[PATCH v2 6/7] arm: dts: apple: Add preliminary device trees

[Mark Kettenis]

> From: Rob Herring <robh at kernel.org>
> Date: Mon, 11 Oct 2021 13:36:29 -0500

Hi Rob,

> On Sun, Oct 3, 2021 at 1:35 PM Mark Kettenis <kettenis at openbsd.org> wrote:
> >
> > Add preliminary device trees for the Apple M1 mini (2020) and
> > Apple M1 Macbook Pro 13" (2020).  Device tree bindings for
> > the Apple M1 SoC are still being formalized and these device
> > trees will be synchronized with the Linux kernel as needed.
> 
> So not synchronized currently? If it is sync'ed, you should specify
> which version you got.

Not synched at the moment.  It is based on what was in 5.13 or 5.14,
but with lots of stuff added so specifying a version would be
misleading.  It should be mostly aligned with the bindings that are
making their way into 5.15 or 5.16 though.

Hopefully now that the power domains are getting addressed we'll have
something that can be synchronized soon.  I was explicitly encouraged
to start upstreaming the U-Boot code even though not all the DT
bindings had been sorted out.

> > These device trees are provided as a reference only as U-Boot
> > uses the device tree passed by the m1n1 bootloader.
> 
> If reference only, why do they need to be checked in here? We're
> trying to get to fewer copies both of dtbs at runtime and dts files in
> source trees.

The U-Boot maintainers insist there is a DT for each supported system
in the U-Boot tree.

> I mainly bring it up here because this is a platform with multiple OS
> targets, following the model that DT comes from the firmware, and
> should be free of schema validation warnings. In other words, it's a
> good candidate to define best practices.

You're preaching to the choir ;).

Must admit that it is somewhat convenient for me to have a somewhat
complete DT for these devices at the moment.  But in the long run I
think it will just confuse people.  That said, I plan to be aggressive
in keeping the U-Boot tree synchronized with Linux.

Cheers,

Mark