rtc: pcf50633: manage RTC alarm "pending" flag

Add setting and clearing of the "pending" flag of the RTC alarm.  The
semantics follow the UEFI specification 2.2 available at
http://www.uefi.org/specs/, i.e., the "pending" flag is cleared by
disabling the alarm, but not by any other condition (such as the passing
of time, a successful wakeup, or setting of a new alarm.)

Signed-off-by: Werner Almesberger <werner@openmoko.org>
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Balaji Rao <balajirrao@openmoko.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-pcf50633.c

@@ -58,6 +58,7 @@ struct pcf50633_time {
 struct pcf50633_rtc {
 	int alarm_enabled;
 	int second_enabled;
+	int alarm_pending;
 
 	struct pcf50633 *pcf;
 	struct rtc_device *rtc_dev;
@@ -209,6 +210,7 @@ static int pcf50633_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	rtc = dev_get_drvdata(dev);
 
 	alrm->enabled = rtc->alarm_enabled;
+	alrm->pending = rtc->alarm_pending;
 
 	ret = pcf50633_read_block(rtc->pcf, PCF50633_REG_RTCSCA,
 				PCF50633_TI_EXTENT, &pcf_tm.time[0]);
@@ -244,6 +246,8 @@ static int pcf50633_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	/* Returns 0 on success */
 	ret = pcf50633_write_block(rtc->pcf, PCF50633_REG_RTCSCA,
 				PCF50633_TI_EXTENT, &pcf_tm.time[0]);
+	if (!alrm->enabled)
+		rtc->alarm_pending = 0;
 
 	if (!alarm_masked || alrm->enabled)
 		pcf50633_irq_unmask(rtc->pcf, PCF50633_IRQ_ALARM);
@@ -268,6 +272,7 @@ static void pcf50633_rtc_irq(int irq, void *data)
 	switch (irq) {
 	case PCF50633_IRQ_ALARM:
 		rtc_update_irq(rtc->rtc_dev, 1, RTC_AF | RTC_IRQF);
+		rtc->alarm_pending = 1;
 		break;
 	case PCF50633_IRQ_SECOND:
 		rtc_update_irq(rtc->rtc_dev, 1, RTC_UF | RTC_IRQF);