+
+ /* RTC_ALM_SET alarms may be up to 24 hours in the future.
+ * Rather than expecting every RTC to implement "don't care"
+ * for day/month/year fields, just force the alarm to have
+ * the right values for those fields.
+ *
+ * RTC_WKALM_SET should be used instead. Not only does it
+ * eliminate the need for a separate RTC_AIE_ON call, it
+ * doesn't have the "alarm 23:59:59 in the future" race.
+ *
+ * NOTE: some legacy code may have used invalid fields as
+ * wildcards, exposing hardware "periodic alarm" capabilities.
+ * Not supported here.
+ */
+ {
+ unsigned long now, then;
+
+ err = rtc_read_time(rtc, &tm);
+ if (err < 0)
+ return err;
+ rtc_tm_to_time(&tm, &now);
+
+ alarm.time.tm_mday = tm.tm_mday;
+ alarm.time.tm_mon = tm.tm_mon;
+ alarm.time.tm_year = tm.tm_year;
+ err = rtc_valid_tm(&alarm.time);
+ if (err < 0)
+ return err;
+ rtc_tm_to_time(&alarm.time, &then);
+
+ /* alarm may need to wrap into tomorrow */
+ if (then < now) {
+ rtc_time_to_tm(now + 24 * 60 * 60, &tm);
+ alarm.time.tm_mday = tm.tm_mday;
+ alarm.time.tm_mon = tm.tm_mon;
+ alarm.time.tm_year = tm.tm_year;
+ }
+ }
+
+ err = rtc_set_alarm(rtc, &alarm);