From: Alexandre Belloni <alexandre.belloni@bootlin.com>
To: linux-rtc@vger.kernel.org
Cc: Dylan Howey <Dylan.Howey@tennantco.com>,
linux-kernel@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@bootlin.com>
Subject: [PATCH] rtc: pcf2123: fix negative offset rounding
Date: Wed, 19 Jun 2019 15:17:53 +0200 [thread overview]
Message-ID: <20190619131753.14802-1-alexandre.belloni@bootlin.com> (raw)
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>
---
drivers/rtc/rtc-pcf2123.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/rtc/rtc-pcf2123.c b/drivers/rtc/rtc-pcf2123.c
index 39da8b214275..80a53d2dc813 100644
--- a/drivers/rtc/rtc-pcf2123.c
+++ b/drivers/rtc/rtc-pcf2123.c
@@ -244,7 +244,7 @@ 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) {
--
2.21.0
reply other threads:[~2019-06-19 13:18 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190619131753.14802-1-alexandre.belloni@bootlin.com \
--to=alexandre.belloni@bootlin.com \
--cc=Dylan.Howey@tennantco.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rtc@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).