| Message ID | 1570193633-6600-4-git-send-email-fabrice.gasnier@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add PM support to STM32 Timer PWM | expand |
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@st.com> > --- > 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 >
On 10/16/19 9:06 AM, Thierry Reding wrote: > 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@st.com> >> --- >> 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. Hi Thierry, Many thanks for all the improvements on this series! Best Regards, Fabrice > > 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 >>
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; + 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); + 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);
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@st.com> --- 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(+)