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* [PATCH v7 00/13] Convert period and duty cycle to u64
@ 2020-03-09 19:35 Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 01/13] clk: pwm: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
                   ` (12 more replies)
  0 siblings, 13 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh

Changes from v6:
  - Split out the driver changes out into separate patches, one patch per file
    for ease of reviewing.

Changes from v5:
  - Dropped the conversion of struct pwm_capture to u64 for reasons mentioned
    in https://www.spinics.net/lists/linux-pwm/msg11541.html

Changes from v4:
  - Split the patch into two: one for changes to the drivers, and the actual
    switch to u64 for ease of reverting should the need arise.
  - Re-examined the patch and made the following corrections:
      * intel_panel.c:
	DIV64_U64_ROUND_UP -> DIV_ROUND_UP_ULL (as only the numerator would be
	64-bit in this case).
      * pwm-sti.c:
	do_div -> div_u64 (do_div is optimized only for x86 architectures, and
	div_u64's comment block suggests to use this as much as possible).

Changes from v3:
  - Rebased to current tip of for-next.

Changes from v2:
  - Fixed %u -> %llu in a dev_dbg in pwm-stm32-lp.c, thanks to kbuild test robot
  - Added a couple of fixes to pwm-imx-tpm.c and pwm-sifive.c

Changes from v1:
  - Fixed compilation errors seen when compiling for different archs.

Reworked the change pushed upstream earlier [1] so as to not add an extension
to an obsolete API. With this change, pwm_ops->apply() can be used to set
pwm_state parameters as usual.

[1] https://lore.kernel.org/lkml/20190916140048.GB7488@ulmo/

Guru Das Srinagesh (13):
  clk: pwm: Use 64-bit division macros for period and duty cycle
  drm/i915: Use 64-bit division macros for period and duty cycle
  hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  ir-rx51: Use 64-bit division macros for period and duty cycle
  pwm: clps711x: Use 64-bit division macros for period and duty cycle
  pwm: pwm-imx-tpm: Use 64-bit division macros for period and duty cycle
  pwm: imx27: Use 64-bit division macros for period and duty cycle
  pwm: sifive: Use 64-bit division macros for period and duty cycle
  pwm: sti: Use 64-bit division macros for period and duty cycle
  pwm: stm32-lp: Use %llu format specifier for period
  pwm: sun4i: Use 64-bit division macros for period and duty cycle
  backlight: pwm_bl: Use 64-bit division macros for period and duty
    cycle
  pwm: core: Convert period and duty cycle to u64

 drivers/clk/clk-pwm.c                      |  2 +-
 drivers/gpu/drm/i915/display/intel_panel.c |  2 +-
 drivers/hwmon/pwm-fan.c                    |  2 +-
 drivers/media/rc/ir-rx51.c                 |  3 ++-
 drivers/pwm/core.c                         |  4 ++--
 drivers/pwm/pwm-clps711x.c                 |  2 +-
 drivers/pwm/pwm-imx-tpm.c                  |  2 +-
 drivers/pwm/pwm-imx27.c                    |  5 ++---
 drivers/pwm/pwm-sifive.c                   |  2 +-
 drivers/pwm/pwm-sti.c                      |  5 +++--
 drivers/pwm/pwm-stm32-lp.c                 |  2 +-
 drivers/pwm/pwm-sun4i.c                    |  2 +-
 drivers/pwm/sysfs.c                        |  8 ++++----
 drivers/video/backlight/pwm_bl.c           |  3 ++-
 include/linux/pwm.h                        | 12 ++++++------
 15 files changed, 29 insertions(+), 27 deletions(-)

-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 01/13] clk: pwm: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 02/13] drm/i915: " Guru Das Srinagesh
                   ` (11 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Michael Turquette,
	Stephen Boyd, linux-clk

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Stephen Boyd <sboyd@kernel.org>
Cc: linux-clk@vger.kernel.org

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/clk/clk-pwm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/clk/clk-pwm.c b/drivers/clk/clk-pwm.c
index 87fe0b0e..7b1f7a0 100644
--- a/drivers/clk/clk-pwm.c
+++ b/drivers/clk/clk-pwm.c
@@ -89,7 +89,7 @@ static int clk_pwm_probe(struct platform_device *pdev)
 	}
 
 	if (of_property_read_u32(node, "clock-frequency", &clk_pwm->fixed_rate))
-		clk_pwm->fixed_rate = NSEC_PER_SEC / pargs.period;
+		clk_pwm->fixed_rate = div64_u64(NSEC_PER_SEC, pargs.period);
 
 	if (pargs.period != NSEC_PER_SEC / clk_pwm->fixed_rate &&
 	    pargs.period != DIV_ROUND_UP(NSEC_PER_SEC, clk_pwm->fixed_rate)) {
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 02/13] drm/i915: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 01/13] clk: pwm: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 03/13] hwmon: pwm-fan: " Guru Das Srinagesh
                   ` (10 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Jani Nikula, Joonas Lahtinen,
	David Airlie, Daniel Vetter, Chris Wilson,
	Ville Syrjälä,
	intel-gfx, dri-devel

