Re: [PATCH v14 12/15] drm/mediatek: dpi: Add YUV422 output support

[Rex-BC Chen]

On Tue, 2022-06-28 at 10:15 +0800, CK Hu wrote:
> Hi, Bo-Chen:
> 
> On Fri, 2022-06-24 at 11:09 +0800, Bo-Chen Chen wrote:
> > Dp_intf supports YUV422 as output format. In MT8195 Chrome project,
> > YUV422 output format is used for 4K resolution.
> > 
> > To support this, it is also needed to support color format
> > transfer.
> > Color format transfer is a new feature for both dpi and dpintf of
> > MT8195.
> > 
> > The input format could be RGB888 and output format for dp_intf
> > should
> > be
> > YUV422. Therefore, we add a mtk_dpi_matrix_sel() helper to update
> > the
> > DPI_MATRIX_SET register depending on the color format.
> > 
> > Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>
> > Signed-off-by: Bo-Chen Chen <rex-bc.chen@xxxxxxxxxxxx>
> > Reviewed-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@xxxxxxxxxxxxx>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c      | 34
> > ++++++++++++++++++++++++-
> >  drivers/gpu/drm/mediatek/mtk_dpi_regs.h |  3 +++
> >  2 files changed, 36 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index 9e4250356342..438bf3bc5e4a 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -128,6 +128,7 @@ struct mtk_dpi_yc_limit {
> >   * @num_output_fmts: Quantity of supported output formats.
> >   * @is_ck_de_pol: Support CK/DE polarity.
> >   * @swap_input_support: Support input swap function.
> > + * @color_fmt_trans_support: Enable color format transfer.
> >   * @dimension_mask: Mask used for HWIDTH, HPORCH, VSYNC_WIDTH and
> > VSYNC_PORCH
> >   *		    (no shift).
> >   * @hvsize_mask: Mask of HSIZE and VSIZE mask (no shift).
> > @@ -144,6 +145,7 @@ struct mtk_dpi_conf {
> >  	u32 num_output_fmts;
> >  	bool is_ck_de_pol;
> >  	bool swap_input_support;
> > +	bool color_fmt_trans_support;
> >  	u32 dimension_mask;
> >  	u32 hvsize_mask;
> >  	u32 channel_swap_shift;
> > @@ -412,6 +414,31 @@ 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;
> > +
> > +	if (!dpi->conf->color_fmt_trans_support) {
> > +		dev_info(dpi->dev, "matrix_sel is not supported.\n");
> > +		return;
> > +	}
> > +
> > +	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:
> 
> I think the transform formula are different for full range and non-
> full 
> range. Please make sure '0x2' is for full range or non-full range. If
> you are not sure, you could provide the transform matrix of '0x2' so
> we
> could find out it's full or non-full.
> 
> > +	case MTK_DPI_COLOR_FORMAT_XV_YCC:
> > +		if (dpi->mode.hdisplay <= 720)
> > +			matrix_sel = 0x2;
> 
> Symbolize '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)
> >  {
> > @@ -419,6 +446,7 @@ 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);
> 
> Why mt8173 support MTK_DPI_COLOR_FORMAT_YCBCR_444_FULL but it does
> not
> call mtk_dpi_matrix_sel()? It seems that mt8173 also need to call
> mtk_dpi_matrix_sel() but lost and this patch looks like a bug fix for
> all SoC DPI driver.
> 
> Regards,
> CK
> 

Hello CK,

MT8173 does not support MTK_DPI_COLOR_FORMAT_YCBCR_444_FULL as output
format, the output format is:

static const u32 mt8173_output_fmts[] = {
	MEDIA_BUS_FMT_RGB888_1X24,
};

or do I misunderstand?

BRs,
Bo-Chen

> >  		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);
> > @@ -426,6 +454,7 @@ 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);
> >  		else
> > @@ -673,7 +702,10 @@ static int mtk_dpi_bridge_atomic_check(struct
> > drm_bridge *bridge,
> >  	dpi->bit_num = MTK_DPI_OUT_BIT_NUM_8BITS;
> >  	dpi->channel_swap = MTK_DPI_OUT_CHANNEL_SWAP_RGB;
> >  	dpi->yc_map = MTK_DPI_OUT_YC_MAP_RGB;
> > -	dpi->color_format = MTK_DPI_COLOR_FORMAT_RGB;
> > +	if (out_bus_format == MEDIA_BUS_FMT_YUYV8_1X16)
> > +		dpi->color_format =
> > MTK_DPI_COLOR_FORMAT_YCBCR_422_FULL;
> > +	else
> > +		dpi->color_format = MTK_DPI_COLOR_FORMAT_RGB;
> >  
> >  	return 0;
> >  }
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> > b/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> > index 3a02fabe1662..cca0dccb84a2 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi_regs.h
> > @@ -217,4 +217,7 @@
> >  
> >  #define EDGE_SEL_EN			BIT(5)
> >  #define H_FRE_2N			BIT(25)
> > +
> > +#define DPI_MATRIX_SET		0xB4
> > +#define INT_MATRIX_SEL_MASK		GENMASK(4, 0)
> >  #endif /* __MTK_DPI_REGS_H */
> 
>