Messages in this thread | | | Date | Fri, 2 Aug 2013 17:18:07 +0530 | From | Gururaja Hebbar <> | Subject | Re: [Patch V2 4/4] ARM: dts: AM33XX: update rtc node compatibility |
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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 <gururaja.hebbar@ti.com> >>>>>>> --- >>>>>>> :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 >>
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