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/gpu/drm/i915/display/intel_panel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index bc14e9c..843cac1 100644
--- a/drivers/gpu/drm/i915/display/intel_panel.c
+++ b/drivers/gpu/drm/i915/display/intel_panel.c
@@ -1868,7 +1868,7 @@ static int pwm_setup_backlight(struct intel_connector *connector,
 
 	panel->backlight.min = 0; /* 0% */
 	panel->backlight.max = 100; /* 100% */
-	panel->backlight.level = DIV_ROUND_UP(
+	panel->backlight.level = DIV_ROUND_UP_ULL(
 				 pwm_get_duty_cycle(panel->backlight.pwm) * 100,
 				 CRC_PMIC_PWM_PERIOD_NS);
 	panel->backlight.enabled = panel->backlight.level != 0;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 03/13] hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 01/13] clk: pwm: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 02/13] drm/i915: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 21:48   ` Guenter Roeck
  2020-03-09 19:35 ` [PATCH v7 04/13] ir-rx51: " Guru Das Srinagesh
                   ` (9 subsequent siblings)
  12 siblings, 1 reply; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Kamil Debski,
	Bartlomiej Zolnierkiewicz, Jean Delvare, Guenter Roeck,
	Liam Girdwood, Mark Brown, linux-hwmon

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Kamil Debski <kamil@wypas.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: linux-hwmon@vger.kernel.org

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/hwmon/pwm-fan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 42ffd2e..283423a 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -437,7 +437,7 @@ static int pwm_fan_resume(struct device *dev)
 		return 0;
 
 	pwm_get_args(ctx->pwm, &pargs);
-	duty = DIV_ROUND_UP(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
+	duty = DIV_ROUND_UP_ULL(ctx->pwm_value * (pargs.period - 1), MAX_PWM);
 	ret = pwm_config(ctx->pwm, duty, pargs.period);
 	if (ret)
 		return ret;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 04/13] ir-rx51: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (2 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 03/13] hwmon: pwm-fan: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 05/13] pwm: clps711x: " Guru Das Srinagesh
                   ` (8 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Mauro Carvalho Chehab,
	Richard Fontana, Thomas Gleixner, Kate Stewart, Allison Randal,
	linux-media

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Richard Fontana <rfontana@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Allison Randal <allison@lohutok.net>
Cc: linux-media@vger.kernel.org

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/media/rc/ir-rx51.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/rc/ir-rx51.c b/drivers/media/rc/ir-rx51.c
index 8574eda..9a5dfd7 100644
--- a/drivers/media/rc/ir-rx51.c
+++ b/drivers/media/rc/ir-rx51.c
@@ -241,7 +241,8 @@ static int ir_rx51_probe(struct platform_device *dev)
 	}
 
 	/* Use default, in case userspace does not set the carrier */
-	ir_rx51.freq = DIV_ROUND_CLOSEST(pwm_get_period(pwm), NSEC_PER_SEC);
+	ir_rx51.freq = DIV_ROUND_CLOSEST_ULL(pwm_get_period(pwm),
+			NSEC_PER_SEC);
 	pwm_put(pwm);
 
 	hrtimer_init(&ir_rx51.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 05/13] pwm: clps711x: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (3 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 04/13] ir-rx51: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 06/13] pwm: pwm-imx-tpm: " Guru Das Srinagesh
                   ` (7 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Alexander Shiyan

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Alexander Shiyan <shc_work@mail.ru>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-clps711x.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-clps711x.c b/drivers/pwm/pwm-clps711x.c
index 924d39a..ba9500a 100644
--- a/drivers/pwm/pwm-clps711x.c
+++ b/drivers/pwm/pwm-clps711x.c
@@ -43,7 +43,7 @@ static void clps711x_pwm_update_val(struct clps711x_chip *priv, u32 n, u32 v)
 static unsigned int clps711x_get_duty(struct pwm_device *pwm, unsigned int v)
 {
 	/* Duty cycle 0..15 max */
-	return DIV_ROUND_CLOSEST(v * 0xf, pwm->args.period);
+	return DIV64_U64_ROUND_CLOSEST(v * 0xf, pwm->args.period);
 }
 
 static int clps711x_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 06/13] pwm: pwm-imx-tpm: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (4 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 05/13] pwm: clps711x: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 07/13] pwm: imx27: " Guru Das Srinagesh
                   ` (6 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Shawn Guo, Sascha Hauer,
	Pengutronix Kernel Team, Fabio Estevam, NXP Linux Team

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-imx-tpm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-imx-tpm.c b/drivers/pwm/pwm-imx-tpm.c
index 9145f61..53bf364 100644
--- a/drivers/pwm/pwm-imx-tpm.c
+++ b/drivers/pwm/pwm-imx-tpm.c
@@ -126,7 +126,7 @@ static int pwm_imx_tpm_round_state(struct pwm_chip *chip,
 		real_state->duty_cycle = state->duty_cycle;
 
 	tmp = (u64)p->mod * real_state->duty_cycle;
-	p->val = DIV_ROUND_CLOSEST_ULL(tmp, real_state->period);
+	p->val = DIV64_U64_ROUND_CLOSEST(tmp, real_state->period);
 
 	real_state->polarity = state->polarity;
 	real_state->enabled = state->enabled;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 07/13] pwm: imx27: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (5 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 06/13] pwm: pwm-imx-tpm: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 08/13] pwm: sifive: " Guru Das Srinagesh
                   ` (5 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Shawn Guo, Sascha Hauer,
	Pengutronix Kernel Team, Fabio Estevam, NXP Linux Team

