diff --git a/drivers/iio/adc/at91-sama5d2_adc.c b/drivers/iio/adc/at91-sama5d2_adc.c
index 6eb72ba6b4d2..9cd6a779a217 100644
--- a/drivers/iio/adc/at91-sama5d2_adc.c
+++ b/drivers/iio/adc/at91-sama5d2_adc.c
@@ -1329,10 +1329,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
 		ret = at91_adc_read_position(st, chan->channel,
 					     &tmp_val);
 		*val = tmp_val;
-		mutex_unlock(&st->lock);
-		iio_device_release_direct_mode(indio_dev);
 		if (ret > 0)
 			ret = at91_adc_adjust_val_osr(st, val);
+		mutex_unlock(&st->lock);
+		iio_device_release_direct_mode(indio_dev);
 
 		return ret;
 	}
@@ -1345,10 +1345,10 @@ static int at91_adc_read_info_raw(struct iio_dev *indio_dev,
 		ret = at91_adc_read_pressure(st, chan->channel,
 					     &tmp_val);
 		*val = tmp_val;
-		mutex_unlock(&st->lock);
-		iio_device_release_direct_mode(indio_dev);
 		if (ret > 0)
 			ret = at91_adc_adjust_val_osr(st, val);
+		mutex_unlock(&st->lock);
+		iio_device_release_direct_mode(indio_dev);
 
 		return ret;
 	}
@@ -1441,16 +1441,20 @@ static int at91_adc_write_raw(struct iio_dev *indio_dev,
 		/* if no change, optimize out */
 		if (val == st->oversampling_ratio)
 			return 0;
+		mutex_lock(&st->lock);
 		st->oversampling_ratio = val;
 		/* update ratio */
 		at91_adc_config_emr(st);
+		mutex_unlock(&st->lock);
 		return 0;
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		if (val < st->soc_info.min_sample_rate ||
 		    val > st->soc_info.max_sample_rate)
 			return -EINVAL;
 
+		mutex_lock(&st->lock);
 		at91_adc_setup_samp_freq(indio_dev, val);
+		mutex_unlock(&st->lock);
 		return 0;
 	default:
 		return -EINVAL;