linux-kernel - Re: [RESEND v4 PATCH] drm/mediatek: Fix mtk_cec

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Date:   Thu, 7 Apr 2022 09:16:15 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Miles Chen <miles.chen@...iatek.com>,
        Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        "David Airlie" <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        "Matthias Brugger" <matthias.bgg@...il.com>,
        Jie Qiu <jie.qiu@...iatek.com>,
        "Junzhi Zhao" <junzhi.zhao@...iatek.com>
CC:     Zhiqiang Lin <zhiqiang.lin@...iatek.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-mediatek@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND v4 PATCH] drm/mediatek: Fix mtk_cec_mask()

Hi, Miles:

On Wed, 2022-03-16 at 07:23 +0800, Miles Chen wrote:
> In current implementation, mtk_cec_mask() writes val into target
> register
> and ignores the mask. After talking to our hdmi experts,
> mtk_cec_mask()
> should read a register, clean only mask bits, and update (val | mask)
> bits
> to the register.

Applied to mediatek-drm-next [1], thanks.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
CK

> 
> Fixes: 8f83f26891e1 ("drm/mediatek: Add HDMI support")
> Signed-off-by: Miles Chen <miles.chen@...iatek.com>
> Reviewed-by: Chun-Kuang Hu <chunkuang.hu@...nel.org>
> Reviewed-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@...labora.com>
> Reviewed-by: Matthias Brugger <matthias.bgg@...il.com>
> Cc: Zhiqiang Lin <zhiqiang.lin@...iatek.com>
> Cc: CK Hu <ck.hu@...iatek.com>
> Cc: Matthias Brugger <matthias.bgg@...il.com>
> Cc: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@...labora.com>
> 
> ---
> 
> Change since v1:
> add Fixes tag
> 
> Change since v2:
> add explanation of mtk_cec_mask()
> 
> Change since v3:
> change misleading subject and modify the commit message since this is
> a bug fix patch
> 
> ---
>  drivers/gpu/drm/mediatek/mtk_cec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_cec.c
> b/drivers/gpu/drm/mediatek/mtk_cec.c
> index e9cef5c0c8f7..cdfa648910b2 100644
> --- a/drivers/gpu/drm/mediatek/mtk_cec.c
> +++ b/drivers/gpu/drm/mediatek/mtk_cec.c
> @@ -85,7 +85,7 @@ static void mtk_cec_mask(struct mtk_cec *cec,
> unsigned int offset,
>  	u32 tmp = readl(cec->regs + offset) & ~mask;
>  
>  	tmp |= val & mask;
> -	writel(val, cec->regs + offset);
> +	writel(tmp, cec->regs + offset);
>  }
>  
>  void mtk_cec_set_hpd_event(struct device *dev,