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authorNobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com>2014-07-14 16:09:58 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-07-17 18:14:44 -0700
commitb7d66397f4d282ddf2a2fe516fc9329c5a063459 (patch)
treee67a8ab952b337f4858a37d6ada0a0a46af5f172 /drivers/tty
parentca17749259d26f7ddbb0678790d5d534018d0a6b (diff)
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>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/sh-sci.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 26dad3e87b5..2ba42069922 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -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;