Re: [PATCH 2/6] dt-bindings: iio: adc: ad7380: fix ad7380-4 reference supply

Jonathan Cameron
2024-10-14T18:37:13Z

On Mon, 14 Oct 2024 11:00:39 +0200
Julien Stephan <jstephan@baylibre.com> wrote:

> Le jeu. 10 oct. 2024 à 20:22, Jonathan Cameron <jic23@kernel.org> a écrit :
> >
> > On Tue, 8 Oct 2024 09:52:50 +0200
> > Krzysztof Kozlowski <krzk@kernel.org> wrote:
> >
> > > On Mon, Oct 07, 2024 at 05:45:45PM +0200, Julien Stephan wrote:
> > > > ad7380-4 is the only device from ad738x family that doesn't have an
> > > > internal reference. Moreover its external reference is called REFIN in
> > > > the datasheet while all other use REFIO as an optional external
> > > > reference. If refio-supply is omitted the internal reference is
> > > > used.
> > > >
> > > > Fix the binding by adding refin-supply and makes it required for
> > > > ad7380-4 only.
> > >
> > > Maybe let's just use refio as refin? Reference-IO fits here well.
> > > Otherwise you have two supplies for the same.
> > Whilst it is ugly, the effort this series is going to in order
> > to paper over a naming mismatch makes me agree with Krzysztof.
> >
> > I think adding a comment to the dt-binding would be sensible
> > though as people might fall into this hole.
> >
>
> Hi Jonathan and Krzysztof,
>
> I am currently adding support for another chip to this family
> (ADAQ4380-4) and it also uses REFIN.. but in another way ad7380-4
> does..
> So:
> - ad7380-4 does not have any internal reference and use a mandatory
> refin supply as external reference
> - adaq4380-4 does not have external reference but uses a 3V internal
> reference derived from a 5V mandatory refin supply
> - all others (AFAIK) use an optional refio external reference. If
> omitted, use an internal 2.5V reference.
>
> I am not sure using a single refio-supply for all will make things
> clearer.. What do you think? Should I also send the adaq series now to
> bring more context? (I wanted feedback on this series first).
>

Sounds like that context would be useful if you have it more or less
ready to send anyway. I don't have particularly strong views on this
either way. If we 'fix' the case you have here, old bindings should
continue to work for the part you are moving over (though no need
to have them in the dt-bindings file).

Jonathan

> Cheers
> Julien
>
> > Other than the missing ret =, rest of series looks fine to me
> >
> > Jonathan
> >
> > >
> > > Best regards,
> > > Krzysztof
> > >
> >