fedora core 6 1.2949 + vserver 2.2.0

[linux-2.6.git] / drivers / rtc / rtc-lib.c

diff --git a/drivers/rtc/rtc-lib.c b/drivers/rtc/rtc-lib.c
index 9812120..7bbc26a 100644 (file)
--- a/drivers/rtc/rtc-lib.c
+++ b/drivers/rtc/rtc-lib.c
@@ -94,12 +94,12 @@ EXPORT_SYMBOL(rtc_time_to_tm);
 int rtc_valid_tm(struct rtc_time *tm)
 {
        if (tm->tm_year < 70
-               || tm->tm_mon >= 12
+               || ((unsigned)tm->tm_mon) >= 12
                || tm->tm_mday < 1
                || tm->tm_mday > rtc_month_days(tm->tm_mon, tm->tm_year + 1900)
-               || tm->tm_hour >= 24
-               || tm->tm_min >= 60
-               || tm->tm_sec >= 60)
+               || ((unsigned)tm->tm_hour) >= 24
+               || ((unsigned)tm->tm_min) >= 60
+               || ((unsigned)tm->tm_sec) >= 60)
                return -EINVAL;
 
        return 0;
@@ -117,4 +117,85 @@ int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
 }
 EXPORT_SYMBOL(rtc_tm_to_time);
 
+
+/* Merge the valid (i.e. non-negative) fields of alarm into the current
+ * time.  If the valid alarm fields are earlier than the equivalent
+ * fields in the time, carry one into the least significant invalid
+ * field, so that the alarm expiry is in the future.  It assumes that the
+ * least significant invalid field is more significant than the most
+ * significant valid field, and that the seconds field is valid.
+ *
+ * This is used by alarms that take relative (rather than absolute)
+ * times, and/or have a simple binary second counter instead of
+ * day/hour/minute/sec registers.
+ */
+void rtc_merge_alarm(struct rtc_time *now, struct rtc_time *alarm)
+{
+       int *alarmp = &alarm->tm_sec;
+       int *timep = &now->tm_sec;
+       int carry_into, i;
+
+       /* Ignore everything past the 6th element (tm_year). */
+       for (i = 5; i > 0; i--) {
+               if (alarmp[i] < 0)
+                       alarmp[i] = timep[i];
+               else
+                       break;
+       }
+
+       /* No carry needed if all fields are valid. */
+       if (i == 5)
+               return;
+
+       for (carry_into = i + 1; i >= 0; i--) {
+               if (alarmp[i] < timep[i])
+                       break;
+
+               if (alarmp[i] > timep[i])
+                       return;
+       }
+
+       switch (carry_into) {
+               case 1:
+                       alarm->tm_min++;
+
+                       if (alarm->tm_min < 60)
+                               return;
+
+                       alarm->tm_min = 0;
+                       /* fall-through */
+
+               case 2:
+                       alarm->tm_hour++;
+
+                       if (alarm->tm_hour < 60)
+                               return;
+
+                       alarm->tm_hour = 0;
+                       /* fall-through */
+
+               case 3:
+                       alarm->tm_mday++;
+
+                       if (alarm->tm_mday <= rtc_days_in_month[alarm->tm_mon])
+                               return;
+
+                       alarm->tm_mday = 1;
+                       /* fall-through */
+
+               case 4:
+                       alarm->tm_mon++;
+
+                       if (alarm->tm_mon <= 12)
+                               return;
+
+                       alarm->tm_mon = 1;
+                       /* fall-through */
+
+               case 5:
+                       alarm->tm_year++;
+       }
+}
+EXPORT_SYMBOL(rtc_merge_alarm);
+
 MODULE_LICENSE("GPL");