[PATCH v2 3/7] USB: serial: ftdi_sio: Extract SIO divisor code to function

[Marek Behún <kabel@xxxxxxxxxx>]

From: Pali Rohár <pali@xxxxxxxxxx>

In preparation for following changes, extract divisor code for SIO chip
into new function ftdi_sio_baud_to_divisor(), as is done for other
chips.

No functional change.

Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
Tested-by: Marek Behún <kabel@xxxxxxxxxx>
Signed-off-by: Marek Behún <kabel@xxxxxxxxxx>
---
 drivers/usb/serial/ftdi_sio.c | 36 ++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 717b97f4e094..5b109714612f 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1150,6 +1150,23 @@ static struct usb_serial_driver * const serial_drivers[] = {
  * ***************************************************************************
  */
 
+static int ftdi_sio_baud_to_divisor(int baud)
+{
+	switch (baud) {
+	case 300: return ftdi_sio_b300;
+	case 600: return ftdi_sio_b600;
+	case 1200: return ftdi_sio_b1200;
+	case 2400: return ftdi_sio_b2400;
+	case 4800: return ftdi_sio_b4800;
+	case 9600: return ftdi_sio_b9600;
+	case 19200: return ftdi_sio_b19200;
+	case 38400: return ftdi_sio_b38400;
+	case 57600: return ftdi_sio_b57600;
+	case 115200: return ftdi_sio_b115200;
+	default: return -1;
+	}
+}
+
 static unsigned short int ftdi_232am_baud_base_to_divisor(int baud, int base)
 {
 	unsigned short int divisor;
@@ -1286,7 +1303,7 @@ static u32 get_ftdi_divisor(struct tty_struct *tty,
 {
 	struct ftdi_private *priv = usb_get_serial_port_data(port);
 	struct device *dev = &port->dev;
-	u32 div_value = 0;
+	int div_value = 0;
 	int div_okay = 1;
 	int baud;
 
@@ -1309,23 +1326,12 @@ static u32 get_ftdi_divisor(struct tty_struct *tty,
 		baud = 9600;
 	switch (priv->chip_type) {
 	case SIO: /* SIO chip */
-		switch (baud) {
-		case 300: div_value = ftdi_sio_b300; break;
-		case 600: div_value = ftdi_sio_b600; break;
-		case 1200: div_value = ftdi_sio_b1200; break;
-		case 2400: div_value = ftdi_sio_b2400; break;
-		case 4800: div_value = ftdi_sio_b4800; break;
-		case 9600: div_value = ftdi_sio_b9600; break;
-		case 19200: div_value = ftdi_sio_b19200; break;
-		case 38400: div_value = ftdi_sio_b38400; break;
-		case 57600: div_value = ftdi_sio_b57600;  break;
-		case 115200: div_value = ftdi_sio_b115200; break;
-		} /* baud */
-		if (div_value == 0) {
+		div_value = ftdi_sio_baud_to_divisor(baud);
+		if (div_value == -1) {
 			dev_dbg(dev, "%s - Baudrate (%d) requested is not supported\n",
 				__func__,  baud);
-			div_value = ftdi_sio_b9600;
 			baud = 9600;
+			div_value = ftdi_sio_baud_to_divisor(baud);
 			div_okay = 0;
 		}
 		break;
-- 
2.35.1