[PATCH v3 09/11] hwmon: chipcap2: do not discard pending alarms on disable

[Javier Carrasco]

cc2_disable() stops processing interrupts before the device is powered
down to ignore the alarms caused by voltage toggling. The handler of an
alarm raised by the last measurement might not have run at that point,
and the alarm is discarded when it finally does.

The sysfs read that triggered the measurement can then report no alarm
although the device raised one.

Wait for the alarm handlers that have already been raised before the
interrupt processing is stopped. This covers the case where the handler
thread has not been scheduled yet; an alarm that has not reached the
interrupt core at that point is discarded.

Fixes: 3af350929e75 ("hwmon: Add support for Amphenol ChipCap 2")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@xxxxxxxxx>
---
 drivers/hwmon/chipcap2.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/hwmon/chipcap2.c b/drivers/hwmon/chipcap2.c
index 952789fdb9db..eba6469940ab 100644
--- a/drivers/hwmon/chipcap2.c
+++ b/drivers/hwmon/chipcap2.c
@@ -146,6 +146,13 @@ static void cc2_disable(struct cc2_data *data)
 {
 	int err;
 
+	/* let the alarms already raised by the last measurement be processed */
+	if (data->irq_low > 0)
+		synchronize_irq(data->irq_low);
+
+	if (data->irq_high > 0)
+		synchronize_irq(data->irq_high);
+
 	/* ignore alarms triggered by voltage toggling when powering up */
 	data->process_irqs = false;
 

-- 
2.43.0