From: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date: Wed, 19 Jun 2019 13:17:53 +0000 (+0200)
Subject: rtc: pcf2123: fix negative offset rounding
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fedc459a3da35ecf171a1d6dd9f7f51fb452baf8;p=linux.git

rtc: pcf2123: fix negative offset rounding

Using result = (value + divisor/2) / divisor is rounding values up and only
works well for positive values. Instead use DIV_ROUND_CLOSEST which does
the correct thing.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---

diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
index 3b314ce991e5a..e8100af789efc 100644
--- a/drivers/rtc/rtc-pcf2123.c
+++ b/drivers/rtc/rtc-pcf2123.c
@@ -161,7 +161,7 @@ static int pcf2123_set_offset(struct device *dev, long offset)
 	else if (offset < OFFSET_STEP * -128)
 		reg = -128;
 	else
-		reg = (s8)((offset + (OFFSET_STEP >> 1)) / OFFSET_STEP);
+		reg = DIV_ROUND_CLOSEST(offset, OFFSET_STEP);
 
 	/* choose fine offset only for odd values in the normal range */
 	if (reg & 1 && reg <= 63 && reg >= -64) {