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From: Daniel Lezcano <daniel.lezcano@linaro.org>
To: tglx@linutronix.de
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, Barry.Song@csr.com,
	baruch@tkos.co.il, linux@rempel-privat.de,
	rob.herring@linaro.org, thierry.reding@gmail.com
Subject: [PATCH 6/9] clocksource: Driver for Conexant Digicolor SoC timer
Date: Thu, 29 Jan 2015 14:08:16 +0100	[thread overview]
Message-ID: <1422536899-16609-6-git-send-email-daniel.lezcano@linaro.org> (raw)
In-Reply-To: <1422536899-16609-1-git-send-email-daniel.lezcano@linaro.org>

From: Baruch Siach <baruch@tkos.co.il>

Add clocksource driver to the Conexant CX92755 SoC, part of the Digicolor SoCs
series. Hardware provides 8 timers, A to H. Timer A is dedicated to a future
watchdog driver so we don't use it here. Use timer B for sched_clock, and timer
C for clock_event.

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/clocksource/Kconfig           |   3 +
 drivers/clocksource/Makefile          |   1 +
 drivers/clocksource/timer-digicolor.c | 199 ++++++++++++++++++++++++++++++++++
 3 files changed, 203 insertions(+)
 create mode 100644 drivers/clocksource/timer-digicolor.c

diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index a89120b..72a3827 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -18,6 +18,9 @@ config CLKBLD_I8253
 config CLKSRC_MMIO
 	bool
 
+config DIGICOLOR_TIMER
+	bool
+
 config DW_APB_TIMER
 	bool
 
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 21c11e2..0f8003d 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_SH_TIMER_TMU)	+= sh_tmu.o
 obj-$(CONFIG_EM_TIMER_STI)	+= em_sti.o
 obj-$(CONFIG_CLKBLD_I8253)	+= i8253.o
 obj-$(CONFIG_CLKSRC_MMIO)	+= mmio.o
+obj-$(CONFIG_DIGICOLOR_TIMER)	+= timer-digicolor.o
 obj-$(CONFIG_DW_APB_TIMER)	+= dw_apb_timer.o
 obj-$(CONFIG_DW_APB_TIMER_OF)	+= dw_apb_timer_of.o
 obj-$(CONFIG_ROCKCHIP_TIMER)      += rockchip_timer.o
diff --git a/drivers/clocksource/timer-digicolor.c b/drivers/clocksource/timer-digicolor.c
new file mode 100644
index 0000000..7f8388c
--- /dev/null
+++ b/drivers/clocksource/timer-digicolor.c
@@ -0,0 +1,199 @@
+/*
+ * Conexant Digicolor timer driver
+ *
+ * Author: Baruch Siach <baruch@tkos.co.il>
+ *
+ * Copyright (C) 2014 Paradox Innovation Ltd.
+ *
+ * Based on:
+ *	Allwinner SoCs hstimer driver
+ *
+ * Copyright (C) 2013 Maxime Ripard
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * 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.
+ */
+
+/*
+ * Conexant Digicolor SoCs have 8 configurable timers, named from "Timer A" to
+ * "Timer H". Timer A is the only one with watchdog support, so it is dedicated
+ * to the watchdog driver. This driver uses Timer B for sched_clock(), and
+ * Timer C for clockevents.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqreturn.h>
+#include <linux/sched_clock.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+enum {
+	TIMER_A,
+	TIMER_B,
+	TIMER_C,
+	TIMER_D,
+	TIMER_E,
+	TIMER_F,
+	TIMER_G,
+	TIMER_H,
+};
+
+#define CONTROL(t)	((t)*8)
+#define COUNT(t)	((t)*8 + 4)
+
+#define CONTROL_DISABLE		0
+#define CONTROL_ENABLE		BIT(0)
+#define CONTROL_MODE(m)		((m) << 4)
+#define CONTROL_MODE_ONESHOT	CONTROL_MODE(1)
+#define CONTROL_MODE_PERIODIC	CONTROL_MODE(2)
+
+struct digicolor_timer {
+	struct clock_event_device ce;
+	void __iomem *base;
+	u32 ticks_per_jiffy;
+	int timer_id; /* one of TIMER_* */
+};
+
+struct digicolor_timer *dc_timer(struct clock_event_device *ce)
+{
+	return container_of(ce, struct digicolor_timer, ce);
+}
+
+static inline void dc_timer_disable(struct clock_event_device *ce)
+{
+	struct digicolor_timer *dt = dc_timer(ce);
+	writeb(CONTROL_DISABLE, dt->base + CONTROL(dt->timer_id));
+}
+
+static inline void dc_timer_enable(struct clock_event_device *ce, u32 mode)
+{
+	struct digicolor_timer *dt = dc_timer(ce);
+	writeb(CONTROL_ENABLE | mode, dt->base + CONTROL(dt->timer_id));
+}
+
+static inline void dc_timer_set_count(struct clock_event_device *ce,
+				      unsigned long count)
+{
+	struct digicolor_timer *dt = dc_timer(ce);
+	writel(count, dt->base + COUNT(dt->timer_id));
+}
+
+static void digicolor_clkevt_mode(enum clock_event_mode mode,
+				  struct clock_event_device *ce)
+{
+	struct digicolor_timer *dt = dc_timer(ce);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		dc_timer_disable(ce);
+		dc_timer_set_count(ce, dt->ticks_per_jiffy);
+		dc_timer_enable(ce, CONTROL_MODE_PERIODIC);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		dc_timer_disable(ce);
+		dc_timer_enable(ce, CONTROL_MODE_ONESHOT);
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	default:
+		dc_timer_disable(ce);
+		break;
+	}
+}
+
+static int digicolor_clkevt_next_event(unsigned long evt,
+				       struct clock_event_device *ce)
+{
+	dc_timer_disable(ce);
+	dc_timer_set_count(ce, evt);
+	dc_timer_enable(ce, CONTROL_MODE_ONESHOT);
+
+	return 0;
+}
+
+static struct digicolor_timer dc_timer_dev = {
+	.ce = {
+		.name = "digicolor_tick",
+		.rating = 340,
+		.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+		.set_mode = digicolor_clkevt_mode,
+		.set_next_event = digicolor_clkevt_next_event,
+	},
+	.timer_id = TIMER_C,
+};
+
+static irqreturn_t digicolor_timer_interrupt(int irq, void *dev_id)
+{
+	struct clock_event_device *evt = dev_id;
+
+	evt->event_handler(evt);
+
+	return IRQ_HANDLED;
+}
+
+static u64 digicolor_timer_sched_read(void)
+{
+	return ~readl(dc_timer_dev.base + COUNT(TIMER_B));
+}
+
+static void __init digicolor_timer_init(struct device_node *node)
+{
+	unsigned long rate;
+	struct clk *clk;
+	int ret, irq;
+
+	/*
+	 * timer registers are shared with the watchdog timer;
+	 * don't map exclusively
+	 */
+	dc_timer_dev.base = of_iomap(node, 0);
+	if (!dc_timer_dev.base) {
+		pr_err("Can't map registers");
+		return;
+	}
+
+	irq = irq_of_parse_and_map(node, dc_timer_dev.timer_id);
+	if (irq <= 0) {
+		pr_err("Can't parse IRQ");
+		return;
+	}
+
+	clk = of_clk_get(node, 0);
+	if (IS_ERR(clk)) {
+		pr_err("Can't get timer clock");
+		return;
+	}
+	clk_prepare_enable(clk);
+	rate = clk_get_rate(clk);
+	dc_timer_dev.ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
+
+	writeb(CONTROL_DISABLE, dc_timer_dev.base + CONTROL(TIMER_B));
+	writel(UINT_MAX, dc_timer_dev.base + COUNT(TIMER_B));
+	writeb(CONTROL_ENABLE, dc_timer_dev.base + CONTROL(TIMER_B));
+
+	sched_clock_register(digicolor_timer_sched_read, 32, rate);
+	clocksource_mmio_init(dc_timer_dev.base + COUNT(TIMER_B), node->name,
+			      rate, 340, 32, clocksource_mmio_readl_down);
+
+	ret = request_irq(irq, digicolor_timer_interrupt,
+			  IRQF_TIMER | IRQF_IRQPOLL, "digicolor_timerC",
+			  &dc_timer_dev.ce);
+	if (ret)
+		pr_warn("request of timer irq %d failed (%d)\n", irq, ret);
+
+	dc_timer_dev.ce.cpumask = cpu_possible_mask;
+	dc_timer_dev.ce.irq = irq;
+
+	clockevents_config_and_register(&dc_timer_dev.ce, rate, 0, 0xffffffff);
+}
+CLOCKSOURCE_OF_DECLARE(conexant_digicolor, "cnxt,cx92755-timer",
+		       digicolor_timer_init);
-- 
1.9.1


