RE: [PATCH v2 2/4] pwm: rcar: Use "atomic" API on rcar_pwm_resume()

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hello Uwe,

> From: Uwe Kleine-Konig, Sent: Tuesday, January 8, 2019 4:48 PM
> > diff --git a/drivers/pwm/pwm-rcar.c b/drivers/pwm/pwm-rcar.c
> > index ba70e83..4987c12 100644
> > --- a/drivers/pwm/pwm-rcar.c
> > +++ b/drivers/pwm/pwm-rcar.c
> > @@ -316,18 +316,16 @@ static int rcar_pwm_suspend(struct device *dev)
> >  static int rcar_pwm_resume(struct device *dev)
> >  {
> >  	struct pwm_device *pwm = rcar_pwm_dev_to_pwm_dev(dev);
> > +	struct pwm_state state;
> >
> >  	if (!test_bit(PWMF_REQUESTED, &pwm->flags))
> >  		return 0;
> >
> >  	pm_runtime_get_sync(dev);
> >
> > -	rcar_pwm_config(pwm->chip, pwm, pwm->state.duty_cycle,
> > -			pwm->state.period);
> > -	if (pwm_is_enabled(pwm))
> > -		rcar_pwm_enable(pwm->chip, pwm);
> > +	pwm_get_state(pwm, &state);
> >
> > -	return 0;
> > +	return rcar_pwm_apply(pwm->chip, pwm, &state);
> >  }
> 
> Orthogonal to this patch I wonder what the intended behaviour for a pwm
> is on suspend. Should it stop oscilating unconditionally? Or should it
> only stop if the consumer stops it as part of its own suspend callback?

I think the second one is better. I checked drivers/video/backlight/pwm_bl.c
and it is possible to call pwm_apply_state() by the driver after rcar_pwm_suspend()
was called. So, I'll fix this as other patch.

> As the patch only reworks and improves the code without a change in
> behaviour, it is fine for me.
> 
> Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

Thanks!

Best regards,
Yoshihiro Shimoda

> Best regards
> Uwe
> 
> --
> Pengutronix e.K.                           | Uwe Kleine-König            |
> Industrial Linux Solutions                 | http://www.pengutronix.de/  |