[PATCH v3 1/8] dt-bindings: power: Add T-HEAD TH1520 GPU power sequencer

[Bartosz Golaszewski]

On Tue, Jun 3, 2025 at 8:24 PM Michal Wilczynski
<m.wilczynski at samsung.com> wrote:
> >
> > Agreed. And as far as implementation goes, you can have the same
> > driver be a PM domain AND pwrseq provider. It just has to bind to the
> > device node that represents an actual component, not a made-up
> > "convenience" node.
>
> Sure - this can be done using existing AON node.
>
> To keep the pwrseq code organized in drivers/power/sequencing/, a
> similar approach to our th1520-pd driver interfacing with the AON
> firmware library (drivers/firmware/thead,th1520-aon.c) could work.
>
> The idea would be to treat code like pwrseq-thead-aon.c (changed from a
> current pwrseq-thead-gpu.c) as a library. It would export its necessary
> functions (e.g., for specific sequence init/deinit steps) using
> EXPORT_SYMBOL_GPL. The main AON driver would then call these to provide
> the pwrseq functionality.
>
> This will introduce a compile-time dependency, as expected.
>
> An alternative would be to keep the driver in drivers/power/sequencing/
> as a platform driver and start it up using, for example, an auxiliary
> bus. This is similar to what the JH7110 clock driver
> (drivers/clk/starfive/clk-starfive-jh7110-sys.c) is doing with a reset
> driver. This could offer a cleaner separation of roles if that's
> preferred.
>
> Please let me know which way would be preferred.

I forgot the auxiliary bus is a thing. Yeah, definitely use that, it's
more elegant than a library function IMO.

Bart