diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index c525b42dadde..1665f5d4bf29 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -459,6 +459,7 @@ static struct usb_device_id id_table_combined [] = {
 	{ USB_DEVICE(FALCOM_VID, FALCOM_TWIST_PID) },
 	{ USB_DEVICE(FALCOM_VID, FALCOM_SAMBA_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_SUUNTO_SPORTS_PID) },
+	{ USB_DEVICE(TTI_VID, TTI_QL355P_PID) },
 	{ USB_DEVICE(FTDI_VID, FTDI_RM_CANVIEW_PID) },
 	{ USB_DEVICE(BANDB_VID, BANDB_USOTL4_PID) },
 	{ USB_DEVICE(BANDB_VID, BANDB_USTL4_PID) },
diff --git a/drivers/usb/serial/ftdi_sio.h b/drivers/usb/serial/ftdi_sio.h
index 1bdda935f7d9..9f5cb912f0df 100644
--- a/drivers/usb/serial/ftdi_sio.h
+++ b/drivers/usb/serial/ftdi_sio.h
@@ -338,6 +338,12 @@
  */
 #define FTDI_SUUNTO_SPORTS_PID	0xF680	/* Suunto Sports instrument */
 
+/*
+ * TTi (Thurlby Thandar Instruments)
+ */
+#define TTI_VID			0x103E	/* Vendor Id */
+#define TTI_QL355P_PID		0x03E8	/* TTi QL355P power supply */
+
 /*
  * Definitions for B&B Electronics products.
  */