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
---
resend v5:
- update collected acks
Changes in v5:
- improve a warning message, fix a style issue.
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(-)
--
2.7.4
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]>
Acked-by: Uwe Kleine-König <[email protected]>
Signed-off-by: Fabrice Gasnier <[email protected]>
---
Changes in v5:
- fix a style issue
- use dev_warn() instead of pr_warn
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 3149204..e8d4958 100644
--- a/drivers/pwm/core.c
+++ b/drivers/pwm/core.c
@@ -639,8 +639,35 @@ 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.
+ */
+ dev_warn(pwm->chip->dev,
+ "No consumer device specified to create a link to\n");
+ 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
*
@@ -658,10 +685,12 @@ 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;
@@ -692,6 +721,14 @@ 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
@@ -767,6 +804,7 @@ 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;
@@ -774,7 +812,7 @@ 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
@@ -851,6 +889,12 @@ 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;
@@ -942,7 +986,7 @@ 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 b628abf..7dad301 100644
--- a/include/linux/pwm.h
+++ b/include/linux/pwm.h
@@ -405,7 +405,8 @@ 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);
@@ -493,7 +494,8 @@ 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);
--
2.7.4
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 struct platform_driver stm32_pwm_lp_driver = {
.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);
--
2.7.4
Add documentation for pinctrl sleep state on STM32 LPTimer PWM.
Reviewed-by: Rob Herring <[email protected]>
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>;
};
};
--
2.7.4
On 4/18/19 11:37 AM, Fabrice Gasnier wrote:
> 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
>
Hi Thierry,
Please let me know if you have some more comments on this series. It's
been under review since quite some time now.
Thanks in advance,
Best Regards,
Fabrice
> ---
> resend v5:
> - update collected acks
>
> Changes in v5:
> - improve a warning message, fix a style issue.
>
> 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(-)
>
Le ven. 10 mai 2019 à 09:51, Fabrice Gasnier <[email protected]> a écrit :
>
> On 4/18/19 11:37 AM, Fabrice Gasnier wrote:
> > 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
> >
>
> Hi Thierry,
>
> Please let me know if you have some more comments on this series. It's
> been under review since quite some time now.
>
Hi Thierry,
Does something is blocking on this series ?
How can we progress on it ?
Regards,
Benjamin
> Thanks in advance,
> Best Regards,
> Fabrice
>
> > ---
> > resend v5:
> > - update collected acks
> >
> > Changes in v5:
> > - improve a warning message, fix a style issue.
> >
> > 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(-)
> >
>
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