diff --git a/drivers/of/base.c b/drivers/of/base.c
index b8b65fddbeb5979a668c705f5878724bcec519be..57ec27bed44f1fbcf6ebb8857a02187008c5289e 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -639,7 +639,7 @@ EXPORT_SYMBOL_GPL(of_property_read_u32);
  * The out_string pointer is modified only if a valid string can be decoded.
  */
 int of_property_read_string(struct device_node *np, char *propname,
-				char **out_string)
+				const char **out_string)
 {
 	struct property *prop = of_find_property(np, propname, NULL);
 	if (!prop)
diff --git a/include/linux/of.h b/include/linux/of.h
index 4fc4c1b8d5d59e6617c9109489ff9bad5c91d787..b23852002b30022d93ce2ec5050dd45c55483ae4 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -198,7 +198,7 @@ extern struct property *of_find_property(const struct device_node *np,
 extern int of_property_read_u32(struct device_node *np, char *propname,
 					u32 *out_value);
 extern int of_property_read_string(struct device_node *np, char *propname,
-					char **out_string);
+					const char **out_string);
 extern int of_device_is_compatible(const struct device_node *device,
 				   const char *);
 extern int of_device_is_available(const struct device_node *device);