RE: [PATCH v5 4/6] dt-bindings: iio: dac: Add adi,ltc2664.yaml

[Paller, Kim Seer]

...
> > > +  adi,manual-span-operation-config:
> > > +    description:
> > > +      This property must mimic the MSPAN pin configurations. By
> > > + tying the
> > MSPAN
> > > +      pins (MSP2, MSP1 and MSP0) to GND and/or VCC, any output
> > > + range can
> > be
> > > +      hardware-configured with different mid-scale or zero-scale
> > > + reset
> > options.
> > > +      The hardware configuration is latched during power on reset for proper
> > > +      operation.
> > > +        0 - MPS2=GND, MPS1=GND, MSP0=GND (+-10V, reset to 0V)
> > > +        1 - MPS2=GND, MPS1=GND, MSP0=VCC (+-5V, reset to 0V)
> > > +        2 - MPS2=GND, MPS1=VCC, MSP0=GND (+-2.5V, reset to 0V)
> > > +        3 - MPS2=GND, MPS1=VCC, MSP0=VCC (0V to 10, reset to 0V)
> > > +        4 - MPS2=VCC, MPS1=GND, MSP0=GND (0V to 10V, reset to 5V)
> > > +        5 - MPS2=VCC, MPS1=GND, MSP0=VCC (0V to 5V, reset to 0V)
> > > +        6 - MPS2=VCC, MPS1=VCC, MSP0=GND (0V to 5V, reset to 2.5V)
> > > +        7 - MPS2=VCC, MPS1=VCC, MSP0=VCC (0V to 5V, reset to 0V,
> > > + enables
> > SoftSpan)
> > > +    $ref: /schemas/types.yaml#/definitions/uint32
> > > +    enum: [0, 1, 2, 3, 4, 5, 6, 7]
> > > +    default: 7
> > > +
> > > +  io-channels:
> > > +    description:
> > > +      ADC channel to monitor voltages and temperature at the MUXOUT pin.
> > > +    maxItems: 1
> > > +
> > > +  '#address-cells':
> > > +    const: 1
> > > +
> > > +  '#size-cells':
> > > +    const: 0
> > > +
> > > +patternProperties:
> > > +  "^channel@[0-3]$":
> > > +    $ref: dac.yaml
> > > +    type: object
> > > +    additionalProperties: false
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description: The channel number representing the DAC output
> channel.
> > > +        maximum: 3
> > > +
> > > +      adi,toggle-mode:
> > > +        description:
> > > +          Set the channel as a toggle enabled channel. Toggle operation
> enables
> > > +          fast switching of a DAC output between two different DAC
> > > + codes
> > without
> > > +          any SPI transaction.
> > > +        type: boolean
> > > +
> > > +      output-range-microvolt:
> >
> > Could be helpful to add a description that says this property is only
> > allowed when SoftSpan is enabled rather than requiring people to
> > reason through the logic.
> >
> > > +        oneOf:
> > > +          - items:
> > > +              - const: 0
> > > +              - enum: [5000000, 10000000]
> > > +          - items:
> > > +              - const: -5000000
> > > +              - const: 5000000
> > > +          - items:
> > > +              - const: -10000000
> > > +              - const: 10000000
> > > +          - items:
> > > +              - const: -2500000
> > > +              - const: 2500000
> >
> >            default: [0, 5000000]
> 
> Adding a default value directly within the schema causes validation error.
> Given this, is it acceptable documenting the intended default value within the
> description?

Before sending the patch, I would like to confirm if it is acceptable to just
document the intended default value within the description, since adding a default
value directly to the schema causes validation error and considering adding the logic,

     - if:
         not:
           properties:
             adi,manual-span-operation-config:
               const: 7
         then:
           patternProperties:
             "^channel@[0-3]$":
               properties:
                 output-range-microvolt: false

> >
> > > +
> > > +    required:
> > > +      - reg
> > > +
> > > +    allOf:
> > > +      - if:
> > > +          properties:
> > > +            adi,manual-span-operation-config:
> > > +              const: 7
> > > +        then:
> > > +          patternProperties:
> > > +            "^channel@[0-3]$":
> > > +              required: [output-range-microvolt]
> >
> >
> > This logic doesn't look right to me. If
> > adi,manual-span-operation-config is not 7, then SoftSpan is disabled, so we
> should have:
> >
> >     output-range-microvolt: false
> >
> > In that case since individual channels can't have a per-channel
> > configuration because SoftSpan is not enabled (unless I am
> > misunderstanding the datasheet?).
> >
> > Also, output-range-microvolt should never be required, even when
> > adi,manual-span-operation-config is 7 because there is already a
> > default value range (0V to 5V) specified by the
> > adi,manual-span-operation-config property.
> >
> > I think the correct logic would be:
> >
> >     - if:
> >         not:
> >           properties:
> >             adi,manual-span-operation-config:
> >               const: 7
> >         then:
> >           patternProperties:
> >             "^channel@[0-3]$":
> >               properties:
> >                 output-range-microvolt: false