Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751699Ab3HBLss (ORCPT ); Fri, 2 Aug 2013 07:48:48 -0400 Received: from devils.ext.ti.com ([198.47.26.153]:51033 "EHLO devils.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751193Ab3HBLsr (ORCPT ); Fri, 2 Aug 2013 07:48:47 -0400 Message-ID: <51FB9C77.3090202@ti.com> Date: Fri, 2 Aug 2013 17:18:07 +0530 From: Gururaja Hebbar User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: Mark Rutland 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 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> <20130802112018.GI2884@e106331-lin.cambridge.arm.com> In-Reply-To: <20130802112018.GI2884@e106331-lin.cambridge.arm.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3847 Lines: 112 On 8/2/2013 4:50 PM, Mark Rutland wrote: > 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? no no. Davinci .dts uses "ti,da830-rtc". I was saying if we reverse the order of "of_device_id" structure in rtc-omap driver, then it would work nicely for am335x but will cause trouble on davinci platform. > > 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/