single, additional configuration for this block for specific
pins may also be mandatory in certain cases.

Series based on v4.0-rc1

Nishanth Menon (2):
  pinctrl: bindings: pinctrl: Add support for TI's IODelay
    configuration
  pinctrl: Introduce TI IOdelay configuration driver

 .../bindings/pinctrl/ti,iodelay-pinctrl.txt        |   86 ++
 drivers/pinctrl/Kconfig                            |   11 +
 drivers/pinctrl/Makefile                           |    1 +
 drivers/pinctrl/pinctrl-ti-iodelay.c               |  963 ++++++++++++++++++++
 include/dt-bindings/pinctrl/dra.h                  |    6 +
 5 files changed, 1067 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/ti,iodelay-pinctrl.txt
 create mode 100644 drivers/pinctrl/pinctrl-ti-iodelay.c

-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 21+ messages in thread

* [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-04  0:00 [PATCH 0/2] pinctrl: Introduce support for iodelay module in TI SoCs Nishanth Menon
@ 2015-03-04  0:00 ` Nishanth Menon
  2015-03-10 10:39   ` Linus Walleij
  2015-03-04  0:00 ` [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver Nishanth Menon
  1 sibling, 1 reply; 21+ messages in thread
From: Nishanth Menon @ 2015-03-04  0:00 UTC (permalink / raw)
  To: Tony Lindgren, Linus Walleij
  Cc: linux-gpio, linux-kernel, devicetree, linux-omap,
	linux-arm-kernel, Lokesh Vutla, Nishanth Menon

SoCs such as DRA7 family from Texas Instruments also include a highly
configurable hardware block called the IOdelay block. This block
allows very specific custom fine tuning for electrical characteristics
of IO pins.

In addition to the regular pin muxing modes supported by the
pinctrl-single, additional configuration for this block for specific
pins may also be mandatory in certain cases.

It is advocated strongly in TI's official documentation considering
the existing design of the DRA7 family of processors, which during mux
or IODelay reconfiguration, has a potential for a significant glitch
which may cause functional impairment to certain hardware. It is hence
recommended to do as little of muxing as absolutely necessary without
IO isolation (which can only be done in initial stages of bootloader).

Even with the above limitation, certain functionality such as MMC may
mandate the need of IODelay reconfiguration depending on speed of
transfer. Hence, introduce a new binding to facilitate programming the
same.

Signed-off-by: Nishanth Menon <nm@ti.com>
---
 .../bindings/pinctrl/ti,iodelay-pinctrl.txt        |   86 ++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/ti,iodelay-pinctrl.txt

diff --git a/Documentation/devicetree/bindings/pinctrl/ti,iodelay-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/ti,iodelay-pinctrl.txt
new file mode 100644
index 000000000000..e12f4e5a3f25
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/ti,iodelay-pinctrl.txt
@@ -0,0 +1,86 @@
+Texas Instruments I/O Delay module configuration pinctrl definition
+
+Used in conjunction with Documentation/devicetree/bindings/pinctrl/ti,omap-pinctrl.txt
+
+Required Properties:
+- compatible: Should be:
+  "ti,dra7-iodelay" - I/O delay configuration for DRA7
+- reg	- must be the register address range of IODelay module
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+Important note: Use of "ti,dra7-iodelay" compatible definition need to be
+carefully evaluated due to the expectation of glitch during configuration.
+
+Example:
+
+dra7_iodelay_core: padconf@4844a000 {
+	compatible = "ti,dra7-iodelay";
+	reg = <0x4844a000 0x0d1c>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+};
+
+Configuration definition follows similar model as the pinctrl-single:
+The groups of pin configuration are defined under "pinctrl-single,pins"
+
+&dra7_iodelay_core {
+	mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
+		pinctrl-single,pins = <
+			0x18c (A_DELAY(0) | G_DELAY(120))	/* CFG_GPMC_A19_IN */
+			0x1a4 (A_DELAY(265) | G_DELAY(360))	/* CFG_GPMC_A20_IN */
+			0x1b0 (A_DELAY(0) | G_DELAY(120))	/* CFG_GPMC_A21_IN */
+			0x1bc (A_DELAY(0) | G_DELAY(120))	/* CFG_GPMC_A22_IN */
+			0x1c8 (A_DELAY(287) | G_DELAY(420))	/* CFG_GPMC_A23_IN */
+			0x1d4 (A_DELAY(144) | G_DELAY(240))	/* CFG_GPMC_A24_IN */
+			0x1e0 (A_DELAY(0) | G_DELAY(0))		/* CFG_GPMC_A25_IN */
+			0x1ec (A_DELAY(120) | G_DELAY(0))	/* CFG_GPMC_A26_IN */
+			0x1f8 (A_DELAY(120) | G_DELAY(180))	/* CFG_GPMC_A27_IN */
+			0x360 (A_DELAY(0) | G_DELAY(0))		/* CFG_GPMC_CS1_IN */
+		>;
+	};
+};
+
+Usage in conjunction with pinctrl single:
+
+For a complete description of the pins both the regular muxing as well as the
+iodelay configuration is necessary. For example:
+
+&dra7_pmx_core {
+	mmc2_pins_default: mmc2_pins_default {
+		pinctrl-single,pins = <
+			0x9c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a23.mmc2_clk */
+			0xb0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_cs1.mmc2_cmd */
+			0xa0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a24.mmc2_dat0 */
+			0xa4 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a25.mmc2_dat1 */
+			0xa8 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a26.mmc2_dat2 */
+			0xac (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a27.mmc2_dat3 */
+			0x8c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a19.mmc2_dat4 */
+			0x90 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a20.mmc2_dat5 */
+			0x94 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a21.mmc2_dat6 */
+			0x98 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /* gpmc_a22.mmc2_dat7 */
+		>;
+	};
+};
+
+&dra7_iodelay_core {
+	mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
+		pinctrl-single,pins = <
+			0x18c (A_DELAY(0) | G_DELAY(120))	/* CFG_GPMC_A19_IN */
+			0x1a4 (A_DELAY(265) | G_DELAY(360))	/* CFG_GPMC_A20_IN */
+			0x1b0 (A_DELAY(0) | G_DELAY(120))	/* CFG_GPMC_A21_IN */
+			0x1bc (A_DELAY(0) | G_DELAY(120))	/* CFG_GPMC_A22_IN */
+			0x1c8 (A_DELAY(287) | G_DELAY(420))	/* CFG_GPMC_A23_IN */
+			0x1d4 (A_DELAY(144) | G_DELAY(240))	/* CFG_GPMC_A24_IN */
+			0x1e0 (A_DELAY(0) | G_DELAY(0))		/* CFG_GPMC_A25_IN */
+			0x1ec (A_DELAY(120) | G_DELAY(0))	/* CFG_GPMC_A26_IN */
+			0x1f8 (A_DELAY(120) | G_DELAY(180))	/* CFG_GPMC_A27_IN */
+			0x360 (A_DELAY(0) | G_DELAY(0))		/* CFG_GPMC_CS1_IN */
+		>;
+	};
+};
+
+&mmc2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&mmc2_pins_default &mmc2_iodelay_3v3_conf>;
+};
-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 21+ messages in thread

* [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver
  2015-03-04  0:00 [PATCH 0/2] pinctrl: Introduce support for iodelay module in TI SoCs Nishanth Menon
  2015-03-04  0:00 ` [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration Nishanth Menon
@ 2015-03-04  0:00 ` Nishanth Menon
  2015-03-04 22:58   ` Paul Bolle
  2015-03-10 11:03   ` Linus Walleij
  1 sibling, 2 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-04  0:00 UTC (permalink / raw)
  To: Tony Lindgren, Linus Walleij
  Cc: linux-gpio, linux-kernel, devicetree, linux-omap,
	linux-arm-kernel, Lokesh Vutla, Nishanth Menon

SoC family such as DRA7 family of processors have, in addition
to the regular muxing of pins (as done by pinctrl-single), an
additional hardware module called IODelay which is also expected to be
configured. This "IODelay" module has it's own register space that is
independent of the control module.

It is advocated strongly in TI's official documentation considering
the existing design of the DRA7 family of processors during mux or
IODelay reconfiguration, there is a potential for a significant glitch
which may cause functional impairment to certain hardware. It is
hence recommended to do as little of muxing as absolutely necessary
without I/O isolation (which can only be done in initial stages of
bootloader).

NOTE: with the system wide I/O isolation scheme present in DRA7 SoC
family, it is not reasonable to do stop all I/O operations for every
such pad configuration scheme. So, we will let it glitch when used in
this mode.

Even with the above limitation, certain functionality such as MMC has
mandatory need for IODelay reconfiguration requirements, depending on
speed of transfer. In these cases, with careful examination of usecase
involved, the expected glitch can be controlled such that it does not
impact functionality.

In short, IODelay module support as a padconf driver being introduced
here is not expected to do SoC wide I/O Isolation and is meant for
a limited subset of IODelay configuration requirements that need to
be dynamic and whose glitchy behavior will not cause functionality
failure for that interface.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
---
 drivers/pinctrl/Kconfig              |   11 +
 drivers/pinctrl/Makefile             |    1 +
 drivers/pinctrl/pinctrl-ti-iodelay.c |  963 ++++++++++++++++++++++++++++++++++
 include/dt-bindings/pinctrl/dra.h    |    6 +
 4 files changed, 981 insertions(+)
 create mode 100644 drivers/pinctrl/pinctrl-ti-iodelay.c

diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
index ee9f44ad7f02..8e463d75fbb2 100644
--- a/drivers/pinctrl/Kconfig
+++ b/drivers/pinctrl/Kconfig
@@ -160,6 +160,17 @@ config PINCTRL_TEGRA_XUSB
 	select PINCONF
 	select PINMUX
 
