diff --git a/include/linux/usb/ch9.h b/include/linux/usb/ch9.h
index 9c210f2..27603bc 100644
--- a/include/linux/usb/ch9.h
+++ b/include/linux/usb/ch9.h
@@ -43,4 +43,13 @@
  */
 extern const char *usb_speed_string(enum usb_device_speed speed);
 
+
+/**
+ * usb_state_string - Returns human readable name for the state.
+ * @state: The state to return a human-readable name for. If it's not
+ *	any of the states devices in usb_device_state_string enum,
+ *	the string UNKNOWN will be returned.
+ */
+extern const char *usb_state_string(enum usb_device_state state);
+
 #endif /* __LINUX_USB_CH9_H */