Re: [PATCH v2] pwm: rockchip: State of pwm clock should synchronize with pwm enabled state

[David.Wu]

Hi Borisï

å 2017/3/1 18:19, Boris Brezillon åé:
> On Wed,  1 Mar 2017 18:16:02 +0800
> David Wu <david.wu@xxxxxxxxxxxxxx> wrote:
>
> > From: "david.wu" <david.wu@xxxxxxxxxxxxxx>
> >
> > If the pwm was not enabled at uboot loader, pwm could not work for clock
> > always disabled at pwm driver. The pwm clock is enabled at beginning of
> > pwm_apply(), but disabled at end of pwm_apply().
> >
> > If the pwm was enabled at uboot loader, pwm clock is always enabled unless
> > closed by ATF. The pwm-backlight might turn off the power at early suspend,
> > should disable pwm clock for saving power consume.
> >
> > It is important to provide opportunity to enable/disable clock at pwm driver,
> > the pwm consumer should ensure correct order to call pwm enable/disable, and
> > pwm driver ensure state of pwm clock synchronized with pwm enabled state.
> >
> > Fixes: 2bf1c98aa5a4 ("pwm: rockchip: Add support for atomic update")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: David Wu <david.wu@xxxxxxxxxxxxxx>
> > Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
> > ---
> >  drivers/pwm/pwm-rockchip.c | 40 +++++++++++++++++++++++++++++++++-------
> >  1 file changed, 33 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/pwm/pwm-rockchip.c b/drivers/pwm/pwm-rockchip.c
> > index ef89df1..dbee3c3 100644
> > --- a/drivers/pwm/pwm-rockchip.c
> > +++ b/drivers/pwm/pwm-rockchip.c
> > @@ -191,6 +191,28 @@ static int rockchip_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
> >  	return 0;
> >  }
> >
> > +static int rk_pwm_enable(struct pwm_chip *chip,
> > +			 struct pwm_device *pwm,
> > +			 bool enable,
> > +			 enum pwm_polarity polarity)
>
> You didn't change the function name:
>
> s/rk_pwm_enable/rockchip_pwm_enable/

Sorry, it is a pity not to fix in in v2.

> > +{
> > +	struct rockchip_pwm_chip *pc = to_rockchip_pwm_chip(chip);
> > +	int ret;
> > +
> > +	if (enable) {
> > +		ret = clk_enable(pc->clk);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	pc->data->set_enable(chip, pwm, enable, polarity);
> > +
> > +	if (!enable)
> > +		clk_disable(pc->clk);
> > +
> > +	return 0;
> > +}
> > +
> >  static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> >  			      struct pwm_state *state)
> >  {
> > @@ -207,22 +229,26 @@ static int rockchip_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> >  		return ret;
> >
> >  	if (state->polarity != curstate.polarity && enabled) {
> > -		pc->data->set_enable(chip, pwm, false, state->polarity);
> > +		ret = rk_pwm_enable(chip, pwm, false, state->polarity);
> > +		if (ret)
> > +			goto out;
> >  		enabled = false;
> >  	}
> >
> >  	ret = rockchip_pwm_config(chip, pwm, state->duty_cycle, state->period);
> >  	if (ret) {
> >  		if (enabled != curstate.enabled)
> > -			pc->data->set_enable(chip, pwm, !enabled,
> > -					     state->polarity);
> > -
> > +			rk_pwm_enable(chip, pwm, !enabled,
> > +				      state->polarity);
> >  		goto out;
> >  	}
> >
> > -	if (state->enabled != enabled)
> > -		pc->data->set_enable(chip, pwm, state->enabled,
> > -				     state->polarity);
> > +	if (state->enabled != enabled) {
> > +		ret = rk_pwm_enable(chip, pwm, state->enabled,
> > +				    state->polarity);
> > +		if (ret)
> > +			goto out;
> > +	}
> >
> >  	/*
> >  	 * Update the state with the real hardware, which can differ a bit