Commit 4ad91a22 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Thierry Reding
Browse files

pwm: Make it explicit that pwm_apply_state() might sleep 



At least some implementations sleep. So mark pwm_apply_state() with a
might_sleep() to make callers aware. In the worst case this uncovers a
valid atomic user, then we revert this patch and at least gained some more
knowledge and then can work on a concept similar to
gpio_get_value/gpio_get_value_cansleep.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
parent 27d9a4d6

drivers/pwm/core.c

+9 −0
Original line number Diff line number Diff line
@@ -532,6 +532,15 @@ int pwm_apply_state(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;

include/linux/pwm.h

+4 −0
Original line number Diff line number Diff line
@@ -441,6 +441,7 @@ static inline void pwm_free(struct pwm_device *pwm) 
static inline int pwm_apply_state(struct pwm_device *pwm,

				  const struct pwm_state *state)

{

	might_sleep();

	return -ENOTSUPP;

}
@@ -452,6 +453,7 @@ static inline int pwm_adjust_config(struct pwm_device *pwm) 
static inline int pwm_config(struct pwm_device *pwm, int duty_ns,

			     int period_ns)

{

	might_sleep();

	return -EINVAL;

}
@@ -464,11 +466,13 @@ static inline int pwm_capture(struct pwm_device *pwm, 


static inline int pwm_enable(struct pwm_device *pwm)

{

	might_sleep();

	return -EINVAL;

}



static inline void pwm_disable(struct pwm_device *pwm)

{

	might_sleep();

}



static inline int pwm_set_chip_data(struct pwm_device *pwm, void *data)