linux-kernel - Re: [PATCH v12 11/14] drm/mediatek: dpi: Add tvd

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Message-ID: <218de671054a2c02d47a0bb4a31a0b07d24d7eee.camel@mediatek.com>
Date:   Tue, 21 Jun 2022 10:55:05 +0800
From:   CK Hu <ck.hu@...iatek.com>
To:     Bo-Chen Chen <rex-bc.chen@...iatek.com>, <chunkuang.hu@...nel.org>,
        <p.zabel@...gutronix.de>, <daniel@...ll.ch>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <matthias.bgg@...il.com>,
        <airlied@...ux.ie>
CC:     <msp@...libre.com>, <granquet@...libre.com>,
        <jitao.shi@...iatek.com>, <wenst@...omium.org>,
        <angelogioacchino.delregno@...labora.com>,
        <dri-devel@...ts.freedesktop.org>,
        <linux-mediatek@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <Project_Global_Chrome_Upstream_Group@...iatek.com>
Subject: Re: [PATCH v12 11/14] drm/mediatek: dpi: Add tvd_clk enable/disable
 flow

Hi, Bo-Chen:

On Mon, 2022-06-20 at 20:10 +0800, Bo-Chen Chen wrote:
> We should enable/disable tvd_clk when power_on/power_off, so add this
> patch to do this.

Without this patch, what would happen?
It seems this patch is redundant for these SoCs:

static const struct of_device_id mtk_dpi_of_ids[] = {
	{ .compatible = "mediatek,mt2701-dpi",
	  .data = &mt2701_conf,
	},
	{ .compatible = "mediatek,mt8173-dpi",
	  .data = &mt8173_conf,
	},
	{ .compatible = "mediatek,mt8183-dpi",
	  .data = &mt8183_conf,
	},
	{ .compatible = "mediatek,mt8192-dpi",
	  .data = &mt8192_conf,
	},
	{ },
};

Regards,
CK


> 
> Signed-off-by: Bo-Chen Chen <rex-bc.chen@...iatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 2717b1741b7a..f83ecb154457 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -455,6 +455,7 @@ static void mtk_dpi_power_off(struct mtk_dpi
> *dpi)
>  	mtk_dpi_disable(dpi);
>  	clk_disable_unprepare(dpi->pixel_clk);
>  	clk_disable_unprepare(dpi->engine_clk);
> +	clk_disable_unprepare(dpi->tvd_clk);
>  }
>  
>  static int mtk_dpi_power_on(struct mtk_dpi *dpi)
> @@ -464,10 +465,16 @@ static int mtk_dpi_power_on(struct mtk_dpi
> *dpi)
>  	if (++dpi->refcount != 1)
>  		return 0;
>  
> +	ret = clk_prepare_enable(dpi->tvd_clk);
> +	if (ret) {
> +		dev_err(dpi->dev, "Failed to enable tvd pll: %d\n",
> ret);
> +		goto err_refcount;
> +	}
> +
>  	ret = clk_prepare_enable(dpi->engine_clk);
>  	if (ret) {
>  		dev_err(dpi->dev, "Failed to enable engine clock:
> %d\n", ret);
> -		goto err_refcount;
> +		goto err_engine;
>  	}
>  
>  	ret = clk_prepare_enable(dpi->pixel_clk);
> @@ -484,6 +491,8 @@ static int mtk_dpi_power_on(struct mtk_dpi *dpi)
>  
>  err_pixel:
>  	clk_disable_unprepare(dpi->engine_clk);
> +err_engine:
> +	clk_disable_unprepare(dpi->tvd_clk);
>  err_refcount:
>  	dpi->refcount--;
>  	return ret;