Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer

["Shilimkar, Santosh" <santosh.shilimkar@ti.com>]

On Wed, Mar 28, 2012 at 7:46 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
> On Wed, Mar 21, 2012 at 19:30:01, Shilimkar, Santosh wrote:
>> On Wed, Mar 21, 2012 at 5:12 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:
>> > On Mon, Mar 19, 2012 at 17:45:32, Shilimkar, Santosh wrote:
>> >> On Monday 19 March 2012 05:14 PM, Ming Lei wrote:
>> >> > On Mon, Mar 19, 2012 at 7:11 PM, Hiremath, Vaibhav <hvaibhav@ti.com> wrote:

[...]

>
>> Btw, if you need PM, how are you going to use GPTIMER
>> as a clocksource. Note sys-clock is generally stopped in
>> low power states. So that leaves you option with using
>> gptimer with 32K clock and in that case, GPTIMER
>> is not a better clock-source compare to 32K sync timer
>> and so shouldn't be the rating.
>>
>
> AM33xx has GPTIMER1 in wakeup domain, so that we are already using as a
> Clocksource, without any issues.
>
GPTIMER1 is in wakeup domain on OMAP too but that doesn't
solve the issue I am talking. Once the sysclock is stopped, GPTIMER
can't tick anymore even if it is in wakeup domain.

The only way it will work is using always running 32KHz clock as
the clock input to GPT1. And then the end result is the accuracy
of GPTIMER = sync 32K timer. So they are of same rating.

Hope it is clear now.

Regards
Santosh