USB: pl2303: refactor baud-rate divisor handling
Refactor baud-rate divisor handling.
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 394903b..44f4b54 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -339,6 +339,28 @@
return baud;
}
+static speed_t pl2303_encode_baud_rate_divisor(unsigned char buf[4],
+ speed_t baud)
+{
+ unsigned int tmp;
+
+ /*
+ * Apparently the formula is:
+ * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
+ */
+ tmp = 12000000 * 32 / baud;
+ buf[3] = 0x80;
+ buf[2] = 0;
+ buf[1] = (tmp >= 256);
+ while (tmp >= 256) {
+ tmp >>= 2;
+ buf[1] <<= 1;
+ }
+ buf[0] = tmp;
+
+ return baud;
+}
+
static void pl2303_encode_baud_rate(struct tty_struct *tty,
struct usb_serial_port *port,
u8 buf[4])
@@ -362,23 +384,10 @@
*/
baud = pl2303_get_supported_baud_rate(baud);
- if (baud <= 115200) {
+ if (baud <= 115200)
put_unaligned_le32(baud, buf);
- } else {
- /*
- * Apparently the formula for higher speeds is:
- * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
- */
- unsigned tmp = 12000000 * 32 / baud;
- buf[3] = 0x80;
- buf[2] = 0;
- buf[1] = (tmp >= 256);
- while (tmp >= 256) {
- tmp >>= 2;
- buf[1] <<= 1;
- }
- buf[0] = tmp;
- }
+ else
+ baud = pl2303_encode_baud_rate_divisor(buf, baud);
/* Save resulting baud rate */
tty_encode_baud_rate(tty, baud, baud);