hwmon: (lm90) Rely on subsystem locking

Attribute access is now serialized in the hardware monitoring core,
so locking n the driver code is no longer necessary. Drop it.

Signed-off-by: Guenter Roeck <[e-mail]>

drivers/hwmon/lm90.c

···
 #include <linux/hwmon.h>
 #include <linux/kstrtox.h>
 #include <linux/module.h>
-#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
···
 	struct hwmon_channel_info temp_info;
 	const struct hwmon_channel_info *info[3];
 	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 */
···
 {
 	int err;
 
-	mutex_lock(&data->update_lock);
+	hwmon_lock(data->hwmon_dev);
 	err = lm90_update_alarms_locked(data, force);
-	mutex_unlock(&data->update_lock);
+	hwmon_unlock(data->hwmon_dev);
 
 	return err;
 }
···
 	int err;
 	u16 bit;
 
-	mutex_lock(&data->update_lock);
 	err = lm90_update_device(dev);
-	mutex_unlock(&data->update_lock);
 	if (err)
 		return err;
 
···
 	struct lm90_data *data = dev_get_drvdata(dev);
 	int err;
 
-	mutex_lock(&data->update_lock);
-
 	err = lm90_update_device(dev);
 	if (err)
-		goto error;
+		return err;
 
 	switch (attr) {
 	case hwmon_temp_min:
···
 		err = -EOPNOTSUPP;
 		break;
 	}
-error:
-	mutex_unlock(&data->update_lock);
-
 	return err;
 }
 
···
 	struct lm90_data *data = dev_get_drvdata(dev);
 	int err;
 
-	mutex_lock(&data->update_lock);
 	err = lm90_update_device(dev);
-	mutex_unlock(&data->update_lock);
 	if (err)
 		return err;
 
···
 	struct i2c_client *client = data->client;
 	int err;
 
-	mutex_lock(&data->update_lock);
-
 	err = lm90_update_device(dev);
 	if (err)
-		goto error;
+		return err;
 
 	switch (attr) {
 	case hwmon_chip_update_interval:
···
 		err = -EOPNOTSUPP;
 		break;
 	}
-error:
-	mutex_unlock(&data->update_lock);
-
 	return err;
 }
 
···
 
 	data->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);