drm/sun4i: Split out code for enumerating endpoints in output port

Until now, each node has one input port and one output port. However,
with TCON TOP this is no longer true. It has 3 input and 3 output ports.

In order to prepare to this situation, split out the code which checks
all endpoints in input port and adds available components to fifo.

This patch doesn't do any functional change.
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180625120304.7543-8-jernej.skrabec@siol.net

drivers/gpu/drm/sun4i/sun4i_drv.c

@@ -231,12 +231,55 @@ struct endpoint_list {
 	DECLARE_KFIFO(fifo, struct device_node *, 16);
 };
 
+static void sun4i_drv_traverse_endpoints(struct endpoint_list *list,
+					 struct device_node *node,
+					 int port_id)
+{
+	struct device_node *ep, *remote, *port;
+
+	port = of_graph_get_port_by_id(node, port_id);
+	if (!port) {
+		DRM_DEBUG_DRIVER("No output to bind on port %d\n", port_id);
+		return;
+	}
+
+	for_each_available_child_of_node(port, ep) {
+		remote = of_graph_get_remote_port_parent(ep);
+		if (!remote) {
+			DRM_DEBUG_DRIVER("Error retrieving the output node\n");
+			continue;
+		}
+
+		/*
+		 * If the node is our TCON, the first port is used for
+		 * panel or bridges, and will not be part of the
+		 * component framework.
+		 */
+		if (sun4i_drv_node_is_tcon(node)) {
+			struct of_endpoint endpoint;
+
+			if (of_graph_parse_endpoint(ep, &endpoint)) {
+				DRM_DEBUG_DRIVER("Couldn't parse endpoint\n");
+				of_node_put(remote);
+				continue;
+			}
+
+			if (!endpoint.id) {
+				DRM_DEBUG_DRIVER("Endpoint is our panel... skipping\n");
+				of_node_put(remote);
+				continue;
+			}
+		}
+
+		kfifo_put(&list->fifo, remote);
+	}
+}
+
 static int sun4i_drv_add_endpoints(struct device *dev,
 				   struct endpoint_list *list,
 				   struct component_match **match,
 				   struct device_node *node)
 {
-	struct device_node *port, *ep, *remote;
 	int count = 0;
 
 	/*
@@ -272,43 +315,8 @@ static int sun4i_drv_add_endpoints(struct device *dev,
 		count++;
 	}
 
-	/* Inputs are listed first, then outputs */
-	port = of_graph_get_port_by_id(node, 1);
-	if (!port) {
-		DRM_DEBUG_DRIVER("No output to bind\n");
-		return count;
-	}
-
-	for_each_available_child_of_node(port, ep) {
-		remote = of_graph_get_remote_port_parent(ep);
-		if (!remote) {
-			DRM_DEBUG_DRIVER("Error retrieving the output node\n");
-			continue;
-		}
-
-		/*
-		 * If the node is our TCON, the first port is used for
-		 * panel or bridges, and will not be part of the
-		 * component framework.
-		 */
-		if (sun4i_drv_node_is_tcon(node)) {
-			struct of_endpoint endpoint;
-
-			if (of_graph_parse_endpoint(ep, &endpoint)) {
-				DRM_DEBUG_DRIVER("Couldn't parse endpoint\n");
-				of_node_put(remote);
-				continue;
-			}
-
-			if (!endpoint.id) {
-				DRM_DEBUG_DRIVER("Endpoint is our panel... skipping\n");
-				of_node_put(remote);
-				continue;
-			}
-		}
-
-		kfifo_put(&list->fifo, remote);
-	}
+	/* each node has at least one output */
+	sun4i_drv_traverse_endpoints(list, node, 1);
 
 	return count;
 }