Merge tag 'of-graph-for-4.0' of git://git.pengutronix.de/git/pza/linux into for-next

Pull of-graph helpers from Philipp Zabel:
of: Add of-graph helpers to loop over endpoints and find ports by id

This series converts of_graph_get_next_endpoint to decrement the refcount of
the passed prev parameter. This allows to add a for_each_endpoint_of_node
helper macro to loop over all endpoints in a device tree node.
The of_graph_get_port_by_id function is added to retrieve a port by its known
port id (contained in the reg property) from the device tree.

1 files changed, 33 insertions, 8 deletions

diff --git a/drivers/of/base.c b/drivers/of/base.c
index 8f165b112e03..69566b6a876d 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2083,13 +2083,44 @@ int of_graph_parse_endpoint(const struct device_node *node,
 EXPORT_SYMBOL(of_graph_parse_endpoint);
 
 /**
+ * of_graph_get_port_by_id() - get the port matching a given id
+ * @parent: pointer to the parent device node
+ * @id: id of the port
+ *
+ * Return: A 'port' node pointer with refcount incremented. The caller
+ * has to use of_node_put() on it when done.
+ */
+struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
+{
+        struct device_node *node, *port;
+
+        node = of_get_child_by_name(parent, "ports");
+        if (node)
+                parent = node;
+
+        for_each_child_of_node(parent, port) {
+                u32 port_id = 0;
+
+                if (of_node_cmp(port->name, "port") != 0)
+                        continue;
+                of_property_read_u32(port, "reg", &port_id);
+                if (id == port_id)
+                        break;
+        }
+
+        of_node_put(node);
+
+        return port;
+}
+EXPORT_SYMBOL(of_graph_get_port_by_id);
+
+/**
  * of_graph_get_next_endpoint() - get next endpoint node
  * @parent: pointer to the parent device node
  * @prev: previous endpoint node, or NULL to get first
  *
  * Return: An 'endpoint' node pointer with refcount incremented. Refcount
- * of the passed @prev node is not decremented, the caller have to use
- * of_node_put() on it when done.
+ * of the passed @prev node is decremented.
  */
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
                                         struct device_node *prev)
@@ -2125,12 +2156,6 @@ struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
                 if (WARN_ONCE(!port, "%s(): endpoint %s has no parent node\n",
                               __func__, prev->full_name))
                         return NULL;
-
-                /*
-                 * Avoid dropping prev node refcount to 0 when getting the next
-                 * child below.
-                 */
-                of_node_get(prev);
         }
 
         while (1) {