RTCIR_PERIOD
vrtc_set_reg_c(vrtc, vrtc->rtcdev.reg_c | RTCIR_PERIOD);
newval &= RTCIR_ALARM | RTCIR_PERIOD | RTCIR_UPDATE;
(pintr_enabled(vrtc) && (newval & RTCIR_PERIOD) != 0) ||
while (rtcin(RTC_INTR) & RTCIR_PERIOD) {