Re: [PATCH v4 1/3] dt-bindings: iio: adc: sophgo,cv18xx-saradc.yaml: Add Sophgo CV18XX SARADC binding

From: Miquel Raynal <miquel.raynal@bootlin.com>
To: Conor Dooley <conor@kernel.org>
Cc: Thomas Bonnefille <thomas.bonnefille@bootlin.com>,
	Jonathan Cameron <jic23@kernel.org>,
	Lars-Peter Clausen <lars@metafoo.de>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Chen Wang <unicorn_wang@outlook.com>,
	Inochi Amaoto <inochiama@outlook.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	linux-iio@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH v4 1/3] dt-bindings: iio: adc: sophgo,cv18xx-saradc.yaml: Add Sophgo CV18XX SARADC binding
Date: Thu, 22 Aug 2024 10:52:49 +0200	[thread overview]
Message-ID: <20240822105249.0fd64d67@xps-13> (raw)
In-Reply-To: <20240821-unholy-statutory-7aa884ebf857@spud>

Hi Conor,

conor@kernel.org wrote on Wed, 21 Aug 2024 16:29:42 +0100:

> On Wed, Aug 21, 2024 at 09:41:50AM +0200, Miquel Raynal wrote:
> > > > > > +      Represents the channels of the ADC.
> > > > > > +
> > > > > > +    properties:
> > > > > > +      reg:
> > > > > > +        description: |
> > > > > > +          The channel number. It can have up to 3 channels numbered from 0 to 2.
> > > > > > +        items:
> > > > > > +          - minimum: 0
> > > > > > +            maximum: 2    
> > > > > 
> > > > > Is this sufficient to limit the number of channels to 3? Aren't you relying
> > > > > on the unique unit addresses warning in dtc to limit it, rather than
> > > > > actually limiting with min/maxItems?
> > > > >     
> > > > It seems like I can't use min/maxItems on this property. I think that it is
> > > > using size-cells + address-cells to deduce that the number of items should
> > > > be equal to 1.    
> > 
> > Looking at dt-schema, I couldn't personally understand from where did
> > the error messages reported by Thomas came from. There are clear  
> 
> I think the complaints are on a more meta level than that. He provided
> an items list
>      properties:
>        reg:
>          maxItems: 1
>          items:
>            - minimum: 0
>              maximum: 2
> but this list only has one entry as there's one -. The first complaint
> from dt_binding_check is that having maxItems is not needed with an
> items list, because the items list contains the maximum number of
> elements.
> 
> The second one comes from cell.yaml:
> https://github.com/devicetree-org/dt-schema/blob/main/dtschema/meta-schemas/cell.yaml
> 
> It either allows a single item, with maxItems: 1 or multiple items, in
> which case maxitems must be greater than 1. That's where the "anyOf
> conditonal failed" and "1 is less than the minimum of 2" stuff comes
> from.
> 
> I hope that helps?

Ah yeah, makes sense. Thanks a lot for your feedback!

Miquèl