iio: adc: ad4030: don't store scan_type in state

Move getting the scan_type to ad4030_conversion(). Previously, we were
getting the scan_type in two other places, then storing it in the
state struct before using it in ad4030_conversion(). This was a bit
fragile against potential future changes since it isn't obvious that
anything that could potentially change the scan_type would need to
also update the state struct. Also, the non-obviousness of this led to
a redundant call to iio_get_current_scan_type() in
ad4030_single_conversion() since it also calls ad4030_set_mode() which
in turn calls ad4030_conversion().

To simplify things, just call iio_get_current_scan_type() in
ad4030_conversion() where the returned struct is actually used and
don't bother storing it in the state struct.

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-v1-4-589e4ebd9711@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 c2117c7a296f22aeeec6911c8a8c74ed576296a0..54ad74b96c9f256a67848330f875379edc828b0b 100644 (file)
--- a/drivers/iio/adc/ad4030.c
+++ b/drivers/iio/adc/ad4030.c
@@ -147,7 +147,6 @@ struct ad4030_state {
        struct spi_device *spi;
        struct regmap *regmap;
        const struct ad4030_chip_info *chip;
-       const struct iio_scan_type *current_scan_type;
        struct gpio_desc *cnv_gpio;
        int vref_uv;
        int vio_uv;
@@ -562,11 +561,6 @@ static int ad4030_set_mode(struct iio_dev *indio_dev, unsigned long mask)
                st->mode = AD4030_OUT_DATA_MD_DIFF;
        }
 
-       st->current_scan_type = iio_get_current_scan_type(indio_dev,
-                                                         st->chip->channels);
-       if (IS_ERR(st->current_scan_type))
-               return PTR_ERR(st->current_scan_type);
-
        return regmap_update_bits(st->regmap, AD4030_REG_MODES,
                                  AD4030_REG_MODES_MASK_OUT_DATA_MODE,
                                  st->mode);
@@ -614,15 +608,20 @@ static void ad4030_extract_interleaved(u8 *src, u32 *ch0, u32 *ch1)
 static int ad4030_conversion(struct iio_dev *indio_dev)
 {
        struct ad4030_state *st = iio_priv(indio_dev);
-       unsigned char diff_realbytes =
-               BITS_TO_BYTES(st->current_scan_type->realbits);
-       unsigned char diff_storagebytes =
-               BITS_TO_BYTES(st->current_scan_type->storagebits);
+       const struct iio_scan_type *scan_type;
+       unsigned char diff_realbytes, diff_storagebytes;
        unsigned int bytes_to_read;
        unsigned long cnv_nb = BIT(st->avg_log2);
        unsigned int i;
        int ret;
 
+       scan_type = iio_get_current_scan_type(indio_dev, st->chip->channels);
+       if (IS_ERR(scan_type))
+               return PTR_ERR(scan_type);
+
+       diff_realbytes = BITS_TO_BYTES(scan_type->realbits);
+       diff_storagebytes = BITS_TO_BYTES(scan_type->storagebits);
+
        /* Number of bytes for one differential channel */
        bytes_to_read = diff_realbytes;
        /* Add one byte if we are using a differential + common byte mode */
@@ -673,11 +672,6 @@ static int ad4030_single_conversion(struct iio_dev *indio_dev,
        if (ret)
                return ret;
 
-       st->current_scan_type = iio_get_current_scan_type(indio_dev,
-                                                         st->chip->channels);
-       if (IS_ERR(st->current_scan_type))
-               return PTR_ERR(st->current_scan_type);
-
        ret = ad4030_conversion(indio_dev);
        if (ret)
                return ret;