USB: PL2303: correctly handle baudrates above 115200
PL2303: correctly handle baudrates above 115200 Signed-off-by: Michal Sroczynski <msroczyn@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -342,10 +342,28 @@ static void pl2303_set_termios(struct tty_struct *tty,
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baud = 6000000;
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}
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dbg("%s - baud set = %d", __func__, baud);
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buf[0] = baud & 0xff;
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buf[1] = (baud >> 8) & 0xff;
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buf[2] = (baud >> 16) & 0xff;
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buf[3] = (baud >> 24) & 0xff;
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if (baud <= 115200) {
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buf[0] = baud & 0xff;
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buf[1] = (baud >> 8) & 0xff;
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buf[2] = (baud >> 16) & 0xff;
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buf[3] = (baud >> 24) & 0xff;
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} else {
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/* apparently the formula for higher speeds is:
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* baudrate = 12M * 32 / (2^buf[1]) / buf[0]
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*/
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unsigned tmp = 12*1000*1000*32 / baud;
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buf[3] = 0x80;
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buf[2] = 0;
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buf[1] = (tmp >= 256);
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while (tmp >= 256) {
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tmp >>= 2;
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buf[1] <<= 1;
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}
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if (tmp > 256) {
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tmp %= 256;
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}
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buf[0] = tmp;
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}
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}
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/* For reference buf[4]=0 is 1 stop bits */
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