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Shawn Guo <shawnguo@kernel.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Pengutronix Kernel Team <kernel@pengutronix.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: NXP Linux Team <linux-imx@nxp.com>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-imx27.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/pwm/pwm-imx27.c b/drivers/pwm/pwm-imx27.c
index 35a7ac42..b7d38d0 100644
--- a/drivers/pwm/pwm-imx27.c
+++ b/drivers/pwm/pwm-imx27.c
@@ -208,7 +208,7 @@ static void pwm_imx27_wait_fifo_slot(struct pwm_chip *chip,
 	sr = readl(imx->mmio_base + MX3_PWMSR);
 	fifoav = FIELD_GET(MX3_PWMSR_FIFOAV, sr);
 	if (fifoav == MX3_PWMSR_FIFOAV_4WORDS) {
-		period_ms = DIV_ROUND_UP(pwm_get_period(pwm),
+		period_ms = DIV_ROUND_UP_ULL(pwm_get_period(pwm),
 					 NSEC_PER_MSEC);
 		msleep(period_ms);
 
@@ -240,8 +240,7 @@ static int pwm_imx27_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	period_cycles /= prescale;
 	c = (unsigned long long)period_cycles * state->duty_cycle;
-	do_div(c, state->period);
-	duty_cycles = c;
+	duty_cycles = div64_u64(c, state->period);
 
 	/*
 	 * according to imx pwm RM, the real period value should be PERIOD
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 08/13] pwm: sifive: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (6 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 07/13] pwm: imx27: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-26 16:37   ` Palmer Dabbelt
  2020-03-09 19:35 ` [PATCH v7 09/13] pwm: sti: " Guru Das Srinagesh
                   ` (4 subsequent siblings)
  12 siblings, 1 reply; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Palmer Dabbelt, Paul Walmsley,
	linux-riscv, Yash Shah, Atish Patra

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-riscv@lists.infradead.org
Cc: Yash Shah <yash.shah@sifive.com>
Cc: Atish Patra <atish.patra@wdc.com>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-sifive.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
index cc63f9b..62de0bb 100644
--- a/drivers/pwm/pwm-sifive.c
+++ b/drivers/pwm/pwm-sifive.c
@@ -181,7 +181,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * consecutively
 	 */
 	num = (u64)duty_cycle * (1U << PWM_SIFIVE_CMPWIDTH);
-	frac = DIV_ROUND_CLOSEST_ULL(num, state->period);
+	frac = DIV64_U64_ROUND_CLOSEST(num, state->period);
 	/* The hardware cannot generate a 100% duty cycle */
 	frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1);
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 09/13] pwm: sti: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (7 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 08/13] pwm: sifive: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 10/13] pwm: stm32-lp: Use %llu format specifier for period Guru Das Srinagesh
                   ` (3 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Lee Jones

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Lee Jones <lee.jones@linaro.org>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-sti.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/pwm/pwm-sti.c b/drivers/pwm/pwm-sti.c
index 1508616..5a7f337 100644
--- a/drivers/pwm/pwm-sti.c
+++ b/drivers/pwm/pwm-sti.c
@@ -371,10 +371,11 @@ static int sti_pwm_capture(struct pwm_chip *chip, struct pwm_device *pwm,
 		effective_ticks = clk_get_rate(pc->cpt_clk);
 
 		result->period = (high + low) * NSEC_PER_SEC;
-		result->period /= effective_ticks;
+		result->period = div_u64(result->period, effective_ticks);
 
 		result->duty_cycle = high * NSEC_PER_SEC;
-		result->duty_cycle /= effective_ticks;
+		result->duty_cycle = div_u64(result->duty_cycle,
+				effective_ticks);
 
 		break;
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 10/13] pwm: stm32-lp: Use %llu format specifier for period
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (8 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 09/13] pwm: sti: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 11/13] pwm: sun4i: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
                   ` (2 subsequent siblings)
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Fabrice Gasnier,
	Maxime Coquelin, Alexandre Torgue

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare this driver to handle the switch to u64 period
and duty_cycle by updating the format specifier in this dev_dbg message.
The actual switch to u64 period and duty_cycle follows as a separate
patch.

