From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH 11/15] ARM: OMAP: timer: Interchange clksrc and clkevt for AM33XX Date: Sat, 03 Nov 2012 13:04:30 +0000 Message-ID: <5095165E.10403@deeprootsystems.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wi0-f178.google.com ([209.85.212.178]:51063 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932534Ab2KCNEb (ORCPT ); Sat, 3 Nov 2012 09:04:31 -0400 Received: by mail-wi0-f178.google.com with SMTP id hr7so1969274wib.1 for ; Sat, 03 Nov 2012 06:04:29 -0700 (PDT) In-Reply-To: Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Bedia, Vaibhav" Cc: "linux-arm-kernel@lists.infradead.org" , "linux-omap@vger.kernel.org" , "paul@pwsan.com" , "Cousson, Benoit" , "tony@atomide.com" 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.