From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gururaja Hebbar Subject: Re: [Patch V2 4/4] ARM: dts: AM33XX: update rtc node compatibility Date: Fri, 2 Aug 2013 17:18:07 +0530 Message-ID: <51FB9C77.3090202@ti.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> <20130802112018.GI2884@e106331-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130802112018.GI2884-NuALmloUBlrZROr8t4l/smS4ubULX0JqMm0uRHvK7Nw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: Errors-To: davinci-linux-open-source-bounces-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org To: Mark Rutland Cc: "davinci-linux-open-source-VycZQUHpC/PFrsHnngEfi1aTQe2KTcn/@public.gmane.org" , "tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org" , "benoit.cousson-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "vaibhav.bedia-l0cyMroinI0@public.gmane.org" , "benoit.cousson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org" , "linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" List-Id: devicetree@vger.kernel.org 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-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>