Re: [PATCH v8 05/19] drm/mediatek: dpi: move dpi limits to board config

[Chun-Kuang Hu]

Hi, Guillaume:

Guillaume Ranquet <granquet@xxxxxxxxxxxx> 於 2022年2月18日 週五 下午10:56寫道：
>
> Add flexibility by moving the dpi limits to the board config

This patch looks good to me. But I would like to know what's this
limit and why it vary in different SoC. If possible, would you please
provide more description for this?

Regards,
Chun-Kuang.

>
> Signed-off-by: Guillaume Ranquet <granquet@xxxxxxxxxxxx>
> ---
>  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 4554e2de14309..4746eb3425674 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 = mt8173_output_fmts,
>         .num_output_fmts = ARRAY_SIZE(mt8173_output_fmts),
> +       .limit = &mtk_dpi_limit,
>  };
>
>  static int mtk_dpi_probe(struct platform_device *pdev)
> --
> 2.34.1
>