diff options
| -rw-r--r-- | drivers/usb/serial/pl2303.c | 26 |
1 files changed, 22 insertions, 4 deletions
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c index 0c208314d6e..1d33260de01 100644 --- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -343,10 +343,28 @@ 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 */ |