* Dave Gerlach <d-gerlach@xxxxxx> [140714 10:44]: > Santosh, Tony, > > On 07/14/2014 09:37 AM, Santosh Shilimkar wrote: > >On Monday 14 July 2014 07:15 AM, Tony Lindgren wrote: > >>* Dave Gerlach <d-gerlach@xxxxxx> [140710 19:59]: > >>>From: Vaibhav Bedia <vaibhav.bedia@xxxxxx> > >>> > >>>OMAP timer code registers two timers - one as clocksource > >>>and one as clockevent. Since AM33XX has only one usable timer > >>>in the WKUP domain 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> > >>>Signed-off-by: Dave Gerlach <d-gerlach@xxxxxx> > >>>--- > >>>v3->v4: > >>> Only use for am33xx soc now. > >>> > >>> arch/arm/mach-omap2/timer.c | 28 ++++++++++++++++++++++++++++ > >>> 1 file changed, 28 insertions(+) > >>> > >>>diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c > >>>index 43d03fb..6fc1748 100644 > >>>--- a/arch/arm/mach-omap2/timer.c > >>>+++ b/arch/arm/mach-omap2/timer.c > >>>@@ -128,6 +128,29 @@ static void omap2_gp_timer_set_mode(enum clock_event_mode mode, > >>> } > >>> } > >>> > >>>+static void omap_clkevt_suspend(struct clock_event_device *unused) > >>>+{ > >>>+ struct omap_hwmod *oh; > >>>+ > >>>+ oh = omap_hwmod_lookup(clockevent_gpt.name); > >>>+ if (!oh) > >>>+ return; > >>>+ > >>>+ omap_hwmod_idle(oh); > >>>+} > >>>+ > >>>+static void omap_clkevt_resume(struct clock_event_device *unused) > >>>+{ > >>>+ struct omap_hwmod *oh; > >>>+ > >>>+ oh = omap_hwmod_lookup(clockevent_gpt.name); > >>>+ if (!oh) > >>>+ return; > >>>+ > >>>+ omap_hwmod_enable(oh); > >>>+ __omap_dm_timer_int_enable(&clkev, OMAP_TIMER_INT_OVERFLOW); > >>>+} > >>>+ > >> > >>This is going to make moving the timer code into drivers one step > >>tougher to do. And you don't need to look up the hwmod entry every > >>time, just initialize it during the init. > > Yes you are right about looking up only at init I need to change that. I > agree that this makes moving the timers harder but I'm not sure there's any > way around this. I attempted to use the omap_device layer here but there is > no device at all created here, it does not hook into the normal PM layer > through omap_device. This clock must be shut off as it sits in the > peripheral power domain and any active clock within the domain will prevent > suspend from happening, so we end up with a platform specific issue here. It > seems that the only way I can get to the clock is through the hwmod. It's best to register these kind of functions as platform_data in pdata-quirks.c auxdata. That way when this moves to live in drivers/clocksource the driver does not need to know anything about the interconnect specific registers. Also, please don't use Linux generic names here.. Maybe use omap_clkevt_idle/unidle? The linux suspend and resume hooks and runtime PM could all use these functions then. > >>>+ if (soc_is_am33xx()) { > >>>+ clockevent_gpt.suspend = omap_clkevt_suspend; > >>>+ clockevent_gpt.resume = omap_clkevt_resume; > >>>+ } > >>>+ > >> > >>Maybe try to set up things so we initialize the SoC specific > >>timer suspend and resume functions in mach-omap2/timer.c > >>in a way where eventually the device driver can easily use > >>them? > >> > >+1. I had similar comments on the previous version too. > > This was my attempt to make things specific to only am335x based on > Santosh's previous comments as last time they were populated for every > device even when unneeded. These are not standard suspend/resume handlers, > they are specific to clock event. I know there will always need to be at > least some code here for the early timer init based on previous timer > cleanup series I've seen, so perhaps I could hook it in there when the time > comes? Well just adding a minimal include/linux/platform_data/timer-omap.h to pass those function pointers to the driver should do the trick. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html