rtc: ds3232: fix read on /dev/rtc after RTC_AIE_ON

The rtctest (tools/testing/selftests/timers/rtctest.c) found that
reading ds3232 rtc device immediately return the value 0x20 (RTC_AF)
without waiting alarm interrupt.

This is because alarm_irq_enable() of ds3232 driver changes RTC_AF
flag in rtc->irq_data.  So calling ioctl with RTC_AIE_ON generates
invalid value in rtc device.

The lower-level driver should not touch rtc->irq_data directly.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/drivers/rtc/rtc-ds3232.c b/drivers/rtc/rtc-ds3232.c
index ca43bfcbb846..6bf7848c1576 100644
--- a/drivers/rtc/rtc-ds3232.c
+++ b/drivers/rtc/rtc-ds3232.c
@@ -272,7 +272,7 @@ out:
         return ret;
 }
 
-static void ds3232_update_alarm(struct device *dev)
+static void ds3232_update_alarm(struct device *dev, unsigned int enabled)
 {
         struct ds3232 *ds3232 = dev_get_drvdata(dev);
         int control;
@@ -302,7 +302,7 @@ static void ds3232_update_alarm(struct device *dev)
         if (ret)
                 goto unlock;
 
-        if (ds3232->rtc->irq_data & (RTC_AF | RTC_UF))
+        if (enabled || (ds3232->rtc->irq_data & RTC_UF))
                 /* enable alarm1 interrupt */
                 control |= DS3232_REG_CR_A1IE;
         else
@@ -321,12 +321,8 @@ static int ds3232_alarm_irq_enable(struct device *dev, unsigned int enabled)
         if (ds3232->irq <= 0)
                 return -EINVAL;
 
-        if (enabled)
-                ds3232->rtc->irq_data |= RTC_AF;
-        else
-                ds3232->rtc->irq_data &= ~RTC_AF;
+        ds3232_update_alarm(dev, enabled);
 
-        ds3232_update_alarm(dev);
         return 0;
 }