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, see [1]. So, perform a check here, and handle the pinctrl states. Also restore the break inputs upon resume, as registers content may be lost when going to low power mode.
[1] https://lkml.org/lkml/2019/2/5/770 Signed-off-by: Fabrice Gasnier <[email protected]> --- drivers/pwm/pwm-stm32.c | 82 +++++++++++++++++++++++++++++++++++++------------ 1 file changed, 62 insertions(+), 20 deletions(-) diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c index 740e2de..9bcd73a 100644 --- a/drivers/pwm/pwm-stm32.c +++ b/drivers/pwm/pwm-stm32.c @@ -12,6 +12,7 @@ #include <linux/mfd/stm32-timers.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/pwm.h> @@ -19,6 +20,12 @@ #define CCMR_CHANNEL_MASK 0xFF #define MAX_BREAKINPUT 2 +struct stm32_breakinput { + u32 index; + u32 level; + u32 filter; +}; + struct stm32_pwm { struct pwm_chip chip; struct mutex lock; /* protect pwm config/enable */ @@ -26,15 +33,11 @@ struct stm32_pwm { struct regmap *regmap; u32 max_arr; bool have_complementary_output; + struct stm32_breakinput breakinput[MAX_BREAKINPUT]; + unsigned int nbreakinput; u32 capture[4] ____cacheline_aligned; /* DMA'able buffer */ }; -struct stm32_breakinput { - u32 index; - u32 level; - u32 filter; -}; - static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip) { return container_of(chip, struct stm32_pwm, chip); @@ -512,15 +515,27 @@ static int stm32_pwm_set_breakinput(struct stm32_pwm *priv, return (bdtr & bke) ? 0 : -EINVAL; } -static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv, +static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv) +{ + int i, ret = 0; + + for (i = 0; i < priv->nbreakinput && !ret; i++) { + ret = stm32_pwm_set_breakinput(priv, + priv->breakinput[i].index, + priv->breakinput[i].level, + priv->breakinput[i].filter); + } + + return ret; +} + +static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv, struct device_node *np) { - struct stm32_breakinput breakinput[MAX_BREAKINPUT]; - int nb, ret, i, array_size; + int nb, ret, array_size; nb = of_property_count_elems_of_size(np, "st,breakinput", sizeof(struct stm32_breakinput)); - /* * Because "st,breakinput" parameter is optional do not make probe * failed if it doesn't exist. @@ -531,20 +546,14 @@ static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv, if (nb > MAX_BREAKINPUT) return -EINVAL; + priv->nbreakinput = nb; array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32); ret = of_property_read_u32_array(np, "st,breakinput", - (u32 *)breakinput, array_size); + (u32 *)priv->breakinput, array_size); if (ret) return ret; - for (i = 0; i < nb && !ret; i++) { - ret = stm32_pwm_set_breakinput(priv, - breakinput[i].index, - breakinput[i].level, - breakinput[i].filter); - } - - return ret; + return stm32_pwm_apply_breakinputs(priv); } static void stm32_pwm_detect_complementary(struct stm32_pwm *priv) @@ -614,7 +623,7 @@ static int stm32_pwm_probe(struct platform_device *pdev) if (!priv->regmap || !priv->clk) return -EINVAL; - ret = stm32_pwm_apply_breakinputs(priv, np); + ret = stm32_pwm_probe_breakinputs(priv, np); if (ret) return ret; @@ -647,6 +656,38 @@ static int stm32_pwm_remove(struct platform_device *pdev) return 0; } +static int __maybe_unused stm32_pwm_suspend(struct device *dev) +{ + struct stm32_pwm *priv = dev_get_drvdata(dev); + struct pwm_state state; + unsigned int i; + + for (i = 0; i < priv->chip.npwm; i++) { + pwm_get_state(&priv->chip.pwms[i], &state); + if (state.enabled) { + dev_err(dev, "The consumer didn't stop us (%s)\n", + priv->chip.pwms[i].label); + return -EBUSY; + } + } + + return pinctrl_pm_select_sleep_state(dev); +} + +static int __maybe_unused stm32_pwm_resume(struct device *dev) +{ + struct stm32_pwm *priv = dev_get_drvdata(dev); + int ret; + + ret = pinctrl_pm_select_default_state(dev); + if (ret) + return ret; + + return stm32_pwm_apply_breakinputs(priv); +} + +static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume); + static const struct of_device_id stm32_pwm_of_match[] = { { .compatible = "st,stm32-pwm", }, { /* end node */ }, @@ -659,6 +700,7 @@ static struct platform_driver stm32_pwm_driver = { .driver = { .name = "stm32-pwm", .of_match_table = stm32_pwm_of_match, + .pm = &stm32_pwm_pm_ops, }, }; module_platform_driver(stm32_pwm_driver); -- 2.7.4
