[PATCH 1/2] drm: Introduce panel_power_saving drm property

[Mario Limonciello]

The `panel_power_saving` DRM property is an optional property that
can be added to a connector by a driver.

This property is for compositors to indicate intent of allowing
policy for the driver to use power saving features that may
compromise color fidelity.

Signed-off-by: Mario Limonciello <mario.limonciello at amd.com>
---
 drivers/gpu/drm/drm_connector.c | 36 +++++++++++++++++++++++++++++++++
 include/drm/drm_connector.h     |  1 +
 include/drm/drm_mode_config.h   |  6 ++++++
 include/uapi/drm/drm_mode.h     |  4 ++++
 4 files changed, 47 insertions(+)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
index 4d2df7f64dc5..ccf672c55e0c 100644
--- a/drivers/gpu/drm/drm_connector.c
+++ b/drivers/gpu/drm/drm_connector.c
@@ -961,6 +961,11 @@ static const struct drm_prop_enum_list drm_scaling_mode_enum_list[] = {
 	{ DRM_MODE_SCALE_ASPECT, "Full aspect" },
 };
 
+static const struct drm_prop_enum_list drm_panel_power_saving_enum_list[] = {
+	{ DRM_MODE_PANEL_POWER_SAVING_ALLOWED, "Allowed" },
+	{ DRM_MODE_PANEL_POWER_SAVING_FORBIDDEN, "Forbidden" },
+};
+
 static const struct drm_prop_enum_list drm_aspect_ratio_enum_list[] = {
 	{ DRM_MODE_PICTURE_ASPECT_NONE, "Automatic" },
 	{ DRM_MODE_PICTURE_ASPECT_4_3, "4:3" },
@@ -1963,6 +1968,37 @@ int drm_mode_create_scaling_mode_property(struct drm_device *dev)
 }
 EXPORT_SYMBOL(drm_mode_create_scaling_mode_property);
 
+/**
+ * drm_mode_create_panel_power_saving_property - create panel power saving property
+ * @dev: DRM device
+ *
+ * Called by a driver the first time it's needed, must be attached to desired
+ * connectors.
+ *
+ * Atomic drivers should use drm_mode_create_panel_power_saving_property()
+ * instead to correctly assign &drm_connector_state.panel_power_saving
+ * in the atomic state.
+ *
+ * Returns: %0
+ */
+int drm_mode_create_panel_power_saving_property(struct drm_device *dev)
+{
+	struct drm_property *panel_power_saving;
+
+	if (dev->mode_config.panel_power_saving)
+		return 0;
+
+	panel_power_saving =
+		drm_property_create_enum(dev, 0, "panel power saving",
+				drm_panel_power_saving_enum_list,
+				    ARRAY_SIZE(drm_panel_power_saving_enum_list));
+
+	dev->mode_config.panel_power_saving = panel_power_saving;
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_mode_create_panel_power_saving_property);
+
 /**
  * DOC: Variable refresh properties
  *
diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
index fe88d7fc6b8f..4ea3f912c641 100644
--- a/include/drm/drm_connector.h
+++ b/include/drm/drm_connector.h
@@ -2025,6 +2025,7 @@ int drm_mode_create_dp_colorspace_property(struct drm_connector *connector,
 					   u32 supported_colorspaces);
 int drm_mode_create_content_type_property(struct drm_device *dev);
 int drm_mode_create_suggested_offset_properties(struct drm_device *dev);
+int drm_mode_create_panel_power_saving_property(struct drm_device *dev);
 
 int drm_connector_set_path_property(struct drm_connector *connector,
 				    const char *path);
diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 973119a9176b..099ad2d8c5c1 100644
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -954,6 +954,12 @@ struct drm_mode_config {
 	 */
 	struct drm_atomic_state *suspend_state;
 
+	/**
+	 * @panel_power_saving: DRM ENUM property for type of
+	 * Panel Power Saving.
+	 */
+	struct drm_property *panel_power_saving;
+
 	const struct drm_mode_config_helper_funcs *helper_private;
 };
 
diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
index 7040e7ea80c7..82e565cc76fb 100644
--- a/include/uapi/drm/drm_mode.h
+++ b/include/uapi/drm/drm_mode.h
@@ -152,6 +152,10 @@ extern "C" {
 #define DRM_MODE_SCALE_CENTER		2 /* Centered, no scaling */
 #define DRM_MODE_SCALE_ASPECT		3 /* Full screen, preserve aspect */
 
+/* Panel power saving options */
+#define DRM_MODE_PANEL_POWER_SAVING_ALLOWED	0 /* Panel power savings features allowed */
+#define DRM_MODE_PANEL_POWER_SAVING_FORBIDDEN	1 /* Panel power savings features not allowed */
+
 /* Dithering mode options */
 #define DRM_MODE_DITHERING_OFF	0
 #define DRM_MODE_DITHERING_ON	1
-- 
2.45.0