Consolidate of_get_parent

This requires creating dummy of_node_{get,put} routines for sparc and
sparc64.  It also adds a read_lock around the parent accesses.

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: David S. Miller <davem@davemloft.net>

drivers/of/base.c

@@ -113,3 +113,24 @@ int of_device_is_compatible(const struct device_node *device,
 	return 0;
 }
 EXPORT_SYMBOL(of_device_is_compatible);
+
+/**
+ *	of_get_parent - Get a node's parent if any
+ *	@node:	Node to get parent
+ *
+ *	Returns a node pointer with refcount incremented, use
+ *	of_node_put() on it when done.
+ */
+struct device_node *of_get_parent(const struct device_node *node)
+{
+	struct device_node *np;
+
+	if (!node)
+		return NULL;
+
+	read_lock(&devtree_lock);
+	np = of_node_get(node->parent);
+	read_unlock(&devtree_lock);
+	return np;
+}
+EXPORT_SYMBOL(of_get_parent);