Subject: [RFC v2 12/18] ARM: OMAP2+: timer: Add suspend-resume callbacks for clockevent device

From: [email-masked] (Santosh Shilimkar)
Date: Tue, 8 Jan 2013 20:45:10 +0530

On Monday 31 December 2012 06:37 PM, Vaibhav Bedia wrote:
> The current OMAP timer code registers two timers -
> one as clocksource and one as clockevent.
> AM33XX has only one usable timer in the WKUP domain
> so one of the timers needs suspend-resume support
> to restore the configuration to pre-suspend state.
>
> commit adc78e6 (timekeeping: Add suspend and resume
> of clock event devices) introduced .suspend and .resume
> callbacks for clock event devices. Leverages these
> callbacks to have AM33XX clockevent timer which is
> in not in WKUP domain to behave properly across system
> suspend.
>
> Signed-off-by: Vaibhav Bedia <[email-masked]>
> Cc: Santosh Shilimkar <[email-masked]>
> Cc: Benoit Cousson <[email-masked]>
> Cc: Paul Walmsley <[email-masked]>
> Cc: Kevin Hilman <[email-masked]>
> Cc: Vaibhav Hiremath <[email-masked]>
> Cc: Jon Hunter <[email-masked]>
> ---
> v1->v2:
> 	Get rid of harcoded timer id.
> 	Note: since a platform device is not created for these timer
> 	instances and because there's very minimal change needed for
> 	restarting the timer a full blown context save and restore
> 	has been skipped.
>
>   arch/arm/mach-omap2/timer.c |   33 +++++++++++++++++++++++++++++++++
>   1 files changed, 33 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
> index 691aa67..38f9cbc 100644
> --- a/arch/arm/mach-omap2/timer.c
> +++ b/arch/arm/mach-omap2/timer.c
> @@ -128,6 +128,36 @@ static void omap2_gp_timer_set_mode(enum clock_event_mode mode,
>   	}
>   }
>
> +static void omap_clkevt_suspend(struct clock_event_device *unused)
> +{
> +	char name[10];
> +	struct omap_hwmod *oh;
> +
> +	sprintf(name, "timer%d", clkev.id);
> +	oh = omap_hwmod_lookup(name);
> +	if (!oh)
> +		return;
> +
> +	__omap_dm_timer_stop(&clkev, 1, clkev.rate);
> +	omap_hwmod_idle(oh);
> +}
> +
> +static void omap_clkevt_resume(struct clock_event_device *unused)
> +{
> +	char name[10];
> +	struct omap_hwmod *oh;
> +
> +	sprintf(name, "timer%d", clkev.id);
> +	oh = omap_hwmod_lookup(name);
> +	if (!oh)
> +		return;
> +
> +	omap_hwmod_enable(oh);
> +	__omap_dm_timer_load_start(&clkev,
> +			OMAP_TIMER_CTRL_ST | OMAP_TIMER_CTRL_AR, 0, 1);
> +	__omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW);
> +}
> +
Am still bit uncomfortable with direct hwmod usage in the suspend/resmue
hooks.

Jon, Any alternatives you can think of ?

Regards,
Santosh