From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shilimkar Subject: Re: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer Date: Tue, 10 Apr 2012 14:27:36 +0530 Message-ID: <4F83F600.4000002@ti.com> References: <79CD15C6BA57404B839C016229A409A8318461E8@DBDE01.ent.ti.com> <79CD15C6BA57404B839C016229A409A83184846A@DBDE01.ent.ti.com> <20120405095221.GC25053@n2100.arm.linux.org.uk> <79CD15C6BA57404B839C016229A409A831848621@DBDE01.ent.ti.com> <87hawxkgoi.fsf@ti.com> <79CD15C6BA57404B839C016229A409A831849432@DBDE01.ent.ti.com> <20120406180452.GB15734@atomide.com> <79CD15C6BA57404B839C016229A409A83184ABEF@DBDE01.ent.ti.com> <4F83440E.70502@ti.com> <20120410084413.GD25053@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from na3sys009aog111.obsmtp.com ([74.125.149.205]:57303 "EHLO na3sys009aog111.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754173Ab2DJI5o (ORCPT ); Tue, 10 Apr 2012 04:57:44 -0400 Received: by obbtb18 with SMTP id tb18so9394842obb.33 for ; Tue, 10 Apr 2012 01:57:43 -0700 (PDT) In-Reply-To: <20120410084413.GD25053@n2100.arm.linux.org.uk> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Russell King - ARM Linux Cc: Jon Hunter , "Hiremath, Vaibhav" , Tony Lindgren , "Hilman, Kevin" , Paul Walmsley , "Cousson, Benoit" , "marc.zyngier@arm.com" , Ming Lei , "Balbi, Felipe" , "johnstul@us.ibm.com" , "linux-omap@vger.kernel.org" , "DebBarma, Tarun Kanti" , "linux-arm-kernel@lists.infradead.org" On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote: > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote: >> True, but we would always want to use the 32k timer if CONFIG_PM is >> specified. So what I am saying is that if a device has a 32ksync timer >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a >> gptimer should never be used. > > Why? What if you want to have PM enabled, and you also want to use the > kernels high resolution timers, or you want more accurate timing than > the 30.5us tick interval of the 32k timer? You might have missed the earlier comments on the thread. High resolution GP timer(sysclk) will stop in deeper power states and hence it can't be used with PM enabled usecases. Regards Santosh From mboxrd@z Thu Jan 1 00:00:00 1970 From: santosh.shilimkar@ti.com (Santosh Shilimkar) Date: Tue, 10 Apr 2012 14:27:36 +0530 Subject: [PATCH 1/3] ARM: OMAP2+: 32k-counter: Use hwmod lookup to check presence of 32k timer In-Reply-To: <20120410084413.GD25053@n2100.arm.linux.org.uk> References: <79CD15C6BA57404B839C016229A409A8318461E8@DBDE01.ent.ti.com> <79CD15C6BA57404B839C016229A409A83184846A@DBDE01.ent.ti.com> <20120405095221.GC25053@n2100.arm.linux.org.uk> <79CD15C6BA57404B839C016229A409A831848621@DBDE01.ent.ti.com> <87hawxkgoi.fsf@ti.com> <79CD15C6BA57404B839C016229A409A831849432@DBDE01.ent.ti.com> <20120406180452.GB15734@atomide.com> <79CD15C6BA57404B839C016229A409A83184ABEF@DBDE01.ent.ti.com> <4F83440E.70502@ti.com> <20120410084413.GD25053@n2100.arm.linux.org.uk> Message-ID: <4F83F600.4000002@ti.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tuesday 10 April 2012 02:14 PM, Russell King - ARM Linux wrote: > On Mon, Apr 09, 2012 at 03:18:22PM -0500, Jon Hunter wrote: >> True, but we would always want to use the 32k timer if CONFIG_PM is >> specified. So what I am saying is that if a device has a 32ksync timer >> and CONFIG_PM is defined, we always want to use the 32ksync timer and a >> gptimer should never be used. > > Why? What if you want to have PM enabled, and you also want to use the > kernels high resolution timers, or you want more accurate timing than > the 30.5us tick interval of the 32k timer? You might have missed the earlier comments on the thread. High resolution GP timer(sysclk) will stop in deeper power states and hence it can't be used with PM enabled usecases. Regards Santosh