Cc: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-stm32-lp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c
index 67fca62..134c146 100644
--- a/drivers/pwm/pwm-stm32-lp.c
+++ b/drivers/pwm/pwm-stm32-lp.c
@@ -61,7 +61,7 @@ static int stm32_pwm_lp_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	do_div(div, NSEC_PER_SEC);
 	if (!div) {
 		/* Clock is too slow to achieve requested period. */
-		dev_dbg(priv->chip.dev, "Can't reach %u ns\n",	state->period);
+		dev_dbg(priv->chip.dev, "Can't reach %llu ns\n", state->period);
 		return -EINVAL;
 	}
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 11/13] pwm: sun4i: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (9 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 10/13] pwm: stm32-lp: Use %llu format specifier for period Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 12/13] backlight: pwm_bl: " Guru Das Srinagesh
  2020-03-09 19:35 ` [PATCH v7 13/13] pwm: core: Convert period and duty cycle to u64 Guru Das Srinagesh
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Maxime Ripard, Chen-Yu Tsai,
	Philipp Zabel

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Maxime Ripard <mripard@kernel.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Philipp Zabel <p.zabel@pengutronix.de>

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/pwm-sun4i.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pwm/pwm-sun4i.c b/drivers/pwm/pwm-sun4i.c
index 3e3efa6..772fdf4 100644
--- a/drivers/pwm/pwm-sun4i.c
+++ b/drivers/pwm/pwm-sun4i.c
@@ -286,7 +286,7 @@ static int sun4i_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	val = (duty & PWM_DTY_MASK) | PWM_PRD(period);
 	sun4i_pwm_writel(sun4i_pwm, val, PWM_CH_PRD(pwm->hwpwm));
 	sun4i_pwm->next_period[pwm->hwpwm] = jiffies +
-		usecs_to_jiffies(cstate.period / 1000 + 1);
+		usecs_to_jiffies(div_u64(cstate.period, 1000) + 1);
 	sun4i_pwm->needs_delay[pwm->hwpwm] = true;
 
 	if (state->polarity != PWM_POLARITY_NORMAL)
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 12/13] backlight: pwm_bl: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (10 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 11/13] pwm: sun4i: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  2020-03-10 14:34   ` Daniel Thompson
  2020-03-09 19:35 ` [PATCH v7 13/13] pwm: core: Convert period and duty cycle to u64 Guru Das Srinagesh
  12 siblings, 1 reply; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh, Lee Jones, Daniel Thompson,
	Jingoo Han, Bartlomiej Zolnierkiewicz, dri-devel, linux-fbdev

Because period and duty cycle are defined in the PWM framework structs
as ints with units of nanoseconds, the maximum time duration that can be
set is limited to ~2.147 seconds. Redefining them as u64 values will
enable larger time durations to be set.

As a first step, prepare drivers to handle the switch to u64 period and
duty_cycle by replacing division operations involving pwm period and duty cycle
with their 64-bit equivalents as appropriate. The actual switch to u64 period
and duty_cycle follows as a separate patch.

Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
macros:
- DIV_ROUND_UP_ULL
- DIV_ROUND_CLOSEST_ULL
- div_u64

Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
DIV64_* macros:
- DIV64_U64_ROUND_CLOSEST
- div64_u64

Cc: Lee Jones <lee.jones@linaro.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: linux-pwm@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/video/backlight/pwm_bl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index efb4efc..3e5dbcf 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 		pb->scale = data->max_brightness;
 	}
 
-	pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
+	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
+				pb->scale));
 
 	props.type = BACKLIGHT_RAW;
 	props.max_brightness = data->max_brightness;
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* [PATCH v7 13/13] pwm: core: Convert period and duty cycle to u64
  2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
                   ` (11 preceding siblings ...)
  2020-03-09 19:35 ` [PATCH v7 12/13] backlight: pwm_bl: " Guru Das Srinagesh
@ 2020-03-09 19:35 ` Guru Das Srinagesh
  12 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-09 19:35 UTC (permalink / raw)
  To: linux-pwm
  Cc: Thierry Reding, Uwe Kleine-König, Subbaraman Narayanamurthy,
	linux-kernel, Guru Das Srinagesh

Because period and duty cycle are defined as ints with units of
nanoseconds, the maximum time duration that can be set is limited to
~2.147 seconds. Change their definitions to u64 in the structs of the
PWM framework so that higher durations may be set.

Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
---
 drivers/pwm/core.c  |  4 ++--
 drivers/pwm/sysfs.c |  8 ++++----
 include/linux/pwm.h | 12 ++++++------
 3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 5a7f659..81aa3c2 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -1163,8 +1163,8 @@ static void pwm_dbg_show(struct pwm_chip *chip, struct seq_file *s)
 		if (state.enabled)
 			seq_puts(s, " enabled");
 
-		seq_printf(s, " period: %u ns", state.period);
-		seq_printf(s, " duty: %u ns", state.duty_cycle);
+		seq_printf(s, " period: %llu ns", state.period);
+		seq_printf(s, " duty: %llu ns", state.duty_cycle);
 		seq_printf(s, " polarity: %s",
 			   state.polarity ? "inverse" : "normal");
 
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 2389b86..449dbc0 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -42,7 +42,7 @@ static ssize_t period_show(struct device *child,
 
 	pwm_get_state(pwm, &state);
 
-	return sprintf(buf, "%u\n", state.period);
+	return sprintf(buf, "%llu\n", state.period);
 }
 
 static ssize_t period_store(struct device *child,
@@ -52,10 +52,10 @@ static ssize_t period_store(struct device *child,
 	struct pwm_export *export = child_to_pwm_export(child);
 	struct pwm_device *pwm = export->pwm;
 	struct pwm_state state;
-	unsigned int val;
+	u64 val;
 	int ret;
 
