From: Michał Sroczyński <msroc...@gmail.com>
-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
If you see a problem with using this for longterm, please comment.
-------------------
commit 8d48fdf689fed2c73c493e5146d1463689246442 upstream.
PL2303: correctly handle baudrates above 115200
Signed-off-by: Michal Sroczynski <msroc...@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gre...@suse.de>
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
---
drivers/usb/serial/pl2303.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 4b357d6..9f49375 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -616,10 +616,28 @@ static void pl2303_set_termios(struct tty_struct *tty,
baud = 6000000;
}
dbg("%s - baud set = %d", __func__, baud);
- buf[0] = baud & 0xff;
- buf[1] = (baud >> 8) & 0xff;
- buf[2] = (baud >> 16) & 0xff;
- buf[3] = (baud >> 24) & 0xff;
+ if (baud <= 115200) {
+ buf[0] = baud & 0xff;
+ buf[1] = (baud >> 8) & 0xff;
+ buf[2] = (baud >> 16) & 0xff;
+ buf[3] = (baud >> 24) & 0xff;
+ } else {
+ /* apparently the formula for higher speeds is:
+ * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
+ */
+ unsigned tmp = 12*1000*1000*32 / baud;
+ buf[3] = 0x80;
+ buf[2] = 0;
+ buf[1] = (tmp >= 256);
+ while (tmp >= 256) {
+ tmp >>= 2;
+ buf[1] <<= 1;
+ }
+ if (tmp > 256) {
+ tmp %= 256;
+ }
+ buf[0] = tmp;
+ }
}
/* For reference buf[4]=0 is 1 stop bits */
--
1.7.12.rc2
--
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