diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
index 204e5dbf03ce..c266169dfe61 100644
--- a/drivers/iio/adc/rockchip_saradc.c
+++ b/drivers/iio/adc/rockchip_saradc.c
@@ -116,6 +116,10 @@ static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
 		mutex_unlock(&indio_dev->mlock);
 		return IIO_VAL_INT;
 	case IIO_CHAN_INFO_SCALE:
+		/* It is a dummy regulator */
+		if (info->uv_vref < 0)
+			return info->uv_vref;
+
 		*val = info->uv_vref / 1000;
 		*val2 = chan->scan_type.realbits;
 		return IIO_VAL_FRACTIONAL_LOG2;