hwmon: (max31790) 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]>

drivers/hwmon/max31790.c

···
  */
 struct max31790_data {
 	struct i2c_client *client;
-	struct mutex update_lock;
 	bool valid; /* zero until following fields are valid */
 	unsigned long last_updated; /* in jiffies */
 
···
 {
 	struct max31790_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
-	struct max31790_data *ret = data;
-	int i;
-	int rv;
-
-	mutex_lock(&data->update_lock);
+	int i, rv;
 
 	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+		data->valid = false;
 		rv = i2c_smbus_read_byte_data(client,
 				MAX31790_REG_FAN_FAULT_STATUS1);
 		if (rv < 0)
-			goto abort;
+			return ERR_PTR(rv);
 		data->fault_status |= rv & 0x3F;
 
 		rv = i2c_smbus_read_byte_data(client,
 				MAX31790_REG_FAN_FAULT_STATUS2);
 		if (rv < 0)
-			goto abort;
+			return ERR_PTR(rv);
 		data->fault_status |= (rv & 0x3F) << 6;
 
 		for (i = 0; i < NR_CHANNEL; i++) {
 			rv = i2c_smbus_read_word_swapped(client,
 					MAX31790_REG_TACH_COUNT(i));
 			if (rv < 0)
-				goto abort;
+				return ERR_PTR(rv);
 			data->tach[i] = rv;
 
 			if (data->fan_config[i]
···
 					MAX31790_REG_TACH_COUNT(NR_CHANNEL
 								+ i));
 				if (rv < 0)
-					goto abort;
+					return ERR_PTR(rv);
 				data->tach[NR_CHANNEL + i] = rv;
 			} else {
 				rv = i2c_smbus_read_word_swapped(client,
 						MAX31790_REG_PWM_DUTY_CYCLE(i));
 				if (rv < 0)
-					goto abort;
+					return ERR_PTR(rv);
 				data->pwm[i] = rv;
 
 				rv = i2c_smbus_read_word_swapped(client,
 						MAX31790_REG_TARGET_COUNT(i));
 				if (rv < 0)
-					goto abort;
+					return ERR_PTR(rv);
 				data->target_count[i] = rv;
 			}
 		}
···
 		data->last_updated = jiffies;
 		data->valid = true;
 	}
-	goto done;
-
-abort:
-	data->valid = false;
-	ret = ERR_PTR(rv);
-
-done:
-	mutex_unlock(&data->update_lock);
-
-	return ret;
+	return data;
 }
 
 static const u8 tach_period[8] = { 1, 2, 4, 8, 16, 32, 32, 32 };
···
 		*val = rpm;
 		return 0;
 	case hwmon_fan_fault:
-		mutex_lock(&data->update_lock);
 		*val = !!(data->fault_status & (1 << channel));
 		data->fault_status &= ~(1 << channel);
 		/*
···
 		if (*val) {
 			int reg = MAX31790_REG_TARGET_COUNT(channel % NR_CHANNEL);
 
-			i2c_smbus_write_byte_data(data->client, reg,
-						  data->target_count[channel % NR_CHANNEL] >> 8);
+			return i2c_smbus_write_byte_data(data->client, reg,
+						data->target_count[channel % NR_CHANNEL] >> 8);
 		}
-		mutex_unlock(&data->update_lock);
 		return 0;
 	case hwmon_fan_enable:
 		*val = !!(data->fan_config[channel] & MAX31790_FAN_CFG_TACH_INPUT_EN);
···
 	int err = 0;
 	u8 bits, fan_config;
 	int sr;
-
-	mutex_lock(&data->update_lock);
 
 	switch (attr) {
 	case hwmon_fan_target:
···
 		err = -EOPNOTSUPP;
 		break;
 	}
-
-	mutex_unlock(&data->update_lock);
-
 	return err;
 }
 
···
 	u8 fan_config;
 	int err = 0;
 
-	mutex_lock(&data->update_lock);
-
 	switch (attr) {
 	case hwmon_pwm_input:
 		if (val < 0 || val > 255) {
···
 		err = -EOPNOTSUPP;
 		break;
 	}
-
-	mutex_unlock(&data->update_lock);
-
 	return err;
 }
 
···
 		return -ENOMEM;
 
 	data->client = client;
-	mutex_init(&data->update_lock);
 
 	/*
 	 * Initialize the max31790 chip