diff --git a/include/rtdef.h b/include/rtdef.h
index 62d0a53685..dac345f26d 100644
--- a/include/rtdef.h
+++ b/include/rtdef.h
@@ -908,6 +908,7 @@ enum rt_device_class_type
     RT_Device_Class_I2CBUS,                             /**< I2C bus device */
     RT_Device_Class_USBDevice,                          /**< USB slave device */
     RT_Device_Class_USBHost,                            /**< USB host bus */
+    RT_Device_Class_USBOTG,                             /**< USB OTG bus */
     RT_Device_Class_SPIBUS,                             /**< SPI bus device */
     RT_Device_Class_SPIDevice,                          /**< SPI device */
     RT_Device_Class_SDIO,                               /**< SDIO bus device */