staging: iio: ad2s1200: Add scaling factor for angular velocity channel

The sysfs iio ABI states radians per second is expected as the unit for
angular velocity, but the 12-bit angular velocity register has
revolution per seconds as its unit. So a scaling factor of approximately
2 * Pi is added to the angular velocity channel.
Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/staging/iio/resolver/ad2s1200.c

@@ -55,6 +55,19 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
 	struct ad2s1200_state *st = iio_priv(indio_dev);
 	int ret;
 
+	switch (m) {
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_ANGL_VEL:
+			/* 2 * Pi ~= 6.283185 */
+			*val = 6;
+			*val2 = 283185;
+			return IIO_VAL_INT_PLUS_MICRO;
+		default:
+			return -EINVAL;
+		}
+		break;
+	case IIO_CHAN_INFO_RAW:
 		mutex_lock(&st->lock);
 		gpiod_set_value(st->sample, 0);
 
@@ -86,6 +99,11 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
 		mutex_unlock(&st->lock);
 
 		return IIO_VAL_INT;
+	default:
+		break;
+	}
+
+	return -EINVAL;
 }
 
 static const struct iio_chan_spec ad2s1200_channels[] = {
@@ -99,6 +117,7 @@ static const struct iio_chan_spec ad2s1200_channels[] = {
 		.indexed = 1,
 		.channel = 0,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
 	}
 };