[PATCH v5 0/4] Improve pwm-ir-tx precision

[PATCH v5 0/4] Improve pwm-ir-tx precision

[Sean Young]

The pwm-ir-tx driver has to turn the pwm signal on and off, and suffers
from delays as this is done in process context. Make this work in atomic
context.

changes:

v5:
 - Use dev_err_probe() as Uwe suggested
 - rebase

v4:
 - Split out the pwm_apply_state() rename into seperate commit
 - Atomic pwm function is called pwm_apply_atomic() and sleeping
   counterpart pwm_apply_cansleep()
 - Fix commit messages

v3:
 - Renamed pwm_apply_state() to pwm_apply_cansleep()
 - Moved pwm atomic to struct pwm_chip
 - Fixed pwm docs
 - Other minor code review comments

v2:
 - Simplified the pwm ir tx based on Ivaylo Dimitrov suggestions
 - Renamed pwm_can_sleep() to pwm_is_atomic
 - Fix sleeping issue in pwm-bcm2835 (clk_get_rate() can sleep)
 - use non_block_start() in pwm to check atomic-ness


Sean Young (4):
  pwm: rename pwm_apply_state() to pwm_apply_cansleep()
  pwm: make it possible to apply pwm changes in atomic context
  pwm: bcm2835: allow pwm driver to be used in atomic context
  media: pwm-ir-tx: trigger edges from hrtimer interrupt context

 Documentation/driver-api/pwm.rst              | 17 +++-
 .../gpu/drm/i915/display/intel_backlight.c    |  6 +-
 drivers/gpu/drm/solomon/ssd130x.c             |  2 +-
 drivers/hwmon/pwm-fan.c                       |  8 +-
 drivers/input/misc/da7280.c                   |  4 +-
 drivers/input/misc/pwm-beeper.c               |  4 +-
 drivers/input/misc/pwm-vibra.c                |  8 +-
 drivers/leds/leds-pwm.c                       |  2 +-
 drivers/leds/rgb/leds-pwm-multicolor.c        |  4 +-
 drivers/media/rc/pwm-ir-tx.c                  | 83 +++++++++++++++++--
 drivers/platform/x86/lenovo-yogabook.c        |  2 +-
 drivers/pwm/core.c                            | 75 +++++++++++++----
 drivers/pwm/pwm-bcm2835.c                     | 31 ++++---
 drivers/pwm/pwm-renesas-tpu.c                 |  1 -
 drivers/pwm/pwm-twl-led.c                     |  2 +-
 drivers/pwm/pwm-vt8500.c                      |  2 +-
 drivers/pwm/sysfs.c                           | 10 +--
 drivers/regulator/pwm-regulator.c             |  4 +-
 drivers/video/backlight/lm3630a_bl.c          |  2 +-
 drivers/video/backlight/lp855x_bl.c           |  2 +-
 drivers/video/backlight/pwm_bl.c              | 12 +--
 drivers/video/fbdev/ssd1307fb.c               |  2 +-
 include/linux/pwm.h                           | 57 +++++++++----
 23 files changed, 248 insertions(+), 92 deletions(-)

-- 
2.42.1

[PATCH v5 1/4] pwm: rename pwm_apply_state() to pwm_apply_cansleep()

[Sean Young]

In order to introduce a pwm api which can be used from atomic context,
we will need two functions for applying pwm changes:

	int pwm_apply_cansleep(struct pwm *, struct pwm_state *);
	int pwm_apply_atomic(struct pwm *, struct pwm_state *);

This commit just deals with renaming pwm_apply_state(), a following
commit will introduce the pwm_apply_atomic() function.

Acked-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Sean Young <sean@mess.org>
---
 Documentation/driver-api/pwm.rst              |  8 +++---
 .../gpu/drm/i915/display/intel_backlight.c    |  6 ++--
 drivers/gpu/drm/solomon/ssd130x.c             |  2 +-
 drivers/hwmon/pwm-fan.c                       |  8 +++---
 drivers/input/misc/da7280.c                   |  4 +--
 drivers/input/misc/pwm-beeper.c               |  4 +--
 drivers/input/misc/pwm-vibra.c                |  8 +++---
 drivers/leds/leds-pwm.c                       |  2 +-
 drivers/leds/rgb/leds-pwm-multicolor.c        |  4 +--
 drivers/media/rc/pwm-ir-tx.c                  |  4 +--
 drivers/platform/x86/lenovo-yogabook.c        |  2 +-
 drivers/pwm/core.c                            | 18 ++++++------
 drivers/pwm/pwm-twl-led.c                     |  2 +-
 drivers/pwm/pwm-vt8500.c                      |  2 +-
 drivers/pwm/sysfs.c                           | 10 +++----
 drivers/regulator/pwm-regulator.c             |  4 +--
 drivers/video/backlight/lm3630a_bl.c          |  2 +-
 drivers/video/backlight/lp855x_bl.c           |  2 +-
 drivers/video/backlight/pwm_bl.c              | 12 ++++----
 drivers/video/fbdev/ssd1307fb.c               |  2 +-
 include/linux/pwm.h                           | 28 +++++++++----------
 21 files changed, 67 insertions(+), 67 deletions(-)

diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst
index bb264490a87a1..5f6d1540dcd7e 100644
--- a/Documentation/driver-api/pwm.rst
+++ b/Documentation/driver-api/pwm.rst
@@ -41,7 +41,7 @@ the getter, devm_pwm_get() and devm_fwnode_pwm_get(), also exist.
 
 After being requested, a PWM has to be configured using::
 
-	int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state);
+	int pwm_apply_cansleep(struct pwm_device *pwm, struct pwm_state *state);
 
 This API controls both the PWM period/duty_cycle config and the
 enable/disable state.
@@ -57,13 +57,13 @@ If supported by the driver, the signal can be optimized, for example to improve
 EMI by phase shifting the individual channels of a chip.
 
 The pwm_config(), pwm_enable() and pwm_disable() functions are just wrappers
-around pwm_apply_state() and should not be used if the user wants to change
+around pwm_apply_cansleep() and should not be used if the user wants to change
 several parameter at once. For example, if you see pwm_config() and
 pwm_{enable,disable}() calls in the same function, this probably means you
-should switch to pwm_apply_state().
+should switch to pwm_apply_cansleep().
 
 The PWM user API also allows one to query the PWM state that was passed to the
-last invocation of pwm_apply_state() using pwm_get_state(). Note this is
+last invocation of pwm_apply_cansleep() using pwm_get_state(). Note this is
 different to what the driver has actually implemented if the request cannot be
 satisfied exactly with the hardware in use. There is currently no way for
 consumers to get the actually implemented settings.
diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
index 2e8f17c045222..cf516190cde8f 100644
--- a/drivers/gpu/drm/i915/display/intel_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_backlight.c
@@ -274,7 +274,7 @@ static void ext_pwm_set_backlight(const struct drm_connector_state *conn_state,
 	struct intel_panel *panel = &to_intel_connector(conn_state->connector)->panel;
 
 	pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
-	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+	pwm_apply_cansleep(panel->backlight.pwm, &panel->backlight.pwm_state);
 }
 
 static void
@@ -427,7 +427,7 @@ static void ext_pwm_disable_backlight(const struct drm_connector_state *old_conn
 	intel_backlight_set_pwm_level(old_conn_state, level);
 
 	panel->backlight.pwm_state.enabled = false;
-	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+	pwm_apply_cansleep(panel->backlight.pwm, &panel->backlight.pwm_state);
 }
 
 void intel_backlight_disable(const struct drm_connector_state *old_conn_state)
@@ -749,7 +749,7 @@ static void ext_pwm_enable_backlight(const struct intel_crtc_state *crtc_state,
 
 	pwm_set_relative_duty_cycle(&panel->backlight.pwm_state, level, 100);
 	panel->backlight.pwm_state.enabled = true;
-	pwm_apply_state(panel->backlight.pwm, &panel->backlight.pwm_state);
+	pwm_apply_cansleep(panel->backlight.pwm, &panel->backlight.pwm_state);
 }
 
 static void __intel_backlight_enable(const struct intel_crtc_state *crtc_state,
diff --git a/drivers/gpu/drm/solomon/ssd130x.c b/drivers/gpu/drm/solomon/ssd130x.c
index e0174f82e3537..46fa3b1cba9ba 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -319,7 +319,7 @@ static int ssd130x_pwm_enable(struct ssd130x_device *ssd130x)
 
 	pwm_init_state(ssd130x->pwm, &pwmstate);
 	pwm_set_relative_duty_cycle(&pwmstate, 50, 100);
-	pwm_apply_state(ssd130x->pwm, &pwmstate);
+	pwm_apply_cansleep(ssd130x->pwm, &pwmstate);
 
