drm/connector: Create a helper to attach the hdr_output_metadata property

All the drivers that implement HDR output call pretty much the same
function to initialise the hdr_output_metadata property, and while the
creation of that property is in a helper, every driver uses the same
code to attach it.

Provide a helper for it as well
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20210430094451.2145002-1-maxime@cerno.tech

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -7498,9 +7498,7 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
 	if (connector_type == DRM_MODE_CONNECTOR_HDMIA ||
 	    connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
 	    connector_type == DRM_MODE_CONNECTOR_eDP) {
-		drm_object_attach_property(
-			&aconnector->base.base,
-			dm->ddev->mode_config.hdr_output_metadata_property, 0);
+		drm_connector_attach_hdr_output_metadata_property(&aconnector->base);
 
 		if (!aconnector->mst_port)
 			drm_connector_attach_vrr_capable_property(&aconnector->base);

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

@@ -2492,8 +2492,7 @@ static int dw_hdmi_connector_create(struct dw_hdmi *hdmi)
 	drm_connector_attach_max_bpc_property(connector, 8, 16);
 
 	if (hdmi->version >= 0x200a && hdmi->plat_data->use_drm_infoframe)
-		drm_object_attach_property(&connector->base,
-			connector->dev->mode_config.hdr_output_metadata_property, 0);
+		drm_connector_attach_hdr_output_metadata_property(connector);
 
 	drm_connector_attach_encoder(connector, hdmi->bridge.encoder);
 

drivers/gpu/drm/drm_connector.c

@@ -2152,6 +2152,27 @@ int drm_connector_attach_max_bpc_property(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_connector_attach_max_bpc_property);
 
+/**
+ * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property
+ * @connector: connector to attach the property on.
+ *
+ * This is used to allow the userspace to send HDR Metadata to the
+ * driver.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int drm_connector_attach_hdr_output_metadata_property(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_property *prop = dev->mode_config.hdr_output_metadata_property;
+
+	drm_object_attach_property(&connector->base, prop, 0);
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_connector_attach_hdr_output_metadata_property);
+
 /**
  * drm_connector_set_vrr_capable_property - sets the variable refresh rate
  * capable property for a connector

drivers/gpu/drm/i915/display/intel_hdmi.c

@@ -2459,8 +2459,7 @@ intel_hdmi_add_properties(struct intel_hdmi *intel_hdmi, struct drm_connector *c
 	drm_connector_attach_content_type_property(connector);
 
 	if (DISPLAY_VER(dev_priv) >= 10)
-		drm_object_attach_property(&connector->base,
-			connector->dev->mode_config.hdr_output_metadata_property, 0);
+		drm_connector_attach_hdr_output_metadata_property(connector);
 
 	if (!HAS_GMCH(dev_priv))
 		drm_connector_attach_max_bpc_property(connector, 8, 12);

include/drm/drm_connector.h

@@ -1671,6 +1671,7 @@ 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);
+int drm_connector_attach_hdr_output_metadata_property(struct drm_connector *connector);
 int drm_mode_create_aspect_ratio_property(struct drm_device *dev);
 int drm_mode_create_hdmi_colorspace_property(struct drm_connector *connector);
 int drm_mode_create_dp_colorspace_property(struct drm_connector *connector);