[PATCH v2 1/3] drm/mediatek: Fix YCbCr422 color format issue for DP

[Chun-Kuang Hu]

Hi, Liankun:

Liankun Yang <liankun.yang at mediatek.com> 於 2024年10月25日 週五 下午4:32寫道：
>
> Setting up misc0 for Pixel Encoding Format.
>
> According to the definition of YCbCr in spec 1.2a Table 2-96,
> 0x1 << 1 should be written to the register.
>
> Use switch case to distinguish RGB, YCbCr422,
> and unsupported color formats.

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

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

Regards,
Chun-Kuang.

>
> Fixes: f70ac097a2cf ("drm/mediatek: Add MT8195 Embedded DisplayPort driver")
> Signed-off-by: Liankun Yang <liankun.yang at mediatek.com>
> ---
> Change in V2
> - Modify the value written to the register
> Per suggestion from the previous thread:
> https://patchwork.kernel.org/project/linux-mediatek/patch/20240510021810.19302-1-liankun.yang@mediatek.com/
> ---
>  drivers/gpu/drm/mediatek/mtk_dp.c | 13 ++++++++-----
>  1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dp.c b/drivers/gpu/drm/mediatek/mtk_dp.c
> index f0f6f402994a..613e1c842478 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dp.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dp.c
> @@ -460,18 +460,16 @@ static int mtk_dp_set_color_format(struct mtk_dp *mtk_dp,
>                                    enum dp_pixelformat color_format)
>  {
>         u32 val;
> -
> -       /* update MISC0 */
> -       mtk_dp_update_bits(mtk_dp, MTK_DP_ENC0_P0_3034,
> -                          color_format << DP_TEST_COLOR_FORMAT_SHIFT,
> -                          DP_TEST_COLOR_FORMAT_MASK);
> +       u32 misc0_color;
>
>         switch (color_format) {
>         case DP_PIXELFORMAT_YUV422:
>                 val = PIXEL_ENCODE_FORMAT_DP_ENC0_P0_YCBCR422;
> +               misc0_color = DP_COLOR_FORMAT_YCbCr422;
>                 break;
>         case DP_PIXELFORMAT_RGB:
>                 val = PIXEL_ENCODE_FORMAT_DP_ENC0_P0_RGB;
> +               misc0_color = DP_COLOR_FORMAT_RGB;
>                 break;
>         default:
>                 drm_warn(mtk_dp->drm_dev, "Unsupported color format: %d\n",
> @@ -479,6 +477,11 @@ static int mtk_dp_set_color_format(struct mtk_dp *mtk_dp,
>                 return -EINVAL;
>         }
>
> +       /* update MISC0 */
> +       mtk_dp_update_bits(mtk_dp, MTK_DP_ENC0_P0_3034,
> +                          misc0_color,
> +                          DP_TEST_COLOR_FORMAT_MASK);
> +
>         mtk_dp_update_bits(mtk_dp, MTK_DP_ENC0_P0_303C,
>                            val, PIXEL_ENCODE_FORMAT_DP_ENC0_P0_MASK);
>         return 0;
> --
> 2.45.2
>