 	/* Enable the PWM */
 	pwm_enable(ssd130x->pwm);
diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 6e4516c2ab894..f68deb1f236b7 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -151,7 +151,7 @@ static int pwm_fan_power_on(struct pwm_fan_ctx *ctx)
 	}
 
 	state->enabled = true;
-	ret = pwm_apply_state(ctx->pwm, state);
+	ret = pwm_apply_cansleep(ctx->pwm, state);
 	if (ret) {
 		dev_err(ctx->dev, "failed to enable PWM\n");
 		goto disable_regulator;
@@ -181,7 +181,7 @@ static int pwm_fan_power_off(struct pwm_fan_ctx *ctx)
 
 	state->enabled = false;
 	state->duty_cycle = 0;
-	ret = pwm_apply_state(ctx->pwm, state);
+	ret = pwm_apply_cansleep(ctx->pwm, state);
 	if (ret) {
 		dev_err(ctx->dev, "failed to disable PWM\n");
 		return ret;
@@ -207,7 +207,7 @@ static int  __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm)
 
 		period = state->period;
 		state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);
-		ret = pwm_apply_state(ctx->pwm, state);
+		ret = pwm_apply_cansleep(ctx->pwm, state);
 		if (ret)
 			return ret;
 		ret = pwm_fan_power_on(ctx);
@@ -278,7 +278,7 @@ static int pwm_fan_update_enable(struct pwm_fan_ctx *ctx, long val)
 						    state,
 						    &enable_regulator);
 
-			pwm_apply_state(ctx->pwm, state);
+			pwm_apply_cansleep(ctx->pwm, state);
 			pwm_fan_switch_power(ctx, enable_regulator);
 			pwm_fan_update_state(ctx, 0);
 		}
diff --git a/drivers/input/misc/da7280.c b/drivers/input/misc/da7280.c
index ce82548916bbc..f10be2cdba803 100644
--- a/drivers/input/misc/da7280.c
+++ b/drivers/input/misc/da7280.c
@@ -352,7 +352,7 @@ static int da7280_haptic_set_pwm(struct da7280_haptic *haptics, bool enabled)
 		state.duty_cycle = period_mag_multi;
 	}
 
-	error = pwm_apply_state(haptics->pwm_dev, &state);
+	error = pwm_apply_cansleep(haptics->pwm_dev, &state);
 	if (error)
 		dev_err(haptics->dev, "Failed to apply pwm state: %d\n", error);
 
@@ -1175,7 +1175,7 @@ static int da7280_probe(struct i2c_client *client)
 		/* Sync up PWM state and ensure it is off. */
 		pwm_init_state(haptics->pwm_dev, &state);
 		state.enabled = false;
-		error = pwm_apply_state(haptics->pwm_dev, &state);
+		error = pwm_apply_cansleep(haptics->pwm_dev, &state);
 		if (error) {
 			dev_err(dev, "Failed to apply PWM state: %d\n", error);
 			return error;
diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
index 1e731d8397c6f..1d6c4fb5f0caf 100644
--- a/drivers/input/misc/pwm-beeper.c
+++ b/drivers/input/misc/pwm-beeper.c
@@ -39,7 +39,7 @@ static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
 	state.period = period;
 	pwm_set_relative_duty_cycle(&state, 50, 100);
 
-	error = pwm_apply_state(beeper->pwm, &state);
+	error = pwm_apply_cansleep(beeper->pwm, &state);
 	if (error)
 		return error;
 
@@ -138,7 +138,7 @@ static int pwm_beeper_probe(struct platform_device *pdev)
 	/* Sync up PWM state and ensure it is off. */
 	pwm_init_state(beeper->pwm, &state);
 	state.enabled = false;
-	error = pwm_apply_state(beeper->pwm, &state);
+	error = pwm_apply_cansleep(beeper->pwm, &state);
 	if (error) {
 		dev_err(dev, "failed to apply initial PWM state: %d\n",
 			error);
diff --git a/drivers/input/misc/pwm-vibra.c b/drivers/input/misc/pwm-vibra.c
index acac79c488aa1..6552ce712d8dc 100644
--- a/drivers/input/misc/pwm-vibra.c
+++ b/drivers/input/misc/pwm-vibra.c
@@ -56,7 +56,7 @@ static int pwm_vibrator_start(struct pwm_vibrator *vibrator)
 	pwm_set_relative_duty_cycle(&state, vibrator->level, 0xffff);
 	state.enabled = true;
 
-	err = pwm_apply_state(vibrator->pwm, &state);
+	err = pwm_apply_cansleep(vibrator->pwm, &state);
 	if (err) {
 		dev_err(pdev, "failed to apply pwm state: %d\n", err);
 		return err;
@@ -67,7 +67,7 @@ static int pwm_vibrator_start(struct pwm_vibrator *vibrator)
 		state.duty_cycle = vibrator->direction_duty_cycle;
 		state.enabled = true;
 
-		err = pwm_apply_state(vibrator->pwm_dir, &state);
+		err = pwm_apply_cansleep(vibrator->pwm_dir, &state);
 		if (err) {
 			dev_err(pdev, "failed to apply dir-pwm state: %d\n", err);
 			pwm_disable(vibrator->pwm);
@@ -160,7 +160,7 @@ static int pwm_vibrator_probe(struct platform_device *pdev)
 	/* Sync up PWM state and ensure it is off. */
 	pwm_init_state(vibrator->pwm, &state);
 	state.enabled = false;
-	err = pwm_apply_state(vibrator->pwm, &state);
+	err = pwm_apply_cansleep(vibrator->pwm, &state);
 	if (err) {
 		dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n",
 			err);
@@ -174,7 +174,7 @@ static int pwm_vibrator_probe(struct platform_device *pdev)
 		/* Sync up PWM state and ensure it is off. */
 		pwm_init_state(vibrator->pwm_dir, &state);
 		state.enabled = false;
-		err = pwm_apply_state(vibrator->pwm_dir, &state);
+		err = pwm_apply_cansleep(vibrator->pwm_dir, &state);
 		if (err) {
 			dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n",
 				err);
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index 2b3bf1353b707..0c7bccbcae408 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -54,7 +54,7 @@ static int led_pwm_set(struct led_classdev *led_cdev,
 
 	led_dat->pwmstate.duty_cycle = duty;
 	led_dat->pwmstate.enabled = true;
-	return pwm_apply_state(led_dat->pwm, &led_dat->pwmstate);
+	return pwm_apply_cansleep(led_dat->pwm, &led_dat->pwmstate);
 }
 