+config PINCTRL_TI_IODELAY
+	bool "TI IODelay Module pinconf driver"
+	depends on OF
+	select PINCONF
+	select GENERIC_PINCONF
+	select REGMAP_MMIO
+	help
+	  Say Y here to support Texas Instruments' IODelay pinconf driver.
+	  IODelay module is used for the DRA7 SoC family. This driver is in
+	  addition to PINCTRL_SINGLE which controls the mux.
+
 config PINCTRL_TZ1090
 	bool "Toumaz Xenif TZ1090 pin control driver"
 	depends on SOC_TZ1090
diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
index 0475206dd600..e441cd71aedf 100644
--- a/drivers/pinctrl/Makefile
+++ b/drivers/pinctrl/Makefile
@@ -28,6 +28,7 @@ obj-$(CONFIG_PINCTRL_TEGRA30)	+= pinctrl-tegra30.o
 obj-$(CONFIG_PINCTRL_TEGRA114)	+= pinctrl-tegra114.o
 obj-$(CONFIG_PINCTRL_TEGRA124)	+= pinctrl-tegra124.o
 obj-$(CONFIG_PINCTRL_TEGRA_XUSB)	+= pinctrl-tegra-xusb.o
+obj-$(CONFIG_PINCTRL_TI_IODELAY)	+= pinctrl-ti-iodelay.o
 obj-$(CONFIG_PINCTRL_TZ1090)	+= pinctrl-tz1090.o
 obj-$(CONFIG_PINCTRL_TZ1090_PDC)	+= pinctrl-tz1090-pdc.o
 obj-$(CONFIG_PINCTRL_U300)	+= pinctrl-u300.o
diff --git a/drivers/pinctrl/pinctrl-ti-iodelay.c b/drivers/pinctrl/pinctrl-ti-iodelay.c
new file mode 100644
index 000000000000..e4c6e25a781c
--- /dev/null
+++ b/drivers/pinctrl/pinctrl-ti-iodelay.c
@@ -0,0 +1,963 @@
+/*
+ * Support for configuration of IO Delay module found on Texas Instruments SoCs
+ * such as DRA7
+ *
+ * Copyright (C) 2015 Texas Instruments, Inc.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/of.h>
+#include <linux/pinctrl/pinconf-generic.h>
+#include <linux/pinctrl/pinconf.h>
+#include <linux/pinctrl/pinctrl.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#define IODELAY_REG_NAME_LEN		((sizeof(u32) * 2) + 3)
+#define DRIVER_NAME			"ti-io-delay"
+/* Should I change this? Abuse? */
+#define IODELAY_MUX_PINS_NAME		"pinctrl-single,pins"
+
+/* Device tree match, populated later */
+static const struct of_device_id ti_iodelay_of_match[];
+
+/**
+ * struct ti_iodelay_conf_vals - Description of each configuration parameters.
+ * @offset:	Configuration register offset
+ * @a_delay:	Agnostic Delay (in ps)
+ * @g_delay:	Gnostic Delay (in ps)
+ */
+struct ti_iodelay_conf_vals {
+	u16 offset;
+	u16 a_delay;
+	u16 g_delay;
+};
+
+/**
+ * struct ti_iodelay_reg_data - Describes the registers for the IOdelay instance
+ * @signature_mask:	Conf reg- mask for the signature bits
+ * @signature_value:	Conf reg- signature value to be written (see TRM)
+ * @lock_mask:		Conf reg- mask for the lock bits
+ * @lock_val:		Conf reg- lock value for the lock bits (see TRM)
+ * @unlock_val:		Conf reg- unlock value for the lock bits (see TRM)
+ * @binary_data_coarse_mask: Conf reg- coarse mask (see TRM)
+ * @binary_data_fine_mask: Conf reg- fine mask (see TRM)
+ * @reg_refclk_offset:	Refclk register offset
+ * @refclk_period_mask:	Refclk mask
+ * @reg_coarse_offset:	Coarse register configuration offset
+ * @coarse_delay_count_mask: Coarse delay count mask
+ * @coarse_ref_count_mask: Coarse ref count mask
+ * @reg_fine_offset:	Fine register configuration offset
+ * @fine_delay_count_mask: Fine delay count mask
+ * @fine_ref_count_mask: Fine  ref count mask
+ * @reg_global_lock_offset: Global(for the IOdelay module) lock register offset
+ * @global_lock_mask:	Lock mask
+ * @global_unlock_val:	unlock value
+ * @global_lock_val:	lock value
+ * @reg_start_offset:	Where does the configuration registers start?
+ * @regmap_config:	Regmap configuration for the IODelay region
+ */
+struct ti_iodelay_reg_data {
+	u32 signature_mask;
+	u32 signature_value;
+	u32 lock_mask;
+	u32 lock_val;
+	u32 unlock_val;
+	u32 binary_data_coarse_mask;
+	u32 binary_data_fine_mask;
+
+	u32 reg_refclk_offset;
+	u32 refclk_period_mask;
+
+	u32 reg_coarse_offset;
+	u32 coarse_delay_count_mask;
+	u32 coarse_ref_count_mask;
+
+	u32 reg_fine_offset;
+	u32 fine_delay_count_mask;
+	u32 fine_ref_count_mask;
+
+	u32 reg_global_lock_offset;
+	u32 global_lock_mask;
+	u32 global_unlock_val;
+	u32 global_lock_val;
+
+	u32 reg_start_offset;
+
+	struct regmap_config *regmap_config;
+};
+
+/**
+ * struct ti_iodelay_reg_values - Computed io_reg configuration values (see TRM)
+ * @coarse_ref_count:	Coarse reference count
+ * @coarse_delay_count:	Coarse delay count
+ * @fine_ref_count:	Fine reference count
+ * @fine_delay_count:	Fine Delay count
+ * @ref_clk_period:	Reference Clock period
+ * @cdpe:		Coarse delay parameter
+ * @fdpe:		Fine delay parameter
+ */
+struct ti_iodelay_reg_values {
+	u16 coarse_ref_count;
+	u16 coarse_delay_count;
+
+	u16 fine_ref_count;
+	u16 fine_delay_count;
+
+	u16 ref_clk_period;
+
+	u32 cdpe;
+	u32 fdpe;
+};
+
+/**
+ * struct ti_iodelay_pin_name - name of the pins
+ * @name: name
+ */
+struct ti_iodelay_pin_name {
+	char name[IODELAY_REG_NAME_LEN];
+};
+
+/**
+ * struct ti_iodelay_pingroup - Structure that describes one group
+ * @np:		Node pointer (device tree)
+ * @name:	Name of the group
+ * @map:	pinctrl map allocated for the group
+ * @vals:	configuration values allocated for the group (from dt)
+ * @nvals:	number of configuration values allocated
+ * @config:	pinconf "Config" - currently a dummy value
+ * @node:	list node to next group
+ */
+struct ti_iodelay_pingroup {
+	struct device_node *np;
+	const char *name;
+	struct pinctrl_map *map;
+	struct ti_iodelay_conf_vals *vals;
+	int nvals;
+	unsigned long config;
+	struct list_head node;
+};
+
+/**
+ * struct ti_iodelay_device - Represents information for a IOdelay instance
+ * @dev: device pointer
+ * @reg_base: Remapped virtual address
+ * @regmap: Regmap for this IOdelay instance
+ * @pctl: Pinctrl device
+ * @desc: pinctrl descriptor for pctl
+ * @pa: pinctrl pin wise description
+ * @names: names of the pins
+ * @groups: list of pinconf groups for iodelay instance
+ * @ngroups: number of groups in the list
+ * @mutex: mutex to protect group list modification
+ * @reg_data: Register definition data for the IODelay instance
+ * @reg_init_conf_values: Initial configuration values.
+ */
+struct ti_iodelay_device {
+	struct device *dev;
+	void __iomem *reg_base;
+	struct regmap *regmap;
+
+	struct pinctrl_dev *pctl;
+	struct pinctrl_desc desc;
+	struct pinctrl_pin_desc *pa;
+	struct ti_iodelay_pin_name *names;
+
+	struct list_head groups;
+	int ngroups;
+	struct mutex mutex; /* list protection */
+
+	const struct ti_iodelay_reg_data *reg_data;
+	struct ti_iodelay_reg_values reg_init_conf_values;
+};
+
+/*--- IOdelay configuration stuff ----*/
+
+/**
+ * ti_iodelay_extract() - extract bits for a field
+ * @val:	register value
+ * @mask:	Mask
+ *
+ * Return: extracted value which is appropriately shifted
+ */
+static inline u32 ti_iodelay_extract(u32 val, u32 mask)
+{
+	return (val & mask) >> __ffs(mask);
+}
+
+/**
+ * ti_iodelay_compute_dpe() - Compute equation for delay parameter
+ * @period:	Period to use
+ * @ref:	Reference Count
+ * @delay:	Delay count
+ * @delay_m:	Delay multiplier
+ *
+ * Return: Computed delay parameter
+ */
+static inline u32 ti_iodelay_compute_dpe(u16 period, u16 ref, u16 delay,
+					 u16 delay_m)
+{
+	u64 m, d;
+
+	/* Handle overflow conditions */
+	m = 10 * (u64)period * (u64)ref;
+	d = 2 * (u64)delay * (u64)delay_m;
+
+	/* Truncate result back to 32 bits */
+	return div64_u64(m, d);
+}
+
+/**
+ * ti_iodelay_pinconf_set() - Configure the pin configuration
+ * @iod:	IODelay device
+ * @val:	Configuration value
+ *
+ * Update the configuration register as per TRM and lockup once done.
+ * *IMPORTANT NOTE* SoC TRM does recommend doing iodelay programmation only
+ * while in Isolation. But, then, isolation also implies that every pin
+ * on the SoC(including DDR) will be isolated out. The only benefit being
+ * a glitchless configuration, However, the intent of this driver is purely
+ * to support a "glitchy" configuration where applicable.
+ *
+ * Return: 0 in case of success, else appropriate error value
+ */
+static int ti_iodelay_pinconf_set(struct ti_iodelay_device *iod,
+				  struct ti_iodelay_conf_vals *val)
+{
+	const struct ti_iodelay_reg_data *reg = iod->reg_data;
+	struct ti_iodelay_reg_values *ival = &iod->reg_init_conf_values;
+	struct device *dev = iod->dev;
+	u32 g_delay_coarse, g_delay_fine;
+	u32 a_delay_coarse, a_delay_fine;
+	u32 c_elements, f_elements;
+	u32 total_delay;
+	u32 reg_mask, reg_val, tmp_val;
+	int r;
+
+	/* NOTE: Truncation is expected in all division below */
+	g_delay_coarse = val->g_delay / 920;
+	g_delay_fine = ((val->g_delay % 920) * 10) / 60;
+
+	a_delay_coarse = val->a_delay / ival->cdpe;
+	a_delay_fine = ((val->a_delay % ival->cdpe) * 10) / ival->fdpe;
+
+	c_elements = g_delay_coarse + a_delay_coarse;
+	f_elements = (g_delay_fine + a_delay_fine) / 10;
+
+	if (f_elements > 22) {
+		total_delay = c_elements * ival->cdpe + f_elements * ival->fdpe;
+		c_elements = total_delay / ival->cdpe;
+		f_elements = (total_delay % ival->cdpe) / ival->fdpe;
+	}
+
+	reg_mask = reg->signature_mask;
+	reg_val = reg->signature_value << __ffs(reg->signature_mask);
+
+	reg_mask |= reg->binary_data_coarse_mask;
+	tmp_val = c_elements << __ffs(reg->binary_data_coarse_mask);
+	if (tmp_val & ~reg->binary_data_coarse_mask) {
+		dev_err(dev, "Masking overflow of coarse elements %08x\n",
+			tmp_val);
+		tmp_val &= reg->binary_data_coarse_mask;
+	}
+	reg_val |= tmp_val;
+
+	reg_mask |= reg->binary_data_fine_mask;
+	tmp_val = f_elements << __ffs(reg->binary_data_fine_mask);
+	if (tmp_val & ~reg->binary_data_fine_mask) {
+		dev_err(dev, "Masking overflow of fine elements %08x\n",
+			tmp_val);
+		tmp_val &= reg->binary_data_fine_mask;
+	}
+	reg_val |= tmp_val;
+
+	/* Write with lock value - we DONOT want h/w updates */
+	reg_mask |= reg->lock_mask;
+	reg_val |= reg->lock_val << __ffs(reg->lock_mask);
+	r = regmap_update_bits(iod->regmap, val->offset, reg_mask, reg_val);
+
+	dev_dbg(dev, "Set reg 0x%x Delay(a=%d g=%d), Elements(C=%d F=%d)0x%x\n",
+		val->offset, val->a_delay, val->g_delay, c_elements,
+		f_elements, reg_val);
+
+	return r;
+}
+
+/**
+ * ti_iodelay_pinconf_init_dev() - Initialize IODelay device
+ * @iod:	IODelay device
+ *
+ * Unlocks the IODelay region, computes the common parameters
+ *
+ * Return: 0 in case of success, else appropriate error value
+ */
+static int ti_iodelay_pinconf_init_dev(struct ti_iodelay_device *iod)
+{
+	const struct ti_iodelay_reg_data *reg = iod->reg_data;
+	struct device *dev = iod->dev;
+	struct ti_iodelay_reg_values *ival = &iod->reg_init_conf_values;
+	u32 val;
+	int r;
+
+	/* unlock the IOdelay region */
+	r = regmap_update_bits(iod->regmap, reg->reg_global_lock_offset,
+			       reg->global_lock_mask, reg->global_unlock_val);
+	if (r)
+		return r;
+
+	/* Read up Recalibration sequence done by bootloader */
+	r = regmap_read(iod->regmap, reg->reg_refclk_offset, &val);
+	if (r)
+		return r;
+	ival->ref_clk_period = ti_iodelay_extract(val, reg->refclk_period_mask);
+	dev_dbg(dev, "refclk_period=0x%04x\n", ival->ref_clk_period);
+
+	r = regmap_read(iod->regmap, reg->reg_coarse_offset, &val);
+	if (r)
+		return r;
+	ival->coarse_ref_count =
+	    ti_iodelay_extract(val, reg->coarse_ref_count_mask);
+	ival->coarse_delay_count =
+	    ti_iodelay_extract(val, reg->coarse_delay_count_mask);
+	if (!ival->coarse_delay_count) {
+		dev_err(dev, "Invalid Coarse delay count (0) (reg=0x%08x)\n",
+			val);
+		return -EINVAL;
+	}
+	ival->cdpe = ti_iodelay_compute_dpe(ival->ref_clk_period,
+					    ival->coarse_ref_count,
+					    ival->coarse_delay_count, 88);
+	if (!ival->cdpe) {
+		dev_err(dev, "Invalid cdpe computed params = %d %d %d\n",
+			ival->ref_clk_period, ival->coarse_ref_count,
+			ival->coarse_delay_count);
+		return -EINVAL;
+	}
+	dev_dbg(iod->dev, "coarse: ref=0x%04x delay=0x%04x cdpe=0x%08x\n",
+		ival->coarse_ref_count, ival->coarse_delay_count, ival->cdpe);
+
+	r = regmap_read(iod->regmap, reg->reg_fine_offset, &val);
+	if (r)
+		return r;
+	ival->fine_ref_count =
+	    ti_iodelay_extract(val, reg->fine_ref_count_mask);
+	ival->fine_delay_count =
+	    ti_iodelay_extract(val, reg->fine_delay_count_mask);
+	if (!ival->fine_delay_count) {
+		dev_err(dev, "Invalid Fine delay count (0) (reg=0x%08x)\n",
+			val);
+		return -EINVAL;
+	}
+	ival->fdpe = ti_iodelay_compute_dpe(ival->ref_clk_period,
+					    ival->fine_ref_count,
+					    ival->fine_delay_count, 264);
+	if (!ival->fdpe) {
+		dev_err(dev, "Invalid fdpe(0) computed params = %d %d %d\n",
+			ival->ref_clk_period, ival->fine_ref_count,
+			ival->fine_delay_count);
+		return -EINVAL;
+	}
+	dev_dbg(iod->dev, "fine: ref=0x%04x delay=0x%04x fdpe=0x%08x\n",
+		ival->fine_ref_count, ival->fine_delay_count, ival->fdpe);
+
+	return 0;
+}
+
+/**
+ * ti_iodelay_pinconf_deinit_dev() - deinit the IOdelay device
+ * @iod:	IODelay device
+ *
+ * Deinitialize the IODelay device (basically just lock the region back up.
+ */
+static void ti_iodelay_pinconf_deinit_dev(struct ti_iodelay_device *iod)
+{
+	const struct ti_iodelay_reg_data *reg = iod->reg_data;
+
+	/* lock the IOdelay region back again */
+	regmap_update_bits(iod->regmap, reg->reg_global_lock_offset,
+			   reg->global_lock_mask, reg->global_lock_val);
+}
+
+/*--- Pinctrl/pinconf framework stuff ----*/
+
+/**
+ * ti_iodelay_get_group() - Find the group mapped by a group selector
+ * @iod:	IODelay device
+ * @gselector:	Group Selector
+ *
+ * Return: Corresponding group representing group selector in list of groups
+ * managed in IOdelay device OR NULL if not found.
+ */
+static struct ti_iodelay_pingroup *ti_iodelay_get_group(struct ti_iodelay_device
+							*iod,
+							unsigned gselector)
+{
+	struct ti_iodelay_pingroup *group;
+	int gid = 0;
+
+	list_for_each_entry(group, &iod->groups, node) {
+		if (gid == gselector)
+			return group;
+		gid++;
+	}
+
+	dev_err(iod->dev, "%s could not find pingroup %i\n", __func__,
+		gselector);
+	return NULL;
+}
+
+/**
+ * ti_iodelay_dt_node_to_map() - Map a device tree node to appropriate group
+ * @pctldev:	pinctrl device representing IODelay device
+ * @np:		Node Pointer (device tree)
+ * @map:	Pinctrl Map returned back to pinctrl framework
+ * @num_maps:	Number of maps (1)
+ *
+ * Maps the device tree description into a group of configuration parameters
+ * for IOdelay block entry.
+ *
+ * Return: 0 in case of success, else appropriate error value
+ */
+static int ti_iodelay_dt_node_to_map(struct pinctrl_dev *pctldev,
+				     struct device_node *np,
+				     struct pinctrl_map **map,
+				     unsigned *num_maps)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	/* const char **pgnames; */
+	int ret = 0;
+	const __be32 *mux;
+	struct ti_iodelay_conf_vals *vals;
+	struct ti_iodelay_pingroup *group;
+	int size, index, idx, rows;
+	u32 offset, val;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	if (!iod)
+		return -EINVAL;
+	dev = iod->dev;
+
+	*map = devm_kzalloc(dev, sizeof(**map), GFP_KERNEL);
+	if (!*map)
+		return -ENOMEM;
+	*num_maps = 0;
+
+	group = devm_kzalloc(dev, sizeof(*group), GFP_KERNEL);
+	if (!group) {
+		ret = -ENOMEM;
+		goto free_map;
+	}
+
+	mux = of_get_property(np, IODELAY_MUX_PINS_NAME, &size);
+	if ((!mux) || (size < sizeof(*mux) * 2)) {
+		dev_err(dev, "bad data for mux %s\n", np->name);
+		ret = -EINVAL;
+		goto free_group;
+	}
+
+	size /= sizeof(*mux);	/* Number of elements in array */
+	rows = size / 2;
+
+	vals = devm_kzalloc(dev, sizeof(*vals) * rows, GFP_KERNEL);
+	if (!vals) {
+		ret = -ENOMEM;
+		goto free_group;
+	}
+
+	index = 0;
+	idx = 0;
+	while (index < size) {
+		offset = be32_to_cpup(mux + index++);
+		val = be32_to_cpup(mux + index++);
+		vals[idx].offset = offset;
+		vals[idx].a_delay = val & 0xFFFF;
+		vals[idx].g_delay = (val & 0xFFFF0000) >> 16;
+		if (offset > iod->reg_data->regmap_config->max_register) {
+			dev_err(dev, "Invalid offset for %s 0x%x\n",
+				np->name, offset);
+			break;
+		}
+		dev_dbg(dev, "%s offset=%x a_delay = %d g_delay = %d\n",
+			np->name, vals[idx].offset, vals[idx].a_delay,
+			vals[idx].g_delay);
+		idx++;
+	}
+
+	group->name = np->name;
+	group->np = np;
+	group->vals = vals;
+	group->nvals = idx;
+	group->config = PIN_CONFIG_END;
+	group->map = *map;
+
+	/* Add to group list */
+	mutex_lock(&iod->mutex);
+	list_add_tail(&group->node, &iod->groups);
+	iod->ngroups++;
+	mutex_unlock(&iod->mutex);
+
+	(*map)->type = PIN_MAP_TYPE_CONFIGS_GROUP;
+	(*map)->data.configs.group_or_pin = np->name;
+	(*map)->data.configs.configs = &group->config;
+	(*map)->data.configs.num_configs = 1;
+	*num_maps = 1;
+
+	return 0;
+
+free_group:
+	devm_kfree(dev, group);
+free_map:
+	devm_kfree(dev, *map);
+	return ret;
+}
+
+/**
+ * ti_iodelay_dt_free_map() - Free map and resource alloted as per the map
+ * @pctldev:	pinctrl device representing IODelay device
+ * @map:	Map allocated by ti_iodelay_dt_node_to_map
+ * @num_maps:	Num maps (1)
+ *
+ * Removes the group associated with the map and frees all resources allocated
+ * for the group.
+ */
+static void ti_iodelay_dt_free_map(struct pinctrl_dev *pctldev,
+				   struct pinctrl_map *map, unsigned num_maps)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+	bool found = false;
+
+	if (!map)
+		return;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	if (!iod)
+		return;
+	dev = iod->dev;
+
+	mutex_lock(&iod->mutex);
+	list_for_each_entry(group, &iod->groups, node) {
+		if (group->map == map) {
+			found = true;
+			list_del(&group->node);
+			iod->ngroups--;
+			break;
+		}
+	}
+	mutex_unlock(&iod->mutex);
+
+	/* If some freaky pinconf framework bug... */
+	if (!found)
+		return;
+
+	devm_kfree(dev, group->vals);
+	devm_kfree(dev, group);
+	devm_kfree(dev, map);
+}
+
+/**
+ * ti_iodelay_pinctrl_get_groups_count() - Get number of groups registered
+ * @pctldev:	pinctrl device representing IODelay device
+ *
+ * Return: number of groups mapped on the IODelay
+ */
+static int ti_iodelay_pinctrl_get_groups_count(struct pinctrl_dev *pctldev)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+
+	return iod->ngroups;
+}
+
+/**
+ * ti_iodelay_pinctrl_get_group_name() - Get the group name
+ * @pctldev:	pinctrl device representing IODelay device
+ * @gselector:	group selector
+ *
+ * Return: name of the Group given a valid gselector, else NULL.
+ */
+static const char *ti_iodelay_pinctrl_get_group_name(struct pinctrl_dev
+						     *pctldev,
+						     unsigned gselector)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+
+	group = ti_iodelay_get_group(iod, gselector);
+	if (!group)
+		return NULL;
+
+	return group->name;
+}
+
+/**
+ * ti_iodelay_pinctrl_get_group_pins() - get group pins
+ * @pctldev:	pinctrl device representing IODelay device
+ * @gselector: Group selector
+ * @pins:	pointer to the pins
+ * @npins:	number of pins
+ *
+ * Dummy implementation since we do not track pins, we track configurations
+ * Forced by pinctrl's pinctrl_check_ops()
+ *
+ * Return: -EINVAL
+ */
+static int ti_iodelay_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
+					     unsigned gselector,
+					     const unsigned **pins,
+					     unsigned *npins)
+{
+	/* Dummy implementation - we dont do pin mux */
+	return -EINVAL;
+}
+
+/**
+ * ti_iodelay_pinconf_group_get() - Get the group configuration
+ * @pctldev:	pinctrl device representing IODelay device
+ * @gselector:	Group selector
+ * @config:	configuration returned
+ *
+ * Return: The configuration if the group is valid, else returns -EINVAL
+ */
+static int ti_iodelay_pinconf_group_get(struct pinctrl_dev *pctldev,
+					unsigned gselector,
+					unsigned long *config)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+	group = ti_iodelay_get_group(iod, gselector);
+
+	if (!group)
+		return -EINVAL;
+
+	*config = group->config;
+	return 0;
+}
+
+/**
+ * ti_iodelay_pinconf_group_set() - Configure the groups of pins
+ * @pctldev:	pinctrl device representing IODelay device
+ * @gselector:	Group selector
+ * @configs:	Configurations
+ * @num_configs: Number of configurations
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_pinconf_group_set(struct pinctrl_dev *pctldev,
+					unsigned gselector,
+					unsigned long *configs,
+					unsigned num_configs)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+	int i;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+	group = ti_iodelay_get_group(iod, gselector);
+
+	if (num_configs != 1) {
+		dev_err(dev, "Unsupported number of configurations %d\n",
+			num_configs);
+		return -EINVAL;
+	}
+
+	if (*configs != PIN_CONFIG_END) {
+		dev_err(dev, "Unsupported configuration\n");
+		return -EINVAL;
+	}
+
+	for (i = 0; i < group->nvals; i++) {
+		if (ti_iodelay_pinconf_set(iod, &group->vals[i]))
+			return -ENOTSUPP;
+	}
+
+	return 0;
+}
+
+#ifdef CONFIG_DEBUG_FS
+/**
+ * ti_iodelay_pinconf_group_dbg_show() - show the group information
+ * @pctldev:	Show the group information
+ * @s:	Sequence file
+ * @gselector:	group selector
+ *
+ * Provide the configuration information of the selected group
+ */
+static void ti_iodelay_pinconf_group_dbg_show(struct pinctrl_dev *pctldev,
+					      struct seq_file *s,
+					      unsigned gselector)
+{
+	struct ti_iodelay_device *iod;
+	struct device *dev;
+	struct ti_iodelay_pingroup *group;
+	int i;
+
+	iod = pinctrl_dev_get_drvdata(pctldev);
+	dev = iod->dev;
+	group = ti_iodelay_get_group(iod, gselector);
+	if (!group)
+		return;
+
+	for (i = 0; i < group->nvals; i++) {
+		struct ti_iodelay_conf_vals *val;
+		u32 reg = 0;
+
+		val = &group->vals[i];
+		regmap_read(iod->regmap, val->offset, &reg),
+		    seq_printf(s, "\n\t0x%08x = 0x%08x (%3d, %3d)",
+			       val->offset, reg, val->a_delay, val->g_delay);
+	}
+}
+#endif
+
+static struct pinctrl_ops ti_iodelay_pinctrl_ops = {
+	.dt_node_to_map = ti_iodelay_dt_node_to_map,
+	.dt_free_map = ti_iodelay_dt_free_map,
+	.get_groups_count = ti_iodelay_pinctrl_get_groups_count,
+	.get_group_name = ti_iodelay_pinctrl_get_group_name,
+	.get_group_pins = ti_iodelay_pinctrl_get_group_pins,
+};
+
+static struct pinconf_ops ti_iodelay_pinctrl_pinconf_ops = {
+	.pin_config_group_get = ti_iodelay_pinconf_group_get,
+	.pin_config_group_set = ti_iodelay_pinconf_group_set,
+#ifdef CONFIG_DEBUG_FS
+	.pin_config_group_dbg_show = ti_iodelay_pinconf_group_dbg_show,
+#endif
+};
+
+/**
+ * ti_iodelay_alloc_pins() - Allocate structures needed for pins for IOdelay
+ * @dev:	device pointer
+ * @iod:	IODelay device
+ * @base_phy:	Base Physical Address
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_alloc_pins(struct device *dev,
+				 struct ti_iodelay_device *iod, u32 base_phy)
+{
+	const struct ti_iodelay_reg_data *r = iod->reg_data;
+	struct pinctrl_pin_desc *pin;
+	struct ti_iodelay_pin_name *pn;
+	u32 phy_reg;
+	int nr_pins, i;
+
+	nr_pins = (r->regmap_config->max_register - r->reg_start_offset) / 4;
+
+	dev_dbg(dev, "Allocating %i pins\n", nr_pins);
+
+	iod->pa = devm_kzalloc(dev, sizeof(*iod->pa) * nr_pins, GFP_KERNEL);
+	if (!iod->pa)
+		return -ENOMEM;
+
+	iod->names =
+	    devm_kzalloc(dev, sizeof(struct ti_iodelay_pin_name) * nr_pins,
+			 GFP_KERNEL);
+	if (!iod->names)
+		return -ENOMEM;
+
+	iod->desc.pins = iod->pa;
+	iod->desc.npins = nr_pins;
+
+	phy_reg = r->reg_start_offset + base_phy;
+	pn = iod->names;
+	for (i = 0; i < nr_pins; i++, pn++, phy_reg += 4) {
+		pin = &iod->pa[i];
+		sprintf(pn->name, "%x.%d", phy_reg, i);
+		pin->number = i;
+		pin->name = pn->name;
+	}
+
+	return 0;
+}
+
+/**
+ * ti_iodelay_probe() - Standard probe
+ * @pdev:	platform device
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = of_node_get(dev->of_node);
+	const struct of_device_id *match;
+	struct resource *res;
+	struct ti_iodelay_device *iod;
+	int ret = 0;
+
+	if (!np) {
+		ret = -EINVAL;
+		dev_err(dev, "No OF node\n");
+		goto exit_out;
+	}
+
+	match = of_match_device(ti_iodelay_of_match, dev);
+	if (!match) {
+		ret = -EINVAL;
+		dev_err(dev, "No DATA match\n");
+		goto exit_out;
+	}
+
+	iod = devm_kzalloc(dev, sizeof(*iod), GFP_KERNEL);
+	if (!iod) {
+		ret = -ENOMEM;
+		goto exit_out;
+	}
+	iod->dev = dev;
+	iod->reg_data = match->data;
+
+	/* So far We can assume there is only 1 bank of registers */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "Missing MEM resource\n");
+		ret = -ENODEV;
+		goto exit_out;
+	}
+
+	iod->reg_base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(iod->reg_base)) {
+		ret = PTR_ERR(iod->reg_base);
+		goto exit_out;
+	}
+
+	iod->regmap = devm_regmap_init_mmio(dev, iod->reg_base,
+					    iod->reg_data->regmap_config);
+	if (IS_ERR(iod->regmap)) {
+		dev_err(dev, "Regmap MMIO init failed.\n");
+		ret = PTR_ERR(iod->regmap);
+		goto exit_out;
+	}
+
+	if (ti_iodelay_pinconf_init_dev(iod))
+		goto exit_out;
+
+	ret = ti_iodelay_alloc_pins(dev, iod, res->start);
+	if (ret)
+		goto exit_out;
+
+	INIT_LIST_HEAD(&iod->groups);
+	mutex_init(&iod->mutex);
+
+	iod->desc.pctlops = &ti_iodelay_pinctrl_ops;
+	/* no pinmux ops - we are pinconf */
+	iod->desc.confops = &ti_iodelay_pinctrl_pinconf_ops;
+	iod->desc.name = dev_name(dev);
+	iod->desc.owner = THIS_MODULE;
+
+	iod->pctl = pinctrl_register(&iod->desc, dev, iod);
+	if (!iod->pctl) {
+		dev_err(dev, "Failed to register pinctrl\n");
+		ret = -ENODEV;
+		goto exit_out;
+	}
+
+	platform_set_drvdata(pdev, iod);
+
+exit_out:
+	of_node_put(np);
+	return ret;
+}
+
+/**
+ * ti_iodelay_remove() - standard remove
+ * @pdev:	platform device
+ *
+ * Return: 0 if all went fine, else appropriate error value.
+ */
+static int ti_iodelay_remove(struct platform_device *pdev)
+{
+	struct ti_iodelay_device *iod = platform_get_drvdata(pdev);
+
+	if (!iod)
+		return 0;
+	if (iod->pctl)
+		pinctrl_unregister(iod->pctl);
+
+	ti_iodelay_pinconf_deinit_dev(iod);
+
+	/* Expect other allocations to be freed by devm */
+
+	return 0;
+}
+
+static struct regmap_config dra7_iodelay_regmap_config = {
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.max_register = 0xD1C,
+};
+
+static struct ti_iodelay_reg_data dra7_iodelay_data = {
+	.signature_mask = 0x0003F000,
+	.signature_value = 0x29,
+	.lock_mask = 0x00000400,
+	.lock_val = 1,
+	.unlock_val = 0,
+	.binary_data_coarse_mask = 0x000003E0,
+	.binary_data_fine_mask = 0x0000001F,
+
+	.reg_refclk_offset = 0x14,
+	.refclk_period_mask = 0xFFFF,
+
+	.reg_coarse_offset = 0x18,
+	.coarse_delay_count_mask = 0xFFFF0000,
+	.coarse_ref_count_mask = 0x0000FFFF,
+
+	.reg_fine_offset = 0x1C,
+	.fine_delay_count_mask = 0xFFFF0000,
+	.fine_ref_count_mask = 0x0000FFFF,
+
+	.reg_global_lock_offset = 0x2C,
+	.global_lock_mask = 0x0000FFFF,
+	.global_unlock_val = 0x0000AAAA,
+	.global_lock_val = 0x0000AAAB,
+
+	.reg_start_offset = 0x30,
+	.regmap_config = &dra7_iodelay_regmap_config,
+};
+
+static const struct of_device_id ti_iodelay_of_match[] = {
+	{.compatible = "ti,dra7-iodelay", .data = &dra7_iodelay_data},
+	{ /* Hopefully no more.. */ },
+};
+MODULE_DEVICE_TABLE(of, ti_iodelay_of_match);
+
+static struct platform_driver ti_iodelay_driver = {
+	.probe = ti_iodelay_probe,
+	.remove = ti_iodelay_remove,
+	.driver = {
+		   .owner = THIS_MODULE,
+		   .name = DRIVER_NAME,
+		   .of_match_table = ti_iodelay_of_match,
+		   },
+};
+module_platform_driver(ti_iodelay_driver);
+
+MODULE_AUTHOR("Texas Instruments, Inc.");
+MODULE_DESCRIPTION("Pinconf driver for TI's IO Delay module");
+MODULE_LICENSE("GPL v2");
diff --git a/include/dt-bindings/pinctrl/dra.h b/include/dt-bindings/pinctrl/dra.h
index 7448edff4723..0a26495c4df5 100644
--- a/include/dt-bindings/pinctrl/dra.h
+++ b/include/dt-bindings/pinctrl/dra.h
@@ -30,6 +30,8 @@
 #define MUX_MODE14	0xe
 #define MUX_MODE15	0xf
 
