From bfe446e37c4efd8ade454911e8f80414bcbfc10d Mon Sep 17 00:00:00 2001
From: Philipp Zabel 
Date: Tue, 11 Mar 2014 11:21:11 +0100
Subject: [PATCH] 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 
Acked-by: Laurent Pinchart 
---
 drivers/of/base.c        | 32 ++++++++++++++++++++++++++++++++
 include/linux/of_graph.h |  7 +++++++
 2 files changed, 39 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index 05b20f1cca7b3..6398b9ca91572 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -2080,6 +2080,38 @@ 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
diff --git a/include/linux/of_graph.h b/include/linux/of_graph.h
index e43442efcbe5e..3c1c95a39e0c1 100644
--- a/include/linux/of_graph.h
+++ b/include/linux/of_graph.h
@@ -40,6 +40,7 @@ struct of_endpoint {
 #ifdef CONFIG_OF
 int of_graph_parse_endpoint(const struct device_node *node,
 				struct of_endpoint *endpoint);
+struct device_node *of_graph_get_port_by_id(struct device_node *node, u32 id);
 struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
 					struct device_node *previous);
 struct device_node *of_graph_get_remote_port_parent(
@@ -53,6 +54,12 @@ static inline int of_graph_parse_endpoint(const struct device_node *node,
 	return -ENOSYS;
 }
 
+static inline struct device_node *of_graph_get_port_by_id(
+					struct device_node *node, u32 id)
+{
+	return NULL;
+}
+
 static inline struct device_node *of_graph_get_next_endpoint(
 					const struct device_node *parent,
 					struct device_node *previous)
-- 
2.51.0