Re: [PATCH] checks: Avoid warnings for reg override in __overlay__

[Brian Norris <briannorris@chromium.org>]

Hi Rob,

On Wed, Jun 17, 2026 at 05:54:42PM -0500, Rob Herring wrote:
> I would argue (and did the last time this came up IIRC) the overlay

I gave a quick look for prior art, but didn't go far enough. I see this
was a similar conversation:

[PATCH v2] checks: Suppress warnings on overlay fragments
https://lore.kernel.org/all/20230308091539.11178-1-qun-wei.lin@mediatek.com/

I don't think it had a satisfying conclusion though.

> should target the parent node instead and then you can put in
> #address-cells and #size-cells in the overlay to make it pass checks
> (and make 'reg' parsable without applying the overlay).

This implies we can't actually target the appropriate node via phandle
any more, and so we lose the ergonomics that phandles provide. Where
previouly an overlay could be resilient to node renaming and other sorts
of incompatibilities between a dtb and a dtbo (the overlay wouldn't
apply if &foo isn't found), now we'd have to open-code the node name and
maybe even its parent node name in the overlay. If either of those were
wrong ... we wouldn't notice at all, unless there's an obvious
functional breakage as a result.

I acknowledge that it's difficult to parse and validate dtbos when they
are low on context. But I don't see why we should emit false warnings
for the possibly-correct, and more ergnomic approach.

Brian