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

[Thomas Bonnefille]

Hello Conor,

On 8/12/24 5:53 PM, Conor Dooley wrote:
> On Mon, Aug 12, 2024 at 05:00:55PM +0200, Thomas Bonnefille wrote:
> > The Sophgo SARADC is a Successive Approximation ADC that can be found in
> > the Sophgo SoC.
> >
> > Signed-off-by: Thomas Bonnefille <thomas.bonnefille@xxxxxxxxxxx>
> > ---
> >   .../bindings/iio/adc/sophgo,cv18xx-saradc.yaml     | 85 ++++++++++++++++++++++
> >   1 file changed, 85 insertions(+)
> >
> > diff --git a/Documentation/devicetree/bindings/iio/adc/sophgo,cv18xx-saradc.yaml b/Documentation/devicetree/bindings/iio/adc/sophgo,cv18xx-saradc.yaml
> > new file mode 100644
> > index 000000000000..846590808e5f
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/adc/sophgo,cv18xx-saradc.yaml
> > @@ -0,0 +1,85 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/adc/sophgo,cv18xx-saradc.yaml#
>
> Filename matching the compatible please.
>
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title:
> > +  Sophgo CV18XX SoC series 3 channels Successive Approximation Analog to
> > +  Digital Converters
> > +
> > +maintainers:
> > +  - Thomas Bonnefille <thomas.bonnefille@xxxxxxxxxxx>
> > +
> > +description:
> > +  Datasheet at https://github.com/sophgo/sophgo-doc/releases
> > +
> > +properties:
> > +  compatible:
> > +    const: sophgo,cv1800b-saradc
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +patternProperties:
> > +  "^channel@[0-3]+$":
> > +    $ref: adc.yaml
> > +
> > +    description: |
>
> This | is not required.
>
> > +      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 the dtschema repository it seems to be the case in reg.yaml 
with address-cells/size-cells = 2/2, 1/1 and 2/1.
If I try to use maxItems here :

    properties:
      reg:
        maxItems: 1
        items:
          - minimum: 0
            maximum: 2

I get this strange error message from `make dt_binding_check`:

DTEX 
Documentation/devicetree/bindings/iio/adc/sophgo,cv1800b-saradc.example.dts
/home/thomas/linux/Documentation/devicetree/bindings/iio/adc/sophgo,cv1800b-saradc.yaml: 
patternProperties:^channel@[0-2]+$:properties:reg: {'maxItems': 1, 
'items': [{'minimum': 0, 'maximum': 2}]} should not be valid under 
{'required': ['maxItems']}
	hint: "maxItems" is not needed with an "items" list
	from schema $id: http://devicetree.org/meta-schemas/items.yaml#
/home/thomas/linux/Documentation/devicetree/bindings/iio/adc/sophgo,cv1800b-saradc.yaml: 
patternProperties:^channel@[0-2]+$:properties:reg: 'anyOf' conditional 
failed, one must be fixed:
	'items' is not one of ['maxItems', 'description', 'deprecated']
		hint: Only "maxItems" is required for a single entry if there are no 
constraints defined for the values.
	'maxItems' is not one of ['description', 'deprecated', 'const', 'enum', 
'minimum', 'maximum', 'multipleOf', 'default', '$ref', 'oneOf']
	'items' is not one of ['description', 'deprecated', 'const', 'enum', 
'minimum', 'maximum', 'multipleOf', 'default', '$ref', 'oneOf']
	1 is less than the minimum of 2
		hint: Arrays must be described with a combination of 
minItems/maxItems/items
	hint: cell array properties must define how many entries and what the 
entries are when there is more than one entry.
	from schema $id: http://devicetree.org/meta-schemas/core.yaml#

Isn't it okay to just use minimum and maximum and rely on 
address-cells/size-cells for the number of items allowed ?