[PATCH 3.6.0-rc5] dt: introduce of_get_child to get child node by name.

[Srinivas KANDAGATLA]

From: Srinivas Kandagatla <srinivas.kandagatla at st.com>

This patch introduces of_get_child function to get a child node by its
name in a given parent node.

Without this patch each driver code has to iterate the parent and do
a string compare, However having of_get_child libary function would
avoid code duplication, errors and is more convenient.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at st.com>
---
 drivers/of/base.c  |   27 +++++++++++++++++++++++++++
 include/linux/of.h |    2 ++
 2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/drivers/of/base.c b/drivers/of/base.c
index d4a1c9a..d4b6840 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -391,6 +391,33 @@ struct device_node *of_get_next_available_child(const struct device_node *node,
 EXPORT_SYMBOL(of_get_next_available_child);
 
 /**
+ *	of_get_child - Find the child node by name for given parent
+ *	@node:	parent node
+ *	@name:	child name to look for.
+ *
+ *      This function looks for child node for given matching name
+ *
+ *	Returns a node pointer if found, with refcount incremented, use
+ *	of_node_put() on it when done.
+ *	else returns NULL.
+ */
+
+struct device_node *of_get_child(const struct device_node *node,
+				const char *name)
+{
+	struct device_node *child;
+
+	read_lock(&devtree_lock);
+	for_each_child_of_node(node, child)
+		if (child->name && (of_node_cmp(child->name, name) == 0)
+			&& of_node_get(child))
+			break;
+	read_unlock(&devtree_lock);
+	return child;
+}
+EXPORT_SYMBOL(of_get_child);
+
+/**
  *	of_find_node_by_path - Find a node matching a full OF path
  *	@path:	The full path to match
  *
diff --git a/include/linux/of.h b/include/linux/of.h
index 1b11632..510e1fe 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -192,6 +192,8 @@ extern struct device_node *of_get_next_child(const struct device_node *node,
 					     struct device_node *prev);
 extern struct device_node *of_get_next_available_child(
 	const struct device_node *node, struct device_node *prev);
+extern struct device_node *of_get_child(const struct device_node *node,
+					const char *name);
 
 #define for_each_child_of_node(parent, child) \
 	for (child = of_get_next_child(parent, NULL); child != NULL; \
-- 
1.7.0.4