-	ret = kstrtouint(buf, 0, &val);
+	ret = kstrtou64(buf, 0, &val);
 	if (ret)
 		return ret;
 
@@ -77,7 +77,7 @@ static ssize_t duty_cycle_show(struct device *child,
 
 	pwm_get_state(pwm, &state);
 
-	return sprintf(buf, "%u\n", state.duty_cycle);
+	return sprintf(buf, "%llu\n", state.duty_cycle);
 }
 
 static ssize_t duty_cycle_store(struct device *child,
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index 0ef808d..b53f13d 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -39,7 +39,7 @@ enum pwm_polarity {
  * current PWM hardware state.
  */
 struct pwm_args {
-	unsigned int period;
+	u64 period;
 	enum pwm_polarity polarity;
 };
 
@@ -56,8 +56,8 @@ enum {
  * @enabled: PWM enabled status
  */
 struct pwm_state {
-	unsigned int period;
-	unsigned int duty_cycle;
+	u64 period;
+	u64 duty_cycle;
 	enum pwm_polarity polarity;
 	bool enabled;
 };
@@ -105,13 +105,13 @@ static inline bool pwm_is_enabled(const struct pwm_device *pwm)
 	return state.enabled;
 }
 
-static inline void pwm_set_period(struct pwm_device *pwm, unsigned int period)
+static inline void pwm_set_period(struct pwm_device *pwm, u64 period)
 {
 	if (pwm)
 		pwm->state.period = period;
 }
 
-static inline unsigned int pwm_get_period(const struct pwm_device *pwm)
+static inline u64 pwm_get_period(const struct pwm_device *pwm)
 {
 	struct pwm_state state;
 
@@ -126,7 +126,7 @@ static inline void pwm_set_duty_cycle(struct pwm_device *pwm, unsigned int duty)
 		pwm->state.duty_cycle = duty;
 }
 
-static inline unsigned int pwm_get_duty_cycle(const struct pwm_device *pwm)
+static inline u64 pwm_get_duty_cycle(const struct pwm_device *pwm)
 {
 	struct pwm_state state;
 
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project


^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 03/13] hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 ` [PATCH v7 03/13] hwmon: pwm-fan: " Guru Das Srinagesh
@ 2020-03-09 21:48   ` Guenter Roeck
  2020-03-10 12:08     ` Uwe Kleine-König
  0 siblings, 1 reply; 22+ messages in thread
From: Guenter Roeck @ 2020-03-09 21:48 UTC (permalink / raw)
  To: Guru Das Srinagesh
  Cc: linux-pwm, Thierry Reding, Uwe Kleine-König,
	Subbaraman Narayanamurthy, linux-kernel, Kamil Debski,
	Bartlomiej Zolnierkiewicz, Jean Delvare, Liam Girdwood,
	Mark Brown, linux-hwmon

On Mon, Mar 09, 2020 at 12:35:06PM -0700, Guru Das Srinagesh wrote:
> Because period and duty cycle are defined in the PWM framework structs
> as ints with units of nanoseconds, the maximum time duration that can be
> set is limited to ~2.147 seconds. Redefining them as u64 values will
> enable larger time durations to be set.
> 
> As a first step, prepare drivers to handle the switch to u64 period and
> duty_cycle by replacing division operations involving pwm period and duty cycle
> with their 64-bit equivalents as appropriate. The actual switch to u64 period
> and duty_cycle follows as a separate patch.
> 
> Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
> macros:
> - DIV_ROUND_UP_ULL
> - DIV_ROUND_CLOSEST_ULL
> - div_u64
> 
> Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
> DIV64_* macros:
> - DIV64_U64_ROUND_CLOSEST
> - div64_u64
> 
There is no explanation why this is necessary. What is the use case ?
It is hard to imagine a real-world use case with a duty cycle of more
than 2 seconds.

Guenter

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 03/13] hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  2020-03-09 21:48   ` Guenter Roeck
@ 2020-03-10 12:08     ` Uwe Kleine-König
  2020-03-10 15:05       ` Guenter Roeck
  0 siblings, 1 reply; 22+ messages in thread
From: Uwe Kleine-König @ 2020-03-10 12:08 UTC (permalink / raw)
  To: Guenter Roeck
  Cc: Guru Das Srinagesh, linux-pwm, Thierry Reding,
	Subbaraman Narayanamurthy, linux-kernel, Kamil Debski,
	Bartlomiej Zolnierkiewicz, Jean Delvare, Liam Girdwood,
	Mark Brown, linux-hwmon

Hello Guenter,

On Mon, Mar 09, 2020 at 02:48:22PM -0700, Guenter Roeck wrote:
> On Mon, Mar 09, 2020 at 12:35:06PM -0700, Guru Das Srinagesh wrote:
> > Because period and duty cycle are defined in the PWM framework structs
> > as ints with units of nanoseconds, the maximum time duration that can be
> > set is limited to ~2.147 seconds. Redefining them as u64 values will
> > enable larger time durations to be set.
> > 
> > As a first step, prepare drivers to handle the switch to u64 period and
> > duty_cycle by replacing division operations involving pwm period and duty cycle
> > with their 64-bit equivalents as appropriate. The actual switch to u64 period
> > and duty_cycle follows as a separate patch.
> > 
> > Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
> > macros:
> > - DIV_ROUND_UP_ULL
> > - DIV_ROUND_CLOSEST_ULL
> > - div_u64
> > 
> > Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
> > DIV64_* macros:
> > - DIV64_U64_ROUND_CLOSEST
> > - div64_u64
>
> There is no explanation why this is necessary. What is the use case ?
> It is hard to imagine a real-world use case with a duty cycle of more
> than 2 seconds.

