iio:ad5755: Report scale as fractional value
Move the complexity of calculating the fixed point scale to the core.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/dac/ad5755.c b/drivers/iio/dac/ad5755.c
index f305a0c..bd31dbc 100644
--- a/drivers/iio/dac/ad5755.c
+++ b/drivers/iio/dac/ad5755.c
@@ -253,15 +253,6 @@
return (min * (1 << chan->scan_type.realbits)) / (max - min);
}
-static inline int ad5755_get_scale(struct ad5755_state *st,
- struct iio_chan_spec const *chan)
-{
- int min, max;
-
- ad5755_get_min_max(st, chan, &min, &max);
- return ((max - min) * 1000000000ULL) >> chan->scan_type.realbits;
-}
-
static int ad5755_chan_reg_info(struct ad5755_state *st,
struct iio_chan_spec const *chan, long info, bool write,
unsigned int *reg, unsigned int *shift, unsigned int *offset)
@@ -303,13 +294,15 @@
{
struct ad5755_state *st = iio_priv(indio_dev);
unsigned int reg, shift, offset;
+ int min, max;
int ret;
switch (info) {
case IIO_CHAN_INFO_SCALE:
- *val = 0;
- *val2 = ad5755_get_scale(st, chan);
- return IIO_VAL_INT_PLUS_NANO;
+ ad5755_get_min_max(st, chan, &min, &max);
+ *val = max - min;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
*val = ad5755_get_offset(st, chan);
return IIO_VAL_INT;