Re: [PATCH 3/3] dt-bindings: iio: Add ltc2688 documentation

[Rob Herring <robh@kernel.org>]

On Tue, Dec 14, 2021 at 05:56:08PM +0100, Nuno Sá wrote:
> Document the LTC2688 devicetree properties.
> 
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> ---
>  .../bindings/iio/dac/adi,ltc2688.yaml         | 146 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 147 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> new file mode 100644
> index 000000000000..7919cd8ec7c9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
> @@ -0,0 +1,146 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/dac/adi,ltc2688.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC2688 DAC
> +
> +maintainers:
> +  - Nuno Sá <nuno.sa@analog.com>
> +
> +description: |
> +  Analog Devices LTC2688 16 channel, 16 bit, +-15V DAC
> +  https://www.analog.com/media/en/technical-documentation/data-sheets/ltc2688.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ltc2688
> +
> +  reg:
> +    maxItems: 1
> +
> +  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. By default, the internal reference is routed to
> +      this pin.
> +
> +  reset-gpios:
> +    description:
> +      If specified, it will be asserted during driver probe. As the line is
> +      active low, it should be marked GPIO_ACTIVE_LOW.
> +    maxItems: 1
> +
> +  clocks:
> +    minItems: 1
> +    maxItems: 3
> +
> +  clock-names:
> +    minItems: 1
> +    maxItems: 3
> +    items:
> +      enum: [TGP1, TGP2, TGP3]

pattern: '^TGP[1-3]$'

> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +patternProperties:
> +  "^channel@([0-9]|1[0-5])$":
> +    type: object
> +
> +    properties:
> +      reg:
> +        description: The channel number representing the DAC output channel.
> +        maximum: 15
> +
> +      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. It will result in a different ABI for the
> +          channel.
> +        type: boolean
> +
> +      adi,output-range-millivolt:

Not one of the defined units. Use '-microvolt'
> +        description:
> +          Specify the channel output full scale range. Allowed values are
> +            <0 5000>
> +            <0 10000>
> +            <-5000 5000>
> +            <-10000 10000>
> +            <-15000 15000>

Looks like constraints.

items:
  - enum: [ -15000, -10000, -5000, 0 ]
  - enum: [ 5000, 10000, 15000 ]

though that will need to all be x1000.

> +        $ref: /schemas/types.yaml#/definitions/int32-array

And drop the type.

> +
> +      adi,overrange:
> +        description: Enable 5% overrange over the selected full scale range.
> +        type: boolean
> +
> +      adi,toggle-dither-input:
> +        description:
> +          Selects the TGPx pin to be associated with this channel. This setting
> +          only makes sense for toggle or dither enabled channels. If
> +          @adi,toggle-mode is not set and this property is given, the channel is
> +          assumed to be a dither capable channel. Note that multiple channels
> +          can be mapped to the same pin. If this setting is given, the
> +          respective @clock must also be provided. Mappings between this and
> +          clocks
> +            0 - TGP1
> +            1 - TGP2
> +            2 - TGP3
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        enum: [0, 1, 2]
> +
> +    required:
> +      - reg
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +
> +    spi {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +          ltc2688: ltc2688@0 {
> +                  compatible = "adi,ltc2688";
> +                  reg = <0>;
> +
> +                  vcc-supply = <&vcc>;
> +                  iovcc-supply = <&vcc>;
> +                  vref-supply = <&vref>;
> +
> +                  clocks = <&clock_tgp2>;
> +                  clock-names = "TGP2";
> +
> +                  #address-cells = <1>;
> +                  #size-cells = <0>;
> +                  channel@0 {
> +                          reg = <0>;
> +                          adi,toggle-mode;
> +                          adi,overrange;
> +                  };
> +
> +                  channel@1 {
> +                          reg = <1>;
> +                          adi,output-range-millivolt = <(-10000) 10000>;
> +                          adi,toggle-dither-input = <2>;
> +                  };
> +          };
> +    };
> +
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 61b1eaad4611..4ee2a1b6bf62 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -11168,6 +11168,7 @@ L:	linux-iio@vger.kernel.org
>  S:	Supported
>  W:	http://ez.analog.com/community/linux-device-drivers
>  F:	Documentation/ABI/testing/sysfs-bus-iio-dac-ltc2688
> +F:	Documentation/devicetree/bindings/iio/dac/adi,ltc2688.yaml
>  F:	drivers/iio/dac/ltc2688.c
>  
>  LTC2947 HARDWARE MONITOR DRIVER
> -- 
> 2.17.1
> 
>