On Tue, Sep 11, 2018 at 07:45:32PM +0200, Hans de Goede wrote:
> Add a helper function to properly get / put the pwm's runtime_pm
> reference when changing from enabled to disable or vice versa.
>
> And use this to ensure the pwm's runtime_pm reference is properly
> released on remove.
>
Can you provide a test sequence to reproduce the issue?
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
> drivers/pwm/pwm-lpss.c | 47 +++++++++++++++++++++++++++++-------------
> 1 file changed, 33 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/pwm/pwm-lpss.c b/drivers/pwm/pwm-lpss.c
> index e602835fd6de..d39158800baa 100644
> --- a/drivers/pwm/pwm-lpss.c
> +++ b/drivers/pwm/pwm-lpss.c
> @@ -120,43 +120,58 @@ static inline void pwm_lpss_cond_enable(struct pwm_device *pwm, bool cond)
> pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_ENABLE);
> }
>
> +static void pwm_lpss_get_put_runtime_pm(struct pwm_chip *chip,
> + bool old_enabled, bool new_enabled)
> +{
> + if (new_enabled == old_enabled)
> + return;
> +
> + if (new_enabled)
> + pm_runtime_get(chip->dev);
> + else
> + pm_runtime_put(chip->dev);
> +}
> +
> static int pwm_lpss_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> struct pwm_state *state)
> {
> struct pwm_lpss_chip *lpwm = to_lpwm(chip);
> - int ret;
> + int ret = 0;
> +
> + pm_runtime_get_sync(chip->dev);
>
> if (state->enabled) {
> if (!pwm_is_enabled(pwm)) {
> - pm_runtime_get_sync(chip->dev);
> ret = pwm_lpss_is_updating(pwm);
> - if (ret) {
> - pm_runtime_put(chip->dev);
> - return ret;
> - }
> + if (ret)
> + goto out;
> +
> pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
> pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
> pwm_lpss_cond_enable(pwm, lpwm->info->bypass == false);
> ret = pwm_lpss_wait_for_update(pwm);
> - if (ret) {
> - pm_runtime_put(chip->dev);
> - return ret;
> - }
> + if (ret)
> + goto out;
> +
> pwm_lpss_cond_enable(pwm, lpwm->info->bypass == true);
> } else {
> ret = pwm_lpss_is_updating(pwm);
> if (ret)
> - return ret;
> + goto out;
> +
> pwm_lpss_prepare(lpwm, pwm, state->duty_cycle, state->period);
> pwm_lpss_write(pwm, pwm_lpss_read(pwm) | PWM_SW_UPDATE);
> - return pwm_lpss_wait_for_update(pwm);
> + ret = pwm_lpss_wait_for_update(pwm);
> }
> } else if (pwm_is_enabled(pwm)) {
> pwm_lpss_write(pwm, pwm_lpss_read(pwm) & ~PWM_ENABLE);
> - pm_runtime_put(chip->dev);
> }
>
> - return 0;
> + pwm_lpss_get_put_runtime_pm(chip, pwm_is_enabled(pwm), state->enabled);
> +
> +out:
> + pm_runtime_put(chip->dev);
> + return ret;
> }
>
> static const struct pwm_ops pwm_lpss_ops = {
> @@ -205,6 +220,10 @@ EXPORT_SYMBOL_GPL(pwm_lpss_probe);
>
> int pwm_lpss_remove(struct pwm_lpss_chip *lpwm)
> {
> + bool enabled = pwm_is_enabled(&lpwm->chip.pwms[0]);
> +
> + pwm_lpss_get_put_runtime_pm(&lpwm->chip, enabled, false);
> +
> return pwmchip_remove(&lpwm->chip);
> }
> EXPORT_SYMBOL_GPL(pwm_lpss_remove);
> --
> 2.19.0.rc0
>
--
With Best Regards,
Andy Shevchenko
