Re: [PATCH v3 4/5] gpu/drm: mediatek: hdmi: add optional limit on maximal HDMI mode clock

[Chun-Kuang Hu]

Hi, Neil:

Neil Armstrong <narmstrong@xxxxxxxxxxxx> 於 2021年4月19日 週一 下午3:33寫道：
>
> Some SoCs like the MT8167 have a hard limit on the maximal supported HDMI TMDS
> clock, so add a configuration value to filter out those modes.

Reviewed-by: Chun-Kuang Hu <chunkuang.hu@xxxxxxxxxx>

>
> Signed-off-by: Fabien Parent <fparent@xxxxxxxxxxxx>
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/mediatek/mtk_hdmi.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_hdmi.c b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> index 0539262e69d3..bc50d97f2553 100644
> --- a/drivers/gpu/drm/mediatek/mtk_hdmi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_hdmi.c
> @@ -149,6 +149,7 @@ struct hdmi_audio_param {
>  struct mtk_hdmi_conf {
>         bool tz_disabled;
>         bool cea_modes_only;
> +       unsigned long max_mode_clock;
>  };
>
>  struct mtk_hdmi {
> @@ -1226,6 +1227,10 @@ static int mtk_hdmi_bridge_mode_valid(struct drm_bridge *bridge,
>         if (hdmi->conf->cea_modes_only && !drm_match_cea_mode(mode))
>                 return MODE_BAD;
>
> +       if (hdmi->conf->max_mode_clock &&
> +           mode->clock > hdmi->conf->max_mode_clock)
> +               return MODE_CLOCK_HIGH;
> +
>         if (mode->clock < 27000)
>                 return MODE_CLOCK_LOW;
>         if (mode->clock > 297000)
> --
> 2.25.1
>