Refactor baud-rate divisor handling.
Signed-off-by: Johan Hovold <jhov...@gmail.com>
---
drivers/usb/serial/pl2303.c | 41 +++++++++++++++++++++++++----------------
1 file changed, 25 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 394903b4ecb7..44f4b546adeb 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -339,6 +339,28 @@ static speed_t pl2303_get_supported_baud_rate(speed_t baud)
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 @@ static void pl2303_encode_baud_rate(struct tty_struct
*tty,
*/
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);
--
1.8.3.2
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