Re: [PATCH] iio: light: apds9960: Fix iio_event_spec structures

[Subhajit Ghosh <subhajit.ghosh@vixtechnology.com>]

> Hmm.  Given that event enables often cover a couple of different things
> (as done here) it isn't unknown for those to not be as easily covered
> as you have done.  As such, we have drivers were the ABI allows for
> enabling one event to end up enabling several others (even though they
> have separate enable attributes).  It's always been permitted for one
> IIO attribute write to have an effect on other attributes simply because
> we can't represent all dependencies.
> 
> Now the bigger complexity / surprise here is the return of the either
> direction in response to enabling either rising or falling. 
> That is going to rather surprise your average writer of userspace cod This is where the inconsistency was found. When an ALS threshold rising 
value was given and as soon as it was enabled, interrupts started firing
in low light conditions as there was some value present in the ALS falling 
threshold(reset value is not defined in the datasheet for this register), 
but falling threshold value was neither fed nor enabled!

> So patch covers what we should definitely have had in the first place.
> Hence it's a question of risk of someone running code that will be affected
> by the ABI change.  One of those fingers crossed moments...
I understand that breaking existing userspace applications is not the best
thing to do.

> 
> Jonathan

Thank you for your time and comments.

Regards,
Subhajit Ghosh

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