Re: [PATCH v4 2/8] dt-bindings: adc: axi-adc: deprecate 'adi,adc-dev'

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 20 Dec 2023 16:34:05 +0100
Nuno Sa <nuno.sa@analog.com> wrote:

> 'adi,adc-dev' is now deprecated and must not be used anymore. Hence,
> also remove it from being required.

With my 'specifications language' brain engaged (also know as pedantic)
I think this is a 'should' not a 'must' case. You aren't breaking
backwards compatibility just advising moving to the newer / better interface.


> 
> The reason why it's being deprecated is because the axi-adc CORE is now
> an IIO service provider hardware (IIO backends) for consumers to make use
> of. Before, the logic with 'adi,adc-dev' was the opposite (it was kind
> of consumer referencing other nodes/devices) and that proved to be wrong
> and to not scale.
> 
> Now, IIO consumers of this hardware are expected to reference it using the
> io-backends property.
> 
> Signed-off-by: Nuno Sa <nuno.sa@analog.com>
> ---
>  Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml b/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
> index 9996dd93f84b..835b40063343 100644
> --- a/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,axi-adc.yaml
> @@ -39,12 +39,12 @@ properties:
>      $ref: /schemas/types.yaml#/definitions/phandle
>      description:
>        A reference to a the actual ADC to which this FPGA ADC interfaces to.
> +    deprecated: true
>  
>  required:
>    - compatible
>    - dmas
>    - reg
> -  - adi,adc-dev

Dropping it from required is fine, but do we have a new condition where one or the other
should be required?  If so good to add the dt-binding magic to enforce that. Look
for a oneOf combined with required. There are a few IIO examples of this either or
type required. You may want to then enforce that both are not provided though I
guess we perhaps don't care - the driver will just prioritise one approach over the other.

Jonathan


>  
>  additionalProperties: false
>  
> @@ -55,7 +55,5 @@ examples:
>          reg = <0x44a00000 0x10000>;
>          dmas = <&rx_dma 0>;
>          dma-names = "rx";
> -
> -        adi,adc-dev = <&spi_adc>;
>      };
>  ...
>