iio: vcnl4000: Factorize data reading and writing.

Factorize data reading in vcnl4000_measure into a vcnl4000_read_data
function. Also add a vcnl4000_write_data function.
Signed-off-by: Mathieu Othacehe <m.othacehe@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/light/vcnl4000.c

@@ -216,6 +216,27 @@ static int vcnl4200_init(struct vcnl4000_data *data)
 	return 0;
 };
 
+static int vcnl4000_read_data(struct vcnl4000_data *data, u8 data_reg, int *val)
+{
+	s32 ret;
+
+	ret = i2c_smbus_read_word_swapped(data->client, data_reg);
+	if (ret < 0)
+		return ret;
+
+	*val = ret;
+	return 0;
+}
+
+static int vcnl4000_write_data(struct vcnl4000_data *data, u8 data_reg, int val)
+{
+	if (val > U16_MAX)
+		return -ERANGE;
+
+	return i2c_smbus_write_word_swapped(data->client, data_reg, val);
+}
+
+
 static int vcnl4000_measure(struct vcnl4000_data *data, u8 req_mask,
 				u8 rdy_mask, u8 data_reg, int *val)
 {
@@ -246,12 +267,11 @@ static int vcnl4000_measure(struct vcnl4000_data *data, u8 req_mask,
 		goto fail;
 	}
 
-	ret = i2c_smbus_read_word_swapped(data->client, data_reg);
+	ret = vcnl4000_read_data(data, data_reg, val);
 	if (ret < 0)
 		goto fail;
 
 	mutex_unlock(&data->vcnl4000_lock);
-	*val = ret;
 
 	return 0;