From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@deeprootsystems.com (Kevin Hilman) Date: Sat, 03 Nov 2012 13:04:30 +0000 Subject: [PATCH 11/15] ARM: OMAP: timer: Interchange clksrc and clkevt for AM33XX In-Reply-To: References: <1351859566-24818-1-git-send-email-vaibhav.bedia@ti.com> <1351859566-24818-12-git-send-email-vaibhav.bedia@ti.com> <5095037A.2020503@deeprootsystems.com> Message-ID: <5095165E.10403@deeprootsystems.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org T On 11/03/2012 12:47 PM, Bedia, Vaibhav wrote: > Hi Kevin, > > On Sat, Nov 03, 2012 at 17:13:54, Kevin Hilman wrote: >> On 11/02/2012 01:32 PM, Vaibhav Bedia wrote: >>> AM33XX has only one usable timer in the WKUP domain. >>> Currently the timer instance in WKUP domain is used >>> as the clockevent and the timer in non-WKUP domain >>> as the clocksource. The timer in WKUP domain can keep >>> running in suspend from a 32K clock and hence serve >>> as the persistent clock. To enable this, interchange >>> the timers used as clocksource and clockevent for >>> AM33XX. >> >> Doesn't this also mean that you won't get timer wakeups >> in idle? Or are you keeping the domain where the clockevent is >> on during idle? >> > > The lowest idle state that we are targeting will have MPU powered > off with external memory in self-refresh mode. Peripheral domain > with the clockevent will be kept on. Is this a limitation of the hardware? or the software? Kevin P.S. I haven't yet made my way through the TRM, so I'll probably figure this out when I read it, but having this summarized in the changelog would be helpful since even after I read the TRM, I'll forget. I'm saving the TRM reading for entertainment on upcoming flight home from Linaro Connect.