Re: [PATCH 1/4] dt-bindings: hid: Add CP2112 HID USB to SMBus Bridge

[Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>]

On 28/01/2023 21:26, Danny Kaehn wrote:
> This is a USB HID device which includes an I2C controller and 8 GPIO pins.
> 
Thank you for your patch. There is something to discuss/improve.

> The binding allows describing the chip's gpio and i2c controller in DT
> using the subnodes named "gpio" and "i2c", respectively. This is
> intended to be used in configurations where the CP2112 is permanently
> connected in hardware.
> 
> Signed-off-by: Danny Kaehn <kaehndan@gmail.com>
> ---
>  .../bindings/hid/silabs,cp2112.yaml           | 82 +++++++++++++++++++

There is no "hid" directory, so I think such devices where going to
different place, didn't they?

>  1 file changed, 82 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hid/silabs,cp2112.yaml
> 
> diff --git a/Documentation/devicetree/bindings/hid/silabs,cp2112.yaml b/Documentation/devicetree/bindings/hid/silabs,cp2112.yaml
> new file mode 100644
> index 000000000000..49287927c63f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hid/silabs,cp2112.yaml
> @@ -0,0 +1,82 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hid/silabs,cp2112.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: CP2112 HID USB to SMBus/I2C Bridge
> +
> +maintainers:
> +  - Danny Kaehn <kaehndan@gmail.com>
> +
> +description:
> +  This is a USB HID device which includes an I2C controller and 8 GPIO pins.

s/This is/CP2112 is/

> +  While USB devices typically aren't described in DeviceTree, doing so with the
> +  CP2112 allows use of its i2c and gpio controllers with other DT nodes when
> +  the chip is expected to be found on a USB port.

Drop these three and replace with description of the hardware.

> +
> +properties:
> +  compatible:
> +    const: usb10c4,ea90

So this is an USB device, so I guess they all go to usb?

Missing blank line.

> +  reg:
> +    maxItems: 1
> +    description: The USB port number on the host controller

Blank line

> +  i2c:
> +    $ref: /schemas/i2c/i2c-controller.yaml#

This is not specific enough. What controller is there?

Missing unevaluatedProperties: false, anyway.

> +  gpio:
> +    $ref: /schemas/gpio/gpio.yaml#

Same comments.

> +
> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/input/input.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    usb1 {
> +      #address-cells = <1>;
> +      #size-cells = <0>;

Drop, not related.

> +
> +      usb@1 {
> +        compatible = "usb424,2514";
> +        reg = <1>;
> +
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        device@1 {	/* CP2112 I2C Bridge */
> +          compatible = "usb10c4,ea90";
> +          reg = <1>;
> +
> +          cp2112_i2c0: i2c {

Drop unneeded labels.

> +            #address-cells = <1>;
> +            #size-cells = <0>;
> +            /* Child I2C Devices can be described as normal here */
> +            temp@48 {
> +              compatible = "national,lm75";
> +              reg = <0x48>;
> +            };
> +          };
> +
> +          cp2112_gpio0: gpio {
> +            gpio-controller;
> +            interrupt-controller;
> +            #gpio-cells = <2>;
> +            gpio-line-names =
> +              "TEST0",
> +              "TEST1",
> +              "TEST2",
> +              "TEST3",
> +              "TEST4",
> +              "TEST5",
> +              "TEST6",
> +              "TEST7";
> +          };
> +        };
> +      };
> +    };

Best regards,
Krzysztof