iio: adc: ad4030: check scan_type for error

Check scan_type for error ad4030_get_chan_scale(). Currently, this
should never fail, but it is good practice to always check for errors
in case of future changes.

Calling iio_get_current_scan_type() is moved out of the if statement
also to avoid potential issues with future changes instead of assuming
that the non-differential case does not use extended scan_type.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202503040954.n6MhjSsV-lkp@intel.com/
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-v1-1-589e4ebd9711@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 9a02068..af7a817 100644 (file)
--- a/drivers/iio/adc/ad4030.c
+++ b/drivers/iio/adc/ad4030.c
@@ -390,16 +390,18 @@ static int ad4030_get_chan_scale(struct iio_dev *indio_dev,
        struct ad4030_state *st = iio_priv(indio_dev);
        const struct iio_scan_type *scan_type;
 
+       scan_type = iio_get_current_scan_type(indio_dev, st->chip->channels);
+       if (IS_ERR(scan_type))
+               return PTR_ERR(scan_type);
+
        if (chan->differential) {
-               scan_type = iio_get_current_scan_type(indio_dev,
-                                                     st->chip->channels);
                *val = (st->vref_uv * 2) / MILLI;
                *val2 = scan_type->realbits;
                return IIO_VAL_FRACTIONAL_LOG2;
        }
 
        *val = st->vref_uv / MILLI;
-       *val2 = chan->scan_type.realbits;
+       *val2 = scan_type->realbits;
        return IIO_VAL_FRACTIONAL_LOG2;
 }