This patch series adds power management support for STM32 LP Timer:
- PWM driver
- Document the pinctrl states for sleep mode
It also adds device link between the PWM consumer and the PWM provider.
This allows proper sequencing for suspend/resume (e.g. user will likely
do a pwm_disable() before the PWM provider suspend executes), see [1].
[1] https://lkml.org/lkml/2019/2/5/770
---
Changes in v4:
- improve error handling when adding the PWM consumer device link.
Changes in v3:
- Move the device_link_add() call to of_pwm_get() as discussed with Uwe.
Changes in v2:
- Don't disable PWM channel in PWM provider: rather refuse to suspend
and report an error as suggested by Uwe and Thierry.
- Add patch 3/3 to propose device link addition.
- No updates for STM32 LP Timer IIO driver. Patches can be send separately.
Fabrice Gasnier (3):
dt-bindings: pwm-stm32-lp: document pinctrl sleep state
pwm: stm32-lp: Add power management support
pwm: core: add consumer device link
.../devicetree/bindings/pwm/pwm-stm32-lp.txt | 9 ++--
drivers/pwm/core.c | 50 ++++++++++++++++++++--
drivers/pwm/pwm-stm32-lp.c | 25 +++++++++++
include/linux/pwm.h | 6 ++-
4 files changed, 82 insertions(+), 8 deletions(-)
--
1.9.1
Add documentation for pinctrl sleep state on STM32 LPTimer PWM.
Signed-off-by: Fabrice Gasnier <[email protected]>
---
Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt b/Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt
index bd23302..6521bc4 100644
--- a/Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt
@@ -11,8 +11,10 @@ Required parameters:
bindings defined in pwm.txt.
Optional properties:
-- pinctrl-names: Set to "default".
-- pinctrl-0: Phandle pointing to pin configuration node for PWM.
+- pinctrl-names: Set to "default". An additional "sleep" state can be
+ defined to set pins in sleep state when in low power.
+- pinctrl-n: Phandle(s) pointing to pin configuration node for PWM,
+ respectively for "default" and "sleep" states.
Example:
timer@40002400 {
@@ -21,7 +23,8 @@ Example:
pwm {
compatible = "st,stm32-pwm-lp";
#pwm-cells = <3>;
- pinctrl-names = "default";
+ pinctrl-names = "default", "sleep";
pinctrl-0 = <&lppwm1_pins>;
+ pinctrl-1 = <&lppwm1_sleep_pins>;
};
};
--
1.9.1
Add suspend/resume PM sleep ops. When going to low power, enforce the PWM
channel isn't active. Let the PWM consumers disable it during their own
suspend sequence. Only perform a check here, and handle the pinctrl states.
See [1].
[1] https://lkml.org/lkml/2019/2/5/770
Signed-off-by: Fabrice Gasnier <[email protected]>
---
Changes in v2:
- Don't disable PWM channel: let the PWM user disable it. Refuse to
suspend in case it's been left enabled.
- Drop the ifdefs, use __maybe_unused instead.
---
drivers/pwm/pwm-stm32-lp.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c
index 0059b24c..2211a64 100644
--- a/drivers/pwm/pwm-stm32-lp.c
+++ b/drivers/pwm/pwm-stm32-lp.c
@@ -13,6 +13,7 @@
#include <linux/mfd/stm32-lptimer.h>
#include <linux/module.h>
#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
@@ -223,6 +224,29 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev)
return pwmchip_remove(&priv->chip);
}
+static int __maybe_unused stm32_pwm_lp_suspend(struct device *dev)
+{
+ struct stm32_pwm_lp *priv = dev_get_drvdata(dev);
+ struct pwm_state state;
+
+ pwm_get_state(&priv->chip.pwms[0], &state);
+ if (state.enabled) {
+ dev_err(dev, "The consumer didn't stop us (%s)\n",
+ priv->chip.pwms[0].label);
+ return -EBUSY;
+ }
+
+ return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int __maybe_unused stm32_pwm_lp_resume(struct device *dev)
+{
+ return pinctrl_pm_select_default_state(dev);
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend,
+ stm32_pwm_lp_resume);
+
static const struct of_device_id stm32_pwm_lp_of_match[] = {
{ .compatible = "st,stm32-pwm-lp", },
{},
@@ -235,6 +259,7 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev)
.driver = {
.name = "stm32-pwm-lp",
.of_match_table = of_match_ptr(stm32_pwm_lp_of_match),
+ .pm = &stm32_pwm_lp_pm_ops,
},
};
module_platform_driver(stm32_pwm_lp_driver);
--
1.9.1
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:
- of_pwm_get()
- pwm_get()
- devm_*pwm_get() variants
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]>
---
Changes in v4:
- rework error handling following Thierry's comments
- turn/split pr_debug() into dev_err()/pr_warn().
