linux-kernel - Re: [PATCH 04/12] clocksource: Sched clock source for Versatile Express

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Date:	Fri, 2 May 2014 15:14:34 -0700
From:	Linus Walleij <linus.walleij@...aro.org>
To:	Pawel Moll <pawel.moll@....com>
Cc:	"arm@...nel.org" <arm@...nel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Daniel Lezcano <daniel.lezcano@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH 04/12] clocksource: Sched clock source for Versatile Express

On Tue, Feb 11, 2014 at 9:10 AM, Pawel Moll <pawel.moll@....com> wrote:

> This patch adds a trival sched clock source using free
> running, 24MHz clocked counter present in the ARM Ltd.
> Versatile Express platform's System Registers block.
>
> This code replaces the call in the VE machine code.
>
> Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Signed-off-by: Pawel Moll <pawel.moll@....com>

Even the Integrator is very similar, albeit using register 0x28 instead
of register 0x5c. cd commit
a79528e9d849803457b6235ddb1a1cfd4e11c6cd

It's one of these things where writing a device driver results in
more code than just registering this counter with the sched_clock
guts :-/

Getting the clock from the DT gives this nice feeling of having it all
complete, and sched_clock cannot really change frequency anyway
so I'm happy with this thing.

I'll augment it for Integrator when/if I find time.

Yours,
Linus Walleij
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