Re: [PATCH v6 08/42] drm/mediatek: mtk_dpi: Support AFIFO 1T1P output and conversion

[CK Hu (胡俊光)]

On Tue, 2025-02-11 at 12:33 +0100, AngeloGioacchino Del Regno wrote:
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> 
> 
> On some SoCs, like MT8195 and MT8188, the DPI's FIFO controller
> (afifo) supports outputting either one or two pixels per round
> regardless of the input being 1T1P or 1T2P.
> 
> Add a `output_1pixel` member to struct mtk_dpi_conf which, if
> set, will enable outputting one pixel per clock.
> 
> In case the input is two pixel per clock (1T2P), the AFIFO HW
> will automatically (and internally) convert it to 1T1P.

Reviewed-by: CK Hu <ck.hu@xxxxxxxxxxxx>

> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index 6493c7e2fae4..5c15c8935916 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -148,6 +148,8 @@ struct mtk_dpi_factor {
>   * @edge_cfg_in_mmsys: If the edge configuration for DPI's output needs to be set in MMSYS.
>   * @clocked_by_hdmi: HDMI IP outputs clock to dpi_pixel_clk input clock, needed
>   *                  for DPI registers access.
> + * @output_1pixel: Enable outputting one pixel per round; if the input is two pixel per
> + *                 round, the DPI hardware will internally transform it to 1T1P.
>   */
>  struct mtk_dpi_conf {
>         const struct mtk_dpi_factor *dpi_factor;
> @@ -170,6 +172,7 @@ struct mtk_dpi_conf {
>         u32 pixels_per_iter;
>         bool edge_cfg_in_mmsys;
>         bool clocked_by_hdmi;
> +       bool output_1pixel;
>  };
> 
>  static void mtk_dpi_mask(struct mtk_dpi *dpi, u32 offset, u32 val, u32 mask)
> @@ -655,7 +658,13 @@ static int mtk_dpi_set_display_mode(struct mtk_dpi *dpi,
>         if (dpi->conf->support_direct_pin) {
>                 mtk_dpi_config_yc_map(dpi, dpi->yc_map);
>                 mtk_dpi_config_2n_h_fre(dpi);
> -               mtk_dpi_dual_edge(dpi);
> +
> +               /* DPI can connect to either an external bridge or the internal HDMI encoder */
> +               if (dpi->conf->output_1pixel)
> +                       mtk_dpi_mask(dpi, DPI_CON, DPI_OUTPUT_1T1P_EN, DPI_OUTPUT_1T1P_EN);
> +               else
> +                       mtk_dpi_dual_edge(dpi);
> +
>                 mtk_dpi_config_disable_edge(dpi);
>         }
>         if (dpi->conf->input_2p_en_bit && dpi->conf->input_2pixel) {
> --
> 2.48.1
>