Hi Philipp,

On Tuesday 27 August 2013 11:30:51 Philipp Zabel wrote:

Hi Laurent,

I have another small issue with the graph helpers below:

Am Samstag, den 10.08.2013, 01:03 +0200 schrieb Laurent Pinchart:
[...]

quoted

+/*
-------------------------------------------------------------------------
----> 
  * Graph Helpers
  */

@@ -420,6 +599,161 @@ int display_entity_link_graph(struct device *dev,

struct list_head *entities)> 
 }
 EXPORT_SYMBOL_GPL(display_entity_link_graph);

+#ifdef CONFIG_OF
+
+static int display_of_entity_link_entity(struct device *dev,
+					 struct display_entity *entity,
+					 struct list_head *entities,
+					 struct display_entity *root)
+{
+	u32 link_flags = MEDIA_LNK_FL_IMMUTABLE | MEDIA_LNK_FL_ENABLED;
+	const struct device_node *node = entity->dev->of_node;
+	struct media_entity *local = &entity->entity;
+	struct device_node *ep = NULL;
+	int ret = 0;
+
+	dev_dbg(dev, "creating links for entity %s\n", local->name);
+
+	while (1) {
+		struct media_entity *remote = NULL;
+		struct media_pad *remote_pad;
+		struct media_pad *local_pad;
+		struct display_of_link link;
+		struct display_entity *ent;
+		struct device_node *next;
+
+		/* Get the next endpoint and parse its link. */
+		next = display_of_get_next_endpoint(node, ep);
+		if (next = NULL)
+			break;
+
+		of_node_put(ep);
+		ep = next;
+
+		dev_dbg(dev, "processing endpoint %s\n", ep->full_name);
+
+		ret = display_of_parse_link(ep, &link);
+		if (ret < 0) {
+			dev_err(dev, "failed to parse link for %s\n",
+				ep->full_name);
+			continue;
+		}
+
+		/* Skip source pads, they will be processed from the other end of
+		 * the link.
+		 */
+		if (link.local_port >= local->num_pads) {
+			dev_err(dev, "invalid port number %u on %s\n",
+				link.local_port, link.local_node->full_name);
+			display_of_put_link(&link);
+			ret = -EINVAL;
+			break;
+		}
+
+		local_pad = &local->pads[link.local_port];
+
+		if (local_pad->flags & MEDIA_PAD_FL_SOURCE) {
+			dev_dbg(dev, "skipping source port %s:%u\n",
+				link.local_node->full_name, link.local_port);
+			display_of_put_link(&link);
+			continue;
+		}
+
+		/* Find the remote entity. If not found, just skip the link as
+		 * it goes out of scope of the entities handled by the notifier.
+		 */
+		list_for_each_entry(ent, entities, list) {
+			if (ent->dev->of_node = link.remote_node) {
+				remote = &ent->entity;
+				break;
+			}
+		}
+
+		if (root->dev->of_node = link.remote_node)
+			remote = &root->entity;
+
+		if (remote = NULL) {
+			dev_dbg(dev, "no entity found for %s\n",
+				link.remote_node->full_name);
+			display_of_put_link(&link);
+			continue;
+		}
+
+		if (link.remote_port >= remote->num_pads) {
+			dev_err(dev, "invalid port number %u on %s\n",
+				link.remote_port, link.remote_node->full_name);
+			display_of_put_link(&link);
+			ret = -EINVAL;
+			break;
+		}
+
+		remote_pad = &remote->pads[link.remote_port];
+
+		display_of_put_link(&link);
+
+		/* Create the media link. */
+		dev_dbg(dev, "creating %s:%u -> %s:%u link\n",
+			remote->name, remote_pad->index,
+			local->name, local_pad->index);
+
+		ret = media_entity_create_link(remote, remote_pad->index,
+					       local, local_pad->index,
+					       link_flags);
+		if (ret < 0) {
+			dev_err(dev,
+				"failed to create %s:%u -> %s:%u link\n",
+				remote->name, remote_pad->index,
+				local->name, local_pad->index);
+			break;
+		}
+	}
+
+	of_node_put(ep);
+	return ret;
+}
+
+/**
+ * display_of_entity_link_graph - Link all entities in a graph
+ * @dev: device used to print debugging and error messages
+ * @root: optional root display entity
+ * @entities: list of display entities in the graph
+ *
+ * This function creates media controller links for all entities in a
graph + * based on the device tree graph representation. It relies on all
entities + * having been instantiated from the device tree.
+ *
+ * The list of entities is typically taken directly from a display
notifier + * done list. It will thus not include any display entity not
handled by the + * notifier, such as entities directly accessible by the
caller without going + * through the notification process. The optional
root entity parameter can be + * used to pass such a display entity and
include it in the graph. For all + * practical purpose the root entity is
handled is if it was part of the + * entities list.
+ *
+ * Return 0 on success or a negative error code otherwise.
+ */
+int display_of_entity_link_graph(struct device *dev, struct list_head
*entities, +				 struct display_entity *root)
+{
+	struct display_entity *entity;
+	int ret;
+
+	list_for_each_entry(entity, entities, list) {
+		if (WARN_ON(entity->match->type != DISPLAY_ENTITY_BUS_DT))
+			return -EINVAL;
+
+		ret = display_of_entity_link_entity(dev, entity, entities,
+						    root);
+		if (ret < 0)
+			return ret;
+	}
+
+	return display_of_entity_link_entity(dev, root, entities, root);
+}
+EXPORT_SYMBOL_GPL(display_of_entity_link_graph);

The root display entity given to display_of_entity_link_graph is documented
to be optional. Therefore, do not try to dereference root if it is NULL:

Good catch ! I'll fix it in v4, thank you.

-- 
Regards,

Laurent Pinchart