linux-kernel - Re: [RFC PATCH 0/4] cpufreq: qcom-hw: Move clocks to CPU node

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Date:   Mon, 1 Aug 2022 08:07:56 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Manivannan Sadhasivam <mani@...nel.org>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Johan Hovold <johan@...nel.org>, devicetree@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [RFC PATCH 0/4] cpufreq: qcom-hw: Move clocks to CPU node

On 18-07-22, 07:27, Viresh Kumar wrote:
> The OPP tables, which are part of the CPU nodes, mentions clock rates.
> Are these values for the cxo/gpll clocks or the clock that reaches the
> CPUs? I believe the latter. The DT is not really complete if the CPU
> node mentions the frequency, but not the source clock. It works for
> you because you don't want to do clk_set_rate() in this case, but then
> it leaves other frameworks, like OPP, confused and rightly so.
> 
> Normally, there is always a difference in what the OPP table contains
> as frequency value and what the hardware programs, mostly it is small
> though. It shouldn't prevent us from having the hierarchy clearly
> defined in the DT.
> 
> Based on your description, I think it would be better to make
> cpufreq-hw a clock provider and CPUs the consumer of it. It would then
> allow the OPP core to not carry the hack to make it all work.

Bjorn / Mani,

Can we please get this sorted out ? I don't want to carry an unnecessary hack in
the OPP core for this.

-- 
viresh