Messages in this thread | | | Date | Wed, 16 Apr 2014 09:45:43 -0500 | Subject | Re: [PATCH 04/12] clocksource: Sched clock source for Versatile Express | From | Rob Herring <> |
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On Wed, Apr 16, 2014 at 9:22 AM, Pawel Moll <pawel.moll@arm.com> wrote: > Hi Rob, > > Thanks for reminding me about this stuff. I'll get around and re-spin > the series this week. >
[snip]
>> > + setup_sched_clock(vexpress_sys_24mhz_read, 32, 24000000); >> >> This frequency should come from a DT clock binding. You will have to >> fallback to 24MHz for backwards compatibility though. > > I don't see why would it go to the binding. You may have noticed the > register is called "SYS_24MHZ", not "SYS_RANDOMCLOCK". The driver > *knows* what the frequency is.
A 24MHz clock is fed to this h/w block to be used by the counter in the block. The DT should describe that.
> >> > +} >> >> Wouldn't this code work for Versatile and Realview ARM reference >> boards? Even the register offset is the same. >> >> > +CLOCKSOURCE_OF_DECLARE(vexpress, "arm,vexpress-sysreg", >> > + vexpress_sched_clock_init); > > I guess it would, yes. The sysregs are annoyingly similar and different > at the same time. > > One could of course try to come up with a "generic mmio clock source" > binding, taking the frequency as a property, but don't count on me doing > this... ;-)
I'm not asking for that. Just take care of all ARM Ltd boards which have the exact same 24MHz counter at offset 0x5C.
Rob
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