Re: [TEGRA194_CPUFREQ Patch 2/3] cpufreq: Add Tegra194 cpufreq driver

[Viresh Kumar]

On 04-12-19, 16:57, Dmitry Osipenko wrote:
> 04.12.2019 14:27, Viresh Kumar ÐÐÑÐÑ:
> > 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