On Tue, Feb 05, 2019 at 01:40:27PM +0100, Fabrice Gasnier wrote: > Add suspend/resume PM sleep ops. When going to low power, disable > active PWM channel. Active PWM channel is resumed, by calling > pwm_apply_state(). This is inspired by Thierry's comment in [1]. > Don't touch inactive channels, as it may be used by other LPTimer MFD > child driver. > [1]https://lkml.org/lkml/2017/12/5/175 > > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx> > --- > drivers/pwm/pwm-stm32-lp.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) > > diff --git a/drivers/pwm/pwm-stm32-lp.c b/drivers/pwm/pwm-stm32-lp.c > index 0059b24c..0c40d48 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> > > @@ -20,6 +21,8 @@ struct stm32_pwm_lp { > struct pwm_chip chip; > struct clk *clk; > struct regmap *regmap; > + struct pwm_state suspend; > + bool suspended; > }; > > static inline struct stm32_pwm_lp *to_stm32_pwm_lp(struct pwm_chip *chip) > @@ -223,6 +226,40 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev) > return pwmchip_remove(&priv->chip); > } > > +#ifdef CONFIG_PM_SLEEP You might consider dropping ifdefs and marking pm functions with __maybe_unused instead. In case CONFIG_PM_SLEEP=n then these two guys will be removed and pm ops structure will be empty. > +static int stm32_pwm_lp_suspend(struct device *dev) > +{ > + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); > + I guess you first need to get platform_device from dev and eventually stm32_pwm_lp. Wondering how this works now. > + pwm_get_state(&priv->chip.pwms[0], &priv->suspend); > + priv->suspended = priv->suspend.enabled; > + > + /* safe to call pwm_disable() for already disabled pwm */ > + pwm_disable(&priv->chip.pwms[0]); > + > + return pinctrl_pm_select_sleep_state(dev); > +} > + > +static int stm32_pwm_lp_resume(struct device *dev) > +{ > + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); > + int ret; > + > + ret = pinctrl_pm_select_default_state(dev); > + if (ret) > + return ret; > + > + /* Only restore suspended pwm, not to disrupt other MFD child */ > + if (!priv->suspended) > + return 0; Would it make sense to use suspend.enabled directly? > + > + return pwm_apply_state(&priv->chip.pwms[0], &priv->suspend); > +} > +#endif > + > +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 +272,7 @@ 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 >