+#define MANUAL_MODE		MODE_SELECT
+
 #define PULL_ENA		(0 << 16)
 #define PULL_DIS		(1 << 16)
 #define PULL_UP			(1 << 17)
@@ -47,5 +49,9 @@
 #define PIN_INPUT_PULLUP	(PULL_ENA | INPUT_EN | PULL_UP)
 #define PIN_INPUT_PULLDOWN	(PULL_ENA | INPUT_EN)
 
+/* DRA7 IODELAY configuration parameters */
+#define A_DELAY(val)		((val) & 0xFFFF)
+#define G_DELAY(val)		(((val) & 0xFFFF) << 16)
+
 #endif
 
-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver
  2015-03-04  0:00 ` [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver Nishanth Menon
@ 2015-03-04 22:58   ` Paul Bolle
  2015-03-04 22:58     ` Tony Lindgren
  2015-03-10 11:03   ` Linus Walleij
  1 sibling, 1 reply; 21+ messages in thread
From: Paul Bolle @ 2015-03-04 22:58 UTC (permalink / raw)
  To: Nishanth Menon
  Cc: Tony Lindgren, Linus Walleij, linux-gpio, linux-kernel,
	devicetree, linux-omap, linux-arm-kernel, Lokesh Vutla

Nishanth Menon schreef op di 03-03-2015 om 18:00 [-0600]:
> diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
> index ee9f44ad7f02..8e463d75fbb2 100644
> --- a/drivers/pinctrl/Kconfig
> +++ b/drivers/pinctrl/Kconfig
> @@ -160,6 +160,17 @@ config PINCTRL_TEGRA_XUSB
>  	select PINCONF
>  	select PINMUX
>  
> +config PINCTRL_TI_IODELAY
> +	bool "TI IODelay Module pinconf driver"

This adds a boolean Kconfig symbol.

> +	depends on OF
> +	select PINCONF
> +	select GENERIC_PINCONF
> +	select REGMAP_MMIO
> +	help
> +	  Say Y here to support Texas Instruments' IODelay pinconf driver.
> +	  IODelay module is used for the DRA7 SoC family. This driver is in
> +	  addition to PINCTRL_SINGLE which controls the mux.
> +
>  config PINCTRL_TZ1090
>  	bool "Toumaz Xenif TZ1090 pin control driver"
>  	depends on SOC_TZ1090
> diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
> index 0475206dd600..e441cd71aedf 100644
> --- a/drivers/pinctrl/Makefile
> +++ b/drivers/pinctrl/Makefile
> @@ -28,6 +28,7 @@ obj-$(CONFIG_PINCTRL_TEGRA30)	+= pinctrl-tegra30.o
>  obj-$(CONFIG_PINCTRL_TEGRA114)	+= pinctrl-tegra114.o
>  obj-$(CONFIG_PINCTRL_TEGRA124)	+= pinctrl-tegra124.o
>  obj-$(CONFIG_PINCTRL_TEGRA_XUSB)	+= pinctrl-tegra-xusb.o
> +obj-$(CONFIG_PINCTRL_TI_IODELAY)	+= pinctrl-ti-iodelay.o

So this objectfile will either be built-in or not be built at all.

>  obj-$(CONFIG_PINCTRL_TZ1090)	+= pinctrl-tz1090.o
>  obj-$(CONFIG_PINCTRL_TZ1090_PDC)	+= pinctrl-tz1090-pdc.o
>  obj-$(CONFIG_PINCTRL_U300)	+= pinctrl-u300.o
> diff --git a/drivers/pinctrl/pinctrl-ti-iodelay.c b/drivers/pinctrl/pinctrl-ti-iodelay.c
> new file mode 100644
> index 000000000000..e4c6e25a781c
> --- /dev/null
> +++ b/drivers/pinctrl/pinctrl-ti-iodelay.c
> @@ -0,0 +1,963 @@
>[...]
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/list.h>
> +#include <linux/module.h>

This is, I think, a bit of a red flag.

> +#include <linux/of_device.h>
> +#include <linux/of.h>
> +#include <linux/pinctrl/pinconf-generic.h>
> +#include <linux/pinctrl/pinconf.h>
> +#include <linux/pinctrl/pinctrl.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>

[...]

> +static const struct of_device_id ti_iodelay_of_match[] = {
> +	{.compatible = "ti,dra7-iodelay", .data = &dra7_iodelay_data},
> +	{ /* Hopefully no more.. */ },
> +};
> +MODULE_DEVICE_TABLE(of, ti_iodelay_of_match);
> +
> +static struct platform_driver ti_iodelay_driver = {
> +	.probe = ti_iodelay_probe,
> +	.remove = ti_iodelay_remove,
> +	.driver = {
> +		   .owner = THIS_MODULE,

So THIS_MODULE will, basically, be NULL.

> +		   .name = DRIVER_NAME,
> +		   .of_match_table = ti_iodelay_of_match,
> +		   },
> +};
> +module_platform_driver(ti_iodelay_driver);
> +
> +MODULE_AUTHOR("Texas Instruments, Inc.");
> +MODULE_DESCRIPTION("Pinconf driver for TI's IO Delay module");
> +MODULE_LICENSE("GPL v2");

And these three macros will be preprocessed away.

(Perhaps there are non-modular alternatives to MODULE_DEVICE_TABLE and
module_platform_driver, but I'm not sure how those two macros actually
work.)


Paul Bolle


^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver
  2015-03-04 22:58   ` Paul Bolle
@ 2015-03-04 22:58     ` Tony Lindgren
  2015-03-05  2:22       ` Nishanth Menon
  0 siblings, 1 reply; 21+ messages in thread
From: Tony Lindgren @ 2015-03-04 22:58 UTC (permalink / raw)
  To: Paul Bolle
  Cc: Nishanth Menon, Linus Walleij, linux-gpio, linux-kernel,
	devicetree, linux-omap, linux-arm-kernel, Lokesh Vutla

* Paul Bolle <pebolle@tiscali.nl> [150304 14:58]:
> Nishanth Menon schreef op di 03-03-2015 om 18:00 [-0600]:
> > diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
> > index ee9f44ad7f02..8e463d75fbb2 100644
> > --- a/drivers/pinctrl/Kconfig
> > +++ b/drivers/pinctrl/Kconfig
> > @@ -160,6 +160,17 @@ config PINCTRL_TEGRA_XUSB
> >  	select PINCONF
> >  	select PINMUX
> >  
> > +config PINCTRL_TI_IODELAY
> > +	bool "TI IODelay Module pinconf driver"
> 
> This adds a boolean Kconfig symbol.
> 
> > +	depends on OF
> > +	select PINCONF
> > +	select GENERIC_PINCONF
> > +	select REGMAP_MMIO
> > +	help
> > +	  Say Y here to support Texas Instruments' IODelay pinconf driver.
> > +	  IODelay module is used for the DRA7 SoC family. This driver is in
> > +	  addition to PINCTRL_SINGLE which controls the mux.
> > +
> >  config PINCTRL_TZ1090
> >  	bool "Toumaz Xenif TZ1090 pin control driver"
> >  	depends on SOC_TZ1090
> > diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
> > index 0475206dd600..e441cd71aedf 100644
> > --- a/drivers/pinctrl/Makefile
> > +++ b/drivers/pinctrl/Makefile
> > @@ -28,6 +28,7 @@ obj-$(CONFIG_PINCTRL_TEGRA30)	+= pinctrl-tegra30.o
> >  obj-$(CONFIG_PINCTRL_TEGRA114)	+= pinctrl-tegra114.o
> >  obj-$(CONFIG_PINCTRL_TEGRA124)	+= pinctrl-tegra124.o
> >  obj-$(CONFIG_PINCTRL_TEGRA_XUSB)	+= pinctrl-tegra-xusb.o
> > +obj-$(CONFIG_PINCTRL_TI_IODELAY)	+= pinctrl-ti-iodelay.o
> 
> So this objectfile will either be built-in or not be built at all.
> 
> >  obj-$(CONFIG_PINCTRL_TZ1090)	+= pinctrl-tz1090.o
> >  obj-$(CONFIG_PINCTRL_TZ1090_PDC)	+= pinctrl-tz1090-pdc.o
> >  obj-$(CONFIG_PINCTRL_U300)	+= pinctrl-u300.o
> > diff --git a/drivers/pinctrl/pinctrl-ti-iodelay.c b/drivers/pinctrl/pinctrl-ti-iodelay.c
> > new file mode 100644
> > index 000000000000..e4c6e25a781c
> > --- /dev/null
> > +++ b/drivers/pinctrl/pinctrl-ti-iodelay.c
> > @@ -0,0 +1,963 @@
> >[...]
> > +#include <linux/err.h>
> > +#include <linux/init.h>
> > +#include <linux/io.h>
> > +#include <linux/list.h>
> > +#include <linux/module.h>
> 
> This is, I think, a bit of a red flag.
> 
> > +#include <linux/of_device.h>
> > +#include <linux/of.h>
> > +#include <linux/pinctrl/pinconf-generic.h>
> > +#include <linux/pinctrl/pinconf.h>
> > +#include <linux/pinctrl/pinctrl.h>
> > +#include <linux/regmap.h>
> > +#include <linux/slab.h>
> 
> [...]
> 
> > +static const struct of_device_id ti_iodelay_of_match[] = {
> > +	{.compatible = "ti,dra7-iodelay", .data = &dra7_iodelay_data},
> > +	{ /* Hopefully no more.. */ },
> > +};
> > +MODULE_DEVICE_TABLE(of, ti_iodelay_of_match);
> > +
> > +static struct platform_driver ti_iodelay_driver = {
> > +	.probe = ti_iodelay_probe,
> > +	.remove = ti_iodelay_remove,
> > +	.driver = {
> > +		   .owner = THIS_MODULE,
> 
> So THIS_MODULE will, basically, be NULL.
> 
> > +		   .name = DRIVER_NAME,
> > +		   .of_match_table = ti_iodelay_of_match,
> > +		   },
> > +};
> > +module_platform_driver(ti_iodelay_driver);
> > +
> > +MODULE_AUTHOR("Texas Instruments, Inc.");
> > +MODULE_DESCRIPTION("Pinconf driver for TI's IO Delay module");
> > +MODULE_LICENSE("GPL v2");
> 
> And these three macros will be preprocessed away.
> 
> (Perhaps there are non-modular alternatives to MODULE_DEVICE_TABLE and
> module_platform_driver, but I'm not sure how those two macros actually
> work.)