 __attribute__((nonnull))
diff --git a/drivers/leds/rgb/leds-pwm-multicolor.c b/drivers/leds/rgb/leds-pwm-multicolor.c
index 46cd062b8b24c..8114adcdad9bb 100644
--- a/drivers/leds/rgb/leds-pwm-multicolor.c
+++ b/drivers/leds/rgb/leds-pwm-multicolor.c
@@ -51,8 +51,8 @@ static int led_pwm_mc_set(struct led_classdev *cdev,
 
 		priv->leds[i].state.duty_cycle = duty;
 		priv->leds[i].state.enabled = duty > 0;
-		ret = pwm_apply_state(priv->leds[i].pwm,
-				      &priv->leds[i].state);
+		ret = pwm_apply_cansleep(priv->leds[i].pwm,
+					 &priv->leds[i].state);
 		if (ret)
 			break;
 	}
diff --git a/drivers/media/rc/pwm-ir-tx.c b/drivers/media/rc/pwm-ir-tx.c
index c5f37c03af9c9..ccb86890adcea 100644
--- a/drivers/media/rc/pwm-ir-tx.c
+++ b/drivers/media/rc/pwm-ir-tx.c
@@ -68,7 +68,7 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
 
 	for (i = 0; i < count; i++) {
 		state.enabled = !(i % 2);
-		pwm_apply_state(pwm, &state);
+		pwm_apply_cansleep(pwm, &state);
 
 		edge = ktime_add_us(edge, txbuf[i]);
 		delta = ktime_us_delta(edge, ktime_get());
@@ -77,7 +77,7 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
 	}
 
 	state.enabled = false;
-	pwm_apply_state(pwm, &state);
+	pwm_apply_cansleep(pwm, &state);
 
 	return count;
 }
diff --git a/drivers/platform/x86/lenovo-yogabook.c b/drivers/platform/x86/lenovo-yogabook.c
index b8d0239192cbf..cbc285f77c2bd 100644
--- a/drivers/platform/x86/lenovo-yogabook.c
+++ b/drivers/platform/x86/lenovo-yogabook.c
@@ -435,7 +435,7 @@ static int yogabook_pdev_set_kbd_backlight(struct yogabook_data *data, u8 level)
 		.enabled = level,
 	};
 
-	pwm_apply_state(data->kbd_bl_pwm, &state);
+	pwm_apply_cansleep(data->kbd_bl_pwm, &state);
 	gpiod_set_value(data->kbd_bl_led_enable, level ? 1 : 0);
 	return 0;
 }
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 29078486534d4..928531c34f481 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -356,8 +356,8 @@ struct pwm_device *pwm_request_from_chip(struct pwm_chip *chip,
 }
 EXPORT_SYMBOL_GPL(pwm_request_from_chip);
 
-static void pwm_apply_state_debug(struct pwm_device *pwm,
-				  const struct pwm_state *state)
+static void pwm_apply_debug(struct pwm_device *pwm,
+			    const struct pwm_state *state)
 {
 	struct pwm_state *last = &pwm->last;
 	struct pwm_chip *chip = pwm->chip;
@@ -463,11 +463,11 @@ static void pwm_apply_state_debug(struct pwm_device *pwm,
 }
 
 /**
- * pwm_apply_state() - atomically apply a new state to a PWM device
+ * pwm_apply_cansleep() - atomically apply a new state to a PWM device
  * @pwm: PWM device
  * @state: new state to apply
  */
-int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
+int pwm_apply_cansleep(struct pwm_device *pwm, const struct pwm_state *state)
 {
 	struct pwm_chip *chip;
 	int err;
@@ -475,7 +475,7 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 	/*
 	 * Some lowlevel driver's implementations of .apply() make use of
 	 * mutexes, also with some drivers only returning when the new
-	 * configuration is active calling pwm_apply_state() from atomic context
+	 * configuration is active calling pwm_apply_cansleep() from atomic context
 	 * is a bad idea. So make it explicit that calling this function might
 	 * sleep.
 	 */
@@ -505,11 +505,11 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 	 * only do this after pwm->state was applied as some
 	 * implementations of .get_state depend on this
 	 */
-	pwm_apply_state_debug(pwm, state);
+	pwm_apply_debug(pwm, state);
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(pwm_apply_state);
+EXPORT_SYMBOL_GPL(pwm_apply_cansleep);
 
 /**
  * pwm_capture() - capture and report a PWM signal
@@ -567,7 +567,7 @@ int pwm_adjust_config(struct pwm_device *pwm)
 		state.period = pargs.period;
 		state.polarity = pargs.polarity;
 
-		return pwm_apply_state(pwm, &state);
+		return pwm_apply_cansleep(pwm, &state);
 	}
 
 	/*
@@ -590,7 +590,7 @@ int pwm_adjust_config(struct pwm_device *pwm)
 		state.duty_cycle = state.period - state.duty_cycle;
 	}
 
-	return pwm_apply_state(pwm, &state);
+	return pwm_apply_cansleep(pwm, &state);
 }
 EXPORT_SYMBOL_GPL(pwm_adjust_config);
 
diff --git a/drivers/pwm/pwm-twl-led.c b/drivers/pwm/pwm-twl-led.c
index 625233f4703a9..9dae9b88d65cb 100644
--- a/drivers/pwm/pwm-twl-led.c
+++ b/drivers/pwm/pwm-twl-led.c
@@ -172,7 +172,7 @@ static int twl4030_pwmled_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * We cannot skip calling ->config even if state->period ==
 	 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
 	 * because we might have exited early in the last call to
-	 * pwm_apply_state because of !state->enabled and so the two values in
+	 * pwm_apply_cansleep because of !state->enabled and so the two values in
 	 * pwm->state might not be configured in hardware.
 	 */
 	ret = twl4030_pwmled_config(pwm->chip, pwm,
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c
index 5568d5312d3ca..b33e315de8fef 100644
--- a/drivers/pwm/pwm-vt8500.c
+++ b/drivers/pwm/pwm-vt8500.c
@@ -206,7 +206,7 @@ static int vt8500_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * We cannot skip calling ->config even if state->period ==
 	 * pwm->state.period && state->duty_cycle == pwm->state.duty_cycle
 	 * because we might have exited early in the last call to
-	 * pwm_apply_state because of !state->enabled and so the two values in
+	 * pwm_apply_cansleep because of !state->enabled and so the two values in
 	 * pwm->state might not be configured in hardware.
 	 */
 	err = vt8500_pwm_config(pwm->chip, pwm, state->duty_cycle, state->period);
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c
index 8d1254761e4dd..eca9cad3be765 100644
--- a/drivers/pwm/sysfs.c
+++ b/drivers/pwm/sysfs.c
@@ -62,7 +62,7 @@ static ssize_t period_store(struct device *child,
 	mutex_lock(&export->lock);
 	pwm_get_state(pwm, &state);
 	state.period = val;
-	ret = pwm_apply_state(pwm, &state);
+	ret = pwm_apply_cansleep(pwm, &state);
 	mutex_unlock(&export->lock);
 
 	return ret ? : size;
@@ -97,7 +97,7 @@ static ssize_t duty_cycle_store(struct device *child,
 	mutex_lock(&export->lock);
 	pwm_get_state(pwm, &state);
 	state.duty_cycle = val;
-	ret = pwm_apply_state(pwm, &state);
+	ret = pwm_apply_cansleep(pwm, &state);
 	mutex_unlock(&export->lock);
 
 	return ret ? : size;
@@ -144,7 +144,7 @@ static ssize_t enable_store(struct device *child,
 		goto unlock;
 	}
 
-	ret = pwm_apply_state(pwm, &state);
+	ret = pwm_apply_cansleep(pwm, &state);
 
 unlock:
 	mutex_unlock(&export->lock);
@@ -194,7 +194,7 @@ static ssize_t polarity_store(struct device *child,
 	mutex_lock(&export->lock);
 	pwm_get_state(pwm, &state);
 	state.polarity = polarity;
-	ret = pwm_apply_state(pwm, &state);
+	ret = pwm_apply_cansleep(pwm, &state);
 	mutex_unlock(&export->lock);
 
 	return ret ? : size;
@@ -401,7 +401,7 @@ static int pwm_class_apply_state(struct pwm_export *export,
 				 struct pwm_device *pwm,
 				 struct pwm_state *state)
 {
-	int ret = pwm_apply_state(pwm, state);
+	int ret = pwm_apply_cansleep(pwm, state);
 
