[Patch V2 4/4] ARM: dts: AM33XX: update rtc node compatibility
From: mark.rutland@arm.com (Mark Rutland)
Date: 2013-08-02 12:41:14
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linux-devicetree, linux-omap, lkml
On Fri, Aug 02, 2013 at 12:48:07PM +0100, Gururaja Hebbar wrote:
On 8/2/2013 4:50 PM, Mark Rutland wrote:quoted
On Fri, Aug 02, 2013 at 12:07:36PM +0100, Gururaja Hebbar wrote:quoted
On 8/1/2013 10:35 PM, Mark Rutland wrote:quoted
On Tue, Jul 30, 2013 at 05:21:14PM +0100, Sekhar Nori wrote:quoted
On 7/30/2013 8:25 PM, Mark Rutland wrote:quoted
On Tue, Jul 30, 2013 at 06:05:52AM +0100, Gururaja Hebbar wrote:quoted
Hi, On 7/3/2013 2:17 PM, Hebbar Gururaja wrote:quoted
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 Gururajaquoted
Signed-off-by: Hebbar Gururaja <redacted> --- :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 at 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".
Ok.
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.
I don't understand. If we place "ti,am3352-rtc" first in the list, it won't be match the davinci dts compatible string, and the code will go over the of_device_id entires until it finds the "ti,da830-rtc" entry used by davinci. What problem would this cause, and why? Thanks, Mark.
quoted
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.quoted
Regards Gururajaquoted
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 at lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel_______________________________________________ linux-arm-kernel mailing list linux-arm-kernel at lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel