hwmon: (adt7411) Rely on subsystem locking

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

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

drivers/hwmon/adt7411.c

···
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/err.h>
-#include <linux/mutex.h>
 #include <linux/jiffies.h>
 #include <linux/i2c.h>
 #include <linux/hwmon.h>
···
 };
 
 struct adt7411_data {
-	struct mutex device_lock;	/* for "atomic" device accesses */
-	struct mutex update_lock;
 	unsigned long next_update;
 	long vref_cached;
 	struct i2c_client *client;
···
 /*
  * When reading a register containing (up to 4) lsb, all associated
  * msb-registers get locked by the hardware. After _one_ of those msb is read,
- * _all_ are unlocked. In order to use this locking correctly, reading lsb/msb
- * is protected here with a mutex, too.
+ * _all_ are unlocked.
  */
 static int adt7411_read_10_bit(struct i2c_client *client, u8 lsb_reg,
-				u8 msb_reg, u8 lsb_shift)
+			       u8 msb_reg, u8 lsb_shift)
 {
-	struct adt7411_data *data = i2c_get_clientdata(client);
 	int val, tmp;
-
-	mutex_lock(&data->device_lock);
 
 	val = i2c_smbus_read_byte_data(client, lsb_reg);
 	if (val < 0)
-		goto exit_unlock;
+		return val;
 
 	tmp = (val >> lsb_shift) & 3;
 	val = i2c_smbus_read_byte_data(client, msb_reg);
+	if (val < 0)
+		return val;
 
-	if (val >= 0)
-		val = (val << 2) | tmp;
-
- exit_unlock:
-	mutex_unlock(&data->device_lock);
-
+	val = (val << 2) | tmp;
 	return val;
 }
 
 static int adt7411_modify_bit(struct i2c_client *client, u8 reg, u8 bit,
-				bool flag)
+			      bool flag)
 {
-	struct adt7411_data *data = i2c_get_clientdata(client);
 	int ret, val;
-
-	mutex_lock(&data->device_lock);
 
 	ret = i2c_smbus_read_byte_data(client, reg);
 	if (ret < 0)
-		goto exit_unlock;
+		return ret;
 
 	if (flag)
 		val = ret | bit;
 	else
 		val = ret & ~bit;
 
-	ret = i2c_smbus_write_byte_data(client, reg, val);
-
- exit_unlock:
-	mutex_unlock(&data->device_lock);
-	return ret;
+	return i2c_smbus_write_byte_data(client, reg, val);
 }
 
 static ssize_t adt7411_show_bit(struct device *dev,
···
 	if (ret || flag > 1)
 		return -EINVAL;
 
+	hwmon_lock(dev);
 	ret = adt7411_modify_bit(client, s_attr2->index, s_attr2->nr, flag);
-
 	/* force update */
-	mutex_lock(&data->update_lock);
 	data->next_update = jiffies;
-	mutex_unlock(&data->update_lock);
+	hwmon_unlock(dev);
 
 	return ret < 0 ? ret : count;
 }
···
 	int reg, lsb_reg, lsb_shift;
 	int nr = channel - 1;
 
-	mutex_lock(&data->update_lock);
 	ret = adt7411_update_vref(dev);
 	if (ret < 0)
-		goto exit_unlock;
+		return ret;
 
 	switch (attr) {
 	case hwmon_in_input:
···
 					  ADT7411_REG_EXT_TEMP_AIN1_MSB + nr,
 					  lsb_shift);
 		if (ret < 0)
-			goto exit_unlock;
+			return ret;
 		*val = ret * data->vref_cached / 1024;
 		ret = 0;
 		break;
···
 			: ADT7411_REG_IN_HIGH(channel);
 		ret = i2c_smbus_read_byte_data(client, reg);
 		if (ret < 0)
-			goto exit_unlock;
+			return ret;
 		*val = ret * data->vref_cached / 256;
 		ret = 0;
 		break;
···
 		ret = -EOPNOTSUPP;
 		break;
 	}
- exit_unlock:
-	mutex_unlock(&data->update_lock);
 	return ret;
 }
 
···
 	struct i2c_client *client = data->client;
 	int ret, reg;
 
-	mutex_lock(&data->update_lock);
 	ret = adt7411_update_vref(dev);
 	if (ret < 0)
-		goto exit_unlock;
+		return ret;
 	val = clamp_val(val, 0, 255 * data->vref_cached / 256);
 	val = DIV_ROUND_CLOSEST(val * 256, data->vref_cached);
 
···
 		reg = ADT7411_REG_IN_HIGH(channel);
 		break;
 	default:
-		ret = -EOPNOTSUPP;
-		goto exit_unlock;
+		return -EOPNOTSUPP;
 	}
 
 	ret = i2c_smbus_write_byte_data(client, reg, val);
- exit_unlock:
-	mutex_unlock(&data->update_lock);
 	return ret;
 }
 
···
 
 	i2c_set_clientdata(client, data);
 	data->client = client;
-	mutex_init(&data->device_lock);
-	mutex_init(&data->update_lock);
 
 	ret = adt7411_init_device(data);
 	if (ret < 0)