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From:   Ulf Hansson <ulf.hansson@linaro.org>
Date:   Fri, 21 Jul 2023 13:52:17 +0200
Message-ID: <CAPDyKFogrwFnz2ZuKE-mLrCQmTCQcrtjhhyzB4CnoVnxAXqKEg@mail.gmail.com>
Subject: Re: [PATCH v2 09/11] cpufreq: scmi: Add support to parse domain-id
 using #power-domain-cells
To:     Sudeep Holla <sudeep.holla@arm.com>
Cc:     Cristian Marussi <cristian.marussi@arm.com>,
        Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
        Stephen Boyd <sboyd@kernel.org>,
        Nikunj Kela <nkela@quicinc.com>,
        Prasad Sodagudi <psodagud@quicinc.com>,
        Alexandre Torgue <alexandre.torgue@foss.st.com>,
        linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-kernel@vger.kernel.org
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On Wed, 19 Jul 2023 at 17:24, Sudeep Holla <sudeep.holla@arm.com> wrote:
>
> On Thu, Jul 13, 2023 at 04:17:36PM +0200, Ulf Hansson wrote:
> > The performance domain-id can be described in DT using the power-domains
> > property or the clock property. The latter is already supported, so let's
> > add support for the power-domains too.
> >
>
> How is this supposed to work for the CPUs ? The CPU power domains are
> generally PSCI on most of the platforms and the one using OSI explicitly
> need to specify the details while ones using PC will not need to. Also they
> can never be performance domains too. So I am not sure if I am following this
> correctly.

Your concerns are certainly correct, I completely forgot about this.
We need to specify what power-domain index belongs to what, by using
power-domain-names in DT. So a CPU node, that has both psci for power
and scmi for performance would then typically look like this:

power-domains = <&CPU_PD0>, <&scmi_dvfs 4>;
power-domain-names = "psci", "scmi";

I will take care of this in the next version - and thanks a lot for
pointing this out!

Kind regards
Uffe