Re: [v5, 1/2] drm/mediatek: mtk_dpi: Add check for max clock rate in mode_valid

[Chun-Kuang Hu <chunkuang.hu@kernel.org>]

Hi, Enric:

Enric Balletbo Serra <eballetbo@gmail.com> 於 2021年3月18日 週四 下午10:25寫道：
>
> Hi Rex-BC Chen,
>
> Thank you for your patch.
>
> Missatge de Rex-BC Chen <rex-bc.chen@mediatek.com> del dia dj., 18 de
> març 2021 a les 6:42:
> >
> > Add per-platform max clock rate check in mtk_dpi_bridge_mode_valid.
> >
> > Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
> > Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dpi.c | 18 ++++++++++++++++++
> >  1 file changed, 18 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > index b05f900d9322..0b427ad0cd9b 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> > @@ -120,6 +120,7 @@ struct mtk_dpi_yc_limit {
> >  struct mtk_dpi_conf {
> >         unsigned int (*cal_factor)(int clock);
> >         u32 reg_h_fre_con;
> > +       u32 max_clock_khz;
> >         bool edge_sel_en;
> >  };
> >
> > @@ -557,9 +558,23 @@ static void mtk_dpi_bridge_enable(struct drm_bridge *bridge)
> >         mtk_dpi_set_display_mode(dpi, &dpi->mode);
> >  }
> >
> > +static enum drm_mode_status
> > +mtk_dpi_bridge_mode_valid(struct drm_bridge *bridge,
> > +                         const struct drm_display_info *info,
> > +                         const struct drm_display_mode *mode)
> > +{
> > +       struct mtk_dpi *dpi = bridge_to_dpi(bridge);
> > +
> > +       if (dpi->conf->max_clock_khz && mode->clock > dpi->conf->max_clock_khz)
>
> Maybe I read this patch too fast, but why the &&? Shouldn't be more
> simple and readable
>
>           if (mode->clock > max_clock)
>

Agree. So I modify in mediatek-drm-next [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-next

Regards,
Chun-Kuang.

> Thanks,
>   Enric
>
>
> > +               return MODE_CLOCK_HIGH;
> > +
> > +       return MODE_OK;
> > +}
> > +
> >  static const struct drm_bridge_funcs mtk_dpi_bridge_funcs = {
> >         .attach = mtk_dpi_bridge_attach,
> >         .mode_set = mtk_dpi_bridge_mode_set,
> > +       .mode_valid = mtk_dpi_bridge_mode_valid,
> >         .disable = mtk_dpi_bridge_disable,
> >         .enable = mtk_dpi_bridge_enable,
> >  };
> > @@ -668,17 +683,20 @@ static unsigned int mt8183_calculate_factor(int clock)
> >  static const struct mtk_dpi_conf mt8173_conf = {
> >         .cal_factor = mt8173_calculate_factor,
> >         .reg_h_fre_con = 0xe0,
> > +       .max_clock_khz = 300000,
> >  };
> >
> >  static const struct mtk_dpi_conf mt2701_conf = {
> >         .cal_factor = mt2701_calculate_factor,
> >         .reg_h_fre_con = 0xb0,
> >         .edge_sel_en = true,
> > +       .max_clock_khz = 150000,
> >  };
> >
> >  static const struct mtk_dpi_conf mt8183_conf = {
> >         .cal_factor = mt8183_calculate_factor,
> >         .reg_h_fre_con = 0xe0,
> > +       .max_clock_khz = 100000,
> >  };
> >
> >  static int mtk_dpi_probe(struct platform_device *pdev)
> > --
> > 2.18.0
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