 	/* release lock taken in pwm_class_get_state */
 	mutex_unlock(&export->lock);
diff --git a/drivers/regulator/pwm-regulator.c b/drivers/regulator/pwm-regulator.c
index 2aff6db748e2c..c19d37a479d43 100644
--- a/drivers/regulator/pwm-regulator.c
+++ b/drivers/regulator/pwm-regulator.c
@@ -90,7 +90,7 @@ static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
 	pwm_set_relative_duty_cycle(&pstate,
 			drvdata->duty_cycle_table[selector].dutycycle, 100);
 
-	ret = pwm_apply_state(drvdata->pwm, &pstate);
+	ret = pwm_apply_cansleep(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
@@ -216,7 +216,7 @@ static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 
 	pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
 
-	ret = pwm_apply_state(drvdata->pwm, &pstate);
+	ret = pwm_apply_cansleep(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
diff --git a/drivers/video/backlight/lm3630a_bl.c b/drivers/video/backlight/lm3630a_bl.c
index 8fcb62be597b8..5cb702989ef61 100644
--- a/drivers/video/backlight/lm3630a_bl.c
+++ b/drivers/video/backlight/lm3630a_bl.c
@@ -180,7 +180,7 @@ static int lm3630a_pwm_ctrl(struct lm3630a_chip *pchip, int br, int br_max)
 
 	pchip->pwmd_state.enabled = pchip->pwmd_state.duty_cycle ? true : false;
 
-	return pwm_apply_state(pchip->pwmd, &pchip->pwmd_state);
+	return pwm_apply_cansleep(pchip->pwmd, &pchip->pwmd_state);
 }
 
 /* update and get brightness */
diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index da1f124db69c0..b7edbaaa169a4 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -234,7 +234,7 @@ static int lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 	state.duty_cycle = div_u64(br * state.period, max_br);
 	state.enabled = state.duty_cycle;
 
-	return pwm_apply_state(lp->pwm, &state);
+	return pwm_apply_cansleep(lp->pwm, &state);
 }
 
 static int lp855x_bl_update_status(struct backlight_device *bl)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c
index 289bd9ce4d36d..a7d3debee4753 100644
--- a/drivers/video/backlight/pwm_bl.c
+++ b/drivers/video/backlight/pwm_bl.c
@@ -103,7 +103,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
 		pwm_get_state(pb->pwm, &state);
 		state.duty_cycle = compute_duty_cycle(pb, brightness, &state);
 		state.enabled = true;
-		pwm_apply_state(pb->pwm, &state);
+		pwm_apply_cansleep(pb->pwm, &state);
 
 		pwm_backlight_power_on(pb);
 	} else {
@@ -120,7 +120,7 @@ static int pwm_backlight_update_status(struct backlight_device *bl)
 		 * inactive output.
 		 */
 		state.enabled = !pb->power_supply && !pb->enable_gpio;
-		pwm_apply_state(pb->pwm, &state);
+		pwm_apply_cansleep(pb->pwm, &state);
 	}
 
 	if (pb->notify_after)
@@ -528,7 +528,7 @@ static int pwm_backlight_probe(struct platform_device *pdev)
 	if (!state.period && (data->pwm_period_ns > 0))
 		state.period = data->pwm_period_ns;
 
-	ret = pwm_apply_state(pb->pwm, &state);
+	ret = pwm_apply_cansleep(pb->pwm, &state);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to apply initial PWM state: %d\n",
 			ret);
@@ -633,7 +633,7 @@ static void pwm_backlight_remove(struct platform_device *pdev)
 	pwm_get_state(pb->pwm, &state);
 	state.duty_cycle = 0;
 	state.enabled = false;
-	pwm_apply_state(pb->pwm, &state);
+	pwm_apply_cansleep(pb->pwm, &state);
 
 	if (pb->exit)
 		pb->exit(&pdev->dev);
@@ -649,7 +649,7 @@ static void pwm_backlight_shutdown(struct platform_device *pdev)
 	pwm_get_state(pb->pwm, &state);
 	state.duty_cycle = 0;
 	state.enabled = false;
-	pwm_apply_state(pb->pwm, &state);
+	pwm_apply_cansleep(pb->pwm, &state);
 }
 
 #ifdef CONFIG_PM_SLEEP
@@ -673,7 +673,7 @@ static int pwm_backlight_suspend(struct device *dev)
 	pwm_get_state(pb->pwm, &state);
 	state.duty_cycle = 0;
 	state.enabled = false;
-	pwm_apply_state(pb->pwm, &state);
+	pwm_apply_cansleep(pb->pwm, &state);
 
 	if (pb->notify_after)
 		pb->notify_after(pb->dev, 0);
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index 5ae48e36fccb4..e5cca01af55f3 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -347,7 +347,7 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
 
 		pwm_init_state(par->pwm, &pwmstate);
 		pwm_set_relative_duty_cycle(&pwmstate, 50, 100);
-		pwm_apply_state(par->pwm, &pwmstate);
+		pwm_apply_cansleep(par->pwm, &pwmstate);
 
 		/* Enable the PWM */
 		pwm_enable(par->pwm);
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index cda3597b84f2c..c4b066f7c5097 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -93,8 +93,8 @@ struct pwm_device {
  * @state: state to fill with the current PWM state
  *
  * The returned PWM state represents the state that was applied by a previous call to
- * pwm_apply_state(). Drivers may have to slightly tweak that state before programming it to
- * hardware. If pwm_apply_state() was never called, this returns either the current hardware
+ * pwm_apply_cansleep(). Drivers may have to slightly tweak that state before programming it to
+ * hardware. If pwm_apply_cansleep() was never called, this returns either the current hardware
  * state (if supported) or the default settings.
  */
 static inline void pwm_get_state(const struct pwm_device *pwm,
@@ -158,20 +158,20 @@ static inline void pwm_get_args(const struct pwm_device *pwm,
 }
 
 /**
- * pwm_init_state() - prepare a new state to be applied with pwm_apply_state()
+ * pwm_init_state() - prepare a new state to be applied with pwm_apply_cansleep()
  * @pwm: PWM device
  * @state: state to fill with the prepared PWM state
  *
  * This functions prepares a state that can later be tweaked and applied
- * to the PWM device with pwm_apply_state(). This is a convenient function
+ * to the PWM device with pwm_apply_cansleep(). This is a convenient function
  * that first retrieves the current PWM state and the replaces the period
  * and polarity fields with the reference values defined in pwm->args.
  * Once the function returns, you can adjust the ->enabled and ->duty_cycle
- * fields according to your needs before calling pwm_apply_state().
+ * fields according to your needs before calling pwm_apply_cansleep().
  *
  * ->duty_cycle is initially set to zero to avoid cases where the current
  * ->duty_cycle value exceed the pwm_args->period one, which would trigger
- * an error if the user calls pwm_apply_state() without adjusting ->duty_cycle
+ * an error if the user calls pwm_apply_cansleep() without adjusting ->duty_cycle
  * first.
  */
 static inline void pwm_init_state(const struct pwm_device *pwm,
@@ -227,7 +227,7 @@ pwm_get_relative_duty_cycle(const struct pwm_state *state, unsigned int scale)
  *
  * pwm_init_state(pwm, &state);
  * pwm_set_relative_duty_cycle(&state, 50, 100);
- * pwm_apply_state(pwm, &state);
+ * pwm_apply_cansleep(pwm, &state);
  *
  * This functions returns -EINVAL if @duty_cycle and/or @scale are
  * inconsistent (@scale == 0 or @duty_cycle > @scale).
@@ -307,7 +307,7 @@ struct pwm_chip {
 
 #if IS_ENABLED(CONFIG_PWM)
 /* PWM user APIs */
-int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state);
+int pwm_apply_cansleep(struct pwm_device *pwm, const struct pwm_state *state);
 int pwm_adjust_config(struct pwm_device *pwm);
 
