Re: [v2 1/3] media: dt-bindings: ov8856: Document YAML bindings

[Sakari Ailus]

Hi Robert,

On Fri, Mar 13, 2020 at 12:03:48PM +0100, Robert Foss wrote:
> From: Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx>
> 
> This patch adds documentation of device tree in YAML schema for the
> OV8856 CMOS image sensor.
> 
> Signed-off-by: Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx>
> Signed-off-by: Robert Foss <robert.foss@xxxxxxxxxx>
> ---
> 
> - Changes since v4:
>   * Fabio: Change reset-gpio to GPIO_ACTIVE_LOW, explain in description
>   * Add clock-lanes property to example
>   * robher: Fix syntax error in devicetree example
> 
> - Changes since v3:
>   * robher: Fix syntax error
>   * robher: Removed maxItems
>   * Fixes yaml 'make dt-binding-check' errors
> 
> - Changes since v2:
>   Fixes comments from from Andy, Tomasz, Sakari, Rob.
>   * Convert text documentation to YAML schema.
> 
> - Changes since v1:
>   Fixes comments from Sakari, Tomasz
>   * Add clock-frequency and link-frequencies in DT
> 
>  .../devicetree/bindings/media/i2c/ov8856.yaml | 133 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 134 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> 
> diff --git a/Documentation/devicetree/bindings/media/i2c/ov8856.yaml b/Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> new file mode 100644
> index 000000000000..f5cb9add9277
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> @@ -0,0 +1,133 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright (c) 2019 MediaTek Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/media/i2c/ov8856.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Omnivision OV8856 CMOS Sensor Device Tree Bindings
> +
> +maintainers:
> +  - Ben Kao <ben.kao@xxxxxxxxx>

Is Ben aware of this?

> +  - Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx>
> +
> +description: |-
> +  The Omnivision OV8856 is a high performance, 1/4-inch, 8 megapixel, CMOS
> +  image sensor that delivers 3264x2448 at 30fps. It provides full-frame,
> +  sub-sampled, and windowed 10-bit MIPI images in various formats via the
> +  Serial Camera Control Bus (SCCB) interface. This chip is programmable
> +  through I2C and two-wire SCCB. The sensor output is available via CSI-2
> +  serial data output (up to 4-lane).
> +
> +properties:
> +  compatible:
> +    const: ovti,ov8856
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  clock-names:
> +    description:
> +      Input clock for the sensor.
> +    items:
> +      - const: xvclk
> +
> +  clock-frequency:
> +    description:
> +      Frequency of the xvclk clock in Hertz.
> +
> +  dovdd-supply:
> +    description:
> +      Definition of the regulator used as interface power supply.
> +
> +  avdd-supply:
> +    description:
> +      Definition of the regulator used as analog power supply.
> +
> +  dvdd-supply:
> +    description:
> +      Definition of the regulator used as digital power supply.
> +
> +  reset-gpios:
> +    description:
> +      The phandle and specifier for the GPIO that controls sensor reset.
> +      This corresponds to the hardware pin XSHUTDOWN which is physically
> +      active low.
> +
> +  port:
> +    type: object
> +    additionalProperties: false
> +    description:
> +      A node containing input and output port nodes with endpoint definitions
> +      as documented in
> +      Documentation/devicetree/bindings/media/video-interfaces.txt
> +
> +    properties:
> +      endpoint:
> +        type: object
> +
> +        properties:
> +          clock-lanes:
> +            maxItems: 1
> +
> +          data-lanes:
> +            maxItems: 1
> +
> +          remote-endpoint: true
> +
> +        required:
> +          - clock-lanes

Do you need the clock-lanes property, i.e. does the device support lane
reordering? If not, it should be removed.

> +          - data-lanes
> +          - remote-endpoint
> +
> +    required:
> +      - endpoint
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - clock-names
> +  - clock-frequency
> +  - dovdd-supply
> +  - avdd-supply
> +  - dvdd-supply
> +  - reset-gpios
> +  - port
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +    #include <dt-bindings/clock/qcom,camcc-sdm845.h>
> +
> +    ov8856: camera-sensor@10 {
> +        compatible = "ovti,ov8856";
> +        reg = <0x10>;
> +        reset-gpios = <&pio 111 GPIO_ACTIVE_LOW>;
> +        pinctrl-names = "default";
> +        pinctrl-0 = <&clk_24m_cam>;
> +
> +        clocks = <&clock_camcc CAM_CC_MCLK0_CLK>;
> +        clock-names = "xvclk";
> +        clock-frequency = <19200000>;
> +
> +        avdd-supply = <&mt6358_vcama2_reg>;
> +        dvdd-supply = <&mt6358_vcamd_reg>;
> +        dovdd-supply = <&mt6358_vcamio_reg>;
> +
> +        port {
> +            wcam_out: endpoint {
> +                remote-endpoint = <&mipi_in_wcam>;
> +                clock-lanes = <0>;
> +                data-lanes = <1 2 3 4>;
> +                link-frequencies = /bits/ 64 <360000000 180000000>;
> +            };
> +        };
> +    };
> +
> +...
> \ No newline at end of file
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a6fbdf354d34..0f99e863978a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12355,6 +12355,7 @@ L:	linux-media@xxxxxxxxxxxxxxx
>  T:	git git://linuxtv.org/media_tree.git
>  S:	Maintained
>  F:	drivers/media/i2c/ov8856.c
> +F:	Documentation/devicetree/bindings/media/i2c/ov8856.yaml
>  
>  OMNIVISION OV9650 SENSOR DRIVER
>  M:	Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>

-- 
Regards,

Sakari Ailus