  parent reply	other threads:[~2015-01-29 13:08 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-29 13:06 [GIT PULL]: clockevents: new material for 3.20 Daniel Lezcano
2015-01-29 13:08 ` [PATCH 1/9] clocksource: sirf: Remove unused variable Daniel Lezcano
2015-01-29 13:08   ` [PATCH 2/9] clocksource: marco: Rename marco to atlas7 Daniel Lezcano
2015-01-29 13:08   ` [PATCH 3/9] ARM: clocksource: Add asm9260_timer driver Daniel Lezcano
2015-01-29 13:08   ` [PATCH 4/9] clockevents: rockchip: Add rockchip timer for rk3288 Daniel Lezcano
2015-01-29 13:08   ` [PATCH 5/9] clocksource: devicetree: Document Conexant Digicolor timer binding Daniel Lezcano
2015-01-29 13:08   ` Daniel Lezcano [this message]
2015-01-29 13:37     ` [PATCH 6/9] clocksource: Driver for Conexant Digicolor SoC timer Paul Bolle
2015-01-29 13:52       ` Daniel Lezcano
2015-01-29 14:26       ` Baruch Siach
2015-01-29 14:33         ` Paul Bolle
2015-01-29 13:08   ` [PATCH 7/9] dt/bindings: Add binding for Versatile system registers Daniel Lezcano
2015-01-29 13:08   ` [PATCH 8/9] clocksource: versatile: Adapt for Versatile AB and PB boards Daniel Lezcano
2015-01-29 13:08   ` [PATCH 9/9] dts: versatile: Add sysregs node Daniel Lezcano
2015-02-02 21:38 ` [GIT PULL]: clockevents: new material for 3.20 Daniel Lezcano

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