Re: [PATCH v3 1/3] dt-bindings: rtc: loongson: Correct Loongson-1C interrupts property

[Conor Dooley <conor@kernel.org>]

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On Tue, Jan 20, 2026 at 08:50:45AM +0100, Alexandre Belloni wrote:
> On 19/01/2026 18:24:36+0000, Conor Dooley wrote:
> > On Sat, Jan 17, 2026 at 10:26:48AM +0800, Binbin Zhou wrote:
> > > The `interrupts` property indicates an RTC alarm interrupt, which is
> > > required for RTCs that support the alarm feature, which is not supported
> > > by the Loongson-1C RTC. We exclude it for a more accurate description.
> > > 
> > > Changing the `allowed` property is ABI-breaking behavior, but
> > > throughout the existing Loongson DTS{i}, the description of the RTC
> > > nodes conforms to the modified bingding rules.
> > 
> > Right, changing properties is an ABI break, but when following the ABI
> > would've produced something non-functional, breaking it is not really
> > relevant.
> 
> 
> But the HW has the interrupt, the fact that is not functional doesn't
> mean it isn't there. I thought we should describe the hardware?

Does the hardware have it? My interpretation of the commit message was
that it didn't have the alarm feature and thus no interrupt? Unless the
interrupt has some other purpose, in which case yeah we shouldn't accept
this change and only the new device should permit there being no
interrupt.

> 
> > Acked-by: Conor Dooley <conor.dooley@microchip.com>
> > pw-bot: not-applicable
> > 
> > > 
> > > Thus, the existing Loongson DTS{i} will not be affected.
> > > 
> > > Fixes: 487ef32caebe ("dt-bindings: rtc: Split loongson,ls2x-rtc into SoC-based compatibles")
> > > Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
> > > Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> > > ---
> > >  .../devicetree/bindings/rtc/loongson,rtc.yaml         | 11 +++++++++++
> > >  1 file changed, 11 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/rtc/loongson,rtc.yaml b/Documentation/devicetree/bindings/rtc/loongson,rtc.yaml
> > > index f89c1f660aee..fac90a18153e 100644
> > > --- a/Documentation/devicetree/bindings/rtc/loongson,rtc.yaml
> > > +++ b/Documentation/devicetree/bindings/rtc/loongson,rtc.yaml
> > > @@ -42,6 +42,17 @@ required:
> > >  
> > >  unevaluatedProperties: false
> > >  
> > > +if:
> > > +  properties:
> > > +    compatible:
> > > +      contains:
> > > +        enum:
> > > +          - loongson,ls1c-rtc
> > > +
> > > +then:
> > > +  properties:
> > > +    interrupts: false
> > > +
> > >  examples:
> > >    - |
> > >      #include <dt-bindings/interrupt-controller/irq.h>
> > > -- 
> > > 2.47.3
> > > 
> 
> 
> 
> -- 
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com

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