[PATCH 1/2] drm/connector: Add a new 'panel_type' property

["Mario Limonciello (AMD)" <superm1@kernel.org>]

If the driver can make an assertion whether a connected panel is an OLED
panel or not then it can attach a property to the connector that userspace
can use as a hint for color schemes.

Signed-off-by: Mario Limonciello (AMD) <superm1@kernel.org>
---
 drivers/gpu/drm/drm_connector.c | 33 +++++++++++++++++++++++++++++++++
 include/drm/drm_connector.h     |  1 +
 include/drm/drm_mode_config.h   |  4 ++++
 include/uapi/drm/drm_mode.h     |  4 ++++
 4 files changed, 42 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 4d6dc9ebfdb5b..7d5279c366583 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -1167,6 +1167,11 @@ static const struct drm_prop_enum_list drm_link_status_enum_list[] = {
 	{ DRM_MODE_LINK_STATUS_BAD, "Bad" },
 };
 
+static const struct drm_prop_enum_list drm_panel_type_enum_list[] = {
+	{ DRM_MODE_PANEL_TYPE_UNKNOWN, "unknown" },
+	{ DRM_MODE_PANEL_TYPE_OLED, "OLED" },
+};
+
 /**
  * drm_display_info_set_bus_formats - set the supported bus formats
  * @info: display info to store bus formats in
@@ -1495,6 +1500,9 @@ EXPORT_SYMBOL(drm_hdmi_connector_get_output_format_name);
  * 	Summarizing: Only set "DPMS" when the connector is known to be enabled,
  * 	assume that a successful SETCONFIG call also sets "DPMS" to on, and
  * 	never read back the value of "DPMS" because it can be incorrect.
+ * panel_type:
+ * 	Immutable enum property to indicate the type of connected panel.
+ * 	Possible values are "unknown" (default) and "OLED".
  * PATH:
  * 	Connector path property to identify how this sink is physically
  * 	connected. Used by DP MST. This should be set by calling
@@ -1845,6 +1853,13 @@ int drm_connector_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.link_status_property = prop;
 
+	prop = drm_property_create_enum(dev, DRM_MODE_PROP_IMMUTABLE, "panel_type",
+					drm_panel_type_enum_list,
+					ARRAY_SIZE(drm_panel_type_enum_list));
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.panel_type_property = prop;
+
 	prop = drm_property_create_bool(dev, DRM_MODE_PROP_IMMUTABLE, "non-desktop");
 	if (!prop)
 		return -ENOMEM;
@@ -3620,3 +3635,21 @@ struct drm_tile_group *drm_mode_create_tile_group(struct drm_device *dev,
 	return tg;
 }
 EXPORT_SYMBOL(drm_mode_create_tile_group);
+
+/**
+ * drm_connector_attach_panel_type_property - attaches panel type property
+ * @connector: connector to attach the property on.
+ *
+ * This is used to add support for panel type detection.
+ */
+void drm_connector_attach_panel_type_property(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_property *prop = dev->mode_config.panel_type_property;
+
+	if (!prop)
+		return;
+
+	drm_object_attach_property(&connector->base, prop, DRM_MODE_PANEL_TYPE_UNKNOWN);
+}
+EXPORT_SYMBOL(drm_connector_attach_panel_type_property);
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index 8f34f4b8183d8..bd460a6d0d052 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2448,6 +2448,7 @@ int drm_connector_attach_scaling_mode_property(struct drm_connector *connector,
 					       u32 scaling_mode_mask);
 int drm_connector_attach_vrr_capable_property(
 		struct drm_connector *connector);
+void drm_connector_attach_panel_type_property(struct drm_connector *connector);
 int drm_connector_attach_broadcast_rgb_property(struct drm_connector *connector);
 int drm_connector_attach_colorspace_property(struct drm_connector *connector);
 int drm_connector_attach_hdr_output_metadata_property(struct drm_connector *connector);
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 895fb820dba07..5e1dd0cfccde2 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -600,6 +600,10 @@ struct drm_mode_config {
 	 * multiple CRTCs.
 	 */
 	struct drm_property *tile_property;
+	/**
+	 * @panel_type_property: Default connector property for panel type
+	 */
+	struct drm_property *panel_type_property;
 	/**
 	 * @link_status_property: Default connector property for link status
 	 * of a connector
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index cbbbfc1dfe2b8..3693d82b5279f 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -166,6 +166,10 @@ extern "C" {
 #define DRM_MODE_LINK_STATUS_GOOD	0
 #define DRM_MODE_LINK_STATUS_BAD	1
 
+/* Panel type property */
+#define DRM_MODE_PANEL_TYPE_UNKNOWN	0
+#define DRM_MODE_PANEL_TYPE_OLED	1
+
 /*
  * DRM_MODE_ROTATE_<degrees>
  *
-- 
2.43.0