Re: [PATCH v4 1/3] dt-bindings: iio: adf4371: add refin mode

Nuno Sá
2025-01-13T11:17:21Z

On Mon, 2025-01-13 at 11:21 +0100, Krzysztof Kozlowski wrote:
> On 13/01/2025 10:55, Nuno Sá wrote:
> > On Mon, 2025-01-13 at 09:37 +0100, Krzysztof Kozlowski wrote:
> > > On Thu, Jan 09, 2025 at 03:37:05PM +0200, Antoniu Miclaus wrote:
> > > >    clock-names:
> > > >      description:
> > > > -      Must be "clkin"
> > > > -    maxItems: 1
> > > > +      Must be "clkin" if the input reference is single ended or "clkin-
> > > > diff"
> > > > +      if the input reference is differential. By default single ended
> > > > input
> > > > is
> > > > +      applied.
> > > > +    enum: [clkin, clkin-diff]
> > > > +    default: clkin
> > >
> > > Which pins are these? I went through adf4371 datasheet and no reference
> > > on clock inputs like clkin or clkin-diff.
> > >
> > >
> >
> > Hmm, I guess we should call this 'refp' and 'refp-n' then (the latter seems
> > a
> > bit more odd)? Or just 'ref' and 'ref-diff'?
>
> That mistake was done at the beginning - the "clkin" is just useless
> name. It cannot be "clkout" and it cannot be anything else than clk, so
> it is 100% redundant.
>

Oh sure... Makes sense and I forgot that the property is not new...

> But looking for pins brought second point - here you claim these are
> mutually exclusive while datasheet suggests that both inputs can be
> connected. Unless they come from the same source always?
>

If you have a single ended input then only one pin (the positive one) will be
used. If the input signal is differential, then both pins will be used. So they
are mutually exclusive... You either have single ended or a differential input.
And depending on the input type, the limit of the input frequency varies.

- Nuno Sá