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serial: sh-sci: Updated calculation of bit error rate and bit rate 

Currently, the decimal point is discarded calculation of BRR.
Therefore, it can not calculate a value close to the correct value.
This patch fixes this problem by using DIV_ROUND_CLOSEST.

Signed-off-by: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nobuhiro Iwamatsu 2014-07-14 16:09:58 +09:00 committed by Greg Kroah-Hartman
parent ca17749259
commit b7d66397f4
1 changed files with 5 additions and 3 deletions
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8
drivers/tty/serial/sh-sci.c
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@ -1789,11 +1789,13 @@ static void sci_baud_calc_hscif(unsigned int bps, unsigned long freq,
for (sr = 8; sr <= 32; sr++) {
for (c = 0; c <= 3; c++) {
/* integerized formulas from HSCIF documentation */
br = freq / (sr * (1 << (2 * c + 1)) * bps) - 1;
br = DIV_ROUND_CLOSEST(freq, (sr *
(1 << (2 * c + 1)) * bps)) - 1;
if (br < 0 || br > 255)
continue;
err = freq / ((br + 1) * bps * sr *
(1 << (2 * c + 1)) / 1000) - 1000;
err = DIV_ROUND_CLOSEST(freq, ((br + 1) * bps * sr *
(1 << (2 * c + 1)) / 1000)) -
1000;
if (min_err > err) {
min_err = err;
*brr = br;