iio: adc: ad4030: explain rearranging raw sample data

Add a comment explaining why the raw sample data is rearranged in the
in the ad4030_conversion() function. It is not so obvious from the code
why this is done.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250310-iio-adc-ad4030-check-scan-type-err-v1-5-589e4ebd9711@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/ad4030.c b/drivers/iio/adc/ad4030.c
index 54ad74b96c9f256a67848330f875379edc828b0b..636f9f33e66af73d102722b984dc1230e1417d1e 100644 (file)
--- a/drivers/iio/adc/ad4030.c
+++ b/drivers/iio/adc/ad4030.c
@@ -646,6 +646,12 @@ static int ad4030_conversion(struct iio_dev *indio_dev)
                                           &st->rx_data.dual.diff[0],
                                           &st->rx_data.dual.diff[1]);
 
+       /*
+        * If no common mode voltage channel is enabled, we can use the raw
+        * data as is. Otherwise, we need to rearrange the data a bit to match
+        * the natural alignment of the IIO buffer.
+        */
+
        if (st->mode != AD4030_OUT_DATA_MD_16_DIFF_8_COM &&
            st->mode != AD4030_OUT_DATA_MD_24_DIFF_8_COM)
                return 0;