From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Grinberg Subject: Re: [PATCH] ARM: OMAP2+: timer: remove CONFIG_OMAP_32K_TIMER Date: Tue, 13 Nov 2012 11:14:12 +0200 Message-ID: <50A20F64.4010902@compulab.co.il> References: <1352299344-8011-1-git-send-email-grinberg@compulab.co.il> <509AD478.1050904@ti.com> <509B666F.6080507@compulab.co.il> <509BFFDF.9040605@ti.com> <79CD15C6BA57404B839C016229A409A83EB68799@DBDE01.ent.ti.com> <509C050C.6010201@ti.com> <509F8BEF.90008@compulab.co.il> <50A14AD1.4070704@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from softlayer.compulab.co.il ([50.23.254.55]:58134 "EHLO compulab.co.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753979Ab2KMJOS (ORCPT ); Tue, 13 Nov 2012 04:14:18 -0500 In-Reply-To: <50A14AD1.4070704@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Jon Hunter Cc: "Hiremath, Vaibhav" , Tony Lindgren , "Hilman, Kevin" , Paul Walmsley , "linux-omap@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "Shilimkar, Santosh" On 11/12/12 21:15, Jon Hunter wrote: > > On 11/11/2012 05:28 AM, Igor Grinberg wrote: >> >> >> On 11/08/12 21:16, Jon Hunter wrote: >>> >>> On 11/08/2012 12:59 PM, Hiremath, Vaibhav wrote: >>>> On Fri, Nov 09, 2012 at 00:24:23, Hunter, Jon wrote: >>>>> >>>>> On 11/08/2012 01:59 AM, Igor Grinberg wrote: >>>>> >>>>> [snip] >>>>> >>>>>> There is no reliable way to determine which source should be used in runtime >>>>>> for boards that do not have the 32k oscillator wired. >>>>> >>>>> So thinking about this some more and given that we are moving away from >>>>> board files, if a board does not provide a 32kHz clock source, then this >>>>> should be reflected in the device-tree source file for that board. >>>>> Hence, at boot time we should be able to determine if a 32kHz clock >>>>> source can be used. >>>>> >>>> >>>> Let me feed some more thoughts here :) >>>> >>>> The way it is being detected currently is based on timer idle status bit. >>>> I am worried that, this is the only option we have. >>> >>> Why not use device-tree to indicate the presence of a 32k clock source? >>> This seems like a board level configuration and so device-tree seems to >>> be the perfect place for this IMO. >> >> Well, that is what my commit message says... > > Sorry, but that was not clear to me from whats in the commit message. >>From the commit message: "1) Timer structures and initialization functions are named by the platform name and the clock source in use. The decision which timer is used is done statically from the machine_desc structure. In the future it should come from DT." The last sentence has it. The transition to DT is not immediate and we can't (still) neglect the non-DT setups. > > Should we be doing this now instead of adding all these static timer > init functions? I don't see this as "adding ...", I see this as expanding the setup which was previously hidden by the CONFIG_OMAP_32K_TIMER option. > > Are there any boards today (supported in the kernel that is), that don't > support a 32k? Yes, starting from revision 1.2, CM-T3517 does not have the 32k. [...] -- Regards, Igor. From mboxrd@z Thu Jan 1 00:00:00 1970 From: grinberg@compulab.co.il (Igor Grinberg) Date: Tue, 13 Nov 2012 11:14:12 +0200 Subject: [PATCH] ARM: OMAP2+: timer: remove CONFIG_OMAP_32K_TIMER In-Reply-To: <50A14AD1.4070704@ti.com> References: <1352299344-8011-1-git-send-email-grinberg@compulab.co.il> <509AD478.1050904@ti.com> <509B666F.6080507@compulab.co.il> <509BFFDF.9040605@ti.com> <79CD15C6BA57404B839C016229A409A83EB68799@DBDE01.ent.ti.com> <509C050C.6010201@ti.com> <509F8BEF.90008@compulab.co.il> <50A14AD1.4070704@ti.com> Message-ID: <50A20F64.4010902@compulab.co.il> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11/12/12 21:15, Jon Hunter wrote: > > On 11/11/2012 05:28 AM, Igor Grinberg wrote: >> >> >> On 11/08/12 21:16, Jon Hunter wrote: >>> >>> On 11/08/2012 12:59 PM, Hiremath, Vaibhav wrote: >>>> On Fri, Nov 09, 2012 at 00:24:23, Hunter, Jon wrote: >>>>> >>>>> On 11/08/2012 01:59 AM, Igor Grinberg wrote: >>>>> >>>>> [snip] >>>>> >>>>>> There is no reliable way to determine which source should be used in runtime >>>>>> for boards that do not have the 32k oscillator wired. >>>>> >>>>> So thinking about this some more and given that we are moving away from >>>>> board files, if a board does not provide a 32kHz clock source, then this >>>>> should be reflected in the device-tree source file for that board. >>>>> Hence, at boot time we should be able to determine if a 32kHz clock >>>>> source can be used. >>>>> >>>> >>>> Let me feed some more thoughts here :) >>>> >>>> The way it is being detected currently is based on timer idle status bit. >>>> I am worried that, this is the only option we have. >>> >>> Why not use device-tree to indicate the presence of a 32k clock source? >>> This seems like a board level configuration and so device-tree seems to >>> be the perfect place for this IMO. >> >> Well, that is what my commit message says... > > Sorry, but that was not clear to me from whats in the commit message. >>From the commit message: "1) Timer structures and initialization functions are named by the platform name and the clock source in use. The decision which timer is used is done statically from the machine_desc structure. In the future it should come from DT." The last sentence has it. The transition to DT is not immediate and we can't (still) neglect the non-DT setups. > > Should we be doing this now instead of adding all these static timer > init functions? I don't see this as "adding ...", I see this as expanding the setup which was previously hidden by the CONFIG_OMAP_32K_TIMER option. > > Are there any boards today (supported in the kernel that is), that don't > support a 32k? Yes, starting from revision 1.2, CM-T3517 does not have the 32k. [...] -- Regards, Igor.