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Groups > linux.kernel > #1585228 > unrolled thread

cpufreq: get cpufreq_frequency_table from clk driver

Started byVlad Zakharov <Vladislav.Zakharov@synopsys.com>
First post2017-02-21 12:20 +0100
Last post2017-02-23 06:00 +0100
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  cpufreq: get cpufreq_frequency_table from clk driver Vlad Zakharov <Vladislav.Zakharov@synopsys.com> - 2017-02-21 12:20 +0100
    Re: cpufreq: get cpufreq_frequency_table from clk driver Viresh Kumar <viresh.kumar@linaro.org> - 2017-02-23 06:00 +0100

#1585228 — cpufreq: get cpufreq_frequency_table from clk driver

FromVlad Zakharov <Vladislav.Zakharov@synopsys.com>
Date2017-02-21 12:20 +0100
Subjectcpufreq: get cpufreq_frequency_table from clk driver
Message-ID<tdgEa-1QZ-5@gated-at.bofh.it>
Hello,

I am trying to implement a cpufreq driver for ARCHS cpu.

And I faced with one question I am not able to answer myself. cpufreq framework allows us using cpufreq frequency tables
that store available for current policy range of frequencies with any additional data. As I understand for example it
can be clock configurations for this particular frequency.

Also I have a clk driver that manages actual cpu frequency. In fact it uses very similar tables that contain frequencies
and corresponding values of clock configurations registers that are to be set up with current frequency.

So the question is can I get such tables from clk driver somehow? I would be very convenient: this tables differs for
ARCHS CPU. E.g. on different boards it is clocked by different PLLs and oscillators.

Do you know any way to get the tables from clk driver? Any suggestions or comments might be very helpful.

Thanks!

-- 
Best regards,
Vlad Zakharov <vzakhar@synopsys.com>

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#1586646

FromViresh Kumar <viresh.kumar@linaro.org>
Date2017-02-23 06:00 +0100
Message-ID<tdTFv-4xm-3@gated-at.bofh.it>
In reply to#1585228
On 21-02-17, 11:13, Vlad Zakharov wrote:
> Hello,
> 
> I am trying to implement a cpufreq driver for ARCHS cpu.

You mean ARC architecture here ?

> And I faced with one question I am not able to answer myself. cpufreq framework allows us using cpufreq frequency tables
> that store available for current policy range of frequencies with any additional data. As I understand for example it
> can be clock configurations for this particular frequency.

Yes, it can be any platform specific data. Yes, but it is better
handled by the clk driver in your case and cpufreq driver just needs
to call clk_set_rate().

> Also I have a clk driver that manages actual cpu frequency. In fact it uses very similar tables that contain frequencies
> and corresponding values of clock configurations registers that are to be set up with current frequency.

Good.

> So the question is can I get such tables from clk driver somehow? I would be very convenient: this tables differs for
> ARCHS CPU. E.g. on different boards it is clocked by different PLLs and oscillators.

Not that I am aware of. Just make copies for every board or if you can
use device tree, get it using OPP tables.

-- 
viresh

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