This should be just made to work as a regular loadable module.
We already have pinctrl-single for the same platforms working
as a loadable module.

Regards,

Tony

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver
  2015-03-04 22:58     ` Tony Lindgren
@ 2015-03-05  2:22       ` Nishanth Menon
  0 siblings, 0 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-05  2:22 UTC (permalink / raw)
  To: Tony Lindgren, Paul Bolle
  Cc: Linus Walleij, linux-gpio, linux-kernel, devicetree, linux-omap,
	linux-arm-kernel, Lokesh Vutla

On 03/04/2015 04:58 PM, Tony Lindgren wrote:
> * Paul Bolle <pebolle@tiscali.nl> [150304 14:58]:
>> Nishanth Menon schreef op di 03-03-2015 om 18:00 [-0600]:
>>> diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
>>> index ee9f44ad7f02..8e463d75fbb2 100644
>>> --- a/drivers/pinctrl/Kconfig
>>> +++ b/drivers/pinctrl/Kconfig
>>> @@ -160,6 +160,17 @@ config PINCTRL_TEGRA_XUSB
>>>  	select PINCONF
>>>  	select PINMUX
>>>  
>>> +config PINCTRL_TI_IODELAY
>>> +	bool "TI IODelay Module pinconf driver"
>>
>> This adds a boolean Kconfig symbol.

Uggh.. thanks for the review and catching this..

>>
>>> +	depends on OF
>>> +	select PINCONF
>>> +	select GENERIC_PINCONF
>>> +	select REGMAP_MMIO
>>> +	help
>>> +	  Say Y here to support Texas Instruments' IODelay pinconf driver.
>>> +	  IODelay module is used for the DRA7 SoC family. This driver is in
>>> +	  addition to PINCTRL_SINGLE which controls the mux.
>>> +
>>>  config PINCTRL_TZ1090
>>>  	bool "Toumaz Xenif TZ1090 pin control driver"
>>>  	depends on SOC_TZ1090
>>> diff --git a/drivers/pinctrl/Makefile b/drivers/pinctrl/Makefile
>>> index 0475206dd600..e441cd71aedf 100644
>>> --- a/drivers/pinctrl/Makefile
>>> +++ b/drivers/pinctrl/Makefile
>>> @@ -28,6 +28,7 @@ obj-$(CONFIG_PINCTRL_TEGRA30)	+= pinctrl-tegra30.o
>>>  obj-$(CONFIG_PINCTRL_TEGRA114)	+= pinctrl-tegra114.o
>>>  obj-$(CONFIG_PINCTRL_TEGRA124)	+= pinctrl-tegra124.o
>>>  obj-$(CONFIG_PINCTRL_TEGRA_XUSB)	+= pinctrl-tegra-xusb.o
>>> +obj-$(CONFIG_PINCTRL_TI_IODELAY)	+= pinctrl-ti-iodelay.o
>>
>> So this objectfile will either be built-in or not be built at all.
>>
>>>  obj-$(CONFIG_PINCTRL_TZ1090)	+= pinctrl-tz1090.o
>>>  obj-$(CONFIG_PINCTRL_TZ1090_PDC)	+= pinctrl-tz1090-pdc.o
>>>  obj-$(CONFIG_PINCTRL_U300)	+= pinctrl-u300.o
>>> diff --git a/drivers/pinctrl/pinctrl-ti-iodelay.c b/drivers/pinctrl/pinctrl-ti-iodelay.c
>>> new file mode 100644
>>> index 000000000000..e4c6e25a781c
>>> --- /dev/null
>>> +++ b/drivers/pinctrl/pinctrl-ti-iodelay.c
>>> @@ -0,0 +1,963 @@
>>> [...]
>>> +#include <linux/err.h>
>>> +#include <linux/init.h>
>>> +#include <linux/io.h>
>>> +#include <linux/list.h>
>>> +#include <linux/module.h>
>>
>> This is, I think, a bit of a red flag.
>>
>>> +#include <linux/of_device.h>
>>> +#include <linux/of.h>
>>> +#include <linux/pinctrl/pinconf-generic.h>
>>> +#include <linux/pinctrl/pinconf.h>
>>> +#include <linux/pinctrl/pinctrl.h>
>>> +#include <linux/regmap.h>
>>> +#include <linux/slab.h>
>>
>> [...]
>>
>>> +static const struct of_device_id ti_iodelay_of_match[] = {
>>> +	{.compatible = "ti,dra7-iodelay", .data = &dra7_iodelay_data},
>>> +	{ /* Hopefully no more.. */ },
>>> +};
>>> +MODULE_DEVICE_TABLE(of, ti_iodelay_of_match);
>>> +
>>> +static struct platform_driver ti_iodelay_driver = {
>>> +	.probe = ti_iodelay_probe,
>>> +	.remove = ti_iodelay_remove,
>>> +	.driver = {
>>> +		   .owner = THIS_MODULE,
>>
>> So THIS_MODULE will, basically, be NULL.
>>
>>> +		   .name = DRIVER_NAME,
>>> +		   .of_match_table = ti_iodelay_of_match,
>>> +		   },
>>> +};
>>> +module_platform_driver(ti_iodelay_driver);
>>> +
>>> +MODULE_AUTHOR("Texas Instruments, Inc.");
>>> +MODULE_DESCRIPTION("Pinconf driver for TI's IO Delay module");
>>> +MODULE_LICENSE("GPL v2");
>>
>> And these three macros will be preprocessed away.
>>
>> (Perhaps there are non-modular alternatives to MODULE_DEVICE_TABLE and
>> module_platform_driver, but I'm not sure how those two macros actually
>> work.)
> 
> This should be just made to work as a regular loadable module.
> We already have pinctrl-single for the same platforms working
> as a loadable module.
> 
Yes, indeed. this can easily be fixed. my bad. will convert this to a
module in the next rev.

I will wait a week before reposting next rev to see if there are
improvements necessary in other areas - specifically in the way
pinconf is being used and if there are any binding related comments.

Will be great to hear any feedback on the same as well.


-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-04  0:00 ` [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration Nishanth Menon
@ 2015-03-10 10:39   ` Linus Walleij
  2015-03-10 15:06     ` Nishanth Menon
  2015-03-10 15:33     ` Tony Lindgren
  0 siblings, 2 replies; 21+ messages in thread
From: Linus Walleij @ 2015-03-10 10:39 UTC (permalink / raw)
  To: Nishanth Menon
  Cc: Tony Lindgren, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:

> +Configuration definition follows similar model as the pinctrl-single:
> +The groups of pin configuration are defined under "pinctrl-single,pins"
> +
> +&dra7_iodelay_core {
> +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
> +               pinctrl-single,pins = <
> +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
> +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
> +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
> +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
> +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
> +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
> +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
> +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
> +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
> +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
> +               >;
> +       };
> +};

But wait.

The promise when we merged pinctrl-single was that this driver was to be used
when the system had a one-register-per-pin layout and it was easy to do device
trees based on that.

We were very reluctant to accept that even though we didn't even have the
generic pin control bindings in place, the argument being that the driver
should know the detailed register layout, it should not be described in the
device tree. We eventually caved in and accepted it as an exception.

Since this pin controller is not using pinctrl-single it does not enjoy that
privilege and you need to explain why this pin controller cannot use the
generic bindings like so many other pin controllers have since started
to do. ("It is in the same SoC" is not an acceptable argument.)

What is wrong with this:
Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

We can add generic delay bindings to the list, it even seems like
a good idea to do so, as it is likely something that will come up in
other hardware and will be needed for ACPI etc going forward.

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver
  2015-03-04  0:00 ` [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver Nishanth Menon
  2015-03-04 22:58   ` Paul Bolle
@ 2015-03-10 11:03   ` Linus Walleij
  2015-03-11 12:39     ` Nishanth Menon
  1 sibling, 1 reply; 21+ messages in thread
From: Linus Walleij @ 2015-03-10 11:03 UTC (permalink / raw)
  To: Nishanth Menon
  Cc: Tony Lindgren, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:

> SoC family such as DRA7 family of processors have, in addition
> to the regular muxing of pins (as done by pinctrl-single), an
> additional hardware module called IODelay which is also expected to be
> configured. This "IODelay" module has it's own register space that is
> independent of the control module.
>
> It is advocated strongly in TI's official documentation considering
> the existing design of the DRA7 family of processors during mux or
> IODelay reconfiguration, there is a potential for a significant glitch
> which may cause functional impairment to certain hardware. It is
> hence recommended to do as little of muxing as absolutely necessary
> without I/O isolation (which can only be done in initial stages of
> bootloader).
>
> NOTE: with the system wide I/O isolation scheme present in DRA7 SoC
> family, it is not reasonable to do stop all I/O operations for every
> such pad configuration scheme. So, we will let it glitch when used in
> this mode.
>
> Even with the above limitation, certain functionality such as MMC has
> mandatory need for IODelay reconfiguration requirements, depending on
> speed of transfer. In these cases, with careful examination of usecase
> involved, the expected glitch can be controlled such that it does not
> impact functionality.
>
> In short, IODelay module support as a padconf driver being introduced
> here is not expected to do SoC wide I/O Isolation and is meant for
> a limited subset of IODelay configuration requirements that need to
> be dynamic and whose glitchy behavior will not cause functionality
> failure for that interface.
>
> Signed-off-by: Nishanth Menon <nm@ti.com>
> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>

Pending the conclusion of my remark on the bindings that this
should use the generic pin config bindings... here are some
"normal" review comments.

> +config PINCTRL_TI_IODELAY
> +       bool "TI IODelay Module pinconf driver"
> +       depends on OF
> +       select PINCONF
> +       select GENERIC_PINCONF
> +       select REGMAP_MMIO
> +       help
> +         Say Y here to support Texas Instruments' IODelay pinconf driver.
> +         IODelay module is used for the DRA7 SoC family. This driver is in
> +         addition to PINCTRL_SINGLE which controls the mux.

If the driver is "in addition to PINCTRL_SINGLE", then it
should depend on it.

> +/* Should I change this? Abuse? */
> +#define IODELAY_MUX_PINS_NAME          "pinctrl-single,pins"

Yeah this is abuse and is why you should use the generic
bindings with just "pins" instead, and use the generic pinconf
parameters to set them up.

> + * struct ti_iodelay_conf_vals - Description of each configuration parameters.
> + * @offset:    Configuration register offset
> + * @a_delay:   Agnostic Delay (in ps)
> + * @g_delay:   Gnostic Delay (in ps)
> + */
> +struct ti_iodelay_conf_vals {
> +       u16 offset;
> +       u16 a_delay;
> +       u16 g_delay;
> +};

So I don't think it's a good idea to get the register offset from
the device tree. The driver should know these.

> +/**
> + * struct ti_iodelay_reg_values - Computed io_reg configuration values (see TRM)
> + * @coarse_ref_count:  Coarse reference count
> + * @coarse_delay_count:        Coarse delay count
> + * @fine_ref_count:    Fine reference count
> + * @fine_delay_count:  Fine Delay count
> + * @ref_clk_period:    Reference Clock period
> + * @cdpe:              Coarse delay parameter
> + * @fdpe:              Fine delay parameter
> + */
> +struct ti_iodelay_reg_values {
> +       u16 coarse_ref_count;

If you're doing reference counting, use kref.
<linux/kref.h>

> +       u16 coarse_delay_count;
> +
> +       u16 fine_ref_count;

Dito.

> +       u16 fine_delay_count;
> +
> +       u16 ref_clk_period;
> +
> +       u32 cdpe;
> +       u32 fdpe;
> +};


> +/**
> + * struct ti_iodelay_pin_name - name of the pins
> + * @name: name
> + */
> +struct ti_iodelay_pin_name {
> +       char name[IODELAY_REG_NAME_LEN];
> +};

What is this? The pin control subsystem already has a struct
for naming pins. struct pinctrl_pin_desc.

Are you reimplementing core functionality?

The generic pin config reference pins by name, and since you
obviously like to encode these into you data you can just
as well use that method for this too.

Again I think this is a side effect from using the pinctrl-single
concepts, if you think of this as some other pinctrl driver
I think this will fall out nicely.

> +/**
> + * struct ti_iodelay_device - Represents information for a IOdelay instance
> + * @dev: device pointer
> + * @reg_base: Remapped virtual address
> + * @regmap: Regmap for this IOdelay instance
> + * @pctl: Pinctrl device
> + * @desc: pinctrl descriptor for pctl
> + * @pa: pinctrl pin wise description
> + * @names: names of the pins
> + * @groups: list of pinconf groups for iodelay instance
> + * @ngroups: number of groups in the list
> + * @mutex: mutex to protect group list modification
> + * @reg_data: Register definition data for the IODelay instance
> + * @reg_init_conf_values: Initial configuration values.
> + */
> +struct ti_iodelay_device {
> +       struct device *dev;
> +       void __iomem *reg_base;
> +       struct regmap *regmap;
> +
> +       struct pinctrl_dev *pctl;
> +       struct pinctrl_desc desc;
> +       struct pinctrl_pin_desc *pa;
> +       struct ti_iodelay_pin_name *names;

Unhappy about that. pinctrl_desc contains
struct pinctrl_pin_desc const *pins; !

> +
> +       struct list_head groups;
> +       int ngroups;
> +       struct mutex mutex; /* list protection */

Why is this needed? Usually the pin control core
serialize calls into the drivers. Care to explain? Have
the potential race really triggered?

> +static inline u32 ti_iodelay_compute_dpe(u16 period, u16 ref, u16 delay,
> +                                        u16 delay_m)
> +{
> +       u64 m, d;
> +
> +       /* Handle overflow conditions */
> +       m = 10 * (u64)period * (u64)ref;
> +       d = 2 * (u64)delay * (u64)delay_m;
> +
> +       /* Truncate result back to 32 bits */
> +       return div64_u64(m, d);
> +}

Serious business ...

