The sysfs iio ABI states radians per second is expected as the unit for
angular velocity, but the 12-bit angular velocity register has rps
as its unit. So a scaling factor of approximately 2 * Pi is
added to the angular velocity channel.
Signed-off-by: David Veenstra <davidjulianveenstra@xxxxxxxxx>
---
Changes in v3:
- A decimal approximation of the scale is used, instead
of a fractional approximation.
- Remove unneeded explanation of iio_convert_raw_to_processed.
drivers/staging/iio/resolver/ad2s1200.c | 71 +++++++++++++++++++++------------
1 file changed, 45 insertions(+), 26 deletions(-)
diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c
index 3c7163610ff6..3e1696e52c38 100644
--- a/drivers/staging/iio/resolver/ad2s1200.c
+++ b/drivers/staging/iio/resolver/ad2s1200.c
@@ -57,37 +57,55 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
struct ad2s1200_state *st = iio_priv(indio_dev);
int ret = 0;
- mutex_lock(&st->lock);
- gpiod_set_value(st->sample, 0);
-
- /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
- udelay(1);
- gpiod_set_value(st->sample, 1);
- gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
-
- ret = spi_read(st->sdev, &st->rx, 2);
- if (ret < 0) {
+ 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);
+
+ /* delay (6 * AD2S1200_TSCLK + 20) nano seconds */
+ udelay(1);
+ gpiod_set_value(st->sample, 1);
+ gpiod_set_value(st->rdvel, !!(chan->type == IIO_ANGL));
+
+ ret = spi_read(st->sdev, &st->rx, 2);
+ if (ret < 0) {
+ mutex_unlock(&st->lock);
+ return ret;
+ }
+
+ switch (chan->type) {
+ case IIO_ANGL:
+ *val = be16_to_cpup(&st->rx) >> 4;
+ break;
+ case IIO_ANGL_VEL:
+ *val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
+ break;
+ default:
+ mutex_unlock(&st->lock);
+ return -EINVAL;
+ }
+
+ /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
+ udelay(1);
mutex_unlock(&st->lock);
- return ret;
- }
- switch (chan->type) {
- case IIO_ANGL:
- *val = be16_to_cpup(&st->rx) >> 4;
- break;
- case IIO_ANGL_VEL:
- *val = sign_extend32(be16_to_cpup(&st->rx) >> 4, 11);
- break;
+ return IIO_VAL_INT;
default:
- mutex_unlock(&st->lock);
- return -EINVAL;
+ break;
}
- /* delay (2 * AD2S1200_TSCLK + 20) ns for sample pulse */
- udelay(1);
- mutex_unlock(&st->lock);
-
- return IIO_VAL_INT;
+ return -EINVAL;
}
static const struct iio_chan_spec ad2s1200_channels[] = {
@@ -101,6 +119,7 @@ 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),
}
};
--
2.16.2
--
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