[PATCH] rtc: Add rtc_merge_alarm()

Add rtc_merge_alarm(), which can be used by rtc drivers to turn a partially
specified alarm expiry (i.e.  most significant fields set to -1, as with the
RTC_ALM_SET ioctl()) into a fully specified expiry.

If the most significant specified field is earlier than the current time, the
least significant unspecified field is incremented.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/rtc.h b/include/linux/rtc.h
index 09ff4c3..5e22d45 100644
--- a/include/linux/rtc.h
+++ b/include/linux/rtc.h
@@ -106,6 +106,7 @@
 extern int rtc_valid_tm(struct rtc_time *tm);
 extern int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time);
 extern void rtc_time_to_tm(unsigned long time, struct rtc_time *tm);
+extern void rtc_merge_alarm(struct rtc_time *now, struct rtc_time *alarm);
 
 #include <linux/device.h>
 #include <linux/seq_file.h>