> +/**
> + * ti_iodelay_pinconf_set() - Configure the pin configuration
> + * @iod:       IODelay device
> + * @val:       Configuration value
> + *
> + * Update the configuration register as per TRM and lockup once done.
> + * *IMPORTANT NOTE* SoC TRM does recommend doing iodelay programmation only
> + * while in Isolation. But, then, isolation also implies that every pin
> + * on the SoC(including DDR) will be isolated out. The only benefit being
> + * a glitchless configuration, However, the intent of this driver is purely
> + * to support a "glitchy" configuration where applicable.
> + *
> + * Return: 0 in case of success, else appropriate error value
> + */
> +static int ti_iodelay_pinconf_set(struct ti_iodelay_device *iod,
> +                                 struct ti_iodelay_conf_vals *val)
> +{
> +       const struct ti_iodelay_reg_data *reg = iod->reg_data;
> +       struct ti_iodelay_reg_values *ival = &iod->reg_init_conf_values;
> +       struct device *dev = iod->dev;
> +       u32 g_delay_coarse, g_delay_fine;
> +       u32 a_delay_coarse, a_delay_fine;
> +       u32 c_elements, f_elements;
> +       u32 total_delay;
> +       u32 reg_mask, reg_val, tmp_val;
> +       int r;
> +
> +       /* NOTE: Truncation is expected in all division below */
> +       g_delay_coarse = val->g_delay / 920;
> +       g_delay_fine = ((val->g_delay % 920) * 10) / 60;
> +
> +       a_delay_coarse = val->a_delay / ival->cdpe;
> +       a_delay_fine = ((val->a_delay % ival->cdpe) * 10) / ival->fdpe;
> +
> +       c_elements = g_delay_coarse + a_delay_coarse;
> +       f_elements = (g_delay_fine + a_delay_fine) / 10;
> +
> +       if (f_elements > 22) {
> +               total_delay = c_elements * ival->cdpe + f_elements * ival->fdpe;
> +               c_elements = total_delay / ival->cdpe;
> +               f_elements = (total_delay % ival->cdpe) / ival->fdpe;
> +       }
> +
> +       reg_mask = reg->signature_mask;
> +       reg_val = reg->signature_value << __ffs(reg->signature_mask);
> +
> +       reg_mask |= reg->binary_data_coarse_mask;
> +       tmp_val = c_elements << __ffs(reg->binary_data_coarse_mask);
> +       if (tmp_val & ~reg->binary_data_coarse_mask) {
> +               dev_err(dev, "Masking overflow of coarse elements %08x\n",
> +                       tmp_val);
> +               tmp_val &= reg->binary_data_coarse_mask;
> +       }
> +       reg_val |= tmp_val;
> +
> +       reg_mask |= reg->binary_data_fine_mask;
> +       tmp_val = f_elements << __ffs(reg->binary_data_fine_mask);
> +       if (tmp_val & ~reg->binary_data_fine_mask) {
> +               dev_err(dev, "Masking overflow of fine elements %08x\n",
> +                       tmp_val);
> +               tmp_val &= reg->binary_data_fine_mask;
> +       }
> +       reg_val |= tmp_val;
> +
> +       /* Write with lock value - we DONOT want h/w updates */
> +       reg_mask |= reg->lock_mask;
> +       reg_val |= reg->lock_val << __ffs(reg->lock_mask);
> +       r = regmap_update_bits(iod->regmap, val->offset, reg_mask, reg_val);
> +
> +       dev_dbg(dev, "Set reg 0x%x Delay(a=%d g=%d), Elements(C=%d F=%d)0x%x\n",
> +               val->offset, val->a_delay, val->g_delay, c_elements,
> +               f_elements, reg_val);
> +
> +       return r;
> +}

Looking at this terse thing I think it's obviously easier to use
a more verbose device tree description with

drive-delay = <some SI unit>;


> +       /* unlock the IOdelay region */
> +       r = regmap_update_bits(iod->regmap, reg->reg_global_lock_offset,
> +                              reg->global_lock_mask, reg->global_unlock_val);
> +       if (r)
> +               return r;
> +
> +       /* Read up Recalibration sequence done by bootloader */
> +       r = regmap_read(iod->regmap, reg->reg_refclk_offset, &val);
> +       if (r)
> +               return r;
> +       ival->ref_clk_period = ti_iodelay_extract(val, reg->refclk_period_mask);
> +       dev_dbg(dev, "refclk_period=0x%04x\n", ival->ref_clk_period);

That sounds hightec. So the bootloader calibrates the delays
and  computes the refclock period? So is that sime PLL or something?

> +       r = regmap_read(iod->regmap, reg->reg_coarse_offset, &val);
> +       if (r)
> +               return r;
> +       ival->coarse_ref_count =
> +           ti_iodelay_extract(val, reg->coarse_ref_count_mask);
> +       ival->coarse_delay_count =
> +           ti_iodelay_extract(val, reg->coarse_delay_count_mask);
> +       if (!ival->coarse_delay_count) {
> +               dev_err(dev, "Invalid Coarse delay count (0) (reg=0x%08x)\n",
> +                       val);
> +               return -EINVAL;
> +       }
> +       ival->cdpe = ti_iodelay_compute_dpe(ival->ref_clk_period,
> +                                           ival->coarse_ref_count,
> +                                           ival->coarse_delay_count, 88);

88? What does that mean... This should be #defined I think.

> +static int ti_iodelay_dt_node_to_map(struct pinctrl_dev *pctldev,
> +                                    struct device_node *np,
> +                                    struct pinctrl_map **map,
> +                                    unsigned *num_maps)

If you use the generic bindings this quite complex parsing and
everything associated with it goes away into the core.

> +static void ti_iodelay_dt_free_map(struct pinctrl_dev *pctldev,
> +                                  struct pinctrl_map *map, unsigned num_maps)

Dito.

BTW even if you proceed this way I suspect these are verbatim
copies from pinctrl-single so they shold obviouslyt be abstracted
out as library functions in that case.

> +/**
> + * ti_iodelay_pinctrl_get_group_pins() - get group pins
> + * @pctldev:   pinctrl device representing IODelay device
> + * @gselector: Group selector
> + * @pins:      pointer to the pins
> + * @npins:     number of pins
> + *
> + * Dummy implementation since we do not track pins, we track configurations
> + * Forced by pinctrl's pinctrl_check_ops()
> + *
> + * Return: -EINVAL
> + */
> +static int ti_iodelay_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
> +                                            unsigned gselector,
> +                                            const unsigned **pins,
> +                                            unsigned *npins)
> +{
> +       /* Dummy implementation - we dont do pin mux */
> +       return -EINVAL;
> +}

This is not about muxing. It is about enumerating the pins in the
group that will be affected by the setting, which is something you
will want to do when using the generic bindings.

> +       group = ti_iodelay_get_group(iod, gselector);

And this seems to be your re-implementation of exactly that pin control
core functionality. Which again should be shared with pinctrl-single if
you anyway go down this path.

I'll halt review here pending discussion on the bindings & stuff.

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 10:39   ` Linus Walleij
@ 2015-03-10 15:06     ` Nishanth Menon
  2015-03-10 15:33     ` Tony Lindgren
  1 sibling, 0 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-10 15:06 UTC (permalink / raw)
  To: Linus Walleij
  Cc: Tony Lindgren, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On 03/10/2015 05:39 AM, Linus Walleij wrote:
> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
> 
>> +Configuration definition follows similar model as the pinctrl-single:
>> +The groups of pin configuration are defined under "pinctrl-single,pins"
>> +
>> +&dra7_iodelay_core {
>> +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
>> +               pinctrl-single,pins = <
>> +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
>> +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
>> +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
>> +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
>> +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
>> +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
>> +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
>> +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
>> +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
>> +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
>> +               >;
>> +       };
>> +};
> 
> But wait.
> 
> The promise when we merged pinctrl-single was that this driver was to be used
> when the system had a one-register-per-pin layout and it was easy to do device
> trees based on that.
> 
> We were very reluctant to accept that even though we didn't even have the
> generic pin control bindings in place, the argument being that the driver
> should know the detailed register layout, it should not be described in the
> device tree. We eventually caved in and accepted it as an exception.
> 
> Since this pin controller is not using pinctrl-single it does not enjoy that
> privilege and you need to explain why this pin controller cannot use the
> generic bindings like so many other pin controllers have since started
> to do. ("It is in the same SoC" is not an acceptable argument.)
> 
> What is wrong with this:
> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> 
> We can add generic delay bindings to the list, it even seems like
> a good idea to do so, as it is likely something that will come up in
> other hardware and will be needed for ACPI etc going forward.

Let me try to explain how the hardware works in this instance - it is
a quirk that we had'nt understood as being mandatory until very recently.

Apologies on pointing to TRM. Unfortunately, understanding this kind
of needs us to understand the hardware a little deeper.

http://www.ti.com/lit/ug/spruhz6/spruhz6.pdf
18.5.2 CTRL_MODULE_CORE registers (page 4040) -> mux starts from
CTRL_CORE_PAD_GPMC_AD0 (page 4390)

This is the basic support needed for DRA7 family of SoC
handled by pinctrl-single. a single register for a single pin -> write
the mux mode, internal pull, wakeup capability etc. handled today as
part of pinctrl-single compatible "ti,dra7-padconf".

This works for almost 95%+ of the pins. few pins need tweaking of the
delay parameters to address per die, operational and board(rarely)
characteristics.

Here is where it gets a little complicated.

18.6.1 IODELAYCONFIG Module Instance Summary (page 4798) - starts at
CFG_RMII_MHZ_50_CLK_IN.

These registers are programmed per "18.4.6.1.4 Manual IO Timing Modes"
(page 4004).

Initial sequence of recalibration involves IO isolation - process
involving isolating every DRA7 pin from the external world - The only
logical place to do this is obviously as part of bootloader. Doing
this from kernel can be more than rationally complicated (IO isolation
for doing recalibration while a video playback or coprocessor like DSP
is active is just plain ridiculous in complexity).

The calibrated values then are read for programming these iodelay
registers per pin as described in the Section "18.4.6.1.4 Manual IO
Timing Modes" (page 4005).


In summary:
- This does not really control traditional points of pinctrl control
such as mux mode, pull direction etc. It is, in short, a tweaking of
delay paths from the IP to the external pin.

- Most pins do not need iodelay register programming. The ones that do
may have upto 3 other registers that may need programming (IN, OUT, OUTEN)

- Unlike pinctrl-single where a value is read from dts and programmed
straight to the register, programming iodelay involves taking two
parameter(a_delay and g_delay) per iodelay register, value for the
registers computed based on two other parameters(cdpe, fdpe). Where
cdpe and fdpe are computed based on "recalibration sequence" generated
values programmed in register fields for ref_count, delay_count and
ref_clk_period.
	- This is also why pinctrl-single wont work here - it is not
	  a copy from dts to register sequence, it is a compute from
	  dts to register sequence.

- The recalibration parameters ref_count, delay_count and
ref_clk_period are die dependent (hence the need of recalibration
sequence).

- The parameters a_delay, g_delay are dependent on operational
mode/board properties.
	- This is why such a data in kernel may not scale with
	  multitude of board variations and operational needs of
	  certain pins.
	- The values themselves come from some automated tool/data
	  sheet with per-board tweaking done under simulation.

Considering this was a "configuration of per pin iodelay", i chose
pinconf-like model here. Unfortunately, The traditional pinconf is a
set of properties for a pin, but it does not give information as to
which register those properties belong to. since these registers do
not form the same pattern of offsets as padconf register, that iodelay
register information will need to be encoded in some form.

The traditional pinctrl does not fit this hardware either. it does not
control mux, rather given that pinctrl has selected a specific mux
mode, it tweaks the delay parameters corresponding to that mux.


This is one of those modules that I cant seem to fit neatly in any of
the existing frameworks, I am most happy to understand if there are
alternatives that can be proposed..

-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 10:39   ` Linus Walleij
  2015-03-10 15:06     ` Nishanth Menon
@ 2015-03-10 15:33     ` Tony Lindgren
  2015-03-10 17:25       ` Nishanth Menon
  1 sibling, 1 reply; 21+ messages in thread
From: Tony Lindgren @ 2015-03-10 15:33 UTC (permalink / raw)
  To: Linus Walleij
  Cc: Nishanth Menon, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

* Linus Walleij <linus.walleij@linaro.org> [150310 03:39]:
> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
> 
> > +Configuration definition follows similar model as the pinctrl-single:
> > +The groups of pin configuration are defined under "pinctrl-single,pins"
> > +
> > +&dra7_iodelay_core {
> > +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
> > +               pinctrl-single,pins = <
> > +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
> > +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
> > +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
> > +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
> > +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
> > +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
> > +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
> > +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
> > +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
> > +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
> > +               >;
> > +       };
> > +};
> 
> But wait.
> 
> The promise when we merged pinctrl-single was that this driver was to be used
> when the system had a one-register-per-pin layout and it was easy to do device
> trees based on that.
> 
> We were very reluctant to accept that even though we didn't even have the
> generic pin control bindings in place, the argument being that the driver
> should know the detailed register layout, it should not be described in the
> device tree. We eventually caved in and accepted it as an exception.

Hey let's get few things straight here. There's nothing stopping the
driver from knowing a detailed register layout with the pinctrl-single
binding. This can be very easily done based on the compatible flag and
match data as needed and check the values provided.

And let's also recap the reasons for the pinctrl-single binding. The
the main reason for the pinctrl-single binding is to avoid mapping
individual register bits to device tree compatible string properties.

Imagine doing that for hundreds of similar registers. Believe me, I tried
using device tree properties initially and it just sucked big time. For
larger amounts of dts data, it's best to stick to numeric values and
phandles in the device tree data and rely on the preprocessor for
getting the values right.

Finally, we don't want to build databases into the kernel drivers for
every SoC. We certainly have plenty fo those already.
 
> Since this pin controller is not using pinctrl-single it does not enjoy that
> privilege and you need to explain why this pin controller cannot use the
> generic bindings like so many other pin controllers have since started
> to do. ("It is in the same SoC" is not an acceptable argument.)
>
> What is wrong with this:
> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

Nishanth, care to explain your reasons for using pinctrl-single binding
here vs the generic binding? Is the amount of string parsing with the
data an issue here?
 
> We can add generic delay bindings to the list, it even seems like
> a good idea to do so, as it is likely something that will come up in
> other hardware and will be needed for ACPI etc going forward.

We certainly need to make setting delays (with values) generic, no
doubt about that.

If the large amount of data is not an issue here, we could maybe set
each iodelay register as a separate device? Then the binding could
be just along the interrupts-extended type binding:

foo = <&bar 0x18c A_DELAY(0) G_DELAY(120)>;

Where the 0x18c is the instance offset of the register within the
ti,dra7-iodelay compatible controller.

Regards,

Tony

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 15:33     ` Tony Lindgren
@ 2015-03-10 17:25       ` Nishanth Menon
  2015-03-10 17:31         ` Tony Lindgren
  0 siblings, 1 reply; 21+ messages in thread
From: Nishanth Menon @ 2015-03-10 17:25 UTC (permalink / raw)
  To: Tony Lindgren, Linus Walleij
  Cc: linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On 03/10/2015 10:33 AM, Tony Lindgren wrote:
> * Linus Walleij <linus.walleij@linaro.org> [150310 03:39]:
>> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
>>
>>> +Configuration definition follows similar model as the pinctrl-single:
>>> +The groups of pin configuration are defined under "pinctrl-single,pins"
>>> +
>>> +&dra7_iodelay_core {
>>> +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
>>> +               pinctrl-single,pins = <
>>> +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
>>> +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
>>> +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
>>> +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
>>> +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
>>> +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
>>> +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
>>> +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
>>> +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
>>> +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
>>> +               >;
>>> +       };
>>> +};
>>
>> But wait.
>>
>> The promise when we merged pinctrl-single was that this driver was to be used
>> when the system had a one-register-per-pin layout and it was easy to do device
>> trees based on that.
>>
>> We were very reluctant to accept that even though we didn't even have the
>> generic pin control bindings in place, the argument being that the driver
>> should know the detailed register layout, it should not be described in the
>> device tree. We eventually caved in and accepted it as an exception.
> 
> Hey let's get few things straight here. There's nothing stopping the
> driver from knowing a detailed register layout with the pinctrl-single
> binding. This can be very easily done based on the compatible flag and
> match data as needed and check the values provided.
> 
> And let's also recap the reasons for the pinctrl-single binding. The
> the main reason for the pinctrl-single binding is to avoid mapping
> individual register bits to device tree compatible string properties.
> 
> Imagine doing that for hundreds of similar registers. Believe me, I tried
> using device tree properties initially and it just sucked big time. For
> larger amounts of dts data, it's best to stick to numeric values and
> phandles in the device tree data and rely on the preprocessor for
> getting the values right.
> 
> Finally, we don't want to build databases into the kernel drivers for
> every SoC. We certainly have plenty fo those already.
>  
>> Since this pin controller is not using pinctrl-single it does not enjoy that
>> privilege and you need to explain why this pin controller cannot use the
>> generic bindings like so many other pin controllers have since started
>> to do. ("It is in the same SoC" is not an acceptable argument.)
>>
>> What is wrong with this:
>> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> 
> Nishanth, care to explain your reasons for using pinctrl-single binding
> here vs the generic binding? Is the amount of string parsing with the
> data an issue here?

Wrong option chosen, I suppose :( - alright, lets discuss the alternative.

