[PATCH 23/35] drm/panel: read the panel orientation in the core

[Dmitry Baryshkov]

Panel orientation describes how the panel is mounted and comes from the
common "rotation" DT property, yet each driver has to parse it and hand
it back through get_orientation(). 24 drivers carry an identical copy of
that code and the rest silently ignore the property.

Parse it once in devm_drm_panel_alloc(). The callback still takes
precedence until the drivers are converted. An invalid value fails the
allocation, just as it fails probe in those drivers today.

As a side effect all panels honour "rotation" now. Among the in-tree DTs
this only changes the Motorola Mapphone panel (panel-dsi-cm,
rotation = <90>).

Assisted-by: LLM
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/drm_connector.c |  5 ++++-
 drivers/gpu/drm/drm_panel.c     |  9 +++++++++
 include/drm/drm_panel.h         | 10 ++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 893716a9e489..efcf1ce979a9 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -3397,7 +3397,8 @@ EXPORT_SYMBOL(drm_connector_set_panel_orientation_with_quirk);
  * @panel: panel that can provide orientation information.
  *
  * Drm drivers should call this function before drm_dev_register().
- * Orientation is obtained from panel's .get_orientation() callback.
+ * Orientation is obtained from panel's .get_orientation() callback, falling
+ * back to &drm_panel.orientation if the panel doesn't implement it.
  *
  * Returns:
  * Zero on success, negative errno on failure.
@@ -3410,6 +3411,8 @@ int drm_connector_set_orientation_from_panel(
 
 	if (panel && panel->funcs && panel->funcs->get_orientation)
 		orientation = panel->funcs->get_orientation(panel);
+	else if (panel)
+		orientation = panel->orientation;
 	else
 		orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
 
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 5bc97166bcb8..1b7ff0bea68e 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -925,6 +925,15 @@ void *__devm_drm_panel_alloc(struct device *dev, size_t size, size_t offset,
 
 	drm_panel_init(panel, dev, funcs, connector_type);
 
+	panel->orientation = DRM_MODE_PANEL_ORIENTATION_UNKNOWN;
+	if (dev->of_node) {
+		err = drm_of_get_panel_orientation(dev->of_node,
+						   &panel->orientation);
+		if (err)
+			return ERR_PTR(dev_err_probe(dev, err,
+						     "failed to get orientation\n"));
+	}
+
 	return container;
 }
 EXPORT_SYMBOL(__devm_drm_panel_alloc);
diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h
index 579b6be855c7..dc4fbeac796b 100644
--- a/include/drm/drm_panel.h
+++ b/include/drm/drm_panel.h
@@ -236,6 +236,16 @@ struct drm_panel {
 	 */
 	struct drm_connector connector;
 
+	/**
+	 * @orientation:
+	 *
+	 * Orientation of the panel, used to set the panel orientation property
+	 * of the connector. It is read from the "rotation" property of the
+	 * panel's device tree node by devm_drm_panel_alloc(). Drivers can
+	 * override it before calling drm_panel_add().
+	 */
+	enum drm_panel_orientation orientation;
+
 	/**
 	 * @list:
 	 *

-- 
2.47.3