diff --git a/include/rtdef.h b/include/rtdef.h
index 95395c7960ce7f530fb4c91a4da5f123a7bcdd1c..16b5439503a5eab7ea0fe520a4c0928b32059692 100644
--- a/include/rtdef.h
+++ b/include/rtdef.h
@@ -567,6 +567,9 @@ enum rt_device_class_type
 	RT_Device_Class_RTC,							/**< RTC device 								*/
 	RT_Device_Class_Sound,							/**< Sound device 								*/
 	RT_Device_Class_Graphic,						/**< Graphic device                             */
+	RT_Device_Class_I2C, 							/**< I2C device                                 */
+	RT_Device_Class_USBDevice,						/**< USB slave device                           */
+	RT_Device_Class_USBHost,						/**< USB host bus								*/
 	RT_Device_Class_Unknown							/**< unknown device 							*/
 };