staging: iio: ad2s1200: Add scaling factor for angle channel

A scaling factor of approximately 2 * Pi / (2^12 -1) is added,
to scale the 12-bits angular position to radians.

A return type of IIO_VAL_INT_PLUS_NANO is used, so that the scale of
both the angle channel and angular velocity channel has 7 significant
digits.

Signed-off-by: David Veenstra <davidjulianveenstra@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/staging/iio/resolver/ad2s1200.c b/drivers/staging/iio/resolver/ad2s1200.c
index 7b8af558e92109885f1ddf4ac24e4b694ab74971..10d6d79dce79ddf8bf99f60ad7ad8f7459823f7e 100644 (file)
--- a/drivers/staging/iio/resolver/ad2s1200.c
+++ b/drivers/staging/iio/resolver/ad2s1200.c
@@ -58,6 +58,11 @@ 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) ~= 0.001534355 */
+                       *val = 0;
+                       *val2 = 1534355;
+                       return IIO_VAL_INT_PLUS_NANO;
                case IIO_ANGL_VEL:
                        /* 2 * Pi ~= 6.283185 */
                        *val = 6;
@@ -112,6 +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),
        }, {
                .type = IIO_ANGL_VEL,
                .indexed = 1,