>  
>> We can add generic delay bindings to the list, it even seems like
>> a good idea to do so, as it is likely something that will come up in
>> other hardware and will be needed for ACPI etc going forward.
> 
> We certainly need to make setting delays (with values) generic, no
> doubt about that.
> 
> If the large amount of data is not an issue here, we could maybe set
> each iodelay register as a separate device? Then the binding could
> be just along the interrupts-extended type binding:
> 
> foo = <&bar 0x18c A_DELAY(0) G_DELAY(120)>;
> 
> Where the 0x18c is the instance offset of the register within the
> ti,dra7-iodelay compatible controller.

if mmc2_pins_default point at pins for mmc pin configuration for
control_core (pinctrl-single), are you proposing the following?

 mmc2_pins_default: mmc2_pins_default {
         pinctrl-single,pins = <
                 0x9c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a23.mmc2_clk */
                 0xb0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_cs1.mmc2_cmd */
                 0xa0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a24.mmc2_dat0 */
                 0xa4 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a25.mmc2_dat1 */
                 0xa8 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a26.mmc2_dat2 */
                 0xac (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a27.mmc2_dat3 */
                 0x8c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a19.mmc2_dat4 */
                 0x90 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a20.mmc2_dat5 */
                 0x94 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a21.mmc2_dat6 */
                 0x98 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
gpmc_a22.mmc2_dat7 */
         >;
 };

&mmc2 {
...
 pinctrl-1 =
 	&mmc2_pins_default,	/* points to mmc control core pins */
 	<&iodelay 0x18c A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A19_IN */
 	<&iodelay 0x1a4 A_DELAY(265) | G_DELAY(360)>,     /* CFG_GPMC_A20_IN */
 	<&iodelay 0x1b0 A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A21_IN */
 	<&iodelay 0x1bc A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A22_IN */
 	<&iodelay 0x1c8 A_DELAY(287) | G_DELAY(420)>,     /* CFG_GPMC_A23_IN */
 	<&iodelay 0x1d4 A_DELAY(144) | G_DELAY(240)>,     /* CFG_GPMC_A24_IN */
 	<&iodelay 0x1e0 A_DELAY(0) | G_DELAY(0)>,         /* CFG_GPMC_A25_IN */
 	<&iodelay 0x1ec A_DELAY(120) | G_DELAY(0)>,       /* CFG_GPMC_A26_IN */
 	<&iodelay 0x1f8 A_DELAY(120) | G_DELAY(180)>,     /* CFG_GPMC_A27_IN */
 	<&iodelay 0x360 A_DELAY(0) | G_DELAY(0)>;         /* CFG_GPMC_CS1_IN */

I have to check if we are capable of parsing that. but if that is the
approach chosen, I suppose we might be able to figure something, I
suppose..

-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 17:25       ` Nishanth Menon
@ 2015-03-10 17:31         ` Tony Lindgren
  2015-03-10 18:33           ` Nishanth Menon
  0 siblings, 1 reply; 21+ messages in thread
From: Tony Lindgren @ 2015-03-10 17:31 UTC (permalink / raw)
  To: Nishanth Menon
  Cc: Linus Walleij, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

* Nishanth Menon <nm@ti.com> [150310 10:25]:
> On 03/10/2015 10:33 AM, Tony Lindgren wrote:
> > * Linus Walleij <linus.walleij@linaro.org> [150310 03:39]:
> >> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
> >>
> >>> +Configuration definition follows similar model as the pinctrl-single:
> >>> +The groups of pin configuration are defined under "pinctrl-single,pins"
> >>> +
> >>> +&dra7_iodelay_core {
> >>> +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
> >>> +               pinctrl-single,pins = <
> >>> +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
> >>> +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
> >>> +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
> >>> +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
> >>> +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
> >>> +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
> >>> +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
> >>> +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
> >>> +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
> >>> +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
> >>> +               >;
> >>> +       };
> >>> +};
> >>
> >> But wait.
> >>
> >> The promise when we merged pinctrl-single was that this driver was to be used
> >> when the system had a one-register-per-pin layout and it was easy to do device
> >> trees based on that.
> >>
> >> We were very reluctant to accept that even though we didn't even have the
> >> generic pin control bindings in place, the argument being that the driver
> >> should know the detailed register layout, it should not be described in the
> >> device tree. We eventually caved in and accepted it as an exception.
> > 
> > Hey let's get few things straight here. There's nothing stopping the
> > driver from knowing a detailed register layout with the pinctrl-single
> > binding. This can be very easily done based on the compatible flag and
> > match data as needed and check the values provided.
> > 
> > And let's also recap the reasons for the pinctrl-single binding. The
> > the main reason for the pinctrl-single binding is to avoid mapping
> > individual register bits to device tree compatible string properties.
> > 
> > Imagine doing that for hundreds of similar registers. Believe me, I tried
> > using device tree properties initially and it just sucked big time. For
> > larger amounts of dts data, it's best to stick to numeric values and
> > phandles in the device tree data and rely on the preprocessor for
> > getting the values right.
> > 
> > Finally, we don't want to build databases into the kernel drivers for
> > every SoC. We certainly have plenty fo those already.
> >  
> >> Since this pin controller is not using pinctrl-single it does not enjoy that
> >> privilege and you need to explain why this pin controller cannot use the
> >> generic bindings like so many other pin controllers have since started
> >> to do. ("It is in the same SoC" is not an acceptable argument.)
> >>
> >> What is wrong with this:
> >> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
> > 
> > Nishanth, care to explain your reasons for using pinctrl-single binding
> > here vs the generic binding? Is the amount of string parsing with the
> > data an issue here?
> 
> Wrong option chosen, I suppose :( - alright, lets discuss the alternative.

Heh well now we know :) 
  
> >> We can add generic delay bindings to the list, it even seems like
> >> a good idea to do so, as it is likely something that will come up in
> >> other hardware and will be needed for ACPI etc going forward.
> > 
> > We certainly need to make setting delays (with values) generic, no
> > doubt about that.
> > 
> > If the large amount of data is not an issue here, we could maybe set
> > each iodelay register as a separate device? Then the binding could
> > be just along the interrupts-extended type binding:
> > 
> > foo = <&bar 0x18c A_DELAY(0) G_DELAY(120)>;
> > 
> > Where the 0x18c is the instance offset of the register within the
> > ti,dra7-iodelay compatible controller.
> 
> if mmc2_pins_default point at pins for mmc pin configuration for
> control_core (pinctrl-single), are you proposing the following?
> 
>  mmc2_pins_default: mmc2_pins_default {
>          pinctrl-single,pins = <
>                  0x9c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a23.mmc2_clk */
>                  0xb0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_cs1.mmc2_cmd */
>                  0xa0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a24.mmc2_dat0 */
>                  0xa4 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a25.mmc2_dat1 */
>                  0xa8 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a26.mmc2_dat2 */
>                  0xac (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a27.mmc2_dat3 */
>                  0x8c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a19.mmc2_dat4 */
>                  0x90 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a20.mmc2_dat5 */
>                  0x94 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a21.mmc2_dat6 */
>                  0x98 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
> gpmc_a22.mmc2_dat7 */
>          >;
>  };

Yeah so existing pinctrl-single binding above, with additional iodelay
binding below..
 
> &mmc2 {
> ...
>  pinctrl-1 =
>  	&mmc2_pins_default,	/* points to mmc control core pins */
>  	<&iodelay 0x18c A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A19_IN */
>  	<&iodelay 0x1a4 A_DELAY(265) | G_DELAY(360)>,     /* CFG_GPMC_A20_IN */
>  	<&iodelay 0x1b0 A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A21_IN */
>  	<&iodelay 0x1bc A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A22_IN */
>  	<&iodelay 0x1c8 A_DELAY(287) | G_DELAY(420)>,     /* CFG_GPMC_A23_IN */
>  	<&iodelay 0x1d4 A_DELAY(144) | G_DELAY(240)>,     /* CFG_GPMC_A24_IN */
>  	<&iodelay 0x1e0 A_DELAY(0) | G_DELAY(0)>,         /* CFG_GPMC_A25_IN */
>  	<&iodelay 0x1ec A_DELAY(120) | G_DELAY(0)>,       /* CFG_GPMC_A26_IN */
>  	<&iodelay 0x1f8 A_DELAY(120) | G_DELAY(180)>,     /* CFG_GPMC_A27_IN */
>  	<&iodelay 0x360 A_DELAY(0) | G_DELAY(0)>;         /* CFG_GPMC_CS1_IN */
> 
> I have to check if we are capable of parsing that. but if that is the
> approach chosen, I suppose we might be able to figure something, I
> suppose..

Yes except I'd make use of some kind of #pinctrl-cells here just like
interrupt controller has #interrupt-cells. Then you can have the values
seprate and the controller knows what to do with them based on the
compatible flag and #pinctrl-cells.

Regards,

Tony

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 17:31         ` Tony Lindgren
@ 2015-03-10 18:33           ` Nishanth Menon
  2015-03-10 19:20             ` Nishanth Menon
  2015-03-18  1:30             ` Linus Walleij
  0 siblings, 2 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-10 18:33 UTC (permalink / raw)
  To: Tony Lindgren
  Cc: Linus Walleij, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On 03/10/2015 12:31 PM, Tony Lindgren wrote:
> * Nishanth Menon <nm@ti.com> [150310 10:25]:
>> On 03/10/2015 10:33 AM, Tony Lindgren wrote:
>>> * Linus Walleij <linus.walleij@linaro.org> [150310 03:39]:
>>>> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
>>>>
>>>>> +Configuration definition follows similar model as the pinctrl-single:
>>>>> +The groups of pin configuration are defined under "pinctrl-single,pins"
>>>>> +
>>>>> +&dra7_iodelay_core {
>>>>> +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
>>>>> +               pinctrl-single,pins = <
>>>>> +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
>>>>> +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
>>>>> +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
>>>>> +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
>>>>> +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
>>>>> +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
>>>>> +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
>>>>> +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
>>>>> +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
>>>>> +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
>>>>> +               >;
>>>>> +       };
>>>>> +};
>>>>
>>>> But wait.
>>>>
>>>> The promise when we merged pinctrl-single was that this driver was to be used
>>>> when the system had a one-register-per-pin layout and it was easy to do device
>>>> trees based on that.
>>>>
>>>> We were very reluctant to accept that even though we didn't even have the
>>>> generic pin control bindings in place, the argument being that the driver
>>>> should know the detailed register layout, it should not be described in the
>>>> device tree. We eventually caved in and accepted it as an exception.
>>>
>>> Hey let's get few things straight here. There's nothing stopping the
>>> driver from knowing a detailed register layout with the pinctrl-single
>>> binding. This can be very easily done based on the compatible flag and
>>> match data as needed and check the values provided.
>>>
>>> And let's also recap the reasons for the pinctrl-single binding. The
>>> the main reason for the pinctrl-single binding is to avoid mapping
>>> individual register bits to device tree compatible string properties.
>>>
>>> Imagine doing that for hundreds of similar registers. Believe me, I tried
>>> using device tree properties initially and it just sucked big time. For
>>> larger amounts of dts data, it's best to stick to numeric values and
>>> phandles in the device tree data and rely on the preprocessor for
>>> getting the values right.
>>>
>>> Finally, we don't want to build databases into the kernel drivers for
>>> every SoC. We certainly have plenty fo those already.
>>>  
>>>> Since this pin controller is not using pinctrl-single it does not enjoy that
>>>> privilege and you need to explain why this pin controller cannot use the
>>>> generic bindings like so many other pin controllers have since started
>>>> to do. ("It is in the same SoC" is not an acceptable argument.)
>>>>
>>>> What is wrong with this:
>>>> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
>>>
>>> Nishanth, care to explain your reasons for using pinctrl-single binding
>>> here vs the generic binding? Is the amount of string parsing with the
>>> data an issue here?
>>
>> Wrong option chosen, I suppose :( - alright, lets discuss the alternative.
> 
> Heh well now we know :) 
>   
>>>> We can add generic delay bindings to the list, it even seems like
>>>> a good idea to do so, as it is likely something that will come up in
>>>> other hardware and will be needed for ACPI etc going forward.
>>>
>>> We certainly need to make setting delays (with values) generic, no
>>> doubt about that.
>>>
>>> If the large amount of data is not an issue here, we could maybe set
>>> each iodelay register as a separate device? Then the binding could
>>> be just along the interrupts-extended type binding:
>>>
>>> foo = <&bar 0x18c A_DELAY(0) G_DELAY(120)>;
>>>
>>> Where the 0x18c is the instance offset of the register within the
>>> ti,dra7-iodelay compatible controller.
>>
>> if mmc2_pins_default point at pins for mmc pin configuration for
>> control_core (pinctrl-single), are you proposing the following?
>>
>>  mmc2_pins_default: mmc2_pins_default {
>>          pinctrl-single,pins = <
>>                  0x9c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a23.mmc2_clk */
>>                  0xb0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_cs1.mmc2_cmd */
>>                  0xa0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a24.mmc2_dat0 */
>>                  0xa4 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a25.mmc2_dat1 */
>>                  0xa8 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a26.mmc2_dat2 */
>>                  0xac (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a27.mmc2_dat3 */
>>                  0x8c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a19.mmc2_dat4 */
>>                  0x90 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a20.mmc2_dat5 */
>>                  0x94 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a21.mmc2_dat6 */
>>                  0x98 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>> gpmc_a22.mmc2_dat7 */
>>          >;
>>  };
> 
> Yeah so existing pinctrl-single binding above, with additional iodelay
> binding below..
>  
>> &mmc2 {
>> ...
>>  pinctrl-1 =
>>  	&mmc2_pins_default,	/* points to mmc control core pins */
>>  	<&iodelay 0x18c A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A19_IN */
>>  	<&iodelay 0x1a4 A_DELAY(265) | G_DELAY(360)>,     /* CFG_GPMC_A20_IN */
>>  	<&iodelay 0x1b0 A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A21_IN */
>>  	<&iodelay 0x1bc A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A22_IN */
>>  	<&iodelay 0x1c8 A_DELAY(287) | G_DELAY(420)>,     /* CFG_GPMC_A23_IN */
>>  	<&iodelay 0x1d4 A_DELAY(144) | G_DELAY(240)>,     /* CFG_GPMC_A24_IN */
>>  	<&iodelay 0x1e0 A_DELAY(0) | G_DELAY(0)>,         /* CFG_GPMC_A25_IN */
>>  	<&iodelay 0x1ec A_DELAY(120) | G_DELAY(0)>,       /* CFG_GPMC_A26_IN */
>>  	<&iodelay 0x1f8 A_DELAY(120) | G_DELAY(180)>,     /* CFG_GPMC_A27_IN */
>>  	<&iodelay 0x360 A_DELAY(0) | G_DELAY(0)>;         /* CFG_GPMC_CS1_IN */
>>
>> I have to check if we are capable of parsing that. but if that is the
>> approach chosen, I suppose we might be able to figure something, I
>> suppose..
> 
> Yes except I'd make use of some kind of #pinctrl-cells here just like
> interrupt controller has #interrupt-cells. Then you can have the values
> seprate and the controller knows what to do with them based on the
> compatible flag and #pinctrl-cells.

Something like the following I suppose, where pinctrl-cells is optional?

dra7_pmx_core: pinmux@4a003400 {
        compatible = "ti,dra7-padconf", "pinctrl-single";
        reg = <0x4a003400 0x0464>;
        #address-cells = <1>;
        #size-cells = <0>;
        #interrupt-cells = <1>;
        interrupt-controller;
        pinctrl-single,register-width = <32>;
        pinctrl-single,function-mask = <0x3fffffff>;
};

dra7_iodelay_core: padconf@4844a000 {
        compatible = "ti,dra7-iodelay";
        reg = <0x4844a000 0x0d1c>;
        #address-cells = <1>;
        #size-cells = <0>;
	#pinctrl-cells = <2>;
};

Linus,

I hope you are ok with the above?

