linux-kernel - Re: [PATCH v4 8/8] drm/mediatek: Config orientation property if panel provides it

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Message-ID: <CAJMQK-gZDR5QmJD4hbn2waB7ej7tmShObrhLMaHii6BSDcozrA@mail.gmail.com>
Date:   Tue, 7 Jun 2022 11:53:04 +0800
From:   Hsin-Yi Wang <hsinyi@...omium.org>
To:     Sam Ravnborg <sam@...nborg.org>
Cc:     Chun-Kuang Hu <chunkuang.hu@...nel.org>,
        Hans de Goede <hdegoede@...hat.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Matthias Brugger <matthias.bgg@...il.com>,
        dri-devel@...ts.freedesktop.org,
        linux-mediatek@...ts.infradead.org,
        Rob Clark <robdclark@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Douglas Anderson <dianders@...omium.org>,
        Rob Herring <robh+dt@...nel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 8/8] drm/mediatek: Config orientation property if panel
 provides it

On Tue, Jun 7, 2022 at 3:31 AM Sam Ravnborg <sam@...nborg.org> wrote:
>
> Hi Hsin-Yi,
>
> On Mon, Jun 06, 2022 at 11:24:31PM +0800, Hsin-Yi Wang wrote:
> > Panel orientation property should be set before drm_dev_register().
> > Mediatek drm driver calls drm_dev_register() in .bind(). However, most
> > panels sets orientation property relatively late, mostly in .get_modes()
> > callback, since this is when they are able to get the connector and
> > binds the orientation property to it, though the value should be known
> > when the panel is probed.
> >
> > Let the drm driver check if the remote end point is a panel and if it
> > contains the orientation property. If it does, set it before
> > drm_dev_register() is called.
>
> I do not know the best way to do what you need to do here.
> But it seems wrong to introduce a deprecated function
> (drm_of_find_panel_or_bridge), to set the rotation property early.
>
How about of_drm_find_panel()?

> I think you need to find a way to do this utilising the panel_bridge or
> something.
>
>         Sam
>
> >
> > Signed-off-by: Hsin-Yi Wang <hsinyi@...omium.org>
> > Reviewed-by: Hans de Goede <hdegoede@...hat.com>
> > Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
> > ---
> >  drivers/gpu/drm/mediatek/mtk_dsi.c | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index d9f10a33e6fa..c56282412bfa 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -185,6 +185,7 @@ struct mtk_dsi {
> >       struct drm_encoder encoder;
> >       struct drm_bridge bridge;
> >       struct drm_bridge *next_bridge;
> > +     struct drm_panel *panel;
> >       struct drm_connector *connector;
> >       struct phy *phy;
> >
> > @@ -822,6 +823,12 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> >               ret = PTR_ERR(dsi->connector);
> >               goto err_cleanup_encoder;
> >       }
> > +
> > +     /* Read panel orientation */
> > +     if (dsi->panel)
> > +             drm_connector_set_panel_orientation(dsi->connector,
> > +                             drm_panel_get_orientation(dsi->panel));
> > +
> >       drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> >
> >       return 0;
> > @@ -837,6 +844,9 @@ static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> >       struct drm_device *drm = data;
> >       struct mtk_dsi *dsi = dev_get_drvdata(dev);
> >
> > +     /* Get panel if existed */
> > +     drm_of_find_panel_or_bridge(dev->of_node, 0, 0, &dsi->panel, NULL);
> > +
> >       ret = mtk_dsi_encoder_init(drm, dsi);
> >       if (ret)
> >               return ret;
> > --
> > 2.36.1.255.ge46751e96f-goog