Re: [PATCH] iio: accel: fix ADXL355 temperature signature value

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 15 Mar 2026 11:18:18 -0500
David Lechner <dlechner@baylibre.com> wrote:

> On 3/15/26 10:35 AM, Andrej Valek wrote:
> > Ah, I see, I described it wrongly.
> > 
> > On 14.03.2026 21:22, David Lechner wrote:  
> >> On 3/13/26 4:24 AM, Andrej Valek wrote:  
> >>> From: "Valek Andrej <andrej.v@skyrain.eu>"
> >>>
> >>> Temperature was wrongly represented as 12-bit signature, confirmed by DS.  
> >> signature == signed integer?  
> > Correct, temperature is wrongly represented as signed 12-bit number, while it has to be unsigned.  
> >>
> >> DS == datasheet?  
> > Yes  
> >>  
> >>> Even if the temperature is negative, the value in the register stays
> >>> unsigned.  
> >> And IIO_CHAN_INFO_OFFSET will be negative.  
> > Not sure what do you mean by this. I can only say, that output type was "be:s12/16>>0" and should be "be:u12/16>>0". So when some upper layer wanted to represent the number it "overflowed", while the bits have been masked.  
> 
> Mostly I was talking to myself on this point. No action is needed here.
> 
> >>  
> >>> Signed-off-by: Valek Andrej <andrej.v@skyrain.eu>
> >>> ---
> >>>   drivers/iio/accel/adxl355_core.c | 2 +-
> >>>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/iio/accel/adxl355_core.c b/drivers/iio/accel/adxl355_core.c
> >>> index 1c1d64d5cbcb2..8f90c58f41008 100644
> >>> --- a/drivers/iio/accel/adxl355_core.c
> >>> +++ b/drivers/iio/accel/adxl355_core.c
> >>> @@ -745,7 +745,7 @@ static const struct iio_chan_spec adxl355_channels[] = {
> >>>                         BIT(IIO_CHAN_INFO_OFFSET),
> >>>           .scan_index = 3,
> >>>           .scan_type = {
> >>> -            .sign = 's',
> >>> +            .sign = 'u',
> >>>               .realbits = 12,
> >>>               .storagebits = 16,
> >>>               .endianness = IIO_BE,  
> >>
> >>  
> > Conclusion = Should I send a new version with "fixed" description?  
> 
> Sometimes, for small tweaks, Jonathan will just fix it while applying the
> patch. So wait for for his feedback.
> 
> You can also see the status of the patch in patchwork at [1]. If the State
> changes to "Changes requested", then you know a new version is expected.
> Right now, it says "New" which means he hasn't looked at it or made a
> decision yet.
> 
> 
> [1]: https://patchwork.kernel.org/project/linux-iio/patch/20260313092413.35912-1-andy@skyrain.eu/

Busy few weeks. Catching up now.

This also needs a fixes tag to indicate how far back we should be looking
to backport it.

Looks like it was all the way so I've added one.
Fixes: 12ed27863ea3 ("iio: accel: Add driver support for ADXL355")

Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks,

Jonathan


> 
> > 
> > BR,
> > Andy  
> 
>