iio:ad7476: Report scale as fractional value

Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/adc/ad7476.c

@@ -127,10 +127,9 @@ static int ad7476_read_raw(struct iio_dev *indio_dev,
 		} else {
 			scale_uv = st->chip_info->int_vref_uv;
 		}
-		scale_uv >>= chan->scan_type.realbits;
 		*val = scale_uv / 1000;
-		*val2 = (scale_uv % 1000) * 1000;
-		return IIO_VAL_INT_PLUS_MICRO;
+		*val2 = chan->scan_type.realbits;
+		return IIO_VAL_FRACTIONAL_LOG2;
 	}
 	return -EINVAL;
 }