staging:iio:cdc:ad7150: Add scale and offset to info_mask_shared_by_type

The datasheet provides these two values on the assumption they are applied
to unshift raw value.  Hence shift both the offset and scale by 4
to compensate.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Link: https://lore.kernel.org/r/20210314181511.531414-19-jic23@kernel.org

diff --git a/drivers/staging/iio/cdc/ad7150.c b/drivers/staging/iio/cdc/ad7150.c
index 5abc4e9..c7d242f 100644 (file)
--- a/drivers/staging/iio/cdc/ad7150.c
+++ b/drivers/staging/iio/cdc/ad7150.c
@@ -122,6 +122,18 @@ static int ad7150_read_raw(struct iio_dev *indio_dev,
                *val = ret;
 
                return IIO_VAL_INT;
+       case IIO_CHAN_INFO_SCALE:
+               /*
+                * Base units for capacitance are nano farads and the value
+                * calculated from the datasheet formula is in picofarad
+                * so multiply by 1000
+                */
+               *val = 1000;
+               *val2 = 40944 >> 4; /* To match shift in _RAW */
+               return IIO_VAL_FRACTIONAL;
+       case IIO_CHAN_INFO_OFFSET:
+               *val = -(12288 >> 4); /* To match shift in _RAW */
+               return IIO_VAL_INT;
        case IIO_CHAN_INFO_SAMP_FREQ:
                /* Strangely same for both 1 and 2 chan parts */
                *val = 100;
@@ -425,6 +437,8 @@ static const struct iio_event_spec ad7150_events[] = {
                .channel = _chan,                               \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
                BIT(IIO_CHAN_INFO_AVERAGE_RAW),                 \
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+                       BIT(IIO_CHAN_INFO_OFFSET),              \
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
                .event_spec = ad7150_events,                    \
                .num_event_specs = ARRAY_SIZE(ad7150_events),   \
@@ -436,6 +450,8 @@ static const struct iio_event_spec ad7150_events[] = {
                .channel = _chan,                               \
                .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |  \
                BIT(IIO_CHAN_INFO_AVERAGE_RAW),                 \
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+                       BIT(IIO_CHAN_INFO_OFFSET),              \
                .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
        }