Changes in v3:
- add struct device to of_get_pwm() arguments to handle device link from
there as discussed with Uwe.
---
drivers/pwm/core.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
include/linux/pwm.h | 6 ++++--
2 files changed, 51 insertions(+), 5 deletions(-)
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
index 1581f6a..64e10a6 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -636,8 +636,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
return ERR_PTR(-EPROBE_DEFER);
}
+static struct device_link *pwm_device_link_add(struct device *dev,
+ struct pwm_device *pwm)
+{
+ struct device_link *dl;
+
+ if (!dev) {
+ /*
+ * No device for the PWM consumer has been provided. It may
+ * impact the PM sequence ordering: the PWM supplier may get
+ * suspended before the consumer.
+ */
+ pr_warn("no consumer dev, can't create device link to %s\n",
+ dev_name(pwm->chip->dev));
+ return NULL;
+ }
+
+ dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
+ if (!dl) {
+ dev_err(dev, "failed to create device link to %s\n",
+ dev_name(pwm->chip->dev));
+ return ERR_PTR(-EINVAL);
+ }
+
+ return dl;
+}
+
/**
* 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
*
@@ -655,10 +682,12 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
* Returns: A pointer to the requested PWM device or an ERR_PTR()-encoded
* error code on failure.
*/
-struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
+struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
+ const char *con_id)
{
struct pwm_device *pwm = NULL;
struct of_phandle_args args;
+ struct device_link *dl;
struct pwm_chip *pc;
int index = 0;
int err;
@@ -689,6 +718,14 @@ struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id)
if (IS_ERR(pwm))
goto put;
+ dl = pwm_device_link_add(dev, pwm);
+ if (IS_ERR(dl)) {
+ /* of_xlate ended up calling pwm_request_from_chip() */
+ pwm_free(pwm);
+ pwm = ERR_CAST(dl);
+ goto put;
+ }
+
/*
* If a consumer name was not given, try to look it up from the
* "pwm-names" property if it exists. Otherwise use the name of
@@ -764,6 +801,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
const char *dev_id = dev ? dev_name(dev) : NULL;
struct pwm_device *pwm;
struct pwm_chip *chip;
+ struct device_link *dl;
unsigned int best = 0;
struct pwm_lookup *p, *chosen = NULL;
unsigned int match;
@@ -771,7 +809,7 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
/* look up via DT first */
if (IS_ENABLED(CONFIG_OF) && dev && dev->of_node)
- return of_pwm_get(dev->of_node, con_id);
+ return of_pwm_get(dev, dev->of_node, con_id);
/*
* We look up the provider in the static table typically provided by
@@ -848,6 +886,12 @@ struct pwm_device *pwm_get(struct device *dev, const char *con_id)
if (IS_ERR(pwm))
return pwm;
+ dl = pwm_device_link_add(dev, pwm);
+ if (IS_ERR(dl)) {
+ pwm_free(pwm);
+ return ERR_CAST(dl);
+ }
+
pwm->args.period = chosen->period;
pwm->args.polarity = chosen->polarity;
@@ -939,7 +983,7 @@ struct pwm_device *devm_of_pwm_get(struct device *dev, struct device_node *np,
if (!ptr)
return ERR_PTR(-ENOMEM);
- pwm = of_pwm_get(np, con_id);
+ pwm = of_pwm_get(dev, np, con_id);
if (!IS_ERR(pwm)) {
*ptr = pwm;
devres_add(dev, ptr);
diff --git a/include/linux/pwm.h b/include/linux/pwm.h
index d5199b5..895e074 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -406,7 +406,8 @@ struct pwm_device *of_pwm_xlate_with_flags(struct pwm_chip *pc,
const struct of_phandle_args *args);
struct pwm_device *pwm_get(struct device *dev, const char *con_id);
-struct pwm_device *of_pwm_get(struct device_node *np, const char *con_id);
+struct pwm_device *of_pwm_get(struct device *dev, struct device_node *np,
+ const char *con_id);
void pwm_put(struct pwm_device *pwm);
struct pwm_device *devm_pwm_get(struct device *dev, const char *con_id);
@@ -494,7 +495,8 @@ static inline struct pwm_device *pwm_get(struct device *dev,
return ERR_PTR(-ENODEV);
}
-static inline struct pwm_device *of_pwm_get(struct device_node *np,
+static inline struct pwm_device *of_pwm_get(struct device *dev,
+ struct device_node *np,
const char *con_id)
{
return ERR_PTR(-ENODEV);
--
1.9.1
On Thu, 14 Feb 2019 11:25:49 +0100, Fabrice Gasnier wrote:
> Add documentation for pinctrl sleep state on STM32 LPTimer PWM.
