Re: [PATCH v2 2/4] iio: core: Add IIO_EV_INFO_SCALE to event info

[Jonathan Cameron <jic23@kernel.org>]

On Mon, 2 Feb 2026 09:31:45 -0600
David Lechner <dlechner@baylibre.com> wrote:

> On 2/2/26 9:19 AM, Taha Ed-Dafili wrote:
> > Hi David,
> > 
> > Thanks for the feedback. You're right—"missing" was poor wording; I’ll
> > rephrase to "implement support in the core" for v3 to reflect that this
> > is an infrastructure addition.
> > 
> > Regarding existing users, the current lack of IIO_EV_INFO_SCALE in the core
> > forces developers into manual workarounds to stay ABI-compliant. For
> > instance, in drivers/iio/accel/mma8452.c, the developer used
> > IIO_CONST_ATTR_NAMED to create a manual in_accel_scale and linked it via
> > .event_attrs. This approach is static and bypasses the standard event_spec
> > infrastructure.  
> 
> OK, so it looks like there is just one existing user of any events/*_scale
> attribute then. That would explain why there isn't a IIO_EV_INFO_SCALE.
> It just isn't very common.
> 
> > 
> > My goal with adding IIO_EV_INFO_SCALE is to provide a standard path to
> > report these scales dynamically through read_event_value(), ensuring ABI
> > compliance without manual sysfs boilerplate.
> > 
> > Does this core infrastructure approach seem like the right architectural
> > path, or would you prefer I stick to a driver-level attribute for the
> > ADXL345? Regardless of the path chosen, I will address your other comments
> > in the next version: I'll fix the "in scale" typo and add the new scale
> > entries to the adxl345 documentation table.  
> 
> If we think there will be more users of this and we want to make it more
> discoverable, then adding IIO_EV_INFO_SCALE seems useful.
> 
> I would wait until Jonathan weighs in with his opinion before taking action
> though.

I agree. Makes sense to add this. 

Jonathan

> 
> > 
> > Thanks,
> > Taha  
>