When my Laptop is in suspend there is an LED that blinks with a period
of approximately 5 seconds. (To be fair, the brightness is more a sinus
than a rectangle, but still.)

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | https://www.pengutronix.de/ |

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 12/13] backlight: pwm_bl: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 ` [PATCH v7 12/13] backlight: pwm_bl: " Guru Das Srinagesh
@ 2020-03-10 14:34   ` Daniel Thompson
  2020-03-10 18:12     ` Guru Das Srinagesh
  0 siblings, 1 reply; 22+ messages in thread
From: Daniel Thompson @ 2020-03-10 14:34 UTC (permalink / raw)
  To: Guru Das Srinagesh
  Cc: linux-pwm, Thierry Reding, Uwe Kleine-König,
	Subbaraman Narayanamurthy, linux-kernel, Lee Jones, Jingoo Han,
	Bartlomiej Zolnierkiewicz, dri-devel, linux-fbdev

On Mon, Mar 09, 2020 at 12:35:15PM -0700, Guru Das Srinagesh wrote:
> Because period and duty cycle are defined in the PWM framework structs
> as ints with units of nanoseconds, the maximum time duration that can be
> set is limited to ~2.147 seconds. Redefining them as u64 values will
> enable larger time durations to be set.
> 
> As a first step, prepare drivers to handle the switch to u64 period and
> duty_cycle by replacing division operations involving pwm period and duty cycle
> with their 64-bit equivalents as appropriate. The actual switch to u64 period
> and duty_cycle follows as a separate patch.
> 
> Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
> macros:
> - DIV_ROUND_UP_ULL
> - DIV_ROUND_CLOSEST_ULL
> - div_u64
> 
> Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
> DIV64_* macros:
> - DIV64_U64_ROUND_CLOSEST
> - div64_u64

This patch looks like it is a tiny change to get the pwm_backlight to
perform 64-bit division. Most of the above text is completely irrelevant
to the change contained in this patch. No need to justify the change in
the PWM structures here since that can go in the patch that changes
those structures.  Just describe what this patch does, perhaps something
like the following:

    The PWM API will shortly switch the state.period and
    state.duty_cycle fields to 64-bit values. Make pwm_bl
    ready for this transition by adopting 64-bit division
    macros.

Also please copy the backlight maintainers into the covering letter. It
is useful to place patches like this into context.


Daniel.

 
> Cc: Lee Jones <lee.jones@linaro.org>
> Cc: Daniel Thompson <daniel.thompson@linaro.org>
> Cc: Jingoo Han <jingoohan1@gmail.com>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: linux-pwm@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-fbdev@vger.kernel.org
> 
> Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
> ---
>  drivers/video/backlight/pwm_bl.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
> index efb4efc..3e5dbcf 100644
> --- a/drivers/video/backlight/pwm_bl.c
> +++ b/drivers/video/backlight/pwm_bl.c
> @@ -625,7 +625,8 @@ static int pwm_backlight_probe(struct platform_device *pdev)
>  		pb->scale = data->max_brightness;
>  	}
>  
> -	pb->lth_brightness = data->lth_brightness * (state.period / pb->scale);
> +	pb->lth_brightness = data->lth_brightness * (div_u64(state.period,
> +				pb->scale));
>  
>  	props.type = BACKLIGHT_RAW;
>  	props.max_brightness = data->max_brightness;
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project
> 

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 03/13] hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  2020-03-10 12:08     ` Uwe Kleine-König
@ 2020-03-10 15:05       ` Guenter Roeck
  2020-03-10 22:24         ` Guru Das Srinagesh
  0 siblings, 1 reply; 22+ messages in thread
From: Guenter Roeck @ 2020-03-10 15:05 UTC (permalink / raw)
  To: Uwe Kleine-König
  Cc: Guru Das Srinagesh, linux-pwm, Thierry Reding,
	Subbaraman Narayanamurthy, linux-kernel, Kamil Debski,
	Bartlomiej Zolnierkiewicz, Jean Delvare, Liam Girdwood,
	Mark Brown, linux-hwmon