>
> Signed-off-by: Fabrice Gasnier <[email protected]>
> ---
> Documentation/devicetree/bindings/pwm/pwm-stm32-lp.txt | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
Reviewed-by: Rob Herring <[email protected]>
Hello,
On Thu, Feb 14, 2019 at 11:25:51AM +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:
> - of_pwm_get()
> - pwm_get()
> - devm_*pwm_get() variants
> 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]>
> ---
> Changes in v4:
> - rework error handling following Thierry's comments
> - turn/split pr_debug() into dev_err()/pr_warn().
>
> Changes in v3:
> - add struct device to of_get_pwm() arguments to handle device link from
> there as discussed with Uwe.
> ---
> drivers/pwm/core.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
> include/linux/pwm.h | 6 ++++--
> 2 files changed, 51 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> index 1581f6a..64e10a6 100644
> --- a/drivers/pwm/core.c
> +++ b/drivers/pwm/core.c
> @@ -636,8 +636,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
> return ERR_PTR(-EPROBE_DEFER);
> }
>
> +static struct device_link *pwm_device_link_add(struct device *dev,
> + struct pwm_device *pwm)
> +{
> + struct device_link *dl;
> +
> + if (!dev) {
> + /*
> + * No device for the PWM consumer has been provided. It may
> + * impact the PM sequence ordering: the PWM supplier may get
> + * suspended before the consumer.
> + */
> + pr_warn("no consumer dev, can't create device link to %s\n",
> + dev_name(pwm->chip->dev));
Maybe use dev_warn(pwm->chip->dev, ...) ?
> + return NULL;
> + }
> +
> + dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
> + if (!dl) {
> + dev_err(dev, "failed to create device link to %s\n",
> + dev_name(pwm->chip->dev));
> + return ERR_PTR(-EINVAL);
broken indention.
> + }
> +
> + return dl;
> +}
> +
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
On 2/18/19 6:22 PM, Uwe Kleine-König wrote:
> Hello,
>
> On Thu, Feb 14, 2019 at 11:25:51AM +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:
>> - of_pwm_get()
>> - pwm_get()
>> - devm_*pwm_get() variants
>> 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]>
>> ---
>> Changes in v4:
>> - rework error handling following Thierry's comments
>> - turn/split pr_debug() into dev_err()/pr_warn().
>>
>> Changes in v3:
>> - add struct device to of_get_pwm() arguments to handle device link from
>> there as discussed with Uwe.
>> ---
>> drivers/pwm/core.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
>> include/linux/pwm.h | 6 ++++--
>> 2 files changed, 51 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
>> index 1581f6a..64e10a6 100644
>> --- a/drivers/pwm/core.c
>> +++ b/drivers/pwm/core.c
>> @@ -636,8 +636,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
>> return ERR_PTR(-EPROBE_DEFER);
>> }
>>
>> +static struct device_link *pwm_device_link_add(struct device *dev,
>> + struct pwm_device *pwm)
>> +{
>> + struct device_link *dl;
>> +
>> + if (!dev) {
>> + /*
>> + * No device for the PWM consumer has been provided. It may
>> + * impact the PM sequence ordering: the PWM supplier may get
>> + * suspended before the consumer.
>> + */
>> + pr_warn("no consumer dev, can't create device link to %s\n",
>> + dev_name(pwm->chip->dev));
>
> Maybe use dev_warn(pwm->chip->dev, ...) ?
Hi Uwe,
I'm wondering a bit about this: In this case, the caller that doesn't
provide a struct device *, PWM provider isn't responsible for that. So I
just hope this wouldn't be miss-leading ?
>
>> + return NULL;
>> + }
>> +
>> + dl = device_link_add(dev, pwm->chip->dev, DL_FLAG_AUTOREMOVE_CONSUMER);
>> + if (!dl) {
>> + dev_err(dev, "failed to create device link to %s\n",
>> + dev_name(pwm->chip->dev));
>> + return ERR_PTR(-EINVAL);
>
> broken indention.
Oops, I'll fix it.
Thanks,
Fabrice
>
>> + }
>> +
>> + return dl;
>> +}
>> +
>
> Best regards
> Uwe
>
On Tue, Feb 19, 2019 at 09:46:32AM +0100, Fabrice Gasnier wrote:
> On 2/18/19 6:22 PM, Uwe Kleine-K?nig wrote:
> > Hello,
> >
> > On Thu, Feb 14, 2019 at 11:25:51AM +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:
> >> - of_pwm_get()
> >> - pwm_get()
> >> - devm_*pwm_get() variants
> >> 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]>
> >> ---
> >> Changes in v4:
> >> - rework error handling following Thierry's comments
> >> - turn/split pr_debug() into dev_err()/pr_warn().
