| Message ID | 1570193633-6600-1-git-send-email-fabrice.gasnier@st.com |
|---|---|
| Headers | show |
| Series | Add PM support to STM32 Timer PWM | expand |
On Fri, Oct 04, 2019 at 02:53:52PM +0200, Fabrice Gasnier wrote: > Split breakinput routine that configures STM32 timers 'break' safety > feature upon probe, into two routines: > - stm32_pwm_apply_breakinputs() sets all the break inputs into registers. > - stm32_pwm_probe_breakinputs() probes the device tree break input settings > before calling stm32_pwm_apply_breakinputs() > > This is a precursor patch to ease PM support. Registers content may get > lost during low power. So, break input settings applied upon probe need > to be restored upon resume (e.g. by calling stm32_pwm_apply_breakinputs()). > > Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com> > --- > drivers/pwm/pwm-stm32.c | 48 ++++++++++++++++++++++++++++-------------------- > 1 file changed, 28 insertions(+), 20 deletions(-) Applied, thanks. I've made some minor changes, mostly for consistency with other drivers and the PWM core. See below. > diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c > index 359b085..cf8658c 100644 > --- a/drivers/pwm/pwm-stm32.c > +++ b/drivers/pwm/pwm-stm32.c > @@ -19,6 +19,12 @@ > #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 +32,11 @@ struct stm32_pwm { > struct regmap *regmap; > u32 max_arr; > bool have_complementary_output; > + struct stm32_breakinput breakinput[MAX_BREAKINPUT]; > + unsigned int nbreakinput; I changed these to breakinputs and num_breakinputs since they are slightly more consistent with the naming elsewhere in PWM. > 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 +514,27 @@ 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; Made i unsigned int. > + > + 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); > + } I thought this was a little odd, so I changed it to explicitly check the value of ret and return on error. > + > + return ret; And then this became "return 0;" > +} > + > +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)); > - Dropped this since it made the code look cluttered. Thierry > /* > * Because "st,breakinput" parameter is optional do not make probe > * failed if it doesn't exist. > @@ -531,20 +545,14 @@ 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 +622,7 @@ 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; > > -- > 2.7.4 >
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 >>