iio: imu: adis: group single conversion under a single state lock

The single conversion function does a series of reads + writes. This change
extends the use of the state_lock for the entire set of operations.
Previously, indio_dev's mlock was used. This change also removes the use of
this lock.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/imu/adis.c

@@ -404,15 +404,15 @@ int adis_single_conversion(struct iio_dev *indio_dev,
 	unsigned int uval;
 	int ret;
 
-	mutex_lock(&indio_dev->mlock);
+	mutex_lock(&adis->state_lock);
 
-	ret = adis_read_reg(adis, chan->address, &uval,
+	ret = __adis_read_reg(adis, chan->address, &uval,
 			chan->scan_type.storagebits / 8);
 	if (ret)
 		goto err_unlock;
 
 	if (uval & error_mask) {
-		ret = adis_check_status(adis);
+		ret = __adis_check_status(adis);
 		if (ret)
 			goto err_unlock;
 	}
@@ -424,7 +424,7 @@ int adis_single_conversion(struct iio_dev *indio_dev,
 
 	ret = IIO_VAL_INT;
 err_unlock:
-	mutex_unlock(&indio_dev->mlock);
+	mutex_unlock(&adis->state_lock);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(adis_single_conversion);