> >>
> >> Changes in v3:
> >> - add struct device to of_get_pwm() arguments to handle device link from
> >> there as discussed with Uwe.
> >> ---
> >> drivers/pwm/core.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
> >> include/linux/pwm.h | 6 ++++--
> >> 2 files changed, 51 insertions(+), 5 deletions(-)
> >>
> >> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
> >> index 1581f6a..64e10a6 100644
> >> --- a/drivers/pwm/core.c
> >> +++ b/drivers/pwm/core.c
> >> @@ -636,8 +636,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
> >> return ERR_PTR(-EPROBE_DEFER);
> >> }
> >>
> >> +static struct device_link *pwm_device_link_add(struct device *dev,
> >> + struct pwm_device *pwm)
> >> +{
> >> + struct device_link *dl;
> >> +
> >> + if (!dev) {
> >> + /*
> >> + * No device for the PWM consumer has been provided. It may
> >> + * impact the PM sequence ordering: the PWM supplier may get
> >> + * suspended before the consumer.
> >> + */
> >> + pr_warn("no consumer dev, can't create device link to %s\n",
> >> + dev_name(pwm->chip->dev));
> >
> > Maybe use dev_warn(pwm->chip->dev, ...) ?
>
> Hi Uwe,
>
> I'm wondering a bit about this: In this case, the caller that doesn't
> provide a struct device *, PWM provider isn't responsible for that. So I
> just hope this wouldn't be miss-leading ?
IMHO it's more the wording that might make the message misleading. If
you use
dev_warn(pwm->chip->dev, "No consumer device specified to create a device link to\n");
that's completely fine in my eyes.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-K?nig |
Industrial Linux Solutions | http://www.pengutronix.de/ |
On 2/19/19 9:55 AM, Uwe Kleine-König wrote:
> On Tue, Feb 19, 2019 at 09:46:32AM +0100, Fabrice Gasnier wrote:
>> On 2/18/19 6:22 PM, Uwe Kleine-König wrote:
>>> Hello,
>>>
>>> On Thu, Feb 14, 2019 at 11:25:51AM +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:
>>>> - of_pwm_get()
>>>> - pwm_get()
>>>> - devm_*pwm_get() variants
>>>> 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]>
>>>> ---
>>>> Changes in v4:
>>>> - rework error handling following Thierry's comments
>>>> - turn/split pr_debug() into dev_err()/pr_warn().
>>>>
>>>> Changes in v3:
>>>> - add struct device to of_get_pwm() arguments to handle device link from
>>>> there as discussed with Uwe.
>>>> ---
>>>> drivers/pwm/core.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++---
>>>> include/linux/pwm.h | 6 ++++--
>>>> 2 files changed, 51 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c
>>>> index 1581f6a..64e10a6 100644
>>>> --- a/drivers/pwm/core.c
>>>> +++ b/drivers/pwm/core.c
>>>> @@ -636,8 +636,35 @@ static struct pwm_chip *of_node_to_pwmchip(struct device_node *np)
>>>> return ERR_PTR(-EPROBE_DEFER);
>>>> }
>>>>
>>>> +static struct device_link *pwm_device_link_add(struct device *dev,
>>>> + struct pwm_device *pwm)
>>>> +{
>>>> + struct device_link *dl;
>>>> +
>>>> + if (!dev) {
>>>> + /*
>>>> + * No device for the PWM consumer has been provided. It may
>>>> + * impact the PM sequence ordering: the PWM supplier may get
>>>> + * suspended before the consumer.
>>>> + */
>>>> + pr_warn("no consumer dev, can't create device link to %s\n",
>>>> + dev_name(pwm->chip->dev));
>>>
>>> Maybe use dev_warn(pwm->chip->dev, ...) ?
>>
>> Hi Uwe,
>>
>> I'm wondering a bit about this: In this case, the caller that doesn't
>> provide a struct device *, PWM provider isn't responsible for that. So I
>> just hope this wouldn't be miss-leading ?
>
> IMHO it's more the wording that might make the message misleading. If
> you use
>
> dev_warn(pwm->chip->dev, "No consumer device specified to create a device link to\n");
>
> that's completely fine in my eyes.
Thanks for the suggestion, I'll update this as well in v5.
Best regards,
Fabrice
>
> Best regards
> Uwe
>