[PATCH 09/12] USB: serial: ftdi_sio: clean up baudrate request

[Johan Hovold <johan@kernel.org>]

Multi-channel devices need to encode the channel selector in their
control requests and newer single-channel chip types use the same
request format.

Set the channel index also for these single-channel types so that the
index can be used to determine the baudrate request format instead of
listing types explicitly.

Note that FT232H and FTX accept either 0 or 1 as selector for their
single channel, presumably for backward compatibility reasons.

Signed-off-by: Johan Hovold <johan@kernel.org>
---
 drivers/usb/serial/ftdi_sio.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 835e12fc971a..e772aacae562 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1407,13 +1407,8 @@ static int change_speed(struct tty_struct *tty, struct usb_serial_port *port)
 	index_value = get_ftdi_divisor(tty, port);
 	value = (u16)index_value;
 	index = (u16)(index_value >> 16);
-	if (priv->chip_type == FT2232C || priv->chip_type == FT2232H ||
-			priv->chip_type == FT4232H || priv->chip_type == FT232H ||
-			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? */
+	if (priv->channel)
 		index = (u16)((index << 8) | priv->channel);
-	}
 
 	rv = usb_control_msg(port->serial->dev,
 			    usb_sndctrlpipe(port->serial->dev, 0),
@@ -1596,10 +1591,12 @@ static int ftdi_determine_type(struct usb_serial_port *port)
 		break;
 	case 0x900:
 		priv->chip_type = FT232H;
+		priv->channel = CHANNEL_A + ifnum;
 		priv->baud_base = 120000000 / 2;
 		break;
 	case 0x1000:
 		priv->chip_type = FTX;
+		priv->channel = CHANNEL_A + ifnum;
 		break;
 	default:
 		if (version < 0x200) {
-- 
2.35.1