linux-kernel - Re: [PATCH,v2] pwm: mtk-disp: Fix the parameters calculated by the enabled flag of disp

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Message-ID: <b594626f-5c73-2a4c-6286-81f9df26832e@collabora.com>
Date:   Mon, 26 Sep 2022 11:13:51 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     xinlei.lee@...iatek.com, thierry.reding@...il.com,
        u.kleine-koenig@...gutronix.de, matthias.bgg@...il.com
Cc:     linux-pwm@...r.kernel.org, linux-mediatek@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Project_Global_Chrome_Upstream_Group@...iatek.com,
        jitao.shi@...iatek.com
Subject: Re: [PATCH,v2] pwm: mtk-disp: Fix the parameters calculated by the
 enabled flag of disp_pwm

Il 23/09/22 14:06, xinlei.lee@...iatek.com ha scritto:
> From: xinlei lee <xinlei.lee@...iatek.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.
> 
> Fixes: 3f2b16734914 ("pwm: mtk-disp: Implement atomic API .get_state()")
> 
> Signed-off-by: xinlei lee <xinlei.lee@...iatek.com>
> ---
> Base on the branch of Linux-next/master.
> 
> change since v1:
> 1. Modify the way to set disp_pwm enbale.
> ---
> ---
>   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..1a9880d 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 + DISP_PWM_EN) & BIT(0));

I think you mean mdp->data->enable_mask here.

Anyway, for the sake of human readability....

u32 clk_div, pwm_en, con0, con1;

pwm_en = readl(mdp->base + DISP_PWM_EN);

state->enabled = !!(pwm_en & mdp->data->enable_mask);

Regards,
Angelo

>   	clk_div = FIELD_GET(PWM_CLKDIV_MASK, con0);
>   	period = FIELD_GET(PWM_PERIOD_MASK, con1);
>   	/*
>