Re: [PATCH v2 08/11] dt-bindings: firmware: arm,scmi: Extend bindings for protocol@13

Sudeep Holla
2023-07-21T11:56:14Z

On Fri, Jul 21, 2023 at 01:42:43PM +0200, Ulf Hansson wrote:
> On Wed, 19 Jul 2023 at 17:17, Sudeep Holla <sudeep.holla@arm.com> wrote:
> >
> > On Thu, Jul 13, 2023 at 04:17:35PM +0200, Ulf Hansson wrote:
> > > The protocol@13 node is describing the performance scaling option for the
> > > ARM SCMI interface, as a clock provider. This is unnecessary limiting, as
> > > performance scaling is in many cases not limited to switching a clock's
> > > frequency.
> > >
> > > Therefore, let's extend the binding so the interface can be modelled as a
> > > generic performance domaintoo. The common way to describe this, is to use
> > > the "power-domain" DT bindings, so let's use that.
> > >
> >
> > One thing I forgot to ask earlier is how we can manage different domain IDs
> > for perf and power domains which is the case with current SCMI platforms as
> > the spec never mandated or can ever mandate the perf and power domains IDs
> > to match. They need not be same anyways.
>
> Based upon what you describe above, I have modelled the perf-domain
> and the power-domain as two separate power-domain providers.
>
> A consumer device being hooked up to both domains, would specify the
> domain IDs in the second power-domain-cell, along the lines of the
> below. Then we would use power-domain-names to specify what each
> power-domain represents.
>
> power-domains = <&scmi_pd 2>, <&scmi_dvfs 4>;
> power-domain-names = "power", "perf";
>
> I hope this makes it clearer!?

Yes it make is clear definitely, but it does change the definition of the
generic binding of the "power-domains" property now. I am interesting in
the feedback from the binding maintainers with respect to that. Or is it
already present ? IIUC, the ones supported already are generally both
power and performance providers. May be it doesn't matter much, just
wanted to explicit ask and confirm those details.

--
Regards,
Sudeep