extern struct device_node *of_get_parent(const struct device_node *node);
extern struct device_node *of_get_next_child(const struct device_node *node,
struct device_node *prev);
extern struct device_node *of_get_parent(const struct device_node *node);
extern struct device_node *of_get_next_child(const struct device_node *node,
struct device_node *prev);