[PATCH] pwm: mtk-disp: Fix the parameters calculated by the enabled flag of disp_pwm.

[xinlei.lee]

On Tue, 2022-09-13 at 11:05 +0200, Uwe Kleine-König wrote:
> Hello,
> 
> On Mon, Aug 29, 2022 at 12:04:12PM +0800, xinlei.lee at mediatek.com
> wrote:
> > From: xinlei lee <xinlei.lee at mediatek.com>
> > 
> > In the original mtk_disp_pwm_get_state() function, the result of
> > reading
> > con0 & BIT(0) is enabled as disp_pwm. 
> > In order to conform to the register table, we should use the
> > disp_pwm 
> > base address as the enabled judgment.
> 
> Do you want to say:
> 
> 	The enable bit of the hardware is bit 0 of the DISP_PWM_EN
> 	register at offset 0 for all supported hardwares. Up to now the
> 	bit was wrongly assumed to be in the CON0 register.
> 
> ?
> 
> > Fixes: 3f2b16734914 ("pwm: mtk-disp: Implement atomic API
> > .get_state()")
> > 
> 
> This newline is unusal.
> 
> > Signed-off-by: xinlei lee <xinlei.lee at mediatek.com>
> > Reviewed-by: Miles Chen <miles.chen at mediatek.com>
> > ---
> > Base on the branch of Linux-next/master.
> > Split from series [1].
> > [1] 
> > https://patchwork.kernel.org/project/linux-mediatek/cover/1661239875-19841-1-git-send-email-xinlei.lee@mediatek.com/
> > ---
> > ---
> >  drivers/pwm/pwm-mtk-disp.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-
> > disp.c
> > index c605013..50425cd 100644
> > --- a/drivers/pwm/pwm-mtk-disp.c
> > +++ b/drivers/pwm/pwm-mtk-disp.c
> > @@ -197,7 +197,7 @@ static void mtk_disp_pwm_get_state(struct
> > pwm_chip *chip,
> >  	rate = clk_get_rate(mdp->clk_main);
> >  	con0 = readl(mdp->base + mdp->data->con0);
> >  	con1 = readl(mdp->base + mdp->data->con1);
> > -	state->enabled = !!(con0 & BIT(0));
> > +	state->enabled = !!(readl(mdp->base) & BIT(0));
> 
> I would expect this to better be:
> 
> 	state->enabled = !!(readl(mdp->base + DISP_PWM_EN) & BIT(0));
> 
> which is the same for the compiler but a bit more descriptive for the
> human reader.
> 
> >  	clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
> >  	period = FIELD_GET(PWM_PERIOD_MASK, con1);
> >  	/*
> 
> Best regards
> Uwe
> 

Hi Uwe:

As you said, what we need to modify is the offset address of enable of
disp_pwm register.
Thanks for your review, I will revise the next version as you
suggested.

Best Regards!
xinlei