Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751464Ab3HBLU5 (ORCPT ); Fri, 2 Aug 2013 07:20:57 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:63086 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750936Ab3HBLU4 (ORCPT ); Fri, 2 Aug 2013 07:20:56 -0400 Date: Fri, 2 Aug 2013 12:20:18 +0100 From: Mark Rutland To: Gururaja Hebbar Cc: "davinci-linux-open-source@linux.davincidsp.com" , "tony@atomide.com" , "benoit.cousson@gmail.com" , Sekhar Nori , "linux-kernel@vger.kernel.org" , "vaibhav.bedia@ti.com" , "benoit.cousson@linaro.org" , "linux-omap@vger.kernel.org" , "devicetree-discuss@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [Patch V2 4/4] ARM: dts: AM33XX: update rtc node compatibility Message-ID: <20130802112018.GI2884@e106331-lin.cambridge.arm.com> References: <1372841225-18813-1-git-send-email-gururaja.hebbar@ti.com> <1372841225-18813-5-git-send-email-gururaja.hebbar@ti.com> <51F749B0.7020802@ti.com> <20130730145501.GA29859@e106331-lin.cambridge.arm.com> <51F7E7FA.3080702@ti.com> <20130801170537.GF8095@e106331-lin.cambridge.arm.com> <51FB92F8.9020801@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51FB92F8.9020801@ti.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3556 Lines: 103 On Fri, Aug 02, 2013 at 12:07:36PM +0100, Gururaja Hebbar wrote: > On 8/1/2013 10:35 PM, Mark Rutland wrote: > > On Tue, Jul 30, 2013 at 05:21:14PM +0100, Sekhar Nori wrote: > >> On 7/30/2013 8:25 PM, Mark Rutland wrote: > >>> On Tue, Jul 30, 2013 at 06:05:52AM +0100, Gururaja Hebbar wrote: > >>>> Hi, > >>>> > >>>> On 7/3/2013 2:17 PM, Hebbar Gururaja wrote: > >>>>> Since AM33xx RTC IP has RTC_IRQWAKEEN to support Alarm Wake-up. > >>>>> > >>>>> Update the rtc compatible property to "ti,am3352-rtc" to enable handling > >>>>> of this feature inside rtc-omap driver. > >>>> > >>>> The other 2 rtc driver related patches have been pulled up. If you have > >>>> no comments, can you please pull this up. > >>>> > >>>> Regards > >>>> Gururaja > >>>> > >>>>> > >>>>> Signed-off-by: Hebbar Gururaja > >>>>> --- > >>>>> :100644 100644 77aa1b0... dde180a... M arch/arm/boot/dts/am33xx.dtsi > >>>>> arch/arm/boot/dts/am33xx.dtsi | 2 +- > >>>>> 1 file changed, 1 insertion(+), 1 deletion(-) > >>>>> > >>>>> diff --git a/arch/arm/boot/dts/am33xx.dtsi b/arch/arm/boot/dts/am33xx.dtsi > >>>>> index 77aa1b0..dde180a 100644 > >>>>> --- a/arch/arm/boot/dts/am33xx.dtsi > >>>>> +++ b/arch/arm/boot/dts/am33xx.dtsi > >>>>> @@ -297,7 +297,7 @@ > >>>>> }; > >>>>> > >>>>> rtc@44e3e000 { > >>>>> - compatible = "ti,da830-rtc"; > >>>>> + compatible = "ti,am3352-rtc"; > >>> > >>> Given that this is backwards compatible with the old binding, it would > >>> be nicer to have this as: > >>> > >>> compatible = "ti,am3352-rtc", "ti,da830-rtc"; > >>> > >>> We must get into the habit of changing dts files in a > >>> backwards-compatible fashion. > >> > >> Right, I suggested this when v1 was posted. It turns out the current > >> kernel does not handle the compatilble list correctly and the string > >> selected actually depends on the order in which it appears in match > >> table in driver instead. > >> > >> I saw there were patches being discussed to fix this issue, but until > >> that is fixed, we cannot really use what you (and I before) suggested. > > > > A temporary solution would be to list the "ti,am3352-rtc" first in the > > of_match_table kernel-side. > > If above method is followed, then it would cause trouble on davinci > platform because this rtc-omap driver is also used by Davinci platform. > On davinci Plaform the driver would match with "ti,am3352-rtc" for > compatible. Sorry, I don't follow. Does the davinci dt have "ti,am3352-rtc" in it's compatible string list? If so, and it's not compatible, the dts is wrong. If not, then we won't use the behaviour specific to "ti,am3352-rtc", and there's no problem. What trouble would this cause? Thanks, Mark. > > Regards > Gururaja > > > That way you can keep the old compatible > > string in the dts compatible list, and maintain backwards compatibilty > > with older kernels. > > > > Later if the way Linux matches compatible strings is changed, this > > shouldn't break the probe order, and the of_match_table order could be > > changed. > > > > Have I missed something? > > > > Thanks, > > Mark. > > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/