From: Marek Vasut marex@denx.de
[ Upstream commit 38ba83598633373f47951384cfc389181c8d1bed ]
If the PWM is exported but not enabled, do not call pwm_class_apply_state(). First of all, in this case, period may still be unconfigured and this would make pwm_class_apply_state() return -EINVAL, and then suspend would fail. Second, it makes little sense to apply state onto PWM that is not enabled before suspend.
Failing case: " $ echo 1 > /sys/class/pwm/pwmchip4/export $ echo mem > /sys/power/state ... pwm pwmchip4: PM: dpm_run_callback(): pwm_class_suspend+0x1/0xa8 returns -22 pwm pwmchip4: PM: failed to suspend: error -22 PM: Some devices failed to suspend, or early wake event detected "
Working case: " $ echo 1 > /sys/class/pwm/pwmchip4/export $ echo 100 > /sys/class/pwm/pwmchip4/pwm1/period $ echo 10 > /sys/class/pwm/pwmchip4/pwm1/duty_cycle $ echo mem > /sys/power/state ... "
Do not call pwm_class_apply_state() in case the PWM is disabled to fix this issue.
Fixes: 7fd4edc57bbae ("pwm: sysfs: Add suspend/resume support") Signed-off-by: Marek Vasut marex@denx.de Fixes: ef2bf4997f7d ("pwm: Improve args checking in pwm_apply_state()") Reviewed-by: Brian Norris briannorris@chromium.org Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Signed-off-by: Thierry Reding thierry.reding@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pwm/sysfs.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/pwm/sysfs.c b/drivers/pwm/sysfs.c index e7db8e45001cf..ba125253857ea 100644 --- a/drivers/pwm/sysfs.c +++ b/drivers/pwm/sysfs.c @@ -424,6 +424,13 @@ static int pwm_class_resume_npwm(struct device *parent, unsigned int npwm) if (!export) continue;
+ /* If pwmchip was not enabled before suspend, do nothing. */ + if (!export->suspend.enabled) { + /* release lock taken in pwm_class_get_state */ + mutex_unlock(&export->lock); + continue; + } + state.enabled = export->suspend.enabled; ret = pwm_class_apply_state(export, pwm, &state); if (ret < 0) @@ -448,7 +455,17 @@ static int pwm_class_suspend(struct device *parent) if (!export) continue;
+ /* + * If pwmchip was not enabled before suspend, save + * state for resume time and do nothing else. + */ export->suspend = state; + if (!state.enabled) { + /* release lock taken in pwm_class_get_state */ + mutex_unlock(&export->lock); + continue; + } + state.enabled = false; ret = pwm_class_apply_state(export, pwm, &state); if (ret < 0) {