libfdt: add convenience function fdt_find_and_setprop()

Given the path to a node, fdt_find_and_setprop() allows a property value
to be set directly.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index 693bfe4..55fcc41 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -188,6 +188,32 @@
 	return 0;
 }
 
+/**
+ * fdt_find_and_setprop: Find a node and set it's property
+ *
+ * @fdt: ptr to device tree
+ * @node: path of node
+ * @prop: property name
+ * @val: ptr to new value
+ * @len: length of new property value
+ * @create: flag to create the property if it doesn't exist
+ *
+ * Convenience function to directly set a property given the path to the node.
+ */
+int fdt_find_and_setprop(void *fdt, const char *node, const char *prop,
+			 const void *val, int len, int create)
+{
+	int nodeoff = fdt_find_node_by_path(fdt, node);
+
+	if (nodeoff < 0)
+		return nodeoff;
+
+	if ((!create) && (fdt_get_property(fdt, nodeoff, prop, 0) == NULL))
+		return 0; /* create flag not set; so exit quietly */
+
+	return fdt_setprop(fdt, nodeoff, prop, val, len);
+}
+
 int fdt_delprop(void *fdt, int nodeoffset, const char *name)
 {
 	struct fdt_property *prop;