Commit 5993b988 authored by Guenter Roeck's avatar Guenter Roeck
Browse files

hwmon: (lm90) Use worker for alarm notifications 



Reporting alarms using hwmon_notify_event() may result in a callback
from the thermal subsystem. This means that such notifications must
not hold the update lock to avoid a deadlock. To avoid this situation,
use a worker to handle notifications.

Reported-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Tested-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Fixes: f6d07751 ("hwmon: (lm90) Rework alarm/status handling")
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 8f9eb10f

drivers/hwmon/lm90.c

+13 −5
Original line number Diff line number Diff line
@@ -693,6 +693,7 @@ struct lm90_data { 
	struct hwmon_chip_info chip;

	struct mutex update_lock;

	struct delayed_work alert_work;

	struct work_struct report_work;

	bool valid;		/* true if register values are valid */

	bool alarms_valid;	/* true if status register values are valid */

	unsigned long last_updated; /* in jiffies */
@@ -1043,13 +1044,18 @@ static int lm90_update_limits(struct device *dev) 
	return 0;

}



static void lm90_report_alarms(struct device *dev, struct lm90_data *data)

static void lm90_report_alarms(struct work_struct *work)

{

	u16 cleared_alarms = data->reported_alarms & ~data->current_alarms;

	u16 new_alarms = data->current_alarms & ~data->reported_alarms;

	struct lm90_data *data = container_of(work, struct lm90_data, report_work);

	u16 cleared_alarms, new_alarms, current_alarms;

	struct device *hwmon_dev = data->hwmon_dev;

	struct device *dev = &data->client->dev;

	int st, st2;



	current_alarms = data->current_alarms;

	cleared_alarms = data->reported_alarms & ~current_alarms;

	new_alarms = current_alarms & ~data->reported_alarms;



	if (!cleared_alarms && !new_alarms)

		return;
@@ -1101,7 +1107,7 @@ static void lm90_report_alarms(struct device *dev, struct lm90_data *data) 
	if (st2 & MAX6696_STATUS2_R2OT2)

		hwmon_notify_event(hwmon_dev, hwmon_temp, hwmon_temp_emergency_alarm, 2);



	data->reported_alarms = data->current_alarms;

	data->reported_alarms = current_alarms;

}



static int lm90_update_alarms_locked(struct lm90_data *data, bool force)
@@ -1143,7 +1149,7 @@ static int lm90_update_alarms_locked(struct lm90_data *data, bool force) 
			(data->config & 0x80);



		if (force || check_enable)

			lm90_report_alarms(&client->dev, data);

			schedule_work(&data->report_work);



		/*

		 * Re-enable ALERT# output if it was originally enabled, relevant
@@ -2552,6 +2558,7 @@ static void lm90_restore_conf(void *_data) 
	struct i2c_client *client = data->client;



	cancel_delayed_work_sync(&data->alert_work);

	cancel_work_sync(&data->report_work);



	/* Restore initial configuration */

	if (data->flags & LM90_HAVE_CONVRATE)
@@ -2769,6 +2776,7 @@ static int lm90_probe(struct i2c_client *client) 
	i2c_set_clientdata(client, data);

	mutex_init(&data->update_lock);

	INIT_DELAYED_WORK(&data->alert_work, lm90_alert_work);

	INIT_WORK(&data->report_work, lm90_report_alarms);



	/* Set the device type */

	if (client->dev.of_node)