diff --git a/drivers/usb/serial/ti_usb_3410_5052.h b/drivers/usb/serial/ti_usb_3410_5052.h
index 98f35c6..0cd247f 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.h
+++ b/drivers/usb/serial/ti_usb_3410_5052.h
@@ -227,7 +227,7 @@
 } __attribute__((packed));
 
 /* Interrupt codes */
-#define TI_GET_PORT_FROM_CODE(c)	(((c) >> 4) - 3)
+#define TI_GET_PORT_FROM_CODE(c)	(((c) >> 6) & 0x01)
 #define TI_GET_FUNC_FROM_CODE(c)	((c) & 0x0f)
 #define TI_CODE_HARDWARE_ERROR		0xFF
 #define TI_CODE_DATA_ERROR		0x03