-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 18:33           ` Nishanth Menon
@ 2015-03-10 19:20             ` Nishanth Menon
  2015-03-18  1:30             ` Linus Walleij
  1 sibling, 0 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-10 19:20 UTC (permalink / raw)
  To: Tony Lindgren
  Cc: Linus Walleij, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On 03/10/2015 01:33 PM, Nishanth Menon wrote:
> On 03/10/2015 12:31 PM, Tony Lindgren wrote:
>> * Nishanth Menon <nm@ti.com> [150310 10:25]:
>>> On 03/10/2015 10:33 AM, Tony Lindgren wrote:
>>>> * Linus Walleij <linus.walleij@linaro.org> [150310 03:39]:
>>>>> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
>>>>>
>>>>>> +Configuration definition follows similar model as the pinctrl-single:
>>>>>> +The groups of pin configuration are defined under "pinctrl-single,pins"
>>>>>> +
>>>>>> +&dra7_iodelay_core {
>>>>>> +       mmc2_iodelay_3v3_conf: mmc2_iodelay_3v3_conf {
>>>>>> +               pinctrl-single,pins = <
>>>>>> +                       0x18c (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A19_IN */
>>>>>> +                       0x1a4 (A_DELAY(265) | G_DELAY(360))     /* CFG_GPMC_A20_IN */
>>>>>> +                       0x1b0 (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A21_IN */
>>>>>> +                       0x1bc (A_DELAY(0) | G_DELAY(120))       /* CFG_GPMC_A22_IN */
>>>>>> +                       0x1c8 (A_DELAY(287) | G_DELAY(420))     /* CFG_GPMC_A23_IN */
>>>>>> +                       0x1d4 (A_DELAY(144) | G_DELAY(240))     /* CFG_GPMC_A24_IN */
>>>>>> +                       0x1e0 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_A25_IN */
>>>>>> +                       0x1ec (A_DELAY(120) | G_DELAY(0))       /* CFG_GPMC_A26_IN */
>>>>>> +                       0x1f8 (A_DELAY(120) | G_DELAY(180))     /* CFG_GPMC_A27_IN */
>>>>>> +                       0x360 (A_DELAY(0) | G_DELAY(0))         /* CFG_GPMC_CS1_IN */
>>>>>> +               >;
>>>>>> +       };
>>>>>> +};
>>>>>
>>>>> But wait.
>>>>>
>>>>> The promise when we merged pinctrl-single was that this driver was to be used
>>>>> when the system had a one-register-per-pin layout and it was easy to do device
>>>>> trees based on that.
>>>>>
>>>>> We were very reluctant to accept that even though we didn't even have the
>>>>> generic pin control bindings in place, the argument being that the driver
>>>>> should know the detailed register layout, it should not be described in the
>>>>> device tree. We eventually caved in and accepted it as an exception.
>>>>
>>>> Hey let's get few things straight here. There's nothing stopping the
>>>> driver from knowing a detailed register layout with the pinctrl-single
>>>> binding. This can be very easily done based on the compatible flag and
>>>> match data as needed and check the values provided.
>>>>
>>>> And let's also recap the reasons for the pinctrl-single binding. The
>>>> the main reason for the pinctrl-single binding is to avoid mapping
>>>> individual register bits to device tree compatible string properties.
>>>>
>>>> Imagine doing that for hundreds of similar registers. Believe me, I tried
>>>> using device tree properties initially and it just sucked big time. For
>>>> larger amounts of dts data, it's best to stick to numeric values and
>>>> phandles in the device tree data and rely on the preprocessor for
>>>> getting the values right.
>>>>
>>>> Finally, we don't want to build databases into the kernel drivers for
>>>> every SoC. We certainly have plenty fo those already.
>>>>  
>>>>> Since this pin controller is not using pinctrl-single it does not enjoy that
>>>>> privilege and you need to explain why this pin controller cannot use the
>>>>> generic bindings like so many other pin controllers have since started
>>>>> to do. ("It is in the same SoC" is not an acceptable argument.)
>>>>>
>>>>> What is wrong with this:
>>>>> Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
>>>>
>>>> Nishanth, care to explain your reasons for using pinctrl-single binding
>>>> here vs the generic binding? Is the amount of string parsing with the
>>>> data an issue here?
>>>
>>> Wrong option chosen, I suppose :( - alright, lets discuss the alternative.
>>
>> Heh well now we know :) 
>>   
>>>>> We can add generic delay bindings to the list, it even seems like
>>>>> a good idea to do so, as it is likely something that will come up in
>>>>> other hardware and will be needed for ACPI etc going forward.
>>>>
>>>> We certainly need to make setting delays (with values) generic, no
>>>> doubt about that.
>>>>
>>>> If the large amount of data is not an issue here, we could maybe set
>>>> each iodelay register as a separate device? Then the binding could
>>>> be just along the interrupts-extended type binding:
>>>>
>>>> foo = <&bar 0x18c A_DELAY(0) G_DELAY(120)>;
>>>>
>>>> Where the 0x18c is the instance offset of the register within the
>>>> ti,dra7-iodelay compatible controller.
>>>
>>> if mmc2_pins_default point at pins for mmc pin configuration for
>>> control_core (pinctrl-single), are you proposing the following?
>>>
>>>  mmc2_pins_default: mmc2_pins_default {
>>>          pinctrl-single,pins = <
>>>                  0x9c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a23.mmc2_clk */
>>>                  0xb0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_cs1.mmc2_cmd */
>>>                  0xa0 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a24.mmc2_dat0 */
>>>                  0xa4 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a25.mmc2_dat1 */
>>>                  0xa8 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a26.mmc2_dat2 */
>>>                  0xac (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a27.mmc2_dat3 */
>>>                  0x8c (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a19.mmc2_dat4 */
>>>                  0x90 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a20.mmc2_dat5 */
>>>                  0x94 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a21.mmc2_dat6 */
>>>                  0x98 (PIN_INPUT_PULLUP | MANUAL_MODE | MUX_MODE1) /*
>>> gpmc_a22.mmc2_dat7 */
>>>          >;
>>>  };
>>
>> Yeah so existing pinctrl-single binding above, with additional iodelay
>> binding below..
>>  
>>> &mmc2 {
>>> ...
>>>  pinctrl-1 =
>>>  	&mmc2_pins_default,	/* points to mmc control core pins */
>>>  	<&iodelay 0x18c A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A19_IN */
>>>  	<&iodelay 0x1a4 A_DELAY(265) | G_DELAY(360)>,     /* CFG_GPMC_A20_IN */
>>>  	<&iodelay 0x1b0 A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A21_IN */
>>>  	<&iodelay 0x1bc A_DELAY(0) | G_DELAY(120)>,       /* CFG_GPMC_A22_IN */
>>>  	<&iodelay 0x1c8 A_DELAY(287) | G_DELAY(420)>,     /* CFG_GPMC_A23_IN */
>>>  	<&iodelay 0x1d4 A_DELAY(144) | G_DELAY(240)>,     /* CFG_GPMC_A24_IN */
>>>  	<&iodelay 0x1e0 A_DELAY(0) | G_DELAY(0)>,         /* CFG_GPMC_A25_IN */
>>>  	<&iodelay 0x1ec A_DELAY(120) | G_DELAY(0)>,       /* CFG_GPMC_A26_IN */
>>>  	<&iodelay 0x1f8 A_DELAY(120) | G_DELAY(180)>,     /* CFG_GPMC_A27_IN */
>>>  	<&iodelay 0x360 A_DELAY(0) | G_DELAY(0)>;         /* CFG_GPMC_CS1_IN */
>>>
>>> I have to check if we are capable of parsing that. but if that is the
>>> approach chosen, I suppose we might be able to figure something, I
>>> suppose..
>>
>> Yes except I'd make use of some kind of #pinctrl-cells here just like
>> interrupt controller has #interrupt-cells. Then you can have the values
>> seprate and the controller knows what to do with them based on the
>> compatible flag and #pinctrl-cells.
> 
> Something like the following I suppose, where pinctrl-cells is optional?
> 
> dra7_pmx_core: pinmux@4a003400 {
>         compatible = "ti,dra7-padconf", "pinctrl-single";
>         reg = <0x4a003400 0x0464>;
>         #address-cells = <1>;
>         #size-cells = <0>;
>         #interrupt-cells = <1>;
>         interrupt-controller;
>         pinctrl-single,register-width = <32>;
>         pinctrl-single,function-mask = <0x3fffffff>;
> };
> 
> dra7_iodelay_core: padconf@4844a000 {
>         compatible = "ti,dra7-iodelay";
>         reg = <0x4844a000 0x0d1c>;
>         #address-cells = <1>;
>         #size-cells = <0>;
> 	#pinctrl-cells = <2>;
> };
> 
> Linus,
> 
> I hope you are ok with the above?
> 

a and g delays are in pico seconds parsed by iodelay driver, so,
revising proposal (and dropping the macros) to something as follows:


 pinctrl-1 =
 	&mmc2_pins_default,	/* points to mmc control core pins */
 	<&iodelay IODELAY_OFFSET(0x18c) 0 120>,       /* CFG_GPMC_A19_IN */
 	<&iodelay IODELAY_OFFSET(0x1a4) 265 360>,     /* CFG_GPMC_A20_IN */
 	<&iodelay IODELAY_OFFSET(0x1b0) 0 120>,       /* CFG_GPMC_A21_IN */
 	<&iodelay IODELAY_OFFSET(0x1bc) 0 120>,       /* CFG_GPMC_A22_IN */
 	<&iodelay IODELAY_OFFSET(0x1c8) 287 420>,     /* CFG_GPMC_A23_IN */
 	<&iodelay IODELAY_OFFSET(0x1d4) 144 240>,     /* CFG_GPMC_A24_IN */
 	<&iodelay IODELAY_OFFSET(0x1e0) 0 0>,         /* CFG_GPMC_A25_IN */
 	<&iodelay IODELAY_OFFSET(0x1ec) 120 0>,       /* CFG_GPMC_A26_IN */
 	<&iodelay IODELAY_OFFSET(0x1f8) 120 180>,     /* CFG_GPMC_A27_IN */
 	<&iodelay IODELAY_OFFSET(0x360) 0 0>;         /* CFG_GPMC_CS1_IN */

it might just need us to define the right parse path etc.. but should
let us scale with other phandle implementations as well.

offsets are computed by a macro IODELAY_OFFSET() -> just throwing in
an example set of values for illustration here.. but just to get the idea.


Will be nice to have some comments before I go down this path. Thanks
for helping review this to a reasonable direction.

-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver
  2015-03-10 11:03   ` Linus Walleij
@ 2015-03-11 12:39     ` Nishanth Menon
  0 siblings, 0 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-03-11 12:39 UTC (permalink / raw)
  To: Linus Walleij
  Cc: devicetree, Tony Lindgren, linux-kernel, linux-gpio,
	Lokesh Vutla, Linux-OMAP, linux-arm-kernel

On Tue, Mar 10, 2015 at 6:03 AM, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Wed, Mar 4, 2015 at 1:00 AM, Nishanth Menon <nm@ti.com> wrote:
>
>> SoC family such as DRA7 family of processors have, in addition
>> to the regular muxing of pins (as done by pinctrl-single), an
>> additional hardware module called IODelay which is also expected to be
>> configured. This "IODelay" module has it's own register space that is
>> independent of the control module.
>>
>> It is advocated strongly in TI's official documentation considering
>> the existing design of the DRA7 family of processors during mux or
>> IODelay reconfiguration, there is a potential for a significant glitch
>> which may cause functional impairment to certain hardware. It is
>> hence recommended to do as little of muxing as absolutely necessary
>> without I/O isolation (which can only be done in initial stages of
>> bootloader).
>>
>> NOTE: with the system wide I/O isolation scheme present in DRA7 SoC
>> family, it is not reasonable to do stop all I/O operations for every
>> such pad configuration scheme. So, we will let it glitch when used in
>> this mode.
>>
>> Even with the above limitation, certain functionality such as MMC has
>> mandatory need for IODelay reconfiguration requirements, depending on
>> speed of transfer. In these cases, with careful examination of usecase
>> involved, the expected glitch can be controlled such that it does not
>> impact functionality.
>>
>> In short, IODelay module support as a padconf driver being introduced
>> here is not expected to do SoC wide I/O Isolation and is meant for
>> a limited subset of IODelay configuration requirements that need to
>> be dynamic and whose glitchy behavior will not cause functionality
>> failure for that interface.
>>
>> Signed-off-by: Nishanth Menon <nm@ti.com>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>
> Pending the conclusion of my remark on the bindings that this
> should use the generic pin config bindings... here are some
> "normal" review comments.
>
>> +config PINCTRL_TI_IODELAY
>> +       bool "TI IODelay Module pinconf driver"
>> +       depends on OF
>> +       select PINCONF
>> +       select GENERIC_PINCONF
>> +       select REGMAP_MMIO
>> +       help
>> +         Say Y here to support Texas Instruments' IODelay pinconf driver.
>> +         IODelay module is used for the DRA7 SoC family. This driver is in
>> +         addition to PINCTRL_SINGLE which controls the mux.
>
> If the driver is "in addition to PINCTRL_SINGLE", then it
> should depend on it.
>
>> +/* Should I change this? Abuse? */
>> +#define IODELAY_MUX_PINS_NAME          "pinctrl-single,pins"
>
> Yeah this is abuse and is why you should use the generic
> bindings with just "pins" instead, and use the generic pinconf
> parameters to set them up.
>
>> + * struct ti_iodelay_conf_vals - Description of each configuration parameters.
>> + * @offset:    Configuration register offset
>> + * @a_delay:   Agnostic Delay (in ps)
>> + * @g_delay:   Gnostic Delay (in ps)
>> + */
>> +struct ti_iodelay_conf_vals {
>> +       u16 offset;
>> +       u16 a_delay;
>> +       u16 g_delay;
>> +};
>
> So I don't think it's a good idea to get the register offset from
> the device tree. The driver should know these.
>
>> +/**
>> + * struct ti_iodelay_reg_values - Computed io_reg configuration values (see TRM)
>> + * @coarse_ref_count:  Coarse reference count
>> + * @coarse_delay_count:        Coarse delay count
>> + * @fine_ref_count:    Fine reference count
>> + * @fine_delay_count:  Fine Delay count
>> + * @ref_clk_period:    Reference Clock period
>> + * @cdpe:              Coarse delay parameter
>> + * @fdpe:              Fine delay parameter
>> + */
>> +struct ti_iodelay_reg_values {
>> +       u16 coarse_ref_count;
>
> If you're doing reference counting, use kref.
> <linux/kref.h>
>
>> +       u16 coarse_delay_count;
>> +
>> +       u16 fine_ref_count;
>
> Dito.
>
>> +       u16 fine_delay_count;
>> +
>> +       u16 ref_clk_period;
>> +
>> +       u32 cdpe;
>> +       u32 fdpe;
>> +};
>
>
>> +/**
>> + * struct ti_iodelay_pin_name - name of the pins
>> + * @name: name
>> + */
>> +struct ti_iodelay_pin_name {
>> +       char name[IODELAY_REG_NAME_LEN];
>> +};
>
> What is this? The pin control subsystem already has a struct
> for naming pins. struct pinctrl_pin_desc.
>
> Are you reimplementing core functionality?
>
> The generic pin config reference pins by name, and since you
> obviously like to encode these into you data you can just
> as well use that method for this too.
>
> Again I think this is a side effect from using the pinctrl-single
> concepts, if you think of this as some other pinctrl driver
> I think this will fall out nicely.
>
>> +/**
>> + * struct ti_iodelay_device - Represents information for a IOdelay instance
>> + * @dev: device pointer
>> + * @reg_base: Remapped virtual address
>> + * @regmap: Regmap for this IOdelay instance
>> + * @pctl: Pinctrl device
>> + * @desc: pinctrl descriptor for pctl
>> + * @pa: pinctrl pin wise description
>> + * @names: names of the pins
>> + * @groups: list of pinconf groups for iodelay instance
>> + * @ngroups: number of groups in the list
>> + * @mutex: mutex to protect group list modification
>> + * @reg_data: Register definition data for the IODelay instance
>> + * @reg_init_conf_values: Initial configuration values.
>> + */
>> +struct ti_iodelay_device {
>> +       struct device *dev;
>> +       void __iomem *reg_base;
>> +       struct regmap *regmap;
>> +
>> +       struct pinctrl_dev *pctl;
>> +       struct pinctrl_desc desc;
>> +       struct pinctrl_pin_desc *pa;
>> +       struct ti_iodelay_pin_name *names;
>
> Unhappy about that. pinctrl_desc contains
> struct pinctrl_pin_desc const *pins; !
>
>> +
>> +       struct list_head groups;
>> +       int ngroups;
>> +       struct mutex mutex; /* list protection */
>
> Why is this needed? Usually the pin control core
> serialize calls into the drivers. Care to explain? Have
> the potential race really triggered?
>
>> +static inline u32 ti_iodelay_compute_dpe(u16 period, u16 ref, u16 delay,
>> +                                        u16 delay_m)
>> +{
>> +       u64 m, d;
>> +
>> +       /* Handle overflow conditions */
>> +       m = 10 * (u64)period * (u64)ref;
>> +       d = 2 * (u64)delay * (u64)delay_m;
>> +
>> +       /* Truncate result back to 32 bits */
>> +       return div64_u64(m, d);
>> +}
>
> Serious business ...
>
>> +/**
>> + * ti_iodelay_pinconf_set() - Configure the pin configuration
>> + * @iod:       IODelay device
>> + * @val:       Configuration value
>> + *
>> + * Update the configuration register as per TRM and lockup once done.
>> + * *IMPORTANT NOTE* SoC TRM does recommend doing iodelay programmation only
>> + * while in Isolation. But, then, isolation also implies that every pin
>> + * on the SoC(including DDR) will be isolated out. The only benefit being
>> + * a glitchless configuration, However, the intent of this driver is purely
>> + * to support a "glitchy" configuration where applicable.
>> + *
>> + * Return: 0 in case of success, else appropriate error value
>> + */
>> +static int ti_iodelay_pinconf_set(struct ti_iodelay_device *iod,
>> +                                 struct ti_iodelay_conf_vals *val)
>> +{
>> +       const struct ti_iodelay_reg_data *reg = iod->reg_data;
>> +       struct ti_iodelay_reg_values *ival = &iod->reg_init_conf_values;
>> +       struct device *dev = iod->dev;
>> +       u32 g_delay_coarse, g_delay_fine;
>> +       u32 a_delay_coarse, a_delay_fine;
>> +       u32 c_elements, f_elements;
>> +       u32 total_delay;
>> +       u32 reg_mask, reg_val, tmp_val;
>> +       int r;
>> +
>> +       /* NOTE: Truncation is expected in all division below */
>> +       g_delay_coarse = val->g_delay / 920;
>> +       g_delay_fine = ((val->g_delay % 920) * 10) / 60;
>> +
>> +       a_delay_coarse = val->a_delay / ival->cdpe;
>> +       a_delay_fine = ((val->a_delay % ival->cdpe) * 10) / ival->fdpe;
>> +
>> +       c_elements = g_delay_coarse + a_delay_coarse;
>> +       f_elements = (g_delay_fine + a_delay_fine) / 10;
>> +
>> +       if (f_elements > 22) {
>> +               total_delay = c_elements * ival->cdpe + f_elements * ival->fdpe;
>> +               c_elements = total_delay / ival->cdpe;
>> +               f_elements = (total_delay % ival->cdpe) / ival->fdpe;
>> +       }
>> +
>> +       reg_mask = reg->signature_mask;
>> +       reg_val = reg->signature_value << __ffs(reg->signature_mask);
>> +
>> +       reg_mask |= reg->binary_data_coarse_mask;
>> +       tmp_val = c_elements << __ffs(reg->binary_data_coarse_mask);
>> +       if (tmp_val & ~reg->binary_data_coarse_mask) {
>> +               dev_err(dev, "Masking overflow of coarse elements %08x\n",
>> +                       tmp_val);
>> +               tmp_val &= reg->binary_data_coarse_mask;
>> +       }
>> +       reg_val |= tmp_val;
>> +
>> +       reg_mask |= reg->binary_data_fine_mask;
>> +       tmp_val = f_elements << __ffs(reg->binary_data_fine_mask);
>> +       if (tmp_val & ~reg->binary_data_fine_mask) {
>> +               dev_err(dev, "Masking overflow of fine elements %08x\n",
>> +                       tmp_val);
>> +               tmp_val &= reg->binary_data_fine_mask;
>> +       }
>> +       reg_val |= tmp_val;
>> +
>> +       /* Write with lock value - we DONOT want h/w updates */
>> +       reg_mask |= reg->lock_mask;
>> +       reg_val |= reg->lock_val << __ffs(reg->lock_mask);
>> +       r = regmap_update_bits(iod->regmap, val->offset, reg_mask, reg_val);
>> +
>> +       dev_dbg(dev, "Set reg 0x%x Delay(a=%d g=%d), Elements(C=%d F=%d)0x%x\n",
>> +               val->offset, val->a_delay, val->g_delay, c_elements,
>> +               f_elements, reg_val);
>> +
>> +       return r;
>> +}
>
> Looking at this terse thing I think it's obviously easier to use
> a more verbose device tree description with
>
> drive-delay = <some SI unit>;
>
>
>> +       /* unlock the IOdelay region */
>> +       r = regmap_update_bits(iod->regmap, reg->reg_global_lock_offset,
>> +                              reg->global_lock_mask, reg->global_unlock_val);
>> +       if (r)
>> +               return r;
>> +
>> +       /* Read up Recalibration sequence done by bootloader */
>> +       r = regmap_read(iod->regmap, reg->reg_refclk_offset, &val);
>> +       if (r)
>> +               return r;
>> +       ival->ref_clk_period = ti_iodelay_extract(val, reg->refclk_period_mask);
>> +       dev_dbg(dev, "refclk_period=0x%04x\n", ival->ref_clk_period);
>
> That sounds hightec. So the bootloader calibrates the delays
> and  computes the refclock period? So is that sime PLL or something?
>
>> +       r = regmap_read(iod->regmap, reg->reg_coarse_offset, &val);
>> +       if (r)
>> +               return r;
>> +       ival->coarse_ref_count =
>> +           ti_iodelay_extract(val, reg->coarse_ref_count_mask);
>> +       ival->coarse_delay_count =
>> +           ti_iodelay_extract(val, reg->coarse_delay_count_mask);
>> +       if (!ival->coarse_delay_count) {
>> +               dev_err(dev, "Invalid Coarse delay count (0) (reg=0x%08x)\n",
>> +                       val);
>> +               return -EINVAL;
>> +       }
>> +       ival->cdpe = ti_iodelay_compute_dpe(ival->ref_clk_period,
>> +                                           ival->coarse_ref_count,
>> +                                           ival->coarse_delay_count, 88);
>
> 88? What does that mean... This should be #defined I think.
>
>> +static int ti_iodelay_dt_node_to_map(struct pinctrl_dev *pctldev,
>> +                                    struct device_node *np,
>> +                                    struct pinctrl_map **map,
>> +                                    unsigned *num_maps)
>
> If you use the generic bindings this quite complex parsing and
> everything associated with it goes away into the core.
>
>> +static void ti_iodelay_dt_free_map(struct pinctrl_dev *pctldev,
>> +                                  struct pinctrl_map *map, unsigned num_maps)
>
> Dito.
>
> BTW even if you proceed this way I suspect these are verbatim
> copies from pinctrl-single so they shold obviouslyt be abstracted
> out as library functions in that case.
>
>> +/**
>> + * ti_iodelay_pinctrl_get_group_pins() - get group pins
>> + * @pctldev:   pinctrl device representing IODelay device
>> + * @gselector: Group selector
>> + * @pins:      pointer to the pins
>> + * @npins:     number of pins
>> + *
>> + * Dummy implementation since we do not track pins, we track configurations
>> + * Forced by pinctrl's pinctrl_check_ops()
>> + *
>> + * Return: -EINVAL
>> + */
>> +static int ti_iodelay_pinctrl_get_group_pins(struct pinctrl_dev *pctldev,
>> +                                            unsigned gselector,
>> +                                            const unsigned **pins,
>> +                                            unsigned *npins)
>> +{
>> +       /* Dummy implementation - we dont do pin mux */
>> +       return -EINVAL;
>> +}
>
> This is not about muxing. It is about enumerating the pins in the
> group that will be affected by the setting, which is something you
> will want to do when using the generic bindings.
>
>> +       group = ti_iodelay_get_group(iod, gselector);
>
> And this seems to be your re-implementation of exactly that pin control
> core functionality. Which again should be shared with pinctrl-single if
> you anyway go down this path.
>
> I'll halt review here pending discussion on the bindings & stuff.

