linux-kernel - Re: [PATCH v3 0/5] clocksource: sun5i: Support parent clock rate changes

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Date:	Fri, 20 Mar 2015 15:04:28 +0100
From:	Daniel Lezcano <daniel.lezcano@...aro.org>
To:	Maxime Ripard <maxime.ripard@...e-electrons.com>,
	Thomas Gleixner <tglx@...utronix.de>
CC:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v3 0/5] clocksource: sun5i: Support parent clock rate
 changes

On 03/19/2015 11:53 PM, Maxime Ripard wrote:
> Hi Daniel,
>
> On Thu, Mar 05, 2015 at 11:20:51AM +0100, Maxime Ripard wrote:
>> Hi,
>>
>> The Allwinner HS timers have the AHB clock as their parent
>> clock. Since this clock is shared with other devices, we could very
>> well have another driver requesting a rate change of that clock,
>> making our timer change frequency at the same time.
>>
>> This is especially true on the A31, where the DMA controller needs to
>> do such a rate change, making the HS timer unreliable at the time on
>> the A31.
>>
>> This serie makes some cleanups and implements clock notifiers to be
>> able to reflect such rate changes and make sure that the timer is
>> always working.
>>
>> Maxime
>>
>> Changes from v2:
>>    - Rebased on top of v4.0-rc1
>>    - Removed the local_irq_save/restore around clockevents_update_freq
>>
>> Changes from v1:
>>    - Changed the interrupt name to its previous value
>>
>> Maxime Ripard (5):
>>    clocksource: sun5i: Switch to request_irq
>>    clocksource: sun5i: Use of_io_request_and_map
>>    clocksource: sun5i: Remove sched_clock
>>    clocksource: sun5i: Refactor the current code
>>    clocksource: sun5i: Add clock notifiers
>
> Have these patches been merged?
>
> If not, it woulde be great if the third one ("clocksource: sun5i:
> Remove sched_clock") was merged for 4.0.
>
> The sched_clock we use on some system is this timer's, and since we
> started using cpufreq, the cpu clock (that is one of the timer's clock
> indirect parent) now changes, along with the actual sched_clock rate.
>
> We can safely remove the sched_clock on those systems, since we have
> other reliable sched_clock in the system.

Ok, I applied the patch for v4.0-rc5 but I had to fix a conflict and 
change the changelog.

Mind to test it works ?

git.linaro.org/people/daniel.lezcano/linux.git clockevents/v4.0-rc4

Thanks
   -- Daniel

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