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Date:   Thu, 5 Dec 2019 08:21:25 +0530
From:   Viresh Kumar <viresh.kumar@linaro.org>
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     sumitg <sumitg@nvidia.com>, rjw@rjwysocki.net,
        catalin.marinas@arm.com, will@kernel.org, thierry.reding@gmail.com,
        jonathanh@nvidia.com, talho@nvidia.com, linux-pm@vger.kernel.org,
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        linux-kernel@vger.kernel.org, bbasu@nvidia.com,
        mperttunen@nvidia.com
Subject: Re: [TEGRA194_CPUFREQ Patch 2/3] cpufreq: Add Tegra194 cpufreq driver
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On 04-12-19, 16:57, Dmitry Osipenko wrote:
> 04.12.2019 14:27, Viresh Kumar пишет:
> > On 04-12-19, 16:25, sumitg wrote:
> >> In T194, CCPLEX doesn't have access to set clocks and the
> >>
> >> clk_{get|set}_rate() functions set clocks by hook to BPMP R5.
> >>
> >> CPU freq can be directly set by CCPLEX using MSR(NVFREQ_REQ_EL1).
> >>
> >> As DVFS run's on BPMP, another MSR (NVFREQ_FEEDBACK_EL1) is
> >>
> >> used to read the counters and calculate "actual" cpu freq at CCPLEX.
> >>
> >> So, "cpuinfo_cur_freq" node gives the actual cpu frequency and not
> >>
> >> given by node "scaling_cur_freq".
> > 
> > Right, but why can't this be hidden in the CPU's clk driver instead,
> > so cpufreq driver can just do clk_get_rate() and clk_set_rate() ?
> 
> What about to make use of dev_pm_opp_register_set_opp_helper()?

It has a different purpose where we have to play with different
regulators. And that won't help with clk_get_rate() anyway.

-- 
viresh