Add a device link between the PWM consumer and the PWM provider. This enforces the PWM user to get suspended before the PWM provider. It allows proper synchronization of suspend/resume sequences: the PWM user is responsible for properly stopping PWM, before the provider gets suspended: see [1]. Add the device link in: - pwm_get() - devm_pwm_get() - devm_of_pwm_get() as it requires a reference to the device for the PWM consumer.
[1] https://lkml.org/lkml/2019/2/5/770 Suggested-by: Thierry Reding <[email protected]> Signed-off-by: Fabrice Gasnier <[email protected]> --- drivers/pwm/core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 1581f6a..2835e27 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -770,8 +770,13 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) int err; /* look up via DT first */ - if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) - return of_pwm_get(dev->of_node, con_id); + if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node) { + pwm = of_pwm_get(dev->of_node, con_id); + if (!IS_ERR(pwm)) + device_link_add(dev, pwm->chip->dev, + DL_FLAG_AUTOREMOVE_CONSUMER); + return pwm; + } /* * We look up the provider in the static table typically provided by @@ -851,6 +856,8 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id) pwm->args.period = chosen->period; pwm->args.polarity = chosen->polarity; + device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER); + return pwm; } EXPORT_SYMBOL_GPL(pwm_get); @@ -943,6 +950,8 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np, if (!IS_ERR(pwm)) { *ptr = pwm; devres_add(dev, ptr); + device_link_add(dev, pwm->chip->dev, + DL_FLAG_AUTOREMOVE_CONSUMER); } else { devres_free(ptr); } -- 1.9.1