On 3/10/20 5:08 AM, Uwe Kleine-König wrote:
> Hello Guenter,
> 
> On Mon, Mar 09, 2020 at 02:48:22PM -0700, Guenter Roeck wrote:
>> On Mon, Mar 09, 2020 at 12:35:06PM -0700, Guru Das Srinagesh wrote:
>>> Because period and duty cycle are defined in the PWM framework structs
>>> as ints with units of nanoseconds, the maximum time duration that can be
>>> set is limited to ~2.147 seconds. Redefining them as u64 values will
>>> enable larger time durations to be set.
>>>
>>> As a first step, prepare drivers to handle the switch to u64 period and
>>> duty_cycle by replacing division operations involving pwm period and duty cycle
>>> with their 64-bit equivalents as appropriate. The actual switch to u64 period
>>> and duty_cycle follows as a separate patch.
>>>
>>> Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
>>> macros:
>>> - DIV_ROUND_UP_ULL
>>> - DIV_ROUND_CLOSEST_ULL
>>> - div_u64
>>>
>>> Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
>>> DIV64_* macros:
>>> - DIV64_U64_ROUND_CLOSEST
>>> - div64_u64
>>
>> There is no explanation why this is necessary. What is the use case ?
>> It is hard to imagine a real-world use case with a duty cycle of more
>> than 2 seconds.
> 
> When my Laptop is in suspend there is an LED that blinks with a period
> of approximately 5 seconds. (To be fair, the brightness is more a sinus
> than a rectangle, but still.)
> 

I don't see support in the LED subsystem to utilize the PWM framework directly
for blinking. Plus, you say yourself that it isn't a _real_ use case, just a
theoretic one.

Either case, the reason / use case for this series should be explained
in the summary patch. That is what it is for. That case is not made.

Guenter

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 12/13] backlight: pwm_bl: Use 64-bit division macros for period and duty cycle
  2020-03-10 14:34   ` Daniel Thompson
@ 2020-03-10 18:12     ` Guru Das Srinagesh
  0 siblings, 0 replies; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-10 18:12 UTC (permalink / raw)
  To: Daniel Thompson
  Cc: linux-pwm, Thierry Reding, Uwe Kleine-König,
	Subbaraman Narayanamurthy, linux-kernel, Lee Jones, Jingoo Han,
	Bartlomiej Zolnierkiewicz, dri-devel, linux-fbdev

On Tue, Mar 10, 2020 at 02:34:32PM +0000, Daniel Thompson wrote:
> This patch looks like it is a tiny change to get the pwm_backlight to
> perform 64-bit division. Most of the above text is completely irrelevant
> to the change contained in this patch. No need to justify the change in
> the PWM structures here since that can go in the patch that changes
> those structures.  Just describe what this patch does, perhaps something
> like the following:
> 
>     The PWM API will shortly switch the state.period and
>     state.duty_cycle fields to 64-bit values. Make pwm_bl
>     ready for this transition by adopting 64-bit division
>     macros.

Will update the commit text accordingly.

> Also please copy the backlight maintainers into the covering letter. It
> is useful to place patches like this into context.

Will do.

Thank you.

Guru Das.

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 03/13] hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  2020-03-10 15:05       ` Guenter Roeck
@ 2020-03-10 22:24         ` Guru Das Srinagesh
  2020-03-10 22:57           ` Guenter Roeck
  0 siblings, 1 reply; 22+ messages in thread
From: Guru Das Srinagesh @ 2020-03-10 22:24 UTC (permalink / raw)
  To: Guenter Roeck
  Cc: Uwe Kleine-König, linux-pwm, Thierry Reding,
	Subbaraman Narayanamurthy, linux-kernel, Kamil Debski,
	Bartlomiej Zolnierkiewicz, Jean Delvare, Liam Girdwood,
	Mark Brown, linux-hwmon

On Tue, Mar 10, 2020 at 08:05:58AM -0700, Guenter Roeck wrote:
> I don't see support in the LED subsystem to utilize the PWM framework directly
> for blinking. Plus, you say yourself that it isn't a _real_ use case, just a
> theoretic one.

An example use case is a mobile phone OEM that wishes to set a period of
5 seconds or more for, say, a low battery slow blinking indication - currently
this is not possible. The PWM framework not having direct support for
blinking should not be a concern if the PWM peripheral being controlled
supports it via register writes.

> Either case, the reason / use case for this series should be explained
> in the summary patch. That is what it is for. That case is not made.

Will upload a new patchset adding more details in the summary patch.

Thank you.

Guru Das.

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 03/13] hwmon: pwm-fan: Use 64-bit division macros for period and duty cycle
  2020-03-10 22:24         ` Guru Das Srinagesh
@ 2020-03-10 22:57           ` Guenter Roeck
  0 siblings, 0 replies; 22+ messages in thread
From: Guenter Roeck @ 2020-03-10 22:57 UTC (permalink / raw)
  To: Guru Das Srinagesh
  Cc: Uwe Kleine-König, linux-pwm, Thierry Reding,
	Subbaraman Narayanamurthy, linux-kernel, Kamil Debski,
	Bartlomiej Zolnierkiewicz, Jean Delvare, Liam Girdwood,
	Mark Brown, linux-hwmon

On 3/10/20 3:24 PM, Guru Das Srinagesh wrote:
> On Tue, Mar 10, 2020 at 08:05:58AM -0700, Guenter Roeck wrote:
>> I don't see support in the LED subsystem to utilize the PWM framework directly
>> for blinking. Plus, you say yourself that it isn't a _real_ use case, just a
>> theoretic one.
> 
> An example use case is a mobile phone OEM that wishes to set a period of
> 5 seconds or more for, say, a low battery slow blinking indication - currently
> this is not possible. The PWM framework not having direct support for
> blinking should not be a concern if the PWM peripheral being controlled
> supports it via register writes.
> 
>> Either case, the reason / use case for this series should be explained
>> in the summary patch. That is what it is for. That case is not made.
> 
> Will upload a new patchset adding more details in the summary patch.
> 

Well, let's assume that this is a real use case.

