[PATCH 18/18] arm64: apple: Add initial Mac Mini 2020 (M1) devicetree

[Arnd Bergmann]

On Fri, Feb 5, 2021 at 8:11 AM Hector Martin 'marcan' <marcan at marcan.st> wrote:
>
> One thing I wanted to ask: is there some kind of "experimental" policy
> for DT bindings? At early platform bring-up stages it seems like it
> could be valuable to allow for breaking DT changes while we flesh out
> the details (this is especially true of a reverse engineered platform
> like this, where we don't have knowledge of all the hardware details a
> priori). The dozen or so users we might have at this stage obviously
> won't complain too much :)

We don't have a hard policy here, other than the obvious "never break
setups that users rely on". As you expected, this usually means that
I wouldn't complain if you change something in the initial versions
and there is a good reason for that change, it shouldn't be a problem.

An extreme example here is the omap platform that keeps making
incompatible dt changes as there is still ongoing work for removing
the remaining platform specific code in arch/arm/ and replacing it
with DT descriptions.

Once your port is fairly complete and there are users that rely on stability
of the bindings, I would expect all further changes to be compatible in
both ways, allowing old kernels with new dtbs and the other way round.

       Arnd