Re: [PATCH] dt-bindings: media: imx214: Convert to json-schema

[Rob Herring <robh@kernel.org>]

On Mon, Aug 24, 2020 at 10:18:10AM +0200, Jacopo Mondi wrote:
> Hi Laurent,
> 
> On Wed, Aug 19, 2020 at 04:28:23PM +0300, Laurent Pinchart wrote:
> > Hi Jacopo,
> >
> > Thank you for the patch.
> >
> > On Tue, Aug 18, 2020 at 02:17:55PM +0200, Jacopo Mondi wrote:
> > > Convert the imx214 bindings document to json-schema and update
> > > the MAINTAINERS file accordingly.
> > >
> > > Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
> > > ---
> > >  .../bindings/media/i2c/sony,imx214.txt        |  53 --------
> > >  .../bindings/media/i2c/sony,imx214.yaml       | 124 ++++++++++++++++++
> > >  MAINTAINERS                                   |   2 +-
> > >  3 files changed, 125 insertions(+), 54 deletions(-)
> > >  delete mode 100644 Documentation/devicetree/bindings/media/i2c/sony,imx214.txt
> > >  create mode 100644 Documentation/devicetree/bindings/media/i2c/sony,imx214.yaml
> > >
> > > diff --git a/Documentation/devicetree/bindings/media/i2c/sony,imx214.txt b/Documentation/devicetree/bindings/media/i2c/sony,imx214.txt
> > > deleted file mode 100644
> > > index f11f28a5fda4..000000000000
> > > --- a/Documentation/devicetree/bindings/media/i2c/sony,imx214.txt
> > > +++ /dev/null
> > > @@ -1,53 +0,0 @@
> > > -* Sony 1/3.06-Inch 13.13Mp CMOS Digital Image Sensor
> > > -
> > > -The Sony imx214 is a 1/3.06-inch CMOS active pixel digital image sensor with
> > > -an active array size of 4224H x 3200V. It is programmable through an I2C
> > > -interface.
> > > -Image data is sent through MIPI CSI-2, through 2 or 4 lanes at a maximum
> > > -throughput of 1.2Gbps/lane.
> > > -
> > > -
> > > -Required Properties:
