Re: [PATCH 1/2] media: dt-bindings: alvium: add document YAML binding

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

On 26/05/2023 12:34, Tommaso Merciai wrote:
> Add documentation of device tree in YAML schema for the ALVIUM
> Camera from Allied Vision Inc.
> 

Thank you for your patch. There is something to discuss/improve.


> References:
>  - https://www.alliedvision.com/en/products/embedded-vision-solutions
> 
> Signed-off-by: Tommaso Merciai <tomm.merciai@gmail.com>
> ---
>  .../media/i2c/alliedvision,alvium.yaml        | 117 ++++++++++++++++++
>  1 file changed, 117 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/alliedvision,alvium.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/alliedvision,alvium.yaml b/Documentation/devicetree/bindings/media/i2c/alliedvision,alvium.yaml
> new file mode 100644
> index 000000000000..5385fe849ffd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/alliedvision,alvium.yaml
> @@ -0,0 +1,117 @@
> +# SPDX-License-Identifier: GPL-2.0

Dual license please.

Please run scripts/checkpatch.pl and fix reported warnings. Some
warnings can be ignored, but the code here looks like it needs a fix.
Feel free to get in touch if the warning is not clear.

It does not look like you tested the bindings, at least after quick
look. Please run `make dt_binding_check` (see
Documentation/devicetree/bindings/writing-schema.rst for instructions).
Maybe you need to update your dtschema and yamllint.

> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/alliedvision,alvium.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Alliedvision Alvium Camera
> +
> +maintainers:
> +  - Tommaso Merciai <tomm.merciai@gmail.com>
> +  - Martin Hecht <martin.hecht@avnet.eu>
> +
> +allOf:
> +  - $ref: /schemas/media/video-interface-devices.yaml#
> +
> +properties:
> +  compatible:
> +    const: alliedvision,alvium

Missing vendor prefix in vendor-prefixes.yaml

> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    description: XCLK Input Clock

maxItems: 1

> +
> +  clock-names:
> +    const: xclk

Drop names, useless for one entry with generic name.

> +
> +  powerdown-gpios:
> +    maxItems: 1
> +    description: >
> +      Reference to the GPIO connected to the powerdown pin, if any.

Drop description, it's obvious.

> +
> +  reset-gpios:
> +    maxItems: 1
> +    description: >
> +      Reference to the GPIO connected to the reset pin, if any.

Drop description, it's obvious.


> +
> +  streamon-delay:
> +    maxItems: 1
> +    description: >
> +      Delay before camera start capturing frames in us.

Missing vendor prefix (unless it is a common property), missing units
suffix in property name (-us). It's not a list. Why this should be a
hardware property?

> +
> +  rotation:
> +    enum:
> +      - 0
> +      - 180
> +
> +  port:
> +    description: Digital Output Port
> +    $ref: /schemas/graph.yaml#/$defs/port-base
> +    additionalProperties: false
> +
> +    properties:
> +      endpoint:
> +        $ref: /schemas/media/video-interfaces.yaml#
> +        unevaluatedProperties: false
> +
> +        properties:
> +          clock-lanes:
> +            const: 0

Blank line

> +          data-lanes:
> +            minItems: 1
> +            maxItems: 4

Four items and each 1 or 4? so <4>, <1>, and what else? Please provide
example for this.

> +            items:
> +              enum: [1, 4]
> +          link-frequencies: true

Drop this one, should not be needed.

> +
> +        required:
> +          - data-lanes
> +          - link-frequencies
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +      #include <dt-bindings/clock/imx6qdl-clock.h>
> +      #include <dt-bindings/gpio/gpio.h>

Use 4 spaces for example indentation. Not 6.

> +
> +      i2c {
> +          #address-cells = <1>;
> +          #size-cells = <0>;
> +
> +          camera: alvium@3c {

Node names should be generic. See also explanation and list of examples
in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

> +              compatible = "alliedvision,alvium";
> +              reg = <0x3c>;
> +              pinctrl-names = "default";
> +              pinctrl-0 = <&pinctrl_csi0_pwn>, <&pinctrl_csi0_rst>, <&pinctrl_csi_mclk>;
> +              clocks = <&clk IMX8MP_CLK_IPP_DO_CLKO2>;
> +              clock-names = "xclk";
> +              assigned-clocks = <&clk IMX8MP_CLK_IPP_DO_CLKO2>;
> +              assigned-clock-parents = <&clk IMX8MP_CLK_24M>;
> +              assigned-clock-rates = <24000000>;
> +              streamon-delay = <20>;
> +              powerdown-gpios = <&gpio2 11 GPIO_ACTIVE_HIGH>;
> +              reset-gpios = <&gpio1 6 GPIO_ACTIVE_LOW>;
> +              status = "okay";

Drop status

> +
> +              port {
> +                  alvium_out: endpoint {
> +                      remote-endpoint = <&mipi_csi_0_in>;
> +                      data-lanes = <1 2 3 4>;

OK, here is the example. You did not test it.



Best regards,
Krzysztof