From patchwork Wed Feb  6 11:39:51 2013
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Subject: rtc: Modify leap year test for more simpler way
Date: Wed, 06 Feb 2013 01:39:51 -0000
From: venu <bvg_1@yahoo.com>
X-Patchwork-Id: 218562
Message-Id: <1360150791.5912.YahooMailNeo@web192506.mail.sg3.yahoo.com>
To: "rtc-linux@googlegroups.com" <rtc-linux@googlegroups.com>,
 "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "a.zummo@towertech.it" <a.zummo@towertech.it>,
 Andrew Morton <akpm@linux-foundation.org>,
 Jonghwa Lee <jonghwa3.lee@samsung.com>

By definition of Leap year,
If a year is multiple of 100 and not 400, then that should not be a leap year.

Your logic does not take care of this condition.

Hence I feel this patch is not correct.

Thanks,
Venu


diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 9531845..d662b8d 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -181,7 +181,7 @@ void rtc_timer_do_work(struct work_struct *work);

static inline bool is_leap_year(unsigned int year)
{
-    return (!(year % 4) && (year % 100)) || !(year % 400);
+    return !(year & 0x3);
}

#ifdef CONFIG_RTC_HCTOSYS_DEVICE