VT8500_RTC_IS
isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
writel(0, vt8500_rtc->regbase + VT8500_RTC_IS);
isr = readl(vt8500_rtc->regbase + VT8500_RTC_IS);
writel(isr, vt8500_rtc->regbase + VT8500_RTC_IS);