USB: serial: ftdi_sio: rename channel index

Multi-channel devices require a channel selector to be included in
control requests.

Replace "interface" with the less ambiguous "channel", which is the
terminology used for newer devices, in the corresponding defines and
variables.

Signed-off-by: Johan Hovold <[e-mail]>

drivers/usb/serial/ftdi_sio.c

···
 	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. */

drivers/usb/serial/ftdi_sio.h

···
 #define FTDI_SIO_READ_PINS		0x0c /* Read immediate value of pins */
 #define FTDI_SIO_READ_EEPROM		0x90 /* Read EEPROM */
 
-/* Interface indices for FT2232, FT2232H and FT4232H devices */
-#define INTERFACE_A		1
-#define INTERFACE_B		2
-#define INTERFACE_C		3
-#define INTERFACE_D		4
+/* Channel indices for FT2232, FT2232H and FT4232H devices */
+#define CHANNEL_A		1
+#define CHANNEL_B		2
+#define CHANNEL_C		3
+#define CHANNEL_D		4
 
 
 /*