Re: [PATCH v11 12/12] drm/mediatek: dpi: Add matrix_sel helper

[CK Hu <ck.hu@mediatek.com>]

Hi, Bo-Chen:

On Mon, 2022-06-13 at 14:48 +0800, Bo-Chen Chen wrote:
> From: Guillaume Ranquet <granquet@baylibre.com>
> 
> Add a mtk_dpi_matrix_sel() helper to update the DPI_MATRIX_SET
> register depending on the color format.

Why set DPI_MATRIX_SET? New feature or bug fix? What does this matrix
work for?

Regards,
CK

> 
> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
> Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c      | 21 +++++++++++++++++++++
>  drivers/gpu/drm/mediatek/mtk_dpi_regs.h |  3 +++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 9668bd5dd14a..dc355a512963 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -387,6 +387,25 @@ static void mtk_dpi_config_disable_edge(struct
> mtk_dpi *dpi)
>  		mtk_dpi_mask(dpi, dpi->conf->reg_h_fre_con, 0,
> EDGE_SEL_EN);
>  }
>  
> +static void mtk_dpi_matrix_sel(struct mtk_dpi *dpi, enum
> mtk_dpi_out_color_format format)
> +{
> +	u32 matrix_sel = 0;
> +
> +	switch (format) {
> +	case MTK_DPI_COLOR_FORMAT_YCBCR_422:
> +	case MTK_DPI_COLOR_FORMAT_YCBCR_422_FULL:
> +	case MTK_DPI_COLOR_FORMAT_YCBCR_444:
> +	case MTK_DPI_COLOR_FORMAT_YCBCR_444_FULL:
> +	case MTK_DPI_COLOR_FORMAT_XV_YCC:
> +		if (dpi->mode.hdisplay <= 720)
> +			matrix_sel = 0x2;
> +		break;
> +	default:
> +		break;
> +	}
> +	mtk_dpi_mask(dpi, DPI_MATRIX_SET, matrix_sel,
> INT_MATRIX_SEL_MASK);
> +}
> +
>  static void mtk_dpi_config_color_format(struct mtk_dpi *dpi,
>  					enum mtk_dpi_out_color_format
> format)
>  {
> @@ -394,6 +413,7 @@ static void mtk_dpi_config_color_format(struct
> mtk_dpi *dpi,
>  	    (format == MTK_DPI_COLOR_FORMAT_YCBCR_444_FULL)) {
>  		mtk_dpi_config_yuv422_enable(dpi, false);
>  		mtk_dpi_config_csc_enable(dpi, true);
> +		mtk_dpi_matrix_sel(dpi, format);
>  		if (dpi->conf->swap_input_support)
>  			mtk_dpi_config_swap_input(dpi, false);
>  		mtk_dpi_config_channel_swap(dpi,
> MTK_DPI_OUT_CHANNEL_SWAP_BGR);
> @@ -401,6 +421,7 @@ static void mtk_dpi_config_color_format(struct
> mtk_dpi *dpi,
>  		   (format == MTK_DPI_COLOR_FORMAT_YCBCR_422_FULL)) {
>  		mtk_dpi_config_yuv422_enable(dpi, true);
>  		mtk_dpi_config_csc_enable(dpi, true);
> +		mtk_dpi_matrix_sel(dpi, format);
>  		if (dpi->conf->swap_input_support)
>  			mtk_dpi_config_swap_input(dpi, true);
>  		mtk_dpi_config_channel_swap(dpi,
> MTK_DPI_OUT_CHANNEL_SWAP_RGB);
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> b/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> index f7f0272dbd6a..96c117202d0d 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> @@ -230,4 +230,7 @@
>  #define EDGE_SEL_EN			BIT(5)
>  #define H_FRE_2N			BIT(25)
>  
> +#define DPI_MATRIX_SET		0xB4
> +#define INT_MATRIX_SEL_MASK	(0x1F << 0)
> +
>  #endif /* __MTK_DPI_REGS_H */