Re: [PATCH v11 02/12] drm/mediatek: dpi: move dpi limits to SoC config

[Rex-BC Chen <rex-bc.chen@mediatek.com>]

On Tue, 2022-06-14 at 11:21 +0800, CK Hu wrote:
> Hi, Bo-Chen:
> 
> On Mon, 2022-06-13 at 14:48 +0800, Bo-Chen Chen wrote:
> > From: Guillaume Ranquet <granquet@baylibre.com>
> > 
> > Add flexibility by moving the dpi limits to the SoC specific
> > config.
> 
> What does this 'limit' mean? Why it's different in DPI vs DP_INTF?
> 
> The hardware design is so weird. If the limit is fixed for DPI and
> DP_INTF, why the hardware export register for software to assign any
> value which may be wrong.
> 
> Regards,
> CK
> 

Hello CK,

For RGB colorimetry, CTA-861 support both limited and full range data
when receiving video with RGB color space.

I will use drm_default_rgb_quant_range() to determine this and drop
const struct mtk_dpi_yc_limit *limit;

BRs,
Bo-Chen
> > 
> > Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
> > Signed-off-by: Bo-Chen Chen <rex-bc.chen@mediatek.com>
> > Reviewed-by: AngeloGioacchino Del Regno <
> > angelogioacchino.delregno@collabora.com>
> > Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c | 25 ++++++++++++++++---------
> >  1 file changed, 16 insertions(+), 9 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index e61cd67b978f..ce8c5eefe5f1 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -125,6 +125,7 @@ struct mtk_dpi_conf {
> >  	bool edge_sel_en;
> >  	const u32 *output_fmts;
> >  	u32 num_output_fmts;
> > +	const struct mtk_dpi_yc_limit *limit;
> >  };
> >  
> >  static void mtk_dpi_mask(struct mtk_dpi *dpi, u32 offset, u32 val,
> > u32 mask)
> > @@ -235,9 +236,10 @@ static void mtk_dpi_config_fb_size(struct
> > mtk_dpi *dpi, u32 width, u32 height)
> >  	mtk_dpi_mask(dpi, DPI_SIZE, height << VSIZE, VSIZE_MASK);
> >  }
> >  
> > -static void mtk_dpi_config_channel_limit(struct mtk_dpi *dpi,
> > -					 struct mtk_dpi_yc_limit
> > *limit)
> > +static void mtk_dpi_config_channel_limit(struct mtk_dpi *dpi)
> >  {
> > +	const struct mtk_dpi_yc_limit *limit = dpi->conf->limit;
> > +
> >  	mtk_dpi_mask(dpi, DPI_Y_LIMIT, limit->y_bottom << Y_LIMINT_BOT,
> >  		     Y_LIMINT_BOT_MASK);
> >  	mtk_dpi_mask(dpi, DPI_Y_LIMIT, limit->y_top << Y_LIMINT_TOP,
> > @@ -449,7 +451,6 @@ static int mtk_dpi_power_on(struct mtk_dpi
> > *dpi)
> >  static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
> >  				    struct drm_display_mode *mode)
> >  {
> > -	struct mtk_dpi_yc_limit limit;
> >  	struct mtk_dpi_polarities dpi_pol;
> >  	struct mtk_dpi_sync_param hsync;
> >  	struct mtk_dpi_sync_param vsync_lodd = { 0 };
> > @@ -484,11 +485,6 @@ static int mtk_dpi_set_display_mode(struct
> > mtk_dpi *dpi,
> >  	dev_dbg(dpi->dev, "Got  PLL %lu Hz, pixel clock %lu Hz\n",
> >  		pll_rate, vm.pixelclock);
> >  
> > -	limit.c_bottom = 0x0010;
> > -	limit.c_top = 0x0FE0;
> > -	limit.y_bottom = 0x0010;
> > -	limit.y_top = 0x0FE0;
> > -
> >  	dpi_pol.ck_pol = MTK_DPI_POLARITY_FALLING;
> >  	dpi_pol.de_pol = MTK_DPI_POLARITY_RISING;
> >  	dpi_pol.hsync_pol = vm.flags & DISPLAY_FLAGS_HSYNC_HIGH ?
> > @@ -536,7 +532,7 @@ static int mtk_dpi_set_display_mode(struct
> > mtk_dpi *dpi,
> >  	else
> >  		mtk_dpi_config_fb_size(dpi, vm.hactive, vm.vactive);
> >  
> > -	mtk_dpi_config_channel_limit(dpi, &limit);
> > +	mtk_dpi_config_channel_limit(dpi);
> >  	mtk_dpi_config_bit_num(dpi, dpi->bit_num);
> >  	mtk_dpi_config_channel_swap(dpi, dpi->channel_swap);
> >  	mtk_dpi_config_yc_map(dpi, dpi->yc_map);
> > @@ -790,12 +786,20 @@ static const u32 mt8183_output_fmts[] = {
> >  	MEDIA_BUS_FMT_RGB888_2X12_BE,
> >  };
> >  
> > +static const struct mtk_dpi_yc_limit mtk_dpi_limit = {
> > +	.c_bottom = 0x0010,
> > +	.c_top = 0x0FE0,
> > +	.y_bottom = 0x0010,
> > +	.y_top = 0x0FE0,
> > +};
> > +
> >  static const struct mtk_dpi_conf mt8173_conf = {
> >  	.cal_factor = mt8173_calculate_factor,
> >  	.reg_h_fre_con = 0xe0,
> >  	.max_clock_khz = 300000,
> >  	.output_fmts = mt8173_output_fmts,
> >  	.num_output_fmts = ARRAY_SIZE(mt8173_output_fmts),
> > +	.limit = &mtk_dpi_limit,
> >  };
> >  
> >  static const struct mtk_dpi_conf mt2701_conf = {
> > @@ -805,6 +809,7 @@ static const struct mtk_dpi_conf mt2701_conf =
> > {
> >  	.max_clock_khz = 150000,
> >  	.output_fmts = mt8173_output_fmts,
> >  	.num_output_fmts = ARRAY_SIZE(mt8173_output_fmts),
> > +	.limit = &mtk_dpi_limit,
> >  };
> >  
> >  static const struct mtk_dpi_conf mt8183_conf = {
> > @@ -813,6 +818,7 @@ static const struct mtk_dpi_conf mt8183_conf =
> > {
> >  	.max_clock_khz = 100000,
> >  	.output_fmts = mt8183_output_fmts,
> >  	.num_output_fmts = ARRAY_SIZE(mt8183_output_fmts),
> > +	.limit = &mtk_dpi_limit,
> >  };
> >  
> >  static const struct mtk_dpi_conf mt8192_conf = {
> > @@ -821,6 +827,7 @@ static const struct mtk_dpi_conf mt8192_conf =
> > {
> >  	.max_clock_khz = 150000,
> >  	.output_fmts = mt8183_output_fmts,
> >  	.num_output_fmts = ARRAY_SIZE(mt8183_output_fmts),
> > +	.limit = &mtk_dpi_limit,
> >  };
> >  
> >  static int mtk_dpi_probe(struct platform_device *pdev)
> 
>