Re: [PATCH v5 1/2] dt-bindings: counter: add event-counter binding

[Rob Herring <robh@kernel.org>]

On Mon, Feb 08, 2021 at 02:53:46PM +0100, Oleksij Rempel wrote:
> Add binding for the event counter node
> 
> Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
> ---
>  .../bindings/counter/event-counter.yaml       | 56 +++++++++++++++++++
>  1 file changed, 56 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/counter/event-counter.yaml
> 
> diff --git a/Documentation/devicetree/bindings/counter/event-counter.yaml b/Documentation/devicetree/bindings/counter/event-counter.yaml
> new file mode 100644
> index 000000000000..bd05c1b38f20
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/counter/event-counter.yaml
> @@ -0,0 +1,56 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/counter/event-counter.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Event counter
> +
> +maintainers:
> +  - Oleksij Rempel <o.rempel@pengutronix.de>
> +
> +description: |
> +  A generic event counter to measure event frequency. It was developed and used
> +  for agricultural devices to measure rotation speed of wheels or other tools.
> +  Since the direction of rotation is not important, only one signal line is
> +  needed.
> +
> +properties:
> +  compatible:
> +    const: event-counter
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  gpios:
> +    description: Optional diagnostic interface to measure signal level

This description seems wrong in the case of only having a GPIO.

Also, a GPIO only implies polled mode because if the GPIO is interrupt 
capable, 'interrupts' should be required. For gpio-keys, we split the 
compatible strings in this case. I leave it to you if you want to make 
it more explicit.

> +    maxItems: 1
> +
> +required:
> +  - compatible

anyOf:
  - required: [ interrupts ]
  - required: [ gpios ]

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    counter-0 {
> +        compatible = "event-counter";
> +        interrupts-extended = <&gpio 0 IRQ_TYPE_EDGE_RISING>;
> +    };
> +
> +    counter-1 {
> +        compatible = "event-counter";
> +        gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
> +    };
> +
> +    counter-2 {
> +        compatible = "event-counter";
> +        interrupts-extended = <&gpio 2 IRQ_TYPE_EDGE_RISING>;
> +        gpios = <&gpio 2 GPIO_ACTIVE_HIGH>;
> +    };
> +
> +...
> -- 
> 2.30.0
>