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Subject: Re: [PATCH 2/5] Implement generic time of day clocksource for
	powerpc machines.
From: john stultz <johnstul@us.ibm.com>
To: Paul Mackerras <paulus@samba.org>
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Date: Thu, 20 Sep 2007 09:35:10 -0700
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Cc: Realtime Kernel <linux-rt-users@vger.kernel.org>,
	Daniel Walker <dwalker@mvista.com>,
	Thomas Gleixner <tglx@linutronix.de>, linuxppc-dev@ozlabs.org
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On Thu, 2007-09-20 at 10:52 +1000, Paul Mackerras wrote:
> Daniel Walker writes:
> 
> > If you switch to the rtc do the shift and mult need to change?
> 
> You can't switch; any given CPU chip will have either the RTC or the
> timebase but not both.

I think what Daniel is pointing out is that the clocksource read
function isn't the place for the __USE_RTC() conditional. 

It would likely be better instead of the timebase clocksource managing
multiple type of hardware (timebase and RTC), to have a separate simple
RTC clocksource, and then conditionally register one or the other at
init time.

thanks
-john