 /**
@@ -335,7 +335,7 @@ static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
 
 	state.duty_cycle = duty_ns;
 	state.period = period_ns;
-	return pwm_apply_state(pwm, &state);
+	return pwm_apply_cansleep(pwm, &state);
 }
 
 /**
@@ -356,7 +356,7 @@ static inline int pwm_enable(struct pwm_device *pwm)
 		return 0;
 
 	state.enabled = true;
-	return pwm_apply_state(pwm, &state);
+	return pwm_apply_cansleep(pwm, &state);
 }
 
 /**
@@ -375,7 +375,7 @@ static inline void pwm_disable(struct pwm_device *pwm)
 		return;
 
 	state.enabled = false;
-	pwm_apply_state(pwm, &state);
+	pwm_apply_cansleep(pwm, &state);
 }
 
 /* PWM provider APIs */
@@ -406,8 +406,8 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
 				       struct fwnode_handle *fwnode,
 				       const char *con_id);
 #else
-static inline int pwm_apply_state(struct pwm_device *pwm,
-				  const struct pwm_state *state)
+static inline int pwm_apply_cansleep(struct pwm_device *pwm,
+				     const struct pwm_state *state)
 {
 	might_sleep();
 	return -ENOTSUPP;
@@ -524,7 +524,7 @@ static inline void pwm_apply_args(struct pwm_device *pwm)
 	state.period = pwm->args.period;
 	state.usage_power = false;
 
-	pwm_apply_state(pwm, &state);
+	pwm_apply_cansleep(pwm, &state);
 }
 
 struct pwm_lookup {
-- 
2.42.1

[PATCH v5 2/4] pwm: make it possible to apply pwm changes in atomic context

[Sean Young]

Some pwm devices require sleeping, for example if the pwm device is
connected over i2c. However, many pwm devices could be used from atomic
context, e.g. memmory mapped pwm. This is useful for, for example, the
pwm-ir-tx driver which requires precise timing. Sleeping causes havoc
with the generated IR signal.

Since not all pmw devices can support atomic context, we also add a
pwm_is_atomic() function to check if it is supported.

Signed-off-by: Sean Young <sean@mess.org>
---
 Documentation/driver-api/pwm.rst |  9 +++++
 drivers/pwm/core.c               | 63 ++++++++++++++++++++++++++------
 drivers/pwm/pwm-renesas-tpu.c    |  1 -
 include/linux/pwm.h              | 29 ++++++++++++++-
 4 files changed, 87 insertions(+), 15 deletions(-)

diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst
index 5f6d1540dcd7e..921d1306e5932 100644
--- a/Documentation/driver-api/pwm.rst
+++ b/Documentation/driver-api/pwm.rst
@@ -43,6 +43,15 @@ After being requested, a PWM has to be configured using::
 
 	int pwm_apply_cansleep(struct pwm_device *pwm, struct pwm_state *state);
 
+Some PWM devices can be used from atomic context. You can check if this is
+supported with::
+
+        bool pwm_is_atomic(struct pwm_device *pwm);
+
+If true, the PWM can be configured from atomic context with::
+
+	int pwm_apply_atomic(struct pwm_device *pwm, struct pwm_state *state);
+
 This API controls both the PWM period/duty_cycle config and the
 enable/disable state.
 
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 928531c34f481..84a849a69b347 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -463,24 +463,15 @@ static void pwm_apply_debug(struct pwm_device *pwm,
 }
 
 /**
- * pwm_apply_cansleep() - atomically apply a new state to a PWM device
+ * pwm_apply_unchecked() - atomically apply a new state to a PWM device
  * @pwm: PWM device
  * @state: new state to apply
  */
-int pwm_apply_cansleep(struct pwm_device *pwm, const struct pwm_state *state)
+static int pwm_apply_unchecked(struct pwm_device *pwm, const struct pwm_state *state)
 {
 	struct pwm_chip *chip;
 	int err;
 
-	/*
-	 * Some lowlevel driver's implementations of .apply() make use of
-	 * mutexes, also with some drivers only returning when the new
-	 * configuration is active calling pwm_apply_cansleep() from atomic context
-	 * is a bad idea. So make it explicit that calling this function might
-	 * sleep.
-	 */
-	might_sleep();
-
 	if (!pwm || !state || !state->period ||
 	    state->duty_cycle > state->period)
 		return -EINVAL;
@@ -501,16 +492,64 @@ int pwm_apply_cansleep(struct pwm_device *pwm, const struct pwm_state *state)
 
 	pwm->state = *state;
 
+	return 0;
+}
+
+/**
+ * pwm_apply_cansleep() - atomically apply a new state to a PWM device
+ * Cannot be used in atomic context.
+ * @pwm: PWM device
+ * @state: new state to apply
+ */
+int pwm_apply_cansleep(struct pwm_device *pwm, const struct pwm_state *state)
+{
+	int err;
+
+	/*
+	 * Some lowlevel driver's implementations of .apply() make use of
+	 * mutexes, also with some drivers only returning when the new
+	 * configuration is active calling pwm_apply_cansleep() from atomic context
+	 * is a bad idea. So make it explicit that calling this function might
+	 * sleep.
+	 */
+	might_sleep();
+
+	if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
+		/*
+		 * Catch any sleeping drivers when atomic is set.
+		 */
+		non_block_start();
+		err = pwm_apply_unchecked(pwm, state);
+		non_block_end();
+	} else {
+		err = pwm_apply_unchecked(pwm, state);
+	}
+
 	/*
 	 * only do this after pwm->state was applied as some
 	 * implementations of .get_state depend on this
 	 */
 	pwm_apply_debug(pwm, state);
 
-	return 0;
+	return err;
 }
 EXPORT_SYMBOL_GPL(pwm_apply_cansleep);
 
+/**
+ * pwm_apply_atomic() - apply a new state to a PWM device from atomic context
+ * Not all pwm devices support this function, check with pwm_is_atomic().
+ * @pwm: PWM device
+ * @state: new state to apply
+ */
+int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state)
+{
+	WARN_ONCE(!pwm->chip->atomic,
+		  "sleeping pwm driver used in atomic context");
+
+	return pwm_apply_unchecked(pwm, state);
+}
+EXPORT_SYMBOL_GPL(pwm_apply_atomic);
+
 /**
  * pwm_capture() - capture and report a PWM signal
  * @pwm: PWM device
diff --git a/drivers/pwm/pwm-renesas-tpu.c b/drivers/pwm/pwm-renesas-tpu.c
index 4239f2c3e8b2a..47ea92cd8c67f 100644
--- a/drivers/pwm/pwm-renesas-tpu.c
+++ b/drivers/pwm/pwm-renesas-tpu.c
@@ -11,7 +11,6 @@
 #include <linux/init.h>
 #include <linux/ioport.h>
 #include <linux/module.h>
-#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index c4b066f7c5097..495aba06c64c3 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -286,6 +286,7 @@ struct pwm_ops {
  * @npwm: number of PWMs controlled by this chip
  * @of_xlate: request a PWM device given a device tree PWM specifier
  * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
+ * @atomic: can the driver execute pwm_apply_cansleep in atomic context
  * @list: list node for internal use
  * @pwms: array of PWM devices allocated by the framework
  */
@@ -299,6 +300,7 @@ struct pwm_chip {
 	struct pwm_device * (*of_xlate)(struct pwm_chip *chip,
 					const struct of_phandle_args *args);
 	unsigned int of_pwm_n_cells;
+	bool atomic;
 
 	/* only used internally by the PWM framework */
 	struct list_head list;
@@ -308,6 +310,7 @@ struct pwm_chip {
 #if IS_ENABLED(CONFIG_PWM)
 /* PWM user APIs */
 int pwm_apply_cansleep(struct pwm_device *pwm, const struct pwm_state *state);
+int pwm_apply_atomic(struct pwm_device *pwm, const struct pwm_state *state);
 int pwm_adjust_config(struct pwm_device *pwm);
 
