linux-kernel - Re: [PATCH 14/15] dt-bindings: iio: adc: adi,ad4030: Add ADAQ4216 and ADAQ4224

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Message-ID: <bf2a2ef0-0ae0-4a57-a3be-e0062190da42@baylibre.com>
Date: Sat, 30 Aug 2025 13:45:15 -0500
From: David Lechner <dlechner@...libre.com>
To: Marcelo Schmitt <marcelo.schmitt@...log.com>, linux-iio@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
 devicetree@...r.kernel.org, linux-spi@...r.kernel.org
Cc: jic23@...nel.org, Michael.Hennerich@...log.com, nuno.sa@...log.com,
 eblanc@...libre.com, andy@...nel.org, corbet@....net, robh@...nel.org,
 krzk+dt@...nel.org, conor+dt@...nel.org, broonie@...nel.org,
 Jonathan.Cameron@...wei.com, andriy.shevchenko@...ux.intel.com,
 ahaslam@...libre.com, marcelo.schmitt1@...il.com
Subject: Re: [PATCH 14/15] dt-bindings: iio: adc: adi,ad4030: Add ADAQ4216 and
 ADAQ4224

On 8/29/25 7:45 PM, Marcelo Schmitt wrote:
> ADAQ4216 and ADAQ4224 are similar to AD4030 except ADAQ devices have a PGA
> (programmable gain amplifier) that scales the input signal prior to it
> reaching the ADC inputs. The PGA is controlled through a couple of pins (A0
> and A1) that set one of four possible signal gain.
> 
> Signed-off-by: Marcelo Schmitt <marcelo.schmitt@...log.com>
> ---
> The PGA doc was inspired on ad7191 dt-binding and uses the same properies (but
> with different values) to describe the hardware.
> 
>  .../bindings/iio/adc/adi,ad4030.yaml          | 39 +++++++++++++++++++
>  1 file changed, 39 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml b/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml
> index 9adb60629631..36fd2aa51922 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad4030.yaml
> @@ -19,6 +19,8 @@ description: |
>    * https://www.analog.com/media/en/technical-documentation/data-sheets/ad4030-24-4032-24.pdf
>    * https://www.analog.com/media/en/technical-documentation/data-sheets/ad4630-24_ad4632-24.pdf
>    * https://www.analog.com/media/en/technical-documentation/data-sheets/ad4630-16-4632-16.pdf
> +  * https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4216.pdf
> +  * https://www.analog.com/media/en/technical-documentation/data-sheets/adaq4224.pdf
>  
>  $ref: /schemas/spi/spi-peripheral-props.yaml#
>  
> @@ -31,6 +33,8 @@ properties:
>        - adi,ad4630-24
>        - adi,ad4632-16
>        - adi,ad4632-24
> +      - adi,adaq4216
> +      - adi,adaq4224
>  
>    reg:
>      maxItems: 1
> @@ -64,6 +68,27 @@ properties:
>        The Reset Input (/RST). Used for asynchronous device reset.
>      maxItems: 1
>  
> +  pga-gpios:
> +    description:
> +      A0 and A1 pins for gain selection. For devices that have PGA configuration
> +      input pins, pga-gpios should be defined if adi,gain-milli is absent.
> +    minItems: 2
> +    maxItems: 2
> +
> +  adi,pga-value:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Should be present if PGA control inputs are pin-strapped. The values
> +      specify the gain per mille. For example, 333 means the input signal is
> +      scaled by a 0.333 factor (i.e. attenuated to one third of it's original
> +      magnitude). Possible values:
> +      Gain 333 (A1=0, A0=0)
> +      Gain 556 (A1=0, A0=1)
> +      Gain 2222 (A1=1, A0=0)
> +      Gain 6667 (A1=1, A0=1)
> +      If defined, pga-gpios must be absent.
> +    enum: [333, 556, 2222, 6667]
> +

It looks like these chips have some different power supplies
as well. E.g. V_DDH, VDD_FDA, VSS_FDA, VLDO. And there is only
REFIN, no REF.

>    pwms:
>      description: PWM signal connected to the CNV pin.
>      maxItems: 1
> @@ -120,6 +145,20 @@ allOf:
>      then:
>        properties:
>          adi,dual-data-rate: false
> +  # ADAQ devices require a gain property to indicate how hardware PGA is set
> +  - if:
> +      properties:
> +        compatible:
> +          contains:
> +            enum:
> +              - adi,adaq4216
> +              - adi,adaq4224

Could use pattern instead:

		pattern: ^adi,adaq

> +    then:
> +      oneOf:
> +        - required:
> +            - adi,pga-value
> +        - required:
> +            - pga-gpios

  	else:
	  adi,pga-value: false
	  pga-gpios: false

>  
>  unevaluatedProperties: false
>