| Message ID | 20220318162722.51215-2-alexandru.tachici@analog.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | iio: adc: ad_sigma_delta: Add sequencer support | expand |
On Fri, 18 Mar 2022 18:27:15 +0200 <alexandru.tachici@analog.com> wrote: > From: Alexandru Tachici <alexandru.tachici@analog.com> > > The 24 bits data is stored in 32 bits in BE. There > is no need to shift it. This confuses user-space apps. > > Fixes: b3af341bbd966 ("iio: adc: Add ad7124 support") > Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com> Hi Alexandru, Just to confirm my understanding (which gets a bit messy when endian conversions are involved - and it occurs to me that our docs are not great on how to handle endian conversions with shifts). With a little endian cpu: After userspace performs the 32bit big endian to little endian conversion the value the shift would have previously dropped the bottom 8 bits of the channel reading? Looking at what ad_sigma_delta is doing it's documented as leaving the upper 8 bits as 0 so this would make sense. Have I understood the issue correctly? I'll need to hold this one for now as I'll need to rebase the fixes-togreg branch of iio.git after rc1 is available. Thanks, Jonathan > --- > drivers/iio/adc/ad7124.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c > index 998a342d51a6..7249db2c4422 100644 > --- a/drivers/iio/adc/ad7124.c > +++ b/drivers/iio/adc/ad7124.c > @@ -188,7 +188,6 @@ static const struct iio_chan_spec ad7124_channel_template = { > .sign = 'u', > .realbits = 24, > .storagebits = 32, > - .shift = 8, > .endianness = IIO_BE, > }, > };
diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c index 998a342d51a6..7249db2c4422 100644 --- a/drivers/iio/adc/ad7124.c +++ b/drivers/iio/adc/ad7124.c @@ -188,7 +188,6 @@ static const struct iio_chan_spec ad7124_channel_template = { .sign = 'u', .realbits = 24, .storagebits = 32, - .shift = 8, .endianness = IIO_BE, }, };