From 4ad91a227817ae48f931595d1101fc7100073ce9 Mon Sep 17 00:00:00 2001 From: Uwe Kleine-König Date: Thu, 9 Sep 2021 11:48:49 +0200 Subject: 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: Uwe Kleine-König Signed-off-by: Thierry Reding --- drivers/pwm/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'drivers') diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 4527f09a5c50..fb04a439462c 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -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; -- cgit v1.2.3