 /**
@@ -378,6 +381,17 @@ static inline void pwm_disable(struct pwm_device *pwm)
 	pwm_apply_cansleep(pwm, &state);
 }
 
+/**
+ * pwm_is_atomic() - is pwm_apply_atomic() supported?
+ * @pwm: PWM device
+ *
+ * Returns: true pwm_apply_atomic() can be called from atomic context.
+ */
+static inline bool pwm_is_atomic(struct pwm_device *pwm)
+{
+	return pwm->chip->atomic;
+}
+
 /* PWM provider APIs */
 int pwm_capture(struct pwm_device *pwm, struct pwm_capture *result,
 		unsigned long timeout);
@@ -406,16 +420,27 @@ struct pwm_device *devm_fwnode_pwm_get(struct device *dev,
 				       struct fwnode_handle *fwnode,
 				       const char *con_id);
 #else
+static inline bool pwm_is_atomic(struct pwm_device *pwm)
+{
+	return false;
+}
+
 static inline int pwm_apply_cansleep(struct pwm_device *pwm,
 				     const struct pwm_state *state)
 {
 	might_sleep();
-	return -ENOTSUPP;
+	return -EOPNOTSUPP;
+}
+
+static inline int pwm_apply_atomic(struct pwm_device *pwm,
+				   const struct pwm_state *state)
+{
+	return -EOPNOTSUPP;
 }
 
 static inline int pwm_adjust_config(struct pwm_device *pwm)
 {
-	return -ENOTSUPP;
+	return -EOPNOTSUPP;
 }
 
 static inline int pwm_config(struct pwm_device *pwm, int duty_ns,
-- 
2.42.1

[PATCH v5 3/4] pwm: bcm2835: allow pwm driver to be used in atomic context

[Sean Young]

clk_get_rate() may do a mutex lock. Fetch the clock rate once, and prevent
rate changes using clk_rate_exclusive_get().

Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/pwm/pwm-bcm2835.c | 31 +++++++++++++++++++++----------
 1 file changed, 21 insertions(+), 10 deletions(-)

diff --git a/drivers/pwm/pwm-bcm2835.c b/drivers/pwm/pwm-bcm2835.c
index 9777babd5b95c..52748194a3dad 100644
--- a/drivers/pwm/pwm-bcm2835.c
+++ b/drivers/pwm/pwm-bcm2835.c
@@ -28,6 +28,7 @@ struct bcm2835_pwm {
 	struct device *dev;
 	void __iomem *base;
 	struct clk *clk;
+	unsigned long rate;
 };
 
 static inline struct bcm2835_pwm *to_bcm2835_pwm(struct pwm_chip *chip)
@@ -63,17 +64,11 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 {
 
 	struct bcm2835_pwm *pc = to_bcm2835_pwm(chip);
-	unsigned long rate = clk_get_rate(pc->clk);
 	unsigned long long period_cycles;
 	u64 max_period;
 
 	u32 val;
 
-	if (!rate) {
-		dev_err(pc->dev, "failed to get clock rate\n");
-		return -EINVAL;
-	}
-
 	/*
 	 * period_cycles must be a 32 bit value, so period * rate / NSEC_PER_SEC
 	 * must be <= U32_MAX. As U32_MAX * NSEC_PER_SEC < U64_MAX the
@@ -88,13 +83,13 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	 * <=> period < ((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate
 	 * <=> period <= ceil((U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC/2) / rate) - 1
 	 */
-	max_period = DIV_ROUND_UP_ULL((u64)U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC / 2, rate) - 1;
+	max_period = DIV_ROUND_UP_ULL((u64)U32_MAX * NSEC_PER_SEC + NSEC_PER_SEC / 2, pc->rate) - 1;
 
 	if (state->period > max_period)
 		return -EINVAL;
 
 	/* set period */
-	period_cycles = DIV_ROUND_CLOSEST_ULL(state->period * rate, NSEC_PER_SEC);
+	period_cycles = DIV_ROUND_CLOSEST_ULL(state->period * pc->rate, NSEC_PER_SEC);
 
 	/* don't accept a period that is too small */
 	if (period_cycles < PERIOD_MIN)
@@ -103,7 +98,7 @@ static int bcm2835_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
 	writel(period_cycles, pc->base + PERIOD(pwm->hwpwm));
 
 	/* set duty cycle */
-	val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * rate, NSEC_PER_SEC);
+	val = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * pc->rate, NSEC_PER_SEC);
 	writel(val, pc->base + DUTY(pwm->hwpwm));
 
 	/* set polarity */
@@ -151,14 +146,29 @@ static int bcm2835_pwm_probe(struct platform_device *pdev)
 		return dev_err_probe(&pdev->dev, PTR_ERR(pc->clk),
 				     "clock not found\n");
 
+	ret = clk_rate_exclusive_get(pc->clk);
+	if (ret)
+		return dev_err_probe(&pdev->dev, ret,
+				     "fail to get exclusive rate\n");
+
+	pc->rate = clk_get_rate(pc->clk);
+	if (!pc->rate) {
+		clk_rate_exclusive_put(pc->clk);
+		return dev_err_probe(&pdev->dev, -EINVAL,
+				     "failed to get clock rate\n");
+	}
+
 	pc->chip.dev = &pdev->dev;
 	pc->chip.ops = &bcm2835_pwm_ops;
+	pc->chip.atomic = true;
 	pc->chip.npwm = 2;
 
 	ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
-	if (ret < 0)
+	if (ret < 0) {
+		clk_rate_exclusive_put(pc->clk);
 		return dev_err_probe(&pdev->dev, ret,
 				     "failed to add pwmchip\n");
+	}
 
 	return 0;
 }
@@ -167,6 +177,7 @@ static int bcm2835_pwm_suspend(struct device *dev)
 {
 	struct bcm2835_pwm *pc = dev_get_drvdata(dev);
 
+	clk_rate_exclusive_put(pc->clk);
 	clk_disable_unprepare(pc->clk);
 
 	return 0;
-- 
2.42.1

[PATCH v5 4/4] media: pwm-ir-tx: trigger edges from hrtimer interrupt context

[Sean Young]

This makes the generated IR much more precise. Before this change, the
driver is unreliable and many users opted to use gpio-ir-tx instead.

Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/media/rc/pwm-ir-tx.c | 79 ++++++++++++++++++++++++++++++++++--
 1 file changed, 76 insertions(+), 3 deletions(-)

diff --git a/drivers/media/rc/pwm-ir-tx.c b/drivers/media/rc/pwm-ir-tx.c
index ccb86890adcea..5465bd38d9412 100644
--- a/drivers/media/rc/pwm-ir-tx.c
+++ b/drivers/media/rc/pwm-ir-tx.c
@@ -10,6 +10,8 @@
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/hrtimer.h>
+#include <linux/completion.h>
 #include <media/rc-core.h>
 
 #define DRIVER_NAME	"pwm-ir-tx"
@@ -17,8 +19,14 @@
 
 struct pwm_ir {
 	struct pwm_device *pwm;
-	unsigned int carrier;
-	unsigned int duty_cycle;
+	struct hrtimer timer;
+	struct completion tx_done;
+	struct pwm_state *state;
+	u32 carrier;
+	u32 duty_cycle;
+	uint *txbuf;
+	uint txbuf_len;
+	uint txbuf_index;
 };
 
 static const struct of_device_id pwm_ir_of_match[] = {
@@ -82,6 +90,62 @@ static int pwm_ir_tx(struct rc_dev *dev, unsigned int *txbuf,
 	return count;
 }
 
