From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756030Ab2IIXQa (ORCPT ); Sun, 9 Sep 2012 19:16:30 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:51263 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755619Ab2IIXQ1 (ORCPT ); Sun, 9 Sep 2012 19:16:27 -0400 Message-Id: <20120909224200.792535794@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Sun, 09 Sep 2012 23:43:04 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Atsushi Nemoto , James Nute Subject: [ 74/95] drivers/rtc/rtc-rs5c348.c: fix hour decoding in 12-hour mode In-Reply-To: <20120909224150.641491654@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Atsushi Nemoto commit 7dbfb315b2aaef0a115765946bf3026d074c33a7 upstream. Correct the offset by subtracting 20 from tm_hour before taking the modulo 12. [ "Why 20?" I hear you ask. Or at least I did. Here's the reason why: RS5C348_BIT_PM is 32, and is - stupidly - included in the RS5C348_HOURS_MASK define. So it's really subtracting out that bit to get "hour+12". But then because it does things modulo 12, it needs to add the 12 in again afterwards anyway. This code is confused. It would be much clearer if RS5C348_HOURS_MASK just didn't include the RS5C348_BIT_PM bit at all, then it wouldn't need to do the silly subtract either. Whatever. It's all just math, the end result is the same. - Linus ] Reported-by: James Nute Tested-by: James Nute Signed-off-by: Atsushi Nemoto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- drivers/rtc/rtc-rs5c348.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/rtc/rtc-rs5c348.c b/drivers/rtc/rtc-rs5c348.c index 77074cc..fd5c7af 100644 --- a/drivers/rtc/rtc-rs5c348.c +++ b/drivers/rtc/rtc-rs5c348.c @@ -122,9 +122,12 @@ rs5c348_rtc_read_time(struct device *dev, struct rtc_time *tm) tm->tm_min = bcd2bin(rxbuf[RS5C348_REG_MINS] & RS5C348_MINS_MASK); tm->tm_hour = bcd2bin(rxbuf[RS5C348_REG_HOURS] & RS5C348_HOURS_MASK); if (!pdata->rtc_24h) { - tm->tm_hour %= 12; - if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) + if (rxbuf[RS5C348_REG_HOURS] & RS5C348_BIT_PM) { + tm->tm_hour -= 20; + tm->tm_hour %= 12; tm->tm_hour += 12; + } else + tm->tm_hour %= 12; } tm->tm_wday = bcd2bin(rxbuf[RS5C348_REG_WDAY] & RS5C348_WDAY_MASK); tm->tm_mday = bcd2bin(rxbuf[RS5C348_REG_DAY] & RS5C348_DAY_MASK);