On Mon, 10 Apr 2017 17:20:20 +0300 Claudiu Beznea <[email protected]> wrote:
> Implement suspend and resume power management specific > function to allow PWM controller to correctly suspend > and resume. > > Signed-off-by: Claudiu Beznea <[email protected]> > --- > drivers/pwm/pwm-atmel.c | 81 > +++++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 81 insertions(+) > > diff --git a/drivers/pwm/pwm-atmel.c b/drivers/pwm/pwm-atmel.c > index 530d7dc..75177c6 100644 > --- a/drivers/pwm/pwm-atmel.c > +++ b/drivers/pwm/pwm-atmel.c > @@ -58,6 +58,8 @@ > #define PWM_MAX_PRD 0xFFFF > #define PRD_MAX_PRES 10 > > +#define PWM_MAX_CH_NUM (4) > + > struct atmel_pwm_registers { > u8 period; > u8 period_upd; > @@ -65,11 +67,18 @@ struct atmel_pwm_registers { > u8 duty_upd; > }; > > +struct atmel_pwm_pm_ctx { > + u32 cmr; > + u32 cdty; > + u32 cprd; > +}; > + > struct atmel_pwm_chip { > struct pwm_chip chip; > struct clk *clk; > void __iomem *base; > const struct atmel_pwm_registers *regs; > + struct atmel_pwm_pm_ctx ctx[PWM_MAX_CH_NUM]; Hm, I'm pretty sure you can rely on the current PWM state and call atmel_pwm_apply() at resume time instead of doing that. See what I did here [1]. Thierry, maybe it's time to start thinking about a generic solution to save/restore PWM states. > > unsigned int updated_pwms; > /* ISR is cleared when read, ensure only one thread does that */ > @@ -333,6 +342,77 @@ atmel_pwm_get_driver_data(struct platform_device *pdev) > return (struct atmel_pwm_registers *)id->driver_data; > } > > +#ifdef CONFIG_PM_SLEEP > +static int atmel_pwm_suspend(struct device *dev) > +{ > + struct atmel_pwm_chip *atmel_pwm = dev_get_drvdata(dev); > + struct pwm_device *pwm = atmel_pwm->chip.pwms; > + int i; > + bool disable_clk = false; > + > + for (i = 0; i < atmel_pwm->chip.npwm; i++, pwm++) { > + if (!pwm_is_enabled(pwm)) > + continue; > + > + disable_clk = true; > + atmel_pwm->ctx[i].cdty = > + atmel_pwm_ch_readl(atmel_pwm, i, > + atmel_pwm->regs->duty); > + atmel_pwm->ctx[i].cprd = > + atmel_pwm_ch_readl(atmel_pwm, i, > + atmel_pwm->regs->period); > + atmel_pwm->ctx[i].cmr = > + atmel_pwm_ch_readl(atmel_pwm, i, PWM_CMR); > + > + atmel_pwm_disable(&atmel_pwm->chip, pwm, false); > + } > + > + if (disable_clk) > + clk_disable(atmel_pwm->clk); I'm not so sure we want to disable the PWM and the PWM chip clk when entering suspend. What if the PWM is driving a critical device (like a regulator) that has to stay enabled in suspend? Shouldn't we delegate this responsibility to the PWM user? [1]http://patchwork.ozlabs.org/patch/734306/
