staging:iio:hmc5843: Reorganize _set_meas_conf()

move locking inside _set() function
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/staging/iio/magnetometer/hmc5843.c

@@ -73,7 +73,6 @@ enum hmc5843_ids {
 #define HMC5843_MEAS_CONF_NORMAL		0x00
 #define HMC5843_MEAS_CONF_POSITIVE_BIAS		0x01
 #define HMC5843_MEAS_CONF_NEGATIVE_BIAS		0x02
-#define HMC5843_MEAS_CONF_NOT_USED		0x03
 #define HMC5843_MEAS_CONF_MASK			0x03
 
 /* Scaling factors: 10000000/Gain */
@@ -211,19 +210,24 @@ static int hmc5843_read_measurement(struct hmc5843_data *data,
  */
 static s32 hmc5843_set_meas_conf(struct hmc5843_data *data, u8 meas_conf)
 {
-	u8 reg_val;
-	reg_val = (meas_conf & HMC5843_MEAS_CONF_MASK) |
-		(data->rate << HMC5843_RATE_OFFSET);
-	return i2c_smbus_write_byte_data(data->client, HMC5843_CONFIG_REG_A,
-		reg_val);
+	int ret;
+
+	mutex_lock(&data->lock);
+	ret = i2c_smbus_write_byte_data(data->client, HMC5843_CONFIG_REG_A,
+		(meas_conf & HMC5843_MEAS_CONF_MASK) |
+		(data->rate << HMC5843_RATE_OFFSET));
+	if (ret >= 0)
+		data->meas_conf = meas_conf;
+	mutex_unlock(&data->lock);
+
+	return ret;
 }
 
 static ssize_t hmc5843_show_measurement_configuration(struct device *dev,
 						struct device_attribute *attr,
 						char *buf)
 {
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct hmc5843_data *data = iio_priv(indio_dev);
+	struct hmc5843_data *data = iio_priv(dev_to_iio_dev(dev));
 	return sprintf(buf, "%d\n", data->meas_conf);
 }
 
@@ -232,28 +236,19 @@ static ssize_t hmc5843_set_measurement_configuration(struct device *dev,
 						const char *buf,
 						size_t count)
 {
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct hmc5843_data *data = iio_priv(indio_dev);
+	struct hmc5843_data *data = iio_priv(dev_to_iio_dev(dev));
 	unsigned long meas_conf = 0;
-	int error;
+	int ret;
 
-	error = kstrtoul(buf, 10, &meas_conf);
-	if (error)
-		return error;
-	if (meas_conf >= HMC5843_MEAS_CONF_NOT_USED)
+	ret = kstrtoul(buf, 10, &meas_conf);
+	if (ret)
+		return ret;
+	if (meas_conf >= HMC5843_MEAS_CONF_MASK)
 		return -EINVAL;
 
-	mutex_lock(&data->lock);
-	dev_dbg(dev, "set measurement configuration to %lu\n", meas_conf);
-	if (hmc5843_set_meas_conf(data, meas_conf)) {
-		count = -EINVAL;
-		goto exit;
-	}
-	data->meas_conf = meas_conf;
+	ret = hmc5843_set_meas_conf(data, meas_conf);
 
-exit:
-	mutex_unlock(&data->lock);
-	return count;
+	return (ret < 0) ? ret : count;
 }
 
 static IIO_DEVICE_ATTR(meas_conf,