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@xxxxxxxxxxx>
---
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 88236da..ce80137 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;
--
2.0.0
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
