Re: [Patch V2 4/4] ARM: dts: AM33XX: update rtc node compatibility
From: Gururaja Hebbar
Date: Fri Aug 02 2013 - 07:49:18 EST
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@xxxxxx>
---
: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.
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