| Message ID | 1549901522-15071-4-git-send-email-fabrice.gasnier@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add PM support to STM32 LP Timer drivers | expand |
Hello Fabrice, On Mon, Feb 11, 2019 at 05:12:02PM +0100, Fabrice Gasnier wrote: > 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 <thierry.reding@gmail.com> > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> > --- > 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); IMHO it's surprising that devm_of_pwm_get() does more than of_pwm_get() + devres stuff. I'd put device_link_add() into of_pwm_get(). Best regards Uwe
On 2/11/19 8:06 PM, Uwe Kleine-König wrote: > Hello Fabrice, > > On Mon, Feb 11, 2019 at 05:12:02PM +0100, Fabrice Gasnier wrote: >> 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 <thierry.reding@gmail.com> >> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> >> --- >> 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); > > IMHO it's surprising that devm_of_pwm_get() does more than of_pwm_get() > + devres stuff. I'd put device_link_add() into of_pwm_get(). Hi Uwe, I also agree with this. But I think this implies modifying the API for of_pwm_get(): /** * of_pwm_get() - request a PWM via the PWM framework + * @dev: device for PWM consumer * @np: device node to get the PWM from * @con_id: consumer name It seems there aren't much of_pwm_get() users currently. Does this look sensible ? Best regards, Fabrice > > Best regards > Uwe >
Hello Fabrice, On Tue, Feb 12, 2019 at 09:31:37AM +0100, Fabrice Gasnier wrote: > On 2/11/19 8:06 PM, Uwe Kleine-König wrote: > > On Mon, Feb 11, 2019 at 05:12:02PM +0100, Fabrice Gasnier wrote: > >> @@ -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); > > > > IMHO it's surprising that devm_of_pwm_get() does more than of_pwm_get() > > + devres stuff. I'd put device_link_add() into of_pwm_get(). > > Hi Uwe, > > I also agree with this. But I think this implies modifying the API for > of_pwm_get(): > /** > * of_pwm_get() - request a PWM via the PWM framework > + * @dev: device for PWM consumer > * @np: device node to get the PWM from > * @con_id: consumer name > > It seems there aren't much of_pwm_get() users currently. > Does this look sensible ? In my eyes this looks sensible, yes. Best regards Uwe
On 2/12/19 10:03 AM, Uwe Kleine-König wrote: > Hello Fabrice, > > On Tue, Feb 12, 2019 at 09:31:37AM +0100, Fabrice Gasnier wrote: >> On 2/11/19 8:06 PM, Uwe Kleine-König wrote: >>> On Mon, Feb 11, 2019 at 05:12:02PM +0100, Fabrice Gasnier wrote: >>>> @@ -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); >>> >>> IMHO it's surprising that devm_of_pwm_get() does more than of_pwm_get() >>> + devres stuff. I'd put device_link_add() into of_pwm_get(). >> >> Hi Uwe, >> >> I also agree with this. But I think this implies modifying the API for >> of_pwm_get(): >> /** >> * of_pwm_get() - request a PWM via the PWM framework >> + * @dev: device for PWM consumer >> * @np: device node to get the PWM from >> * @con_id: consumer name >> >> It seems there aren't much of_pwm_get() users currently. >> Does this look sensible ? > > In my eyes this looks sensible, yes. Hello Uwe, I just sent a v3 with that change, Thanks Fabrice > > Best regards > Uwe >
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); }
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 <thierry.reding@gmail.com> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> --- drivers/pwm/core.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)