Re: [PATCH 1/8] dt-bindings: media: ov5640: Convert to json-schema

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: robh+dt@kernel.org, devicetree@vger.kernel.org,
	linux-media@vger.kernel.org, mchehab@kernel.org,
	sakari.ailus@linux.intel.com, hverkuil-cisco@xs4all.nl,
	linux-renesas-soc@vger.kernel.org,
	Steve Longerbeam <slongerbeam@gmail.com>
Subject: Re: [PATCH 1/8] dt-bindings: media: ov5640: Convert to json-schema
Date: Thu, 16 Jul 2020 04:53:23 +0300	[thread overview]
Message-ID: <20200716015323.GQ6144@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200715140951.90753-2-jacopo+renesas@jmondi.org>

Hi Jacopo,

Thank you for the patch.

On Wed, Jul 15, 2020 at 04:09:44PM +0200, Jacopo Mondi wrote:
> Convert the ov5640 bindings document to json-schema and update
> the MAINTAINERS file accordingly.
> 
> Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> ---
> Hi Steve,
>   I've added myself as maintainer in the bindings, with your ack
> I would be happy to add myself as maintainer or reviewer for this driver
> in MAINTAINERS, as I've recently been looking after this driver, mostly
> for the MIPI CSI-2 interface part.
> 
> Thanks
>   j
> 
> ---
>  .../devicetree/bindings/media/i2c/ov5640.txt  |  92 ---------
>  .../devicetree/bindings/media/i2c/ov5640.yaml | 181 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  3 files changed, 182 insertions(+), 92 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/media/i2c/ov5640.txt
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/ov5640.txt b/Documentation/devicetree/bindings/media/i2c/ov5640.txt
> deleted file mode 100644
> index c97c2f2da12d..000000000000
> --- a/Documentation/devicetree/bindings/media/i2c/ov5640.txt
> +++ /dev/null
> @@ -1,92 +0,0 @@
> -* Omnivision OV5640 MIPI CSI-2 / parallel sensor
> -
> -Required Properties:
> -- compatible: should be "ovti,ov5640"
> -- clocks: reference to the xclk input clock.
> -- clock-names: should be "xclk".
> -- DOVDD-supply: Digital I/O voltage supply, 1.8 volts
> -- AVDD-supply: Analog voltage supply, 2.8 volts
> -- DVDD-supply: Digital core voltage supply, 1.5 volts
> -
> -Optional Properties:
> -- reset-gpios: reference to the GPIO connected to the reset pin, if any.
> -	       This is an active low signal to the OV5640.
> -- powerdown-gpios: reference to the GPIO connected to the powerdown pin,
> -		   if any. This is an active high signal to the OV5640.
> -- rotation: as defined in
> -	    Documentation/devicetree/bindings/media/video-interfaces.txt,
> -	    valid values are 0 (sensor mounted upright) and 180 (sensor
> -	    mounted upside down).
> -
> -The device node must contain one 'port' child node for its digital output
> -video port, in accordance with the video interface bindings defined in
> -Documentation/devicetree/bindings/media/video-interfaces.txt.
> -
> -OV5640 can be connected to a MIPI CSI-2 bus or a parallel bus endpoint.
> -
> -Endpoint node required properties for CSI-2 connection are:
> -- remote-endpoint: a phandle to the bus receiver's endpoint node.
> -- clock-lanes: should be set to <0> (clock lane on hardware lane 0)
> -- data-lanes: should be set to <1> or <1 2> (one or two CSI-2 lanes supported)
> -
> -Endpoint node required properties for parallel connection are:
> -- remote-endpoint: a phandle to the bus receiver's endpoint node.
> -- bus-width: shall be set to <8> for 8 bits parallel bus
> -	     or <10> for 10 bits parallel bus
> -- data-shift: shall be set to <2> for 8 bits parallel bus
> -	      (lines 9:2 are used) or <0> for 10 bits parallel bus
> -- hsync-active: active state of the HSYNC signal, 0/1 for LOW/HIGH respectively.
> -- vsync-active: active state of the VSYNC signal, 0/1 for LOW/HIGH respectively.
> -- pclk-sample: sample data on rising (1) or falling (0) edge of the pixel clock
> -	       signal.
> -
> -Examples:
> -
> -&i2c1 {
> -	ov5640: camera@3c {
> -		compatible = "ovti,ov5640";
> -		pinctrl-names = "default";
> -		pinctrl-0 = <&pinctrl_ov5640>;
> -		reg = <0x3c>;
> -		clocks = <&clks IMX6QDL_CLK_CKO>;
> -		clock-names = "xclk";
> -		DOVDD-supply = <&vgen4_reg>; /* 1.8v */
> -		AVDD-supply = <&vgen3_reg>;  /* 2.8v */
> -		DVDD-supply = <&vgen2_reg>;  /* 1.5v */
> -		powerdown-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
> -		reset-gpios = <&gpio1 20 GPIO_ACTIVE_LOW>;
> -		rotation = <180>;
> -
> -		port {
> -			/* MIPI CSI-2 bus endpoint */
> -			ov5640_to_mipi_csi2: endpoint {
> -				remote-endpoint = <&mipi_csi2_from_ov5640>;
> -				clock-lanes = <0>;
> -				data-lanes = <1 2>;
> -			};
> -		};
> -	};
> -};
> -
> -&i2c1 {
> -	ov5640: camera@3c {
> -		compatible = "ovti,ov5640";
> -		pinctrl-names = "default";
> -		pinctrl-0 = <&pinctrl_ov5640>;
> -		reg = <0x3c>;
> -		clocks = <&clk_ext_camera>;
> -		clock-names = "xclk";
> -
> -		port {
> -			/* Parallel bus endpoint */
> -			ov5640_to_parallel: endpoint {
> -				remote-endpoint = <&parallel_from_ov5640>;
> -				bus-width = <8>;
> -				data-shift = <2>; /* lines 9:2 are used */
> -				hsync-active = <0>;
> -				vsync-active = <0>;
> -				pclk-sample = <1>;
> -			};
> -		};
> -	};
> -};
> diff --git a/Documentation/devicetree/bindings/media/i2c/ov5640.yaml b/Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> new file mode 100644
> index 000000000000..9c32262a3621
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> @@ -0,0 +1,181 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/ov5640.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Omnivision OV5640 MIPI CSI-2 / parallel sensor
> +
> +maintainers:
> +  - Steve Longerbeam <slongerbeam@gmail.com>
> +  - Jacopo Mondi <jacopo@jmondi.org>
> +
> +description: -|
> +  OV5640 is a 5 megapixels image sensor capable of producing images in RBG, RAW,

