A fractional scaling factor of approximately 2 * Pi / (2^12 -1) is added,
to scale the 12-bits angular position to radians.
Signed-off-by: David Veenstra <davidjulianveenstra@xxxxxxxxx>
---
Changes in v2:
- This patch replaces the patch that changed the
the channel for angular position to inclination
channel.
drivers/staging/iio/resolver/ad2s1200.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c
index 6c56257be3b1..4f5dd28b174a 100644
--- a/drivers/staging/iio/resolver/ad2s1200.c
+++ b/drivers/staging/iio/resolver/ad2s1200.c
@@ -71,6 +71,17 @@ static int ad2s1200_read_raw(struct iio_dev *indio_dev,
switch (m) {
case IIO_CHAN_INFO_SCALE:
switch (chan->type) {
+ case IIO_ANGL:
+ /*
+ * 2 * Pi / (2^12 - 1) ~= 2 * 103993 / (33102 * 0xFFF)
+ *
+ * Since there only fit 3 whole radians in 360 degrees,
+ * usage of iio_convert_raw_to_processed for this
+ * channel will be highly inaccurate.
+ */
+ *val = 103993;
+ *val2 = 16551 * 0xFFF;
+ return IIO_VAL_FRACTIONAL;
case IIO_ANGL_VEL:
/*
* 2 * Pi ~= 2 * 103993 / 33102
@@ -133,6 +144,7 @@ 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),
}, {
.type = IIO_ANGL_VEL,
.indexed = 1,
--
2.16.2
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