Messages in this thread Patch in this message | | | Date | Wed, 02 Nov 2011 15:13:58 -0700 | From | Greg KH <> | Subject | [032/107] USB: PL2303: correctly handle baudrates above 115200 |
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2.6.32-longterm review patch. If anyone has any objections, please let us know.
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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 */
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