Re: [PATCH 2/2] cpufreq: mediatek: Add MT8173 cpufreq driver

From	Pi-Cheng Chen <pi-cheng.chen@linaro.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/2] cpufreq: mediatek: Add MT8173 cpufreq driver
Date	2015-06-24 11:20 +0200
Message-ID	<pEP0B-5yL-1@gated-at.bofh.it> (permalink)
References	(2 earlier) <pE8oG-2AP-13@gated-at.bofh.it> <pEyj9-6AI-41@gated-at.bofh.it> <pEHcJ-2vM-7@gated-at.bofh.it> <pEOxC-4Lc-37@gated-at.bofh.it> <pEOHh-4WG-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Wed, Jun 24, 2015 at 4:56 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 24-06-15, 16:44, Pi-Cheng Chen wrote:
>> One reason to put those initialization and resource allocation in probe is
>> that it's easier to handle the return value -PROBE_DEFER from clock
>> and regulator framework when trying to get clocks and regulators
>> consumed by cpufreq driver.
>
> This is the sequence of events if you move these things to ->init().
>
> - your driver's probe()
>   -> cpufreq_register_driver()
>     -> init()
>       -> clk/reg get, failed, return -EPROBE_DEFER
>
> And the failure here will be propagated to probe(). So, it should
> work IMHO.

I will try it.

>
>> The other reason is when the whole system is resuming from suspend,
>> the other subsystem e.g. i2c on which cpufreq driver depends might not
>> ready yet during cpufreq driver initialization. In this case, the cpufreq
>> driver will be blocked when trying to get resources e.g. regulator on i2c
>> bus, and the whole system will stuck for seconds.
>
> That's something else you must investigate on. This dependency should
> be resolved in some other way, I thought DT might have taken care of
> such dependencies.

I will check if it could be solved in some other way.
Thanks.

Pi-Cheng

>
> --
> viresh
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Re: [PATCH 2/2] cpufreq: mediatek: Add MT8173 cpufreq driver Viresh Kumar <viresh.kumar@linaro.org> - 2015-06-24 03:00 +0200
  Re: [PATCH 2/2] cpufreq: mediatek: Add MT8173 cpufreq driver Pi-Cheng Chen <pi-cheng.chen@linaro.org> - 2015-06-24 10:50 +0200
    Re: [PATCH 2/2] cpufreq: mediatek: Add MT8173 cpufreq driver Viresh Kumar <viresh.kumar@linaro.org> - 2015-06-24 11:00 +0200
      Re: [PATCH 2/2] cpufreq: mediatek: Add MT8173 cpufreq driver Pi-Cheng Chen <pi-cheng.chen@linaro.org> - 2015-06-24 11:20 +0200

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