From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Rutland Subject: Re: [PATCH] ARM: architected timers: allow dt based discovery using clocksource_of_init Date: Wed, 30 Jan 2013 17:19:44 +0000 Message-ID: <20130130171930.GA23801@e106331-lin.cambridge.arm.com> References: <1358731326-2979-1-git-send-email-thomas.abraham@linaro.org> <50FD7904.1070201@wwwdotorg.org> <20130122110456.GC18876@e106331-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130122110456.GC18876@e106331-lin.cambridge.arm.com> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Thomas Abraham Cc: "johnstul@us.ibm.com" , "devicetree-discuss@lists.ozlabs.org" , "swarren@nvidia.com" , "linux-arm-kernel@lists.infradead.org" , "rob.herring@calxeda.com" List-Id: devicetree@vger.kernel.org Thomas, On Tue, Jan 22, 2013 at 11:04:56AM +0000, Mark Rutland wrote: > On Mon, Jan 21, 2013 at 06:30:47PM +0000, Thomas Abraham wrote: > > Hi Stephen, > > > > On 21 January 2013 09:21, Stephen Warren wrote: > > > On 01/20/2013 06:22 PM, Thomas Abraham wrote: > > >> Add an entry in __clksrc_of_table so that ARMv7 architected timer is > > >> discoverable using call to clocksource_of_init. > > > > > >> diff --git a/arch/arm/kernel/arch_timer.c b/arch/arm/kernel/arch_timer.c > > > > > >> +#ifdef CONFIG_CLKSRC_OF > > >> +CLOCKSOURCE_OF_DECLARE(armv7_timer, "arm,armv7-timer", arch_timer_of_register) > > >> +#endif > > > > > > I wonder if we shouldn't enhance include/linux/clocksource.h to define > > > CLOCKSOURCE_OF_DECLARE even when !CONFIG_CLKSRC_OF; that way, drivers > > > wouldn't need that ifdef. > > > > Yes, it will be helpful to have a !CONFIG_CLKSRC_OF version of > > CLOCKSOURCE_OF_DECLARE. And can CONFIG_CLKSRC_OF be enabled by default > > for all ARM platforms? > > > > Thanks, > > Thomas. > > Thomas, > > Once the above is worked out, could you send me the updated patch with a > pointer to whichever {branch,patch}(es) I need for CLKSRC_OF? Is there any news on this? I'd like to be able to push out a branch ready for merging soon. I've also realised that platforms using of_clocksource_init won't get the architected timer registered as a sched_clock, which would seem like a loss. I'm not sure what the relative requirements are for sched_clock and clocksource, so there may be some platforms that want it and some that don't. I see for exynos5440 the architected timer is regsitered as a clock{source,_event_device}, but not as a sched_clock, and omap5 is similar, but may register dmtimer_read_sched_clock first. We can probably leave it out for now, but it's something we'll need to consider in future. Thanks, Mark.