[PATCH] ARM: clps711x: convert to clocksource/clockevents

On Thu, 30 Aug 2012 10:21:44 -0700
Linus Walleij [off-list ref] wrote:

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This converts the ageing clps711x timer driver to the modern
clocksource/clockevent API.

The patch does not account for the changes that I sent to the mailing list
recently, where I did support different clock frequencies for the processor.

No problem, I can rebase on top of your patches as soon as you
submit them to ARM SoC so I can see them in linux-next.

Patches have already been sent to the mailing list, and as far I understand,
these patches are awaiting approval from Arnd.

...

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The patch uses a second timer, which does not allow its use for other purposes, 

What does this mean? Reading the datasheet it didn't say anything about
this timer being dedicated to something else.
I am using TC1D as clocksource and TC2D as clockevent, repurposing
it from the previous use as singe time source.
Doing "git grep TC1D" I cannot see any code in the kernel making use
of this timer?

These timers are only two in the processor and I just want to say that the second
timer CAN be used for other purposes, such as I use. In the kernel of the second
timer is really not used.

I could think of things like the boot loader or firmware setting it up
to run in free-running mode ... in that case we use
it as clocksource without initialization as long as we know what
frequency it's running on.

Not understand this...

As far as I could understand from the datasheet there is really
no way to actually disable these timers, so they always run
anyway?

Yes. We can only enable/disable IRQ for the timers, switch clock source and mode.

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I have also tried to do something like this without using additional processor
resources, but not yet brought to the finish line yet.

OK do you think you can switch the clps71x over to generic time and
clockevents inspired by this patch or so?

Unfortunately, I'm leaving tomorrow for a little while so I can not check anything
or try to do better, but the idea of ??switching to a new API I like. Upon arrival back,
I'll try to make a similar using only one timer or use the CLOCKSOURCE/CLOCKEVENTS
resources to generate intervals necessary for me.

-- 
Alexander Shiyan [off-list ref]