drm: add a path blob property

This property will be used by the MST code to provide userspace
with a path to parse so it can recognise connectors around hotplugs.
Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_crtc.c

@@ -1257,6 +1257,7 @@ static int drm_mode_create_standard_connector_properties(struct drm_device *dev)
 {
 	struct drm_property *edid;
 	struct drm_property *dpms;
+	struct drm_property *dev_path;
 
 	/*
 	 * Standard properties (apply to all connectors)
@@ -1271,6 +1272,12 @@ static int drm_mode_create_standard_connector_properties(struct drm_device *dev)
 				   ARRAY_SIZE(drm_dpms_enum_list));
 	dev->mode_config.dpms_property = dpms;
 
+	dev_path = drm_property_create(dev,
+				       DRM_MODE_PROP_BLOB |
+				       DRM_MODE_PROP_IMMUTABLE,
+				       "PATH", 0);
+	dev->mode_config.path_property = dev_path;
+
 	return 0;
 }
 
@@ -3755,6 +3762,25 @@ int drm_mode_getblob_ioctl(struct drm_device *dev,
 	return ret;
 }
 
+int drm_mode_connector_set_path_property(struct drm_connector *connector,
+					 char *path)
+{
+	struct drm_device *dev = connector->dev;
+	int ret, size;
+	size = strlen(path) + 1;
+
+	connector->path_blob_ptr = drm_property_create_blob(connector->dev,
+							    size, path);
+	if (!connector->path_blob_ptr)
+		return -EINVAL;
+
+	ret = drm_object_property_set_value(&connector->base,
+					    dev->mode_config.path_property,
+					    connector->path_blob_ptr->base.id);
+	return ret;
+}
+EXPORT_SYMBOL(drm_mode_connector_set_path_property);
+
 /**
  * drm_mode_connector_update_edid_property - update the edid property of a connector
  * @connector: drm connector

include/drm/drm_crtc.h

@@ -524,6 +524,8 @@ struct drm_connector {
 	struct drm_property_blob *edid_blob_ptr;
 	struct drm_object_properties properties;
 
+	struct drm_property_blob *path_blob_ptr;
+
 	uint8_t polled; /* DRM_CONNECTOR_POLL_* */
 
 	/* requested DPMS state */
@@ -803,6 +805,7 @@ struct drm_mode_config {
 	struct list_head property_blob_list;
 	struct drm_property *edid_property;
 	struct drm_property *dpms_property;
+	struct drm_property *path_property;
 	struct drm_property *plane_type_property;
 
 	/* DVI-I properties */
@@ -952,6 +955,8 @@ extern void drm_mode_config_init(struct drm_device *dev);
 extern void drm_mode_config_reset(struct drm_device *dev);
 extern void drm_mode_config_cleanup(struct drm_device *dev);
 
+extern int drm_mode_connector_set_path_property(struct drm_connector *connector,
+						char *path);
 extern int drm_mode_connector_update_edid_property(struct drm_connector *connector,
 						struct edid *edid);