Re: [PATCH 1/4] dt-bindings: iio: dac: Add adi,ltc2664.yaml

[Krzysztof Kozlowski]

On 12/04/2024 05:20, Kim Seer Paller wrote:
> Add documentation for ltc2664 and ltc2672.
> 
> Co-developed-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> Signed-off-by: Kim Seer Paller <kimseer.paller@xxxxxxxxxx>
> ---
>  .../bindings/iio/dac/adi,ltc2664.yaml         | 230 ++++++++++++++++++
>  MAINTAINERS                                   |   8 +
>  2 files changed, 238 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
> new file mode 100644
> index 000000000..2f581a9e5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/adi,ltc2664.yaml
> @@ -0,0 +1,230 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/dac/adi,ltc2664.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC2664 and LTC2672 DAC
> +
> +maintainers:
> +  - Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> +  - Kim Seer Paller <kimseer.paller@xxxxxxxxxx>
> +
> +description: |
> +  Analog Devices LTC2664 4 channel, 16 bit, +-10V DAC
> +  Analog Devices LTC2672 5 channel, 16 bit, 300mA DAC
> +  https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2664.pdf
> +  https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2672.pdf
> +
> +$defs:
> +  toggle-operation:
> +    type: object
> +    description: Toggle mode channel setting.
> +
> +    properties:
> +      reg:
> +        description: Channel number.
> +        minimum: 0
> +        maximum: 4
> +
> +      adi,toggle-mode:
> +        description:
> +          Set the channel as a toggle enabled channel. Toggle operation enables
> +          fast switching of a DAC output between two different DAC codes without
> +          any SPI transaction.
> +        type: boolean
> +
> +patternProperties:
> +  "^channel@[0-4]$":
> +    type: object

patternProps go after properties.  You miss additionalProperties: false
and actual properties defined in top-level part of the binding.

I wouldn't call your schema easiest to read. You have two quite
different devices.

> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ltc2664
> +      - adi,ltc2672
> +
> +  reg:
> +    maxItems: 1
> +
> +  spi-max-frequency:
> +    maximum: 50000000

Missing definition of this property, so ref to spi-peripheral-props.
Look at other bindings having this property.

> +
> +  vcc-supply:
> +    description: Analog Supply Voltage Input.
> +
> +  iovcc-supply:
> +    description: Digital Input/Output Supply Voltage.
> +
> +  vref-supply:
> +    description:
> +      Reference Input/Output. The voltage at the REF pin sets the full-scale
> +      range of all channels. If not provided the internal reference is used and
> +      also provided on the VREF pin.
> +
> +  clr-gpios:
> +    description:
> +      If specified, it will be asserted during driver probe. As the line is
> +      active low, it should be marked GPIO_ACTIVE_LOW.

First sentence tells nothing about hardware. Do not describe driver
behavior, but hardware.

Second sentence is 90% redundant - just say, when describing the
hardware, that the line for foo bar is active low.


> +    maxItems: 1
> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +allOf:
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: adi,ltc2664
> +    then:
> +      properties:
> +        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
> +              1 - MPS2=GND, MPS1=GND, MSP0=VCC
> +              2 - MPS2=GND, MPS1=VCC, MSP0=GND
> +              3 - MPS2=GND, MPS1=VCC, MSP0=VCC
> +              4 - MPS2=VCC, MPS1=GND, MSP0=GND
> +              5 - MPS2=VCC, MPS1=GND, MSP0=VCC
> +              6 - MPS2=VCC, MPS1=VCC, MSP0=GND
> +              7 - MPS2=VCC, MPS1=VCC, MSP0=VCC (enables SoftSpan feature)
> +          $ref: /schemas/types.yaml#/definitions/uint32
> +          enum: [0, 1, 2, 3, 4, 5, 6, 7]
> +          default: 7
> +
> +      patternProperties:
> +        "^channel@([0-3])$":

and the channel@4 is? You allow anything.

> +          $ref: '#/$defs/toggle-operation'
> +          unevaluatedProperties: false
> +
> +          description: Channel in toggle functionality.
> +
> +          properties:
> +            adi,output-range-microvolt:
> +              description: Specify the channel output full scale range.
> +              oneOf:
> +                - items:
> +                    - const: 0
> +                    - enum: [5000000, 10000000]
> +                - items:
> +                    - const: -5000000
> +                    - const: 5000000
> +                - items:
> +                    - const: -10000000
> +                    - const: 10000000
> +                - items:
> +                    - const: -2500000
> +                    - const: 2500000
> +
> +          required:
> +            - adi,output-range-microvolt
> +
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            const: adi,ltc2672
> +    then:
> +      properties:
> +        adi,rfsadj-ohms:
> +          description: If FSADJ is tied to VCC, an internal RFSADJ (20 kΩ) is
> +            selected, which results in nominal output ranges. When an external
> +            resistor of 19 kΩ to 41 kΩ can be used instead by connecting the
> +            resistor between FSADJ and GND it controls the scaling of the
> +            ranges, and the internal resistor is automatically disconnected.
> +          minimum: 19000
> +          maximum: 41000
> +          default: 20000
> +
> +      patternProperties:
> +        "^channel@([0-4])$":
> +          $ref: '#/$defs/toggle-operation'
> +          unevaluatedProperties: false
> +
> +          description: Configuration properties for a channel in toggle mode
> +
> +          properties:
> +            adi,output-range-microamp:
> +              description: Specify the channel output full scale range.
> +              $ref: /schemas/types.yaml#/definitions/uint32
> +              enum: [3125000, 6250000, 12500000, 25000000, 50000000, 100000000,
> +                     200000000, 300000000]
> +
> +          required:
> +            - adi,output-range-microamp
> +
> +required:
> +  - compatible
> +  - reg
> +  - spi-max-frequency
> +  - vcc-supply
> +  - iovcc-supply
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    spi {
> +          #address-cells = <1>;

Use 4 spaces for example indentation.



Best regards,
Krzysztof