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 <[email protected]> --- 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 +static int stm32_pwm_lp_suspend(struct device *dev) +{ + struct stm32_pwm_lp *priv = dev_get_drvdata(dev); + + 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; + + 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
