Date:   Sat, 11 Dec 2021 12:44:40 +0000
Message-ID: <87tuff9upz.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Hector Martin <marcan@marcan.st>
Cc:     Rob Herring <robh@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Sven Peter <sven@svenpeter.dev>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org
Subject: Re: [PATCH 1/6] dt-bindings: interrupt-controller: apple,aic: Add apple,aic2 support
In-Reply-To: <8c099fc2-a319-7c80-3053-ed2b39b86835@marcan.st>
References: <20211209043249.65474-1-marcan@marcan.st>
        <20211209043249.65474-2-marcan@marcan.st>
        <YbI8wBS2mrETiTfw@robh.at.kernel.org>
        <8c099fc2-a319-7c80-3053-ed2b39b86835@marcan.st>
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On Sat, 11 Dec 2021 12:28:10 +0000,
Hector Martin <marcan@marcan.st> wrote:
> 
> On 10/12/2021 02.28, Rob Herring wrote:
> > On Thu, Dec 09, 2021 at 01:32:44PM +0900, Hector Martin wrote:
> <snip>
> >> +  - if:
> >> +      properties:
> >> +        compatible:
> >> +          contains:
> >> +            enum:
> >> +              - apple,aic2
> >> +    then:
> >> +      required:
> >> +        - apple,event-reg
> > 
> > Is this property valid for aic1? If not, you need:
> > 
> > else:
> >    not:
> >      required:
> >        - apple,event-reg
> > 
> 
> Thanks, I wasn't sure how to do this. Took me a second to realize how
> the logic works here, heh.
> 
> > 
> > I tend to think you should just make this a separate document. There's
> > not a whole lot of sharing (compared to any other interrupt controller).
> 
> Good point. I just kind of defaulted to this way because the driver is
> the same (and does share a bunch), but indeed the binding doesn't
> really reflect any of that. I'll split it off into another document
> for v2. Might as well make the 4-argument interrupt form mandatory
> then (we use it for all DTs, even the current 1-die machines, on AICv2
> SoCs; the driver can handle both but we might as well be stricter with
> the binding).

Well, I'm about to add this 4th cell for FIQ signalled interrupts so
that we can specify an affinity (similarly to what we do with GICv3, 0
meaning no specific affinity and a non-zero phandle indicating a
specific affinity).

Generalising the 4-cell even on AICv1 systems would be pretty nice,
and we can always keep the backward compat as a fallback for old DTs
(that'd pretty cheap).

	M.

-- 
Without deviation from the norm, progress is not possible.