Re: must #address-cells and #size-cells be explicitly defined or not?

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On Mon, Aug 6, 2018 at 10:53 AM Robert P. J. Day <rpjday@xxxxxxxxxxxxxx> wrote:
>
>
>   section 2.3.5 of the spec seems contradictory:
>
> "The #address-cells and #size-cells properties are not inherited from
> ancestors in the devicetree. They shall be explicitly defined.
>
> "A DTSpec-compliant boot program shall supply #address-cells and
> #size-cells on all nodes that have children.

That should be amended to "... that have children with 'reg' property".

> "If missing, a client program should assume a default value of 2 for
> #address-cells, and a value of 1 for #size-cells."
>
>   those first two sentences clearly imply that those properties *must*
> be explicitly defined, while the immediately following sentence allows
> a client program to fill them in if they're missing. that seems
> confusing.

I'd guess the last sentence was put there because there were DT's in
the wild which didn't have the properties. We can probably remove the
last sentence. dtc has had a warning for this for ages.

Interestingly, this isn't even the defaults the kernel uses. Both are
1 for all but Sparc.

Rob
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