lkml.org 
[lkml]   [2011]   [Nov]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[032/107] USB: PL2303: correctly handle baudrates above 115200
2.6.32-longterm review patch.  If anyone has any objections, please let us know.

------------------

From: Michal Sroczynski <msroczyn@gmail.com>

commit 8d48fdf689fed2c73c493e5146d1463689246442 upstream.

PL2303: correctly handle baudrates above 115200

Signed-off-by: Michal Sroczynski <msroczyn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/usb/serial/pl2303.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)

--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -617,10 +617,28 @@ static void pl2303_set_termios(struct tt
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 */



\
 
 \ /
  Last update: 2011-11-03 02:37    [W:0.323 / U:1.676 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site