[PATCH v2] ARM: davinci: convert to clockevents_config_and_register

[u.kleine-koenig@pengutronix.de (Uwe Kleine-König)]

Hello,

On Wed, Oct 16, 2013 at 08:49:17AM +0530, Sekhar Nori wrote:
> On Sunday 13 October 2013 02:06 PM, Uwe Kleine-K?nig wrote:
> > clockevents_config_and_register is superior compared to setting
> > shift/mult and {min,max}_delta_ns by hand.
> > 
> > Tested-by: Prabhakar Lad <prabhakar.csengg@gmail.com>
> > Signed-off-by: Uwe Kleine-K?nig <u.kleine-koenig@pengutronix.de>
> > ---
> > Prabhakar Lad wrote:
> >> I have boot tested this patch on OMAP-L138 and tested the uptime
> >> (with min ticks set to 1), should that be enough ?
> > I don't know for sure, but I guess so. If you agree, here is an updated
> > patch.
> > 
> > Best regards
> > Uwe
> > 
> > 
> >  arch/arm/mach-davinci/time.c | 9 ++-------
> >  1 file changed, 2 insertions(+), 7 deletions(-)
> > 
> > diff --git a/arch/arm/mach-davinci/time.c b/arch/arm/mach-davinci/time.c
> > index 7a55b5c..29a1a5d 100644
> > --- a/arch/arm/mach-davinci/time.c
> > +++ b/arch/arm/mach-davinci/time.c
> > @@ -331,7 +331,6 @@ static void davinci_set_mode(enum clock_event_mode mode,
> >  
> >  static struct clock_event_device clockevent_davinci = {
> >  	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
> > -	.shift		= 32,
> >  	.set_next_event	= davinci_set_next_event,
> >  	.set_mode	= davinci_set_mode,
> >  };
> > @@ -397,14 +396,10 @@ void __init davinci_timer_init(void)
> >  
> >  	/* setup clockevent */
> >  	clockevent_davinci.name = id_to_name[timers[TID_CLOCKEVENT].id];
> > -	clockevent_davinci.mult = div_sc(davinci_clock_tick_rate, NSEC_PER_SEC,
> > -					 clockevent_davinci.shift);
> > -	clockevent_davinci.max_delta_ns =
> > -		clockevent_delta2ns(0xfffffffe, &clockevent_davinci);
> > -	clockevent_davinci.min_delta_ns = 50000; /* 50 usec */
> >  
> >  	clockevent_davinci.cpumask = cpumask_of(0);
> > -	clockevents_register_device(&clockevent_davinci);
> > +	clockevents_config_and_register(&clockevent_davinci,
> > +		davinci_clock_tick_rate, 1, 0xfffffffe);
> 
> checkpatch --strict complains about alignment of line break. Fixed locally.
I used the same style as in other places in that file.

Another thought that came to me is that it's probably worth mentioning
that the min_delta_ns is changed from 50 usec to 1 hw tick. Something
like:

	Note that the minimum delay is changed from 50 us to 1 hw tick
	(which corresponds to 42 ns assuming a 24 MHz clock). It's
	expected that the old value was miscalculated.

That would be interesting in case that the patch results in regressions.

Best regards
Uwe


-- 
Pengutronix e.K.                           | Uwe Kleine-K?nig            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |