From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Gerlach Subject: Re: [PATCH v4 03/11] ARM: OMAP2+: timer: Add suspend-resume callbacks for clkevent device Date: Tue, 15 Jul 2014 14:10:55 -0500 Message-ID: <53C57CBF.2090507@ti.com> References: <1405047349-15101-1-git-send-email-d-gerlach@ti.com> <1405047349-15101-4-git-send-email-d-gerlach@ti.com> <20140714111536.GC20068@atomide.com> <53C3EB1F.2010109@ti.com> <53C4166F.1050003@ti.com> <20140715064807.GJ20068@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from bear.ext.ti.com ([192.94.94.41]:41304 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932850AbaGOTLZ (ORCPT ); Tue, 15 Jul 2014 15:11:25 -0400 In-Reply-To: <20140715064807.GJ20068@atomide.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Tony Lindgren Cc: Santosh Shilimkar , linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, Paul Walmsley , Kevin Hilman , Tero Kristo , Nishanth Menon , Russ Dill , Daniel Mack , Suman Anna , Benoit Cousson , Vaibhav Bedia On 07/15/2014 01:48 AM, Tony Lindgren wrote: > * Dave Gerlach [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 [140710 19:59]: >>>>> From: Vaibhav Bedia >>>>> >>>>> 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 >>>>> Signed-off-by: Dave Gerlach >>>>> --- >>>>> 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. Ok to both of the above, I definitely like your suggestion better. Regards, Dave > >>>>> + 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 >