+static int pwm_ir_tx_atomic(struct rc_dev *dev, unsigned int *txbuf,
+			    unsigned int count)
+{
+	struct pwm_ir *pwm_ir = dev->priv;
+	struct pwm_device *pwm = pwm_ir->pwm;
+	struct pwm_state state;
+
+	pwm_init_state(pwm, &state);
+
+	state.period = DIV_ROUND_CLOSEST(NSEC_PER_SEC, pwm_ir->carrier);
+	pwm_set_relative_duty_cycle(&state, pwm_ir->duty_cycle, 100);
+
+	pwm_ir->txbuf = txbuf;
+	pwm_ir->txbuf_len = count;
+	pwm_ir->txbuf_index = 0;
+	pwm_ir->state = &state;
+
+	hrtimer_start(&pwm_ir->timer, 0, HRTIMER_MODE_REL);
+
+	wait_for_completion(&pwm_ir->tx_done);
+
+	return count;
+}
+
+static enum hrtimer_restart pwm_ir_timer(struct hrtimer *timer)
+{
+	struct pwm_ir *pwm_ir = container_of(timer, struct pwm_ir, timer);
+	ktime_t now;
+
+	/*
+	 * If we happen to hit an odd latency spike, loop through the
+	 * pulses until we catch up.
+	 */
+	do {
+		u64 ns;
+
+		pwm_ir->state->enabled = !(pwm_ir->txbuf_index % 2);
+		pwm_apply_atomic(pwm_ir->pwm, pwm_ir->state);
+
+		if (pwm_ir->txbuf_index >= pwm_ir->txbuf_len) {
+			complete(&pwm_ir->tx_done);
+
+			return HRTIMER_NORESTART;
+		}
+
+		ns = US_TO_NS(pwm_ir->txbuf[pwm_ir->txbuf_index]);
+		hrtimer_add_expires_ns(timer, ns);
+
+		pwm_ir->txbuf_index++;
+
+		now = timer->base->get_time();
+	} while (hrtimer_get_expires_tv64(timer) < now);
+
+	return HRTIMER_RESTART;
+}
+
 static int pwm_ir_probe(struct platform_device *pdev)
 {
 	struct pwm_ir *pwm_ir;
@@ -103,10 +167,19 @@ static int pwm_ir_probe(struct platform_device *pdev)
 	if (!rcdev)
 		return -ENOMEM;
 
+	if (pwm_is_atomic(pwm_ir->pwm)) {
+		init_completion(&pwm_ir->tx_done);
+		hrtimer_init(&pwm_ir->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+		pwm_ir->timer.function = pwm_ir_timer;
+		rcdev->tx_ir = pwm_ir_tx_atomic;
+	} else {
+		dev_info(&pdev->dev, "tx will not be accurate as pwm device does not support atomic mode");
+		rcdev->tx_ir = pwm_ir_tx;
+	}
+
 	rcdev->priv = pwm_ir;
 	rcdev->driver_name = DRIVER_NAME;
 	rcdev->device_name = DEVICE_NAME;
-	rcdev->tx_ir = pwm_ir_tx;
 	rcdev->s_tx_duty_cycle = pwm_ir_set_duty_cycle;
 	rcdev->s_tx_carrier = pwm_ir_set_carrier;
 
-- 
2.42.1

Re: [PATCH v5 0/4] Improve pwm-ir-tx precision

[Sean Young]

On Sat, Nov 18, 2023 at 04:16:16PM +0000, Sean Young wrote:
> The pwm-ir-tx driver has to turn the pwm signal on and off, and suffers
> from delays as this is done in process context. Make this work in atomic
> context.

Hi Uwe,

Do you have any comments on this series?

I hope you don't dislike the pwm_apply_atomic()/pwm_apply_cansleep(), I am
not wedded to this name, it's just me reading the room and thinking that
would be the most acceptable to everyone - I may have misread this.

Thank you for any feedback

Sean

> 
> changes:
> 
> v5:
>  - Use dev_err_probe() as Uwe suggested
>  - rebase
> 
> v4:
>  - Split out the pwm_apply_state() rename into seperate commit
>  - Atomic pwm function is called pwm_apply_atomic() and sleeping
>    counterpart pwm_apply_cansleep()
>  - Fix commit messages
> 
> v3:
>  - Renamed pwm_apply_state() to pwm_apply_cansleep()
>  - Moved pwm atomic to struct pwm_chip
>  - Fixed pwm docs
>  - Other minor code review comments
> 
> v2:
>  - Simplified the pwm ir tx based on Ivaylo Dimitrov suggestions
>  - Renamed pwm_can_sleep() to pwm_is_atomic
>  - Fix sleeping issue in pwm-bcm2835 (clk_get_rate() can sleep)
>  - use non_block_start() in pwm to check atomic-ness
> 
> 
> Sean Young (4):
>   pwm: rename pwm_apply_state() to pwm_apply_cansleep()
>   pwm: make it possible to apply pwm changes in atomic context
>   pwm: bcm2835: allow pwm driver to be used in atomic context
>   media: pwm-ir-tx: trigger edges from hrtimer interrupt context
> 
>  Documentation/driver-api/pwm.rst              | 17 +++-
>  .../gpu/drm/i915/display/intel_backlight.c    |  6 +-
>  drivers/gpu/drm/solomon/ssd130x.c             |  2 +-
>  drivers/hwmon/pwm-fan.c                       |  8 +-
>  drivers/input/misc/da7280.c                   |  4 +-
>  drivers/input/misc/pwm-beeper.c               |  4 +-
>  drivers/input/misc/pwm-vibra.c                |  8 +-
>  drivers/leds/leds-pwm.c                       |  2 +-
>  drivers/leds/rgb/leds-pwm-multicolor.c        |  4 +-
>  drivers/media/rc/pwm-ir-tx.c                  | 83 +++++++++++++++++--
>  drivers/platform/x86/lenovo-yogabook.c        |  2 +-
>  drivers/pwm/core.c                            | 75 +++++++++++++----
>  drivers/pwm/pwm-bcm2835.c                     | 31 ++++---
>  drivers/pwm/pwm-renesas-tpu.c                 |  1 -
>  drivers/pwm/pwm-twl-led.c                     |  2 +-
>  drivers/pwm/pwm-vt8500.c                      |  2 +-
>  drivers/pwm/sysfs.c                           | 10 +--
>  drivers/regulator/pwm-regulator.c             |  4 +-
>  drivers/video/backlight/lm3630a_bl.c          |  2 +-
>  drivers/video/backlight/lp855x_bl.c           |  2 +-
>  drivers/video/backlight/pwm_bl.c              | 12 +--
>  drivers/video/fbdev/ssd1307fb.c               |  2 +-
>  include/linux/pwm.h                           | 57 +++++++++----
>  23 files changed, 248 insertions(+), 92 deletions(-)
> 
> -- 
> 2.42.1
> 

Re: [PATCH v5 1/4] pwm: rename pwm_apply_state() to pwm_apply_cansleep()

[Lee Jones]

On Sat, 18 Nov 2023, Sean Young wrote:

> In order to introduce a pwm api which can be used from atomic context,
> we will need two functions for applying pwm changes:
> 
> 	int pwm_apply_cansleep(struct pwm *, struct pwm_state *);
> 	int pwm_apply_atomic(struct pwm *, struct pwm_state *);
> 
> This commit just deals with renaming pwm_apply_state(), a following
> commit will introduce the pwm_apply_atomic() function.
> 
> Acked-by: Hans de Goede <hdegoede@redhat.com>
> Acked-by: Jani Nikula <jani.nikula@intel.com>
> Signed-off-by: Sean Young <sean@mess.org>
> ---
>  Documentation/driver-api/pwm.rst              |  8 +++---
>  .../gpu/drm/i915/display/intel_backlight.c    |  6 ++--
>  drivers/gpu/drm/solomon/ssd130x.c             |  2 +-
>  drivers/hwmon/pwm-fan.c                       |  8 +++---
>  drivers/input/misc/da7280.c                   |  4 +--
>  drivers/input/misc/pwm-beeper.c               |  4 +--
>  drivers/input/misc/pwm-vibra.c                |  8 +++---