s/OV5640/The OV5640/
s/RBG/RGB/

> +  YUV and compressed formats. It features a MIPI CSI-2 and a parallel data
> +  interface and an I2C-compatible (CCI) control interface.
> +
> +properties:
> +  compatible:
> +    const: ovti,ov5640
> +
> +  reg:
> +    description: I2C device address
> +    maxItems: 1
> +
> +  clocks:
> +    description: Reference to the xclk input clock.

I'd drop this, it's implied by the clock-names

> +    maxItems: 1
> +
> +  clock-names:
> +    description: Should be "xclk".

This should be replaced with

   const: xclk

> +    maxItems: 1
> +
> +  DOVDD-supply:
> +    description: Digital I/O voltage supply, 1.8 volts.
> +    maxItems: 1
> +
> +  AVDD-supply:
> +    description: Analog voltage supply, 2.8 volts.
> +    maxItems: 1
> +
> +  DVDD-supply:
> +    description: Digital core voltage supply.
> +    maxItems: 1
> +
> +  reset-gpios:
> +    description: |
> +      Reference to the GPIO connected to the reset pin, if any. This is an
> +      active low signal to the OV5640.
> +    maxItems: 1
> +
> +  powerdown-gpios:
> +    description: |
> +      Reference tot he GPIO connected to the powerdown pin, if any. This is an
> +      active high signal to the OV5640.
> +    maxItems: 1
> +
> +  rotation:
> +    description: |
> +      As defined in Documentation/devicetree/bindings/media/video-interfaces.txt,
> +      valid values are 0 (sensor mounted upright) and 180 (sensor mounted upside
> +      down).

The second sentence should be replaced with
  enum:
    - 0
    - 180

> +
> +  port:
> +    type: object
> +    description: |
> +      The device node must contain one 'port' child node for its digital output
> +      video port, in accordance with the video interface bindings defined in
> +      Documentation/devicetree/bindings/media/video-interfaces.txt.
> +
> +      OV5640 can be connected to a MIPI CSI-2 bus or a parallel bus endpoint.
> +
> +    properties:
> +      endpoint:
> +        type: object
> +        properties:
> +          remote-endpoint:
> +            description: A phandle to the bus receiver's endpoint node.
> +
> +          clock-lanes:
> +            description: Should be set to 0 (clock lane on hardware lane 0).

The description of most of these properties should also be replaced with
yaml schema rules. Ideally there should also be constraints that tell
which properties can be specified together. For instance here's the
corresponding rules from the MT9M114 DT binding (not upstream yet).

