of: Add of_graph_get_port_by_id function
This patch adds a function to get a port device tree node by port id,
or reg property value.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 05b20f1..6398b9c 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2081,6 +2081,38 @@
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