>  drivers/leds/leds-pwm.c                       |  2 +-
>  drivers/leds/rgb/leds-pwm-multicolor.c        |  4 +--

Acked-by: Lee Jones <lee@kernel.org>

>  drivers/media/rc/pwm-ir-tx.c                  |  4 +--
>  drivers/platform/x86/lenovo-yogabook.c        |  2 +-
>  drivers/pwm/core.c                            | 18 ++++++------
>  drivers/pwm/pwm-twl-led.c                     |  2 +-
>  drivers/pwm/pwm-vt8500.c                      |  2 +-
>  drivers/pwm/sysfs.c                           | 10 +++----
>  drivers/regulator/pwm-regulator.c             |  4 +--

>  drivers/video/backlight/lm3630a_bl.c          |  2 +-
>  drivers/video/backlight/lp855x_bl.c           |  2 +-
>  drivers/video/backlight/pwm_bl.c              | 12 ++++----

Acked-by: Lee Jones <lee@kernel.org>

>  drivers/video/fbdev/ssd1307fb.c               |  2 +-
>  include/linux/pwm.h                           | 28 +++++++++----------
>  21 files changed, 67 insertions(+), 67 deletions(-)

[...]

-- 
Lee Jones [李琼斯]

Re: [PATCH v5 0/4] Improve pwm-ir-tx precision

[Uwe Kleine-König]

[-- Attachment #1: Type: text/plain, Size: 913 bytes --]

Hello,

On Wed, Nov 22, 2023 at 08:51:51AM +0000, Sean Young wrote:
> On Sat, Nov 18, 2023 at 04:16:16PM +0000, Sean Young wrote:
> > The pwm-ir-tx driver has to turn the pwm signal on and off, and suffers
> > from delays as this is done in process context. Make this work in atomic
> > context.
> 
> Hi Uwe,
> 
> Do you have any comments on this series?
> 
> I hope you don't dislike the pwm_apply_atomic()/pwm_apply_cansleep(), I am
> not wedded to this name, it's just me reading the room and thinking that
> would be the most acceptable to everyone - I may have misread this.
> 
> Thank you for any feedback

I didn't find much time to look into it. Skimming over it, I like it.
I'll take a deeper look soon.

Best regards
Uwe

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

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 488 bytes --]

Re: [PATCH v5 0/4] Improve pwm-ir-tx precision

[Sean Young]

Hello,

On Thu, Nov 23, 2023 at 05:58:42PM +0100, Uwe Kleine-König wrote:
> On Wed, Nov 22, 2023 at 08:51:51AM +0000, Sean Young wrote:
> > On Sat, Nov 18, 2023 at 04:16:16PM +0000, Sean Young wrote:
> > > The pwm-ir-tx driver has to turn the pwm signal on and off, and suffers
> > > from delays as this is done in process context. Make this work in atomic
> > > context.
> > 
> > Hi Uwe,
> > 
> > Do you have any comments on this series?
> > 
> > I hope you don't dislike the pwm_apply_atomic()/pwm_apply_cansleep(), I am
> > not wedded to this name, it's just me reading the room and thinking that
> > would be the most acceptable to everyone - I may have misread this.
> > 
> > Thank you for any feedback
> 
> I didn't find much time to look into it. Skimming over it, I like it.
> I'll take a deeper look soon.

Great, thanks! No rush just wanted to make sure it wasn't forgotten.


Sean

Re: [PATCH v5 1/4] pwm: rename pwm_apply_state() to pwm_apply_cansleep()

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 744 bytes --]

On Sat, Nov 18, 2023 at 04:16:17PM +0000, Sean Young wrote:
> In order to introduce a pwm api which can be used from atomic context,
> we will need two functions for applying pwm changes:
> 
> 	int pwm_apply_cansleep(struct pwm *, struct pwm_state *);
> 	int pwm_apply_atomic(struct pwm *, struct pwm_state *);
> 
> This commit just deals with renaming pwm_apply_state(), a following
> commit will introduce the pwm_apply_atomic() function.

Sorry, I still don't agree with that _cansleep suffix. I think it's the
wrong terminology. Just because something can sleep doesn't mean that it
ever will. "Might sleep" is much more accurate because it says exactly
what might happen and indicates what we're guarding against.

Thierry

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v5 2/4] pwm: make it possible to apply pwm changes in atomic context

[Thierry Reding]

[-- Attachment #1: Type: text/plain, Size: 966 bytes --]

On Sat, Nov 18, 2023 at 04:16:18PM +0000, Sean Young wrote:
[...]
> diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> index c4b066f7c5097..495aba06c64c3 100644
> --- a/include/linux/pwm.h
> +++ b/include/linux/pwm.h
> @@ -286,6 +286,7 @@ struct pwm_ops {
>   * @npwm: number of PWMs controlled by this chip
>   * @of_xlate: request a PWM device given a device tree PWM specifier
>   * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
> + * @atomic: can the driver execute pwm_apply_cansleep in atomic context

I'm a little reluctant to suggest that we rename this to might_sleep as
well because it would require that we audit each and every driver to set
this properly, since by default all devices have so far been defaulting
to "might_sleep". But then again, I think that's something that we're
going to need to do at some point anyway.

In the interim, I think we could keep it like this and address this as a
follow-up.

Thierry

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v5 2/4] pwm: make it possible to apply pwm changes in atomic context

[Sean Young]

On Fri, Nov 24, 2023 at 02:36:51PM +0100, Thierry Reding wrote:
> On Sat, Nov 18, 2023 at 04:16:18PM +0000, Sean Young wrote:
> [...]
> > diff --git a/include/linux/pwm.h b/include/linux/pwm.h
> > index c4b066f7c5097..495aba06c64c3 100644
> > --- a/include/linux/pwm.h
> > +++ b/include/linux/pwm.h
> > @@ -286,6 +286,7 @@ struct pwm_ops {
> >   * @npwm: number of PWMs controlled by this chip
> >   * @of_xlate: request a PWM device given a device tree PWM specifier
> >   * @of_pwm_n_cells: number of cells expected in the device tree PWM specifier
> > + * @atomic: can the driver execute pwm_apply_cansleep in atomic context
> 
> I'm a little reluctant to suggest that we rename this to might_sleep as
> well because it would require that we audit each and every driver to set
> this properly, since by default all devices have so far been defaulting
> to "might_sleep". But then again, I think that's something that we're
> going to need to do at some point anyway.
> 
> In the interim, I think we could keep it like this and address this as a
> follow-up.

Yes, I agree that the name atomic is not ideal. However, calling it
might_sleep means we have to touch every driver. That's not impossible,
but not ideal either.

For now, I'll leave it as is.


Sean

Re: [PATCH v5 1/4] pwm: rename pwm_apply_state() to pwm_apply_cansleep()

[Sean Young]

On Fri, Nov 24, 2023 at 02:31:18PM +0100, Thierry Reding wrote:
> On Sat, Nov 18, 2023 at 04:16:17PM +0000, Sean Young wrote:
> > In order to introduce a pwm api which can be used from atomic context,
> > we will need two functions for applying pwm changes:
> > 
> > 	int pwm_apply_cansleep(struct pwm *, struct pwm_state *);
> > 	int pwm_apply_atomic(struct pwm *, struct pwm_state *);
> > 
> > This commit just deals with renaming pwm_apply_state(), a following
> > commit will introduce the pwm_apply_atomic() function.
> 
> Sorry, I still don't agree with that _cansleep suffix. I think it's the
> wrong terminology. Just because something can sleep doesn't mean that it
> ever will. "Might sleep" is much more accurate because it says exactly
> what might happen and indicates what we're guarding against.

Sorry, I forgot about this in the last round. I've renamed it _might_sleep
in v6 which I'll post shortly.


Sean