unsigned long last_dtr_rts;     /* saved modem control outputs */
        char prev_status;        /* Used for TIOCMIWAIT */
        char transmit_empty;    /* If transmitter is empty or not */
-       u16 interface;          /* FT2232C, FT2232H or FT4232H port interface
-                                  (0 for FT232/245) */
+       u16 channel;            /* channel index, or 0 for legacy types */
 
        speed_t force_baud;     /* if non-zero, force the baud rate to
                                   this value */
                               usb_sndctrlpipe(port->serial->dev, 0),
                               FTDI_SIO_SET_MODEM_CTRL_REQUEST,
                               FTDI_SIO_SET_MODEM_CTRL_REQUEST_TYPE,
-                              value, priv->interface,
+                              value, priv->channel,
                               NULL, 0, WDR_TIMEOUT);
        if (rv < 0) {
                dev_dbg(dev, "%s Error from MODEM_CTRL urb: DTR %s, RTS %s\n",
                        priv->chip_type == FTX) {
                /* Probably the BM type needs the MSB of the encoded fractional
                 * divider also moved like for the chips above. Any infos? */
-               index = (u16)((index << 8) | priv->interface);
+               index = (u16)((index << 8) | priv->channel);
        }
 
        rv = usb_control_msg(port->serial->dev,
                             usb_sndctrlpipe(udev, 0),
                             FTDI_SIO_SET_LATENCY_TIMER_REQUEST,
                             FTDI_SIO_SET_LATENCY_TIMER_REQUEST_TYPE,
-                            l, priv->interface,
+                            l, priv->channel,
                             NULL, 0, WDR_TIMEOUT);
        if (rv < 0)
                dev_err(&port->dev, "Unable to write latency timer: %i\n", rv);
 
        rv = usb_control_msg_recv(udev, 0, FTDI_SIO_GET_LATENCY_TIMER_REQUEST,
                                  FTDI_SIO_GET_LATENCY_TIMER_REQUEST_TYPE, 0,
-                                 priv->interface, &buf, 1, WDR_TIMEOUT,
+                                 priv->channel, &buf, 1, WDR_TIMEOUT,
                                  GFP_KERNEL);
        if (rv == 0)
                rv = buf;
                } else
                        priv->chip_type = FT2232C;
 
-               /* Determine interface code. */
                if (ifnum == 0)
-                       priv->interface = INTERFACE_A;
+                       priv->channel = CHANNEL_A;
                else if (ifnum == 1)
-                       priv->interface = INTERFACE_B;
+                       priv->channel = CHANNEL_B;
                else if (ifnum == 2)
-                       priv->interface = INTERFACE_C;
+                       priv->channel = CHANNEL_C;
                else if (ifnum == 3)
-                       priv->interface = INTERFACE_D;
+                       priv->channel = CHANNEL_D;
 
                /* BM-type devices have a bug where bcdDevice gets set
                 * to 0x200 when iSerialNumber is 0.  */
                             usb_sndctrlpipe(udev, 0),
                             FTDI_SIO_SET_EVENT_CHAR_REQUEST,
                             FTDI_SIO_SET_EVENT_CHAR_REQUEST_TYPE,
-                            v, priv->interface,
+                            v, priv->channel,
                             NULL, 0, WDR_TIMEOUT);
        if (rv < 0) {
                dev_dbg(&port->dev, "Unable to write event character: %i\n", rv);
                                 usb_sndctrlpipe(serial->dev, 0),
                                 FTDI_SIO_SET_BITMODE_REQUEST,
                                 FTDI_SIO_SET_BITMODE_REQUEST_TYPE, val,
-                                priv->interface, NULL, 0, WDR_TIMEOUT);
+                                priv->channel, NULL, 0, WDR_TIMEOUT);
        if (result < 0) {
                dev_err(&serial->interface->dev,
                        "bitmode request failed for value 0x%04x: %d\n",
        result = usb_control_msg_recv(serial->dev, 0,
                                      FTDI_SIO_READ_PINS_REQUEST,
                                      FTDI_SIO_READ_PINS_REQUEST_TYPE, 0,
-                                     priv->interface, &buf, 1, WDR_TIMEOUT,
+                                     priv->channel, &buf, 1, WDR_TIMEOUT,
                                      GFP_KERNEL);
        if (result == 0)
                result = buf;
        usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                        FTDI_SIO_RESET_REQUEST, FTDI_SIO_RESET_REQUEST_TYPE,
                        FTDI_SIO_RESET_SIO,
-                       priv->interface, NULL, 0, WDR_TIMEOUT);
+                       priv->channel, NULL, 0, WDR_TIMEOUT);
 
        /* Termios defaults are set by usb_serial_init. We don't change
           port->tty->termios - this would lose speed settings, etc.
                            usb_sndctrlpipe(port->serial->dev, 0),
                            FTDI_SIO_SET_FLOW_CTRL_REQUEST,
                            FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
-                           0, priv->interface, NULL, 0,
+                           0, priv->channel, NULL, 0,
                            WDR_TIMEOUT) < 0) {
                        dev_err(&port->dev, "error from flowcontrol urb\n");
                }
                        usb_sndctrlpipe(port->serial->dev, 0),
                        FTDI_SIO_SET_DATA_REQUEST,
                        FTDI_SIO_SET_DATA_REQUEST_TYPE,
-                       value , priv->interface,
+                       value, priv->channel,
                        NULL, 0, WDR_TIMEOUT) < 0) {
                dev_err(&port->dev, "%s FAILED to enable/disable break state (state was %d)\n",
                        __func__, break_state);
        if (usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                            FTDI_SIO_SET_DATA_REQUEST,
                            FTDI_SIO_SET_DATA_REQUEST_TYPE,
-                           value , priv->interface,
+                           value, priv->channel,
                            NULL, 0, WDR_SHORT_TIMEOUT) < 0) {
                dev_err(ddev, "%s FAILED to set databits/stopbits/parity\n",
                        __func__);
                if (usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                                    FTDI_SIO_SET_FLOW_CTRL_REQUEST,
                                    FTDI_SIO_SET_FLOW_CTRL_REQUEST_TYPE,
-                                   0, priv->interface,
+                                   0, priv->channel,
                                    NULL, 0, WDR_TIMEOUT) < 0) {
                        dev_err(ddev, "%s error from disable flowcontrol urb\n",
                                __func__);
                index = FTDI_SIO_DISABLE_FLOW_CTRL;
        }
 
-       index |= priv->interface;
+       index |= priv->channel;
 
        ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
                        FTDI_SIO_SET_FLOW_CTRL_REQUEST,
                        usb_rcvctrlpipe(port->serial->dev, 0),
                        FTDI_SIO_GET_MODEM_STATUS_REQUEST,
                        FTDI_SIO_GET_MODEM_STATUS_REQUEST_TYPE,
-                       0, priv->interface,
+                       0, priv->channel,
                        buf, len, WDR_TIMEOUT);
 
        /* NOTE: We allow short responses and handle that below. */