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Date:   Mon, 31 Oct 2022 10:44:09 -0500
From:   Rob Herring <robh@kernel.org>
To:     Vladimir Oltean <olteanv@gmail.com>
Cc:     Colin Foster <colin.foster@in-advantage.com>,
        linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Claudiu Manoil <claudiu.manoil@nxp.com>,
        John Crispin <john@phrozen.org>,
        Sean Wang <sean.wang@mediatek.com>,
        DENG Qingfang <dqfext@gmail.com>,
        Landen Chao <Landen.Chao@mediatek.com>,
        =?iso-8859-1?Q?n=E7_=DCNAL?= <arinc.unal@arinc9.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Eric Dumazet <edumazet@google.com>,
        "David S. Miller" <davem@davemloft.net>,
        Florian Fainelli <f.fainelli@gmail.com>,
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        Andrew Lunn <andrew@lunn.ch>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Lee Jones <lee@kernel.org>
Subject: Re: [PATCH v1 net-next 3/7] dt-bindings: net: dsa: qca8k: utilize
 shared dsa.yaml
Message-ID: <20221031154409.GA2861119-robh@kernel.org>
References: <20221025050355.3979380-1-colin.foster@in-advantage.com>
 <20221025050355.3979380-4-colin.foster@in-advantage.com>
 <20221025050355.3979380-1-colin.foster@in-advantage.com>
 <20221025050355.3979380-4-colin.foster@in-advantage.com>
 <20221025212114.GA3322299-robh@kernel.org>
 <20221025212114.GA3322299-robh@kernel.org>
 <20221027012553.zb3zjwmw3x6kw566@skbuf>
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On Thu, Oct 27, 2022 at 04:25:53AM +0300, Vladimir Oltean wrote:
> Hi Rob,
> 
> On Tue, Oct 25, 2022 at 04:21:14PM -0500, Rob Herring wrote:
> > On Mon, Oct 24, 2022 at 10:03:51PM -0700, Colin Foster wrote:
> > > The dsa.yaml binding contains duplicated bindings for address and size
> > > cells, as well as the reference to dsa-port.yaml. Instead of duplicating
> > > this information, remove the reference to dsa-port.yaml and include the
> > > full reference to dsa.yaml.
> > 
> > I don't think this works without further restructuring. Essentially, 
> > 'unevaluatedProperties' on works on a single level. So every level has 
> > to define all properties at that level either directly in 
> > properties/patternProperties or within a $ref.
> > 
> > See how graph.yaml is structured and referenced for an example how this 
> > has to work.
> > 
> > > @@ -104,8 +98,6 @@ patternProperties:
> > >                SGMII on the QCA8337, it is advised to set this unless a communication
> > >                issue is observed.
> > >  
> > > -        unevaluatedProperties: false
> > > -
> > 
> > Dropping this means any undefined properties in port nodes won't be an 
> > error. Once I fix all the issues related to these missing, there will be 
> > a meta-schema checking for this (this could be one I fixed already).
> 
> I may be misreading, but here, "unevaluatedProperties: false" from dsa.yaml
> (under patternProperties: "^(ethernet-)?port@[0-9]+$":) is on the same
> level as the "unevaluatedProperties: false" that Colin is deleting.
> 
> In fact, I believe that it is precisely due to the "unevaluatedProperties: false"
> from dsa.yaml that this is causing a failure now:
> 
> net/dsa/qca8k.example.dtb: switch@10: ports:port@6: Unevaluated properties are not allowed ('qca,sgmii-rxclk-falling-edge' was unexpected)
> 
> Could you please explain why is the 'qca,sgmii-rxclk-falling-edge'
> property not evaluated from the perspective of dsa.yaml in the example?
> It's a head scratcher to me.

A schema with unevaluatedProperties can "see" into a $ref, but the 
ref'ed schema having unevaluatedProperties can't see back to the 
referring schema for properties defined there.

So if a schema is referenced by other schemas which can define their own 
additional properties, that schema cannot have 'unevaluatedProperties: 
false'. If both schemas have 'unevaluatedProperties: false', then it's 
just redundant. We may end up doing that just because it's not obvious 
when we have both or not, and no unevaluatedProperties/ 
additionalProperties at all is a bigger issue. I'm working on a 
meta-schema to check this.


> May it have something to do with the fact that Colin's addition:
> 
> $ref: "dsa.yaml#"
> 
> is not expressed as:
> 
> allOf:
>   - $ref: "dsa.yaml#"
> 
> ?

No. Either way behaves the same. We generally only use 'allOf' when 
there might be more than 1 entry. That is mostly just at the top-level.

Rob