On Fri, Oct 04, 2019 at 02:53:53PM +0200, Fabrice Gasnier wrote: > 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 <fabrice.gasnier@xxxxxx> > --- > Changes in v2: > Follow Uwe suggestions/remarks: > - Add a precursor patch to ease reviewing > - Use registers read instead of pwm_get_state > - Add a comment to mention registers content may be lost in low power mode > --- > drivers/pwm/pwm-stm32.c | 38 ++++++++++++++++++++++++++++++++++++++ > 1 file changed, 38 insertions(+) Applied, thanks. I made two minor changes, though, see below. > > diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c > index cf8658c..546b661 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> > > @@ -655,6 +656,42 @@ 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); > + unsigned int ch; I renamed this to just "i", which is more idiomatic for loop variables. The function is small enough not to need to differentiate between loop variables. > + u32 ccer, mask; > + > + /* Look for active channels */ > + ccer = active_channels(priv); > + > + for (ch = 0; ch < priv->chip.npwm; ch++) { > + mask = TIM_CCER_CC1E << (ch * 4); > + if (ccer & mask) { > + dev_err(dev, "The consumer didn't stop us (%s)\n", > + priv->chip.pwms[ch].label); Changed this to: "PWM %u still in use by consumer %s\n", i, priv->chip.pwms[i].label I think that might help clarify which PWM is still enabled in case the consumers don't set a label. Thierry > + 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; > + > + /* restore breakinput registers that may have been lost in low power */ > + 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 */ }, > @@ -667,6 +704,7 @@ 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 >
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