Please also add information about alternatives considered, such as keeping
the second-part of the period in a separate variable.

Guenter

^ permalink raw reply	[flat|nested] 22+ messages in thread

* Re: [PATCH v7 08/13] pwm: sifive: Use 64-bit division macros for period and duty cycle
  2020-03-09 19:35 ` [PATCH v7 08/13] pwm: sifive: " Guru Das Srinagesh
@ 2020-03-26 16:37   ` Palmer Dabbelt
  0 siblings, 0 replies; 22+ messages in thread
From: Palmer Dabbelt @ 2020-03-26 16:37 UTC (permalink / raw)
  To: gurus
  Cc: linux-pwm, thierry.reding, uwe, subbaram, linux-kernel, gurus,
	Paul Walmsley, linux-riscv, yash.shah, Atish Patra

On Mon, 09 Mar 2020 12:35:11 PDT (-0700), gurus@codeaurora.org wrote:
> Because period and duty cycle are defined in the PWM framework structs
> as ints with units of nanoseconds, the maximum time duration that can be
> set is limited to ~2.147 seconds. Redefining them as u64 values will
> enable larger time durations to be set.
>
> As a first step, prepare drivers to handle the switch to u64 period and
> duty_cycle by replacing division operations involving pwm period and duty cycle
> with their 64-bit equivalents as appropriate. The actual switch to u64 period
> and duty_cycle follows as a separate patch.
>
> Where the dividend is 64-bit but the divisor is 32-bit, use *_ULL
> macros:
> - DIV_ROUND_UP_ULL
> - DIV_ROUND_CLOSEST_ULL
> - div_u64
>
> Where the divisor is 64-bit (dividend may be 32-bit or 64-bit), use
> DIV64_* macros:
> - DIV64_U64_ROUND_CLOSEST
> - div64_u64
>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: linux-riscv@lists.infradead.org
> Cc: Yash Shah <yash.shah@sifive.com>
> Cc: Atish Patra <atish.patra@wdc.com>
>
> Signed-off-by: Guru Das Srinagesh <gurus@codeaurora.org>
> ---
>  drivers/pwm/pwm-sifive.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pwm/pwm-sifive.c b/drivers/pwm/pwm-sifive.c
> index cc63f9b..62de0bb 100644
> --- a/drivers/pwm/pwm-sifive.c
> +++ b/drivers/pwm/pwm-sifive.c
> @@ -181,7 +181,7 @@ static int pwm_sifive_apply(struct pwm_chip *chip, struct pwm_device *pwm,
>  	 * consecutively
>  	 */
>  	num = (u64)duty_cycle * (1U << PWM_SIFIVE_CMPWIDTH);
> -	frac = DIV_ROUND_CLOSEST_ULL(num, state->period);
> +	frac = DIV64_U64_ROUND_CLOSEST(num, state->period);
>  	/* The hardware cannot generate a 100% duty cycle */
>  	frac = min(frac, (1U << PWM_SIFIVE_CMPWIDTH) - 1);

Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

^ permalink raw reply	[flat|nested] 22+ messages in thread

end of thread, other threads:[~2020-03-26 16:37 UTC | newest]

Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-03-09 19:35 [PATCH v7 00/13] Convert period and duty cycle to u64 Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 01/13] clk: pwm: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 02/13] drm/i915: " Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 03/13] hwmon: pwm-fan: " Guru Das Srinagesh
2020-03-09 21:48   ` Guenter Roeck
2020-03-10 12:08     ` Uwe Kleine-König
2020-03-10 15:05       ` Guenter Roeck
2020-03-10 22:24         ` Guru Das Srinagesh
2020-03-10 22:57           ` Guenter Roeck
2020-03-09 19:35 ` [PATCH v7 04/13] ir-rx51: " Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 05/13] pwm: clps711x: " Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 06/13] pwm: pwm-imx-tpm: " Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 07/13] pwm: imx27: " Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 08/13] pwm: sifive: " Guru Das Srinagesh
2020-03-26 16:37   ` Palmer Dabbelt
2020-03-09 19:35 ` [PATCH v7 09/13] pwm: sti: " Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 10/13] pwm: stm32-lp: Use %llu format specifier for period Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 11/13] pwm: sun4i: Use 64-bit division macros for period and duty cycle Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 12/13] backlight: pwm_bl: " Guru Das Srinagesh
2020-03-10 14:34   ` Daniel Thompson
2020-03-10 18:12     ` Guru Das Srinagesh
2020-03-09 19:35 ` [PATCH v7 13/13] pwm: core: Convert period and duty cycle to u64 Guru Das Srinagesh

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