Re: [RFC] [PATCH] ARM: OMAP1: Add clocksource driver for OMAP1

[David Brownell <david-b@pacbell.net>]

On Thursday 30 November 2006 1:49 pm, Woodruff, Richard wrote:

> The only thing about using two timers which made me think twice was what
> happens during retention/off mode sleeps.  This forces you to add a
> little code to account for clock switching (sys_clk to 32KHz) at the
> periodic timer, and adding knowledge about the stopped free running one.
> 
> Having a single GPT1 timer active which is wake up capable makes it all
> simpler.  I did ask for a 2nd timer in the wake up domain and that
> actually happened in 3430.
> 
> ... Actually, I would guess many use cases would be find using a CORE
> domain timer and setting the target for the system sleep to be
> 'request-idle' this removes any worry about the clock transition as the
> functional clock of the CORE timer can run and its ISR can issue a PRCM
> wake up.  This is the state you want to generally go into anyway in an
> idle routine if you any kind of peripheral activity.

Not that I have time to look into OMAP2 low power modes ... but I'd thought
the preferred solution when low power was a concern would be to use the
32k timers not the general purpose ones, and that you more or less said
just that.  Did I translate that correctly?  :)