From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH v12 4/9] OMAP2+: dmtimer: convert to platform devices Date: Fri, 11 Mar 2011 11:13:24 -0800 Message-ID: <20110311191324.GE10079@atomide.com> References: <1299627948-20040-1-git-send-email-tarun.kanti@ti.com> <1299627948-20040-5-git-send-email-tarun.kanti@ti.com> <87oc5ifu12.fsf@ti.com> <5A47E75E594F054BAF48C5E4FC4B92AB037A4DD948@dbde02.ent.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mho-02-ewr.mailhop.org ([204.13.248.72]:11359 "EHLO mho-02-ewr.mailhop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753851Ab1CKTNZ (ORCPT ); Fri, 11 Mar 2011 14:13:25 -0500 Content-Disposition: inline In-Reply-To: <5A47E75E594F054BAF48C5E4FC4B92AB037A4DD948@dbde02.ent.ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "DebBarma, Tarun Kanti" Cc: "Hilman, Kevin" , "linux-omap@vger.kernel.org" , "Gopinath, Thara" * DebBarma, Tarun Kanti [110310 20:18]: > > From: Hilman, Kevin > > > > I guess Tony has the final say here, but personally, I don't really like > > the special treatment of a system timer, unless it is an init-time only > > special treatment. Since we now have dynamically configurable > > clocksources, the concept of a system timer doesn't really exist (except > > for in early boot.) At any time during runtime, we could dynamically > > switch the clocksource to a different timer device. At this point, one > > would expect runtime PM for the previous timer to kick in and idle the > > timer. That cannot happen with this approach. > > I am open to suggestions. There's no need to dynamically change the clocksource. We can to set up things so we have a system timer running with minimal code and faster clock rate. Then we can use a separate timer with the 32KiHZ source just to provide wake-up events for idle modes. And this second wake-up timer can be just a regular device driver. The system timer code needs to be fast. And I don't want to add any dependencies to anything except clock framework. Like I've said, the rest of the timers can be just a regular device driver. I'll post some patches after the merge window for the system timer related code. Regards, Tony