staging:iio:ad7192: Report channel offset

In bipolar mode there is a a binary offset of 2**(N-1) (with N being the number
of bits) on the reported value. Currently this value is subtracted when doing a
manual read. While this works for manual channel readings it does not work for
buffered mode. So report the offset in the channels offset property, which will
work in both modes.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>

diff --git a/drivers/staging/iio/adc/ad7192.c b/drivers/staging/iio/adc/ad7192.c
index 7ba69948632664a5a87d44772c625c7eaad6bd54..73483d26a034808f7fdd5f752c58e6d9de99bfb4 100644 (file)
--- a/drivers/staging/iio/adc/ad7192.c
+++ b/drivers/staging/iio/adc/ad7192.c
@@ -826,8 +826,6 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
 
                switch (chan->type) {
                case IIO_VOLTAGE:
-                       if (!unipolar)
-                               *val -= (1 << (chan->scan_type.realbits - 1));
                        break;
                case IIO_TEMP:
                        *val -= 0x800000;
@@ -853,6 +851,12 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
                default:
                        return -EINVAL;
                }
+       case IIO_CHAN_INFO_OFFSET:
+               if (!unipolar)
+                       *val -= (1 << (chan->scan_type.realbits - 1));
+               else
+                       *val = 0;
+               return IIO_VAL_INT;
        }
 
        return -EINVAL;
@@ -942,7 +946,8 @@ static const struct iio_info ad7195_info = {
          .channel = _chan,                                             \
          .channel2 = _chan2,                                           \
          .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |                 \
-         IIO_CHAN_INFO_SCALE_SHARED_BIT,                               \
+         IIO_CHAN_INFO_SCALE_SHARED_BIT |                              \
+         IIO_CHAN_INFO_OFFSET_SHARED_BIT,                              \
          .address = _address,                                          \
          .scan_index = _si,                                            \
          .scan_type =  IIO_ST('u', 24, 32, 0)}
@@ -952,7 +957,8 @@ static const struct iio_info ad7195_info = {
          .indexed = 1,                                                 \
          .channel = _chan,                                             \
          .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |                 \
-         IIO_CHAN_INFO_SCALE_SHARED_BIT,                               \
+         IIO_CHAN_INFO_SCALE_SHARED_BIT |                              \
+         IIO_CHAN_INFO_OFFSET_SHARED_BIT,                              \
          .address = _address,                                          \
          .scan_index = _si,                                            \
          .scan_type =  IIO_ST('u', 24, 32, 0)}