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>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 26dad3e87b52..2ba42069922f 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;