[PATCH v3 1/3] pwm: make it possible to apply pwm changes in atomic context

Sean Young
2023-10-17T09:29:58Z

Some drivers require sleeping, for example if the pwm device is connected
over i2c. The pwm-ir-tx requires precise timing, and sleeping causes havoc
with the generated IR signal when sleeping occurs.

This patch makes it possible to use pwm when the driver does not sleep,
by introducing the pwm_can_sleep() function.

Signed-off-by: Sean Young <sean@mess.org>
---
Documentation/driver-api/pwm.rst | 16 +++-
.../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 | 75 ++++++++++++++-----
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 | 6 +-
drivers/video/fbdev/ssd1307fb.c | 2 +-
include/linux/pwm.h | 57 ++++++++++----
22 files changed, 147 insertions(+), 76 deletions(-)

diff --git a/Documentation/driver-api/pwm.rst b/Documentation/driver-api/pwm.rst
index 3fdc95f7a1d15..a2fb5f8f6e1f8 100644
--- a/Documentation/driver-api/pwm.rst
+++ b/Documentation/driver-api/pwm.rst
@@ -41,7 +41,15 @@ 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);
+
+If the PWM support atomic mode, which can be determined with::
+
+ bool pwm_is_atomic(struct pwm_device *pwm);
+
+Then the PWM can be configured with::
+
+ int pwm_apply(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 +65,13 @@ 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 5a80b228d18ca..5045966d43039 100644
--- a/drivers/gpu/drm/solomon/ssd130x.c
+++ b/drivers/gpu/drm/solomon/ssd130x.c
@@ -267,7 +267,7 @@ 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 419b710984ab6..e1fe1fd8f189a 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 = duty > 0;
- 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 dc66e3405bf50..99896a59a25aa 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -382,8 +382,8 @@ 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_cansleep_debug(struct pwm_device *pwm,
+ const struct pwm_state *state)
{
struct pwm_state *last = &pwm->last;
struct pwm_chip *chip = pwm->chip;
@@ -489,24 +489,15 @@ static void pwm_apply_state_debug(struct pwm_device *pwm,
}

/**
- * pwm_apply_state() - 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_state(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_state() 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;
@@ -527,15 +518,63 @@ int pwm_apply_state(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_state_debug(pwm, state);
+ pwm_apply_cansleep_debug(pwm, state);

- return 0;
+ return err;
+}
+EXPORT_SYMBOL_GPL(pwm_apply_cansleep);
+
+/**
+ * pwm_apply() - atomically apply a new state to a PWM device
+ * Can be used from atomic context.
+ * @pwm: PWM device
+ * @state: new state to apply
+ */
+int pwm_apply(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_state);
+EXPORT_SYMBOL_GPL(pwm_apply);

/**
* pwm_capture() - capture and report a PWM signal
@@ -593,7 +632,7 @@ 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);
}

/*
@@ -616,7 +655,7 @@ 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-renesas-tpu.c b/drivers/pwm/pwm-renesas-tpu.c
index d7311614c846d..96797a33d8c62 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/drivers/pwm/pwm-twl-led.c b/drivers/pwm/pwm-twl-led.c
index 8fb84b4418538..a1fc2fa0d03e0 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 6d46db51daacc..3a815dfbf31ce 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 a51fbab963680..f2568aaae4769 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);
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 d2f9f690a9c14..373b5a4fe27dc 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -95,8 +95,8 @@ 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,
@@ -160,20 +160,20 @@ 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,
@@ -229,7 +229,7 @@ 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).
@@ -289,6 +289,7 @@ 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
*/
@@ -301,6 +302,7 @@ 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;
@@ -309,7 +311,8 @@ 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_apply(struct pwm_device *pwm, const struct pwm_state *state);
int pwm_adjust_config(struct pwm_device *pwm);

/**
@@ -337,7 +340,7 @@ 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);
}

/**
@@ -358,7 +361,7 @@ 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);
}

/**
@@ -377,7 +380,18 @@ static inline void pwm_disable(struct pwm_device *pwm)
return;

state.enabled = false;
- pwm_apply_state(pwm, &state);
+ pwm_apply_cansleep(pwm, &state);
+}
+
+/**
+ * pwm_is_atomic() - is pwm_apply() supported?
+ * @pwm: PWM device
+ *
+ * Returns: true pwm_apply() can be called from atomic context.
+ */
+static inline bool pwm_is_atomic(struct pwm_device *pwm)
+{
+ return pwm->chip->atomic;
}

/* PWM provider APIs */
@@ -408,16 +422,27 @@ 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 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(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,
@@ -536,7 +561,7 @@ 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 {
--
2.42.0