Hi,
On Tue, Jun 7, 2022 at 2:06 AM Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx> 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.
>
> Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
> Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>
> ---
> v4->v5:
> - use the new function in v5.
> - don't use drm_of_find_panel_or_bridge().
> ---
> drivers/gpu/drm/mediatek/mtk_dsi.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index d9f10a33e6fa..998b1237e193 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 +823,10 @@ 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 */
> + drm_connector_set_orientation_from_panel(dsi->connector, dsi->panel);
> +
> drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
>
> return 0;
> @@ -836,6 +841,16 @@ static int mtk_dsi_bind(struct device *dev, struct device *master, void *data)
> int ret;
> struct drm_device *drm = data;
> struct mtk_dsi *dsi = dev_get_drvdata(dev);
> + struct device_node *panel_node;
> +
> + /* Get panel if existed */
> + panel_node = of_graph_get_remote_node(dev->of_node, 0, 0);
> + if (panel_node) {
> + dsi->panel = of_drm_find_panel(panel_node);
> + if (IS_ERR(dsi->panel))
> + dsi->panel = NULL;
> + of_node_put(panel_node);
> + }
While the above works, it feels like we could do better. What about this?
* We add _some_ way to determine if a bridge is actually a
panel_bridge. If nothing else maybe this could be
drm_bridge_is_panel() and it could just check if bridge.funcs ==
panel_bridge_bridge_funcs
* In drm_bridge_connector_init(), when we're looping through all the
bridges we find the panel_bridge if it's there.
* At the end of drm_bridge_connector_init() if we found a panel_bridge
then we call a function like drm_panel_bridge_set_orientation().
Then you can fully get rid of the mediatek patch, right? The above
will only work if you're using a panel_bridge / bridge_connector, but
that's "the future" anyway and we want to encourage people to
transition to that.
-Doug
