On 12/31/2012 07:07 AM, 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 <vaibhav.bedia@xxxxxx>
> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> Cc: Benoit Cousson <b-cousson@xxxxxx>
> Cc: Paul Walmsley <paul@xxxxxxxxx>
> Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx>
> Cc: Vaibhav Hiremath <hvaibhav@xxxxxx>
> Cc: Jon Hunter <jon-hunter@xxxxxx>
> ---
> 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);
I am not sure you need to call __omap_dm_timer_stop() here. This should
have already been called as timekeeping_suspend() will call
omap2_gp_timer_set_mode() to shutdown the timer.
> + 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);
Similarly here, I am not sure these __omap_dm_timer_xxxx calls are needed.
> +}
> +
> static struct clock_event_device clockevent_gpt = {
> .name = "gp_timer",
> .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
> @@ -135,6 +165,8 @@ static struct clock_event_device clockevent_gpt = {
> .rating = 300,
> .set_next_event = omap2_gp_timer_set_next_event,
> .set_mode = omap2_gp_timer_set_mode,
> + .suspend = omap_clkevt_suspend,
> + .resume = omap_clkevt_resume,
AFAIK, this is only applicable for AM335x devices and so should not be
added for all.
> };
>
> static struct property device_disabled = {
> @@ -323,6 +355,7 @@ static void __init omap2_gp_clockevent_init(int gptimer_id,
> int res;
>
> clkev.errata = omap_dm_timer_get_errata();
> + clkev.id = gptimer_id;
We should not use gptimer_id anymore. This will go away once the
migration to dev-tree is completed. You may be better off storing the
oh_name in the clock_event_device name field and passing to the
suspend/resume handlers.
Cheers
Jon
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