  # See ../video-interfaces.txt for more details
  port:
    type: object
    properties:
      endpoint:
        type: object
        properties:
          bus-type:
            enum: [4, 5, 6]

          clock-lanes:
            items:
              - const: 0

          data-lanes:
            items:
              - const: 1

          bus-width:
            items:
              - const: 8

          hsync-active:
            items:
              - const: 1

          vsync-active:
            items:
              - const: 1

        required:
          - bus-type

        allOf:
          - if:
              properties:
                bus-type:
                  const: 4
            then:
              properties:
                bus-width: false
                hsync-active: false
                vsync-active: false

          - if:
              properties:
                bus-type:
                  const: 5
            then:
              properties:
                clock-lanes: false
                data-lanes: false

          - if:
              properties:
                bus-type:
                  const: 6
            then:
              properties:
                clock-lanes: false
                data-lanes: false
                hsync-active: false
                vsync-active: false

        unevaluatedProperties: false

These comments apply to other patches in this series.

> +
> +          data-lanes:
> +            description: |
> +              Should be set to <1> or <1 2> (one or two CSI-2 lanes supported).
> +
> +          bus-width:
> +            description: |
> +              Shall be set to <8> for 8 bits parallel bus or <10> for 10 bits
> +              parallel bus.
> +
> +          data-shift:
> +            description: |
> +              Shall be set to <2> for 8 bits parallel bus (lines 9:2 are used) or
> +              <0> for 10 bits parallel bus.
> +
> +          hsync-active:
> +            description: |
> +              Active state of the HSYNC signal, 0/1 for LOW/HIGH respectively.
> +
> +          vsync-active:
> +            description: |
> +              Active state of the VSYNC signal, 0/1 for LOW/HIGH respectively.
> +
> +          pclk-sample:
> +            description: |
> +              Sample data on rising (1) or falling (0) edge of the pixel clock
> +              signal.
> +
> +        required:
> +          - remote-endpoint
> +
> +    additionalProperties: false
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - DOVDD-supply
> +  - AVDD-supply
> +  - DVDD-supply
> +  - port
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/clock/imx6qdl-clock.h>
> +
> +    i2c0 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        camera@3c {
> +            compatible = "ovti,ov5640";
> +            reg = <0x3c>;
> +            clocks = <&clks IMX6QDL_CLK_CKO>;
> +            clock-names = "xclk";
> +            DOVDD-supply = <&vgen4_reg>; /* 1.8v */
> +            AVDD-supply = <&vgen3_reg>;  /* 2.8v */
> +            DVDD-supply = <&vgen2_reg>;  /* 1.5v */
> +            powerdown-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
> +            reset-gpios = <&gpio1 20 GPIO_ACTIVE_LOW>;
> +            rotation = <180>;
> +
> +            port {
> +                ov5640_to_mipi_csi2: endpoint {
> +                    remote-endpoint = <&mipi_csi2_from_ov5640>;
> +                    clock-lanes = <0>;
> +                    data-lanes = <1 2>;
> +                };
> +            };
> +        };
> +    };
> +
> +    i2c1 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        camera@3c {
> +            compatible = "ovti,ov5640";
> +            reg = <0x3c>;
> +            clocks = <&clks IMX6QDL_CLK_CKO>;
> +            clock-names = "xclk";
> +            DOVDD-supply = <&vgen4_reg>; /* 1.8v */
> +            AVDD-supply = <&vgen3_reg>;  /* 2.8v */
> +            DVDD-supply = <&vgen2_reg>;  /* 1.5v */
> +            powerdown-gpios = <&gpio1 19 GPIO_ACTIVE_HIGH>;
> +            reset-gpios = <&gpio1 20 GPIO_ACTIVE_LOW>;
> +            rotation = <180>;
> +
> +            port {
> +                ov5640_to_parallel: endpoint {
> +                    remote-endpoint = <&parallel_from_ov5640>;
> +                    bus-width = <8>;
> +                };
> +            };
> +        };
> +    };
> +
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index c74d25c58e1a..0160d7567ed3 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12605,6 +12605,7 @@ L:	linux-media@vger.kernel.org
>  S:	Maintained
>  T:	git git://linuxtv.org/media_tree.git
>  F:	drivers/media/i2c/ov5640.c
> +F:	Documentation/devicetree/bindings/media/i2c/ov5640.yaml
> 
>  OMNIVISION OV5647 SENSOR DRIVER
>  M:	Jacopo Mondi <jacopo@jmondi.org>

-- 
Regards,

Laurent Pinchart