[RFC,1/2] dt-bindings: input: gpio-keys: enforce node names to match all properties

The gpio-keys DT schema matches all properties with a wide pattern and
applies specific schema to children.  This has drawback - all regular
properties are also matched and are silently ignored, even if they are
not described in schema.  Basically this allows any non-object property
to be present.

Enforce specific naming pattern for children (keys) to narrow the
pattern thus do not match other properties.  This will require all
children to be named with 'key-' prefix or '-key' suffix.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
 .../devicetree/bindings/input/gpio-keys.yaml  | 169 +++++++++---------
 1 file changed, 83 insertions(+), 86 deletions(-)

Hi Krzysztof,

On Fri, Jun 03, 2022 at 12:16:00PM +0200, Krzysztof Kozlowski wrote:
> The gpio-keys DT schema matches all properties with a wide pattern and
> applies specific schema to children.  This has drawback - all regular
> properties are also matched and are silently ignored, even if they are
> not described in schema.  Basically this allows any non-object property
> to be present.
> 
> Enforce specific naming pattern for children (keys) to narrow the
> pattern thus do not match other properties.  This will require all
> children to be named with 'key-' prefix or '-key' suffix.
> 
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> ---
>  .../devicetree/bindings/input/gpio-keys.yaml  | 169 +++++++++---------
>  1 file changed, 83 insertions(+), 86 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/input/gpio-keys.yaml b/Documentation/devicetree/bindings/input/gpio-keys.yaml
> index 93f601c58984..49d388dc8d78 100644
> --- a/Documentation/devicetree/bindings/input/gpio-keys.yaml
> +++ b/Documentation/devicetree/bindings/input/gpio-keys.yaml
> @@ -16,92 +16,89 @@ properties:
>        - gpio-keys-polled
>  
>  patternProperties:
> -  ".*":
> -    if:
> -      type: object
> -    then:
> -      $ref: input.yaml#
> -
> -      properties:
> -        gpios:
> -          maxItems: 1
> -
> -        interrupts:
> -          maxItems: 1
> -
> -        label:
> -          description: Descriptive name of the key.
> -
> -        linux,code:
> -          description: Key / Axis code to emit.
> -          $ref: /schemas/types.yaml#/definitions/uint32
> -
> -        linux,input-type:
> -          description:
> -            Specify event type this button/key generates. If not specified defaults to
> -            <1> == EV_KEY.
> -          $ref: /schemas/types.yaml#/definitions/uint32
> -
> -          default: 1
> -
> -        linux,input-value:
> -          description: |
> -            If linux,input-type is EV_ABS or EV_REL then this
> -            value is sent for events this button generates when pressed.
> -            EV_ABS/EV_REL axis will generate an event with a value of 0
> -            when all buttons with linux,input-type == type and
> -            linux,code == axis are released. This value is interpreted
> -            as a signed 32 bit value, e.g. to make a button generate a
> -            value of -1 use:
> -
> -            linux,input-value = <0xffffffff>; /* -1 */
> -
> -          $ref: /schemas/types.yaml#/definitions/uint32
> -
> -        debounce-interval:
> -          description:
> -            Debouncing interval time in milliseconds. If not specified defaults to 5.
> -          $ref: /schemas/types.yaml#/definitions/uint32
> -
> -          default: 5
> -
> -        wakeup-source:
> -          description: Button can wake-up the system.
> -
> -        wakeup-event-action:
> -          description: |
> -            Specifies whether the key should wake the system when asserted, when
> -            deasserted, or both. This property is only valid for keys that wake up the
> -            system (e.g., when the "wakeup-source" property is also provided).
> -
> -            Supported values are defined in linux-event-codes.h:
> -
> -              EV_ACT_ANY        - both asserted and deasserted
> -              EV_ACT_ASSERTED   - asserted
> -              EV_ACT_DEASSERTED - deasserted
> -          $ref: /schemas/types.yaml#/definitions/uint32
> -          enum: [0, 1, 2]
> -
> -        linux,can-disable:
> -          description:
> -            Indicates that button is connected to dedicated (not shared) interrupt
> -            which can be disabled to suppress events from the button.
> -          type: boolean
> -
> -      required:
> -        - linux,code
> -
> -      anyOf:
> -        - required:
> -            - interrupts
> -        - required:
> -            - gpios
> -
> -      dependencies:
> -        wakeup-event-action: [ wakeup-source ]
> -        linux,input-value: [ gpios ]
> -
> -      unevaluatedProperties: false
> +  "^(key|key-[a-z0-9-]+|[a-z0-9-]+-key)$":

Maybe this would be better as:

"^((key|switch|axis)|(key|switch|axis)-[a-z0-9-]+|[a-z0-9-]+-(key|switch|axis))$":

...or perhaps a more efficient version of my counter-proposal.

The reason is because it is confusing to see a lid or dock switch named
as "key-lid", etc.

> +    $ref: input.yaml#
> +
> +    properties:
> +      gpios:
> +        maxItems: 1
> +
> +      interrupts:
> +        maxItems: 1
> +
> +      label:
> +        description: Descriptive name of the key.
> +
> +      linux,code:
> +        description: Key / Axis code to emit.
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +
> +      linux,input-type:
> +        description:
> +          Specify event type this button/key generates. If not specified defaults to
> +          <1> == EV_KEY.
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +
> +        default: 1
> +
> +      linux,input-value:
> +        description: |
> +          If linux,input-type is EV_ABS or EV_REL then this
> +          value is sent for events this button generates when pressed.
> +          EV_ABS/EV_REL axis will generate an event with a value of 0
> +          when all buttons with linux,input-type == type and
> +          linux,code == axis are released. This value is interpreted
> +          as a signed 32 bit value, e.g. to make a button generate a
> +          value of -1 use:
> +
> +          linux,input-value = <0xffffffff>; /* -1 */
> +
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +
> +      debounce-interval:
> +        description:
> +          Debouncing interval time in milliseconds. If not specified defaults to 5.
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +
> +        default: 5
> +
> +      wakeup-source:
> +        description: Button can wake-up the system.
> +
> +      wakeup-event-action:
> +        description: |
> +          Specifies whether the key should wake the system when asserted, when
> +          deasserted, or both. This property is only valid for keys that wake up the
> +          system (e.g., when the "wakeup-source" property is also provided).
> +
> +          Supported values are defined in linux-event-codes.h:
> +
> +            EV_ACT_ANY        - both asserted and deasserted
> +            EV_ACT_ASSERTED   - asserted
> +            EV_ACT_DEASSERTED - deasserted
> +        $ref: /schemas/types.yaml#/definitions/uint32
> +        enum: [0, 1, 2]
> +
> +      linux,can-disable:
> +        description:
> +          Indicates that button is connected to dedicated (not shared) interrupt
> +          which can be disabled to suppress events from the button.
> +        type: boolean
> +
> +    required:
> +      - linux,code
> +
> +    anyOf:
> +      - required:
> +          - interrupts
> +      - required:
> +          - gpios
> +
> +    dependencies:
> +      wakeup-event-action: [ wakeup-source ]
> +      linux,input-value: [ gpios ]
> +
> +    unevaluatedProperties: false
>  
>  if:
>    properties:
> -- 
> 2.34.1
> 

Kind regards,
Jeff LaBundy