rtc: update vr41xx alarm handling

- vr41xx_rtc_read_alarm() reports alarm enabled.
- vr41xx_rtc_set_alarm() sets alarm disable/enable by rtc_wkalrm.enabled.
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-vr41xx.c

@@ -97,6 +97,7 @@ static DEFINE_SPINLOCK(rtc_lock);
 static char rtc_name[] = "RTC";
 static unsigned long periodic_frequency;
 static unsigned long periodic_count;
+static unsigned int alarm_enabled;
 
 struct resource rtc_resource[2] = {
 	{	.name	= rtc_name,
@@ -188,6 +189,7 @@ static int vr41xx_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 	low = rtc1_read(ECMPLREG);
 	mid = rtc1_read(ECMPMREG);
 	high = rtc1_read(ECMPHREG);
+	wkalrm->enabled = alarm_enabled;
 
 	spin_unlock_irq(&rtc_lock);
 
@@ -206,10 +208,18 @@ static int vr41xx_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
 
 	spin_lock_irq(&rtc_lock);
 
+	if (alarm_enabled)
+		disable_irq(ELAPSEDTIME_IRQ);
+
 	rtc1_write(ECMPLREG, (uint16_t)(alarm_sec << 15));
 	rtc1_write(ECMPMREG, (uint16_t)(alarm_sec >> 1));
 	rtc1_write(ECMPHREG, (uint16_t)(alarm_sec >> 17));
 
+	if (wkalrm->enabled)
+		enable_irq(ELAPSEDTIME_IRQ);
+
+	alarm_enabled = wkalrm->enabled;
+
 	spin_unlock_irq(&rtc_lock);
 
 	return 0;
@@ -221,10 +231,24 @@ static int vr41xx_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long
 
 	switch (cmd) {
 	case RTC_AIE_ON:
+		spin_lock_irq(&rtc_lock);
+
+		if (!alarm_enabled) {
 			enable_irq(ELAPSEDTIME_IRQ);
+			alarm_enabled = 1;
+		}
+
+		spin_unlock_irq(&rtc_lock);
 		break;
 	case RTC_AIE_OFF:
+		spin_lock_irq(&rtc_lock);
+
+		if (alarm_enabled) {
 			disable_irq(ELAPSEDTIME_IRQ);
+			alarm_enabled = 0;
+		}
+
+		spin_unlock_irq(&rtc_lock);
 		break;
 	case RTC_PIE_ON:
 		enable_irq(RTCLONG1_IRQ);