| From 79253be887e74e8c7e6e5c963eb918772ffdd0d4 Mon Sep 17 00:00:00 2001 |
| From: Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@renesas.com> |
| Date: Mon, 14 Jul 2014 16:09:58 +0900 |
| Subject: 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> |
| (cherry picked from commit b7d66397f4d282ddf2a2fe516fc9329c5a063459) |
| Signed-off-by: Simon Horman <horms+renesas@verge.net.au> |
| --- |
| drivers/tty/serial/sh-sci.c | 8 +++++--- |
| 1 file changed, 5 insertions(+), 3 deletions(-) |
| |
| diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c |
| index 88236da0ddf7..ce8013702560 100644 |
| --- a/drivers/tty/serial/sh-sci.c |
| +++ b/drivers/tty/serial/sh-sci.c |
| @@ -1796,11 +1796,13 @@ 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; |
| -- |
| 2.1.2 |
| |