I assume we want to close on binding before looking at implementation
- definitely needs a rewrite - only guidance I'd probably need is
about which model you'd suggest I should follow(pinconf/pinctrl) once
we are done with the bindings discussion.

-- 
---
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-10 18:33           ` Nishanth Menon
  2015-03-10 19:20             ` Nishanth Menon
@ 2015-03-18  1:30             ` Linus Walleij
  2015-03-18  1:41               ` Tony Lindgren
  1 sibling, 1 reply; 21+ messages in thread
From: Linus Walleij @ 2015-03-18  1:30 UTC (permalink / raw)
  To: Nishanth Menon
  Cc: Tony Lindgren, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On Tue, Mar 10, 2015 at 7:33 PM, Nishanth Menon <nm@ti.com> wrote:
> On 03/10/2015 12:31 PM, Tony Lindgren wrote:

>> Yes except I'd make use of some kind of #pinctrl-cells here just like
>> interrupt controller has #interrupt-cells. Then you can have the values
>> seprate and the controller knows what to do with them based on the
>> compatible flag and #pinctrl-cells.
>
> Something like the following I suppose, where pinctrl-cells is optional?
>
> dra7_pmx_core: pinmux@4a003400 {
>         compatible = "ti,dra7-padconf", "pinctrl-single";
>         reg = <0x4a003400 0x0464>;
>         #address-cells = <1>;
>         #size-cells = <0>;
>         #interrupt-cells = <1>;
>         interrupt-controller;
>         pinctrl-single,register-width = <32>;
>         pinctrl-single,function-mask = <0x3fffffff>;
> };
>
> dra7_iodelay_core: padconf@4844a000 {
>         compatible = "ti,dra7-iodelay";
>         reg = <0x4844a000 0x0d1c>;
>         #address-cells = <1>;
>         #size-cells = <0>;
>         #pinctrl-cells = <2>;
> };
>
> Linus,
>
> I hope you are ok with the above?

Hm depends on where the documentation hits I guess?

Such a generic cell count property has to be to the generic
pinctrl-bindings.txt document if I read it right.

Overall I guess this will be acceptable but you really need to
reuse some more code between this driver and pinctrl-single.c
if I read it right.

Yours,
Linus Walleij

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-18  1:30             ` Linus Walleij
@ 2015-03-18  1:41               ` Tony Lindgren
  2015-04-15  1:29                 ` Lennart Sorensen
  0 siblings, 1 reply; 21+ messages in thread
From: Tony Lindgren @ 2015-03-18  1:41 UTC (permalink / raw)
  To: Linus Walleij
  Cc: Nishanth Menon, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

* Linus Walleij <linus.walleij@linaro.org> [150317 18:31]:
> On Tue, Mar 10, 2015 at 7:33 PM, Nishanth Menon <nm@ti.com> wrote:
> > On 03/10/2015 12:31 PM, Tony Lindgren wrote:
> 
> >> Yes except I'd make use of some kind of #pinctrl-cells here just like
> >> interrupt controller has #interrupt-cells. Then you can have the values
> >> seprate and the controller knows what to do with them based on the
> >> compatible flag and #pinctrl-cells.
> >
> > Something like the following I suppose, where pinctrl-cells is optional?
> >
> > dra7_pmx_core: pinmux@4a003400 {
> >         compatible = "ti,dra7-padconf", "pinctrl-single";
> >         reg = <0x4a003400 0x0464>;
> >         #address-cells = <1>;
> >         #size-cells = <0>;
> >         #interrupt-cells = <1>;
> >         interrupt-controller;
> >         pinctrl-single,register-width = <32>;
> >         pinctrl-single,function-mask = <0x3fffffff>;
> > };
> >
> > dra7_iodelay_core: padconf@4844a000 {
> >         compatible = "ti,dra7-iodelay";
> >         reg = <0x4844a000 0x0d1c>;
> >         #address-cells = <1>;
> >         #size-cells = <0>;
> >         #pinctrl-cells = <2>;
> > };
> >
> > Linus,
> >
> > I hope you are ok with the above?
> 
> Hm depends on where the documentation hits I guess?
> 
> Such a generic cell count property has to be to the generic
> pinctrl-bindings.txt document if I read it right.

Yeah agreed. I suggest discussing the binding and the generic
parsing code for it first :)
 
> Overall I guess this will be acceptable but you really need to
> reuse some more code between this driver and pinctrl-single.c
> if I read it right.

It seems with the generic binding the actual driver should be
just the hardware specific code hopefully.

Regards,

Tony

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-03-18  1:41               ` Tony Lindgren
@ 2015-04-15  1:29                 ` Lennart Sorensen
  2015-04-15 16:51                   ` Nishanth Menon
  0 siblings, 1 reply; 21+ messages in thread
From: Lennart Sorensen @ 2015-04-15  1:29 UTC (permalink / raw)
  To: Tony Lindgren
  Cc: Linus Walleij, Nishanth Menon, linux-gpio, linux-kernel,
	devicetree, Linux-OMAP, linux-arm-kernel, Lokesh Vutla

On Tue, Mar 17, 2015 at 06:41:51PM -0700, Tony Lindgren wrote:
> Yeah agreed. I suggest discussing the binding and the generic
> parsing code for it first :)
>  
> It seems with the generic binding the actual driver should be
> just the hardware specific code hopefully.

Did this thread go anywhere in the last month?  I am certainly looking
forward to seeing what the resolution is to this, given for our use the
boot loader setup is not appealing at all.

-- 
Len Sorensen

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-04-15  1:29                 ` Lennart Sorensen
@ 2015-04-15 16:51                   ` Nishanth Menon
  2015-04-15 18:44                     ` Lennart Sorensen
  0 siblings, 1 reply; 21+ messages in thread
From: Nishanth Menon @ 2015-04-15 16:51 UTC (permalink / raw)
  To: Lennart Sorensen, Tony Lindgren
  Cc: Linus Walleij, linux-gpio, linux-kernel, devicetree, Linux-OMAP,
	linux-arm-kernel, Lokesh Vutla

On 04/14/2015 08:29 PM, Lennart Sorensen wrote:
> On Tue, Mar 17, 2015 at 06:41:51PM -0700, Tony Lindgren wrote:
>> Yeah agreed. I suggest discussing the binding and the generic
>> parsing code for it first :)
>>  
>> It seems with the generic binding the actual driver should be
>> just the hardware specific code hopefully.
> 
> Did this thread go anywhere in the last month?  I am certainly looking
> forward to seeing what the resolution is to this, given for our use the
> boot loader setup is not appealing at all.
> 
I am yet to post a new revision to this series - few other stuff got
in the way. IODelay driver in no way removes the constraint that the
SoC architecture has - most of the pins still need to be muxed in
bootloader - we cannot escape that. The reasoning for doing the mux in
bootloader is independent of the need for iodelay.

Reasoning for mux in bootloader is because the mux and pull fields are
glitchy - much more than previous generations of TI SoCs and
significantly long enough to cause issues depending on the pins being
muxed.

Reasoning for iodelay is different - it is a hardware block meant to
control the timing of signals in a particular signal path to ensure
that specification compliance is met.

Lets try not to mix the two.

-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-04-15 16:51                   ` Nishanth Menon
@ 2015-04-15 18:44                     ` Lennart Sorensen
  2015-04-15 18:53                       ` Nishanth Menon
  0 siblings, 1 reply; 21+ messages in thread
From: Lennart Sorensen @ 2015-04-15 18:44 UTC (permalink / raw)
  To: Nishanth Menon
  Cc: Tony Lindgren, Linus Walleij, linux-gpio, linux-kernel,
	devicetree, Linux-OMAP, linux-arm-kernel, Lokesh Vutla

On Wed, Apr 15, 2015 at 11:51:32AM -0500, Nishanth Menon wrote:
> I am yet to post a new revision to this series - few other stuff got
> in the way. IODelay driver in no way removes the constraint that the
> SoC architecture has - most of the pins still need to be muxed in
> bootloader - we cannot escape that. The reasoning for doing the mux in
> bootloader is independent of the need for iodelay.
> 
> Reasoning for mux in bootloader is because the mux and pull fields are
> glitchy - much more than previous generations of TI SoCs and
> significantly long enough to cause issues depending on the pins being
> muxed.

Well if we know glitching is NOT an issue on our boards, then we don't
have to do anything in the boot loader other than the basic setup for
the serial console and emmc and SD, which has always been necesary.

I consider moving the mux setup to the bootloader a terrible design and
won't go along with it.  We make sure all external devices have reset
lines being held while the pinmux is being setup, so glitching is a
non issue.

> Reasoning for iodelay is different - it is a hardware block meant to
> control the timing of signals in a particular signal path to ensure
> that specification compliance is met.
> 
> Lets try not to mix the two.

Well I was told by multiple people from TI that the reason for moving
the pinmux setup to the bootloader was because of the iodelay issue,
so you will have to get the message made clear within TI then.

-- 
Len Sorensen

^ permalink raw reply	[flat|nested] 21+ messages in thread

* Re: [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration
  2015-04-15 18:44                     ` Lennart Sorensen
@ 2015-04-15 18:53                       ` Nishanth Menon
  0 siblings, 0 replies; 21+ messages in thread
From: Nishanth Menon @ 2015-04-15 18:53 UTC (permalink / raw)
  To: Lennart Sorensen
  Cc: Tony Lindgren, Linus Walleij, linux-gpio, linux-kernel,
	devicetree, Linux-OMAP, linux-arm-kernel, Lokesh Vutla

On 04/15/2015 01:44 PM, Lennart Sorensen wrote:
> On Wed, Apr 15, 2015 at 11:51:32AM -0500, Nishanth Menon wrote:
>> I am yet to post a new revision to this series - few other stuff got
>> in the way. IODelay driver in no way removes the constraint that the
>> SoC architecture has - most of the pins still need to be muxed in
>> bootloader - we cannot escape that. The reasoning for doing the mux in
>> bootloader is independent of the need for iodelay.
>>
>> Reasoning for mux in bootloader is because the mux and pull fields are
>> glitchy - much more than previous generations of TI SoCs and
>> significantly long enough to cause issues depending on the pins being
>> muxed.
> 
> Well if we know glitching is NOT an issue on our boards, then we don't
> have to do anything in the boot loader other than the basic setup for
> the serial console and emmc and SD, which has always been necesary.
> 
> I consider moving the mux setup to the bootloader a terrible design and
> won't go along with it.  We make sure all external devices have reset
> lines being held while the pinmux is being setup, so glitching is a
> non issue.

I cannot discuss customer boards on this list - the right forum for TI
support is e2e.ti.com or in cases where FAE (Field Applications
Engineer) is involved, via appropriate support path.

Now, that said, even with personal opinions in place, I have to stick
with what the SoC constraints on hand and suggested architecture we
have discussed to ensure safe platform operation at least for the
platforms we are contributing to. again... muxing in the bootloader IS
NOT what this patch is about. If we can stick to the topic in
discussion, it is probably more effective. Any improvement suggestions
to the code is more than appreciated.

>> Reasoning for iodelay is different - it is a hardware block meant to
>> control the timing of signals in a particular signal path to ensure
>> that specification compliance is met.
>>
>> Lets try not to mix the two.
> 
> Well I was told by multiple people from TI that the reason for moving
> the pinmux setup to the bootloader was because of the iodelay issue,
> so you will have to get the message made clear within TI then.
> 
I have passed on this message.

-- 
Regards,
Nishanth Menon

^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2015-04-15 18:54 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-03-04  0:00 [PATCH 0/2] pinctrl: Introduce support for iodelay module in TI SoCs Nishanth Menon
2015-03-04  0:00 ` [PATCH 1/2] pinctrl: bindings: pinctrl: Add support for TI's IODelay configuration Nishanth Menon
2015-03-10 10:39   ` Linus Walleij
2015-03-10 15:06     ` Nishanth Menon
2015-03-10 15:33     ` Tony Lindgren
2015-03-10 17:25       ` Nishanth Menon
2015-03-10 17:31         ` Tony Lindgren
2015-03-10 18:33           ` Nishanth Menon
2015-03-10 19:20             ` Nishanth Menon
2015-03-18  1:30             ` Linus Walleij
2015-03-18  1:41               ` Tony Lindgren
2015-04-15  1:29                 ` Lennart Sorensen
2015-04-15 16:51                   ` Nishanth Menon
2015-04-15 18:44                     ` Lennart Sorensen
2015-04-15 18:53                       ` Nishanth Menon
2015-03-04  0:00 ` [PATCH 2/2] pinctrl: Introduce TI IOdelay configuration driver Nishanth Menon
2015-03-04 22:58   ` Paul Bolle
2015-03-04 22:58     ` Tony Lindgren
2015-03-05  2:22       ` Nishanth Menon
2015-03-10 11:03   ` Linus Walleij
2015-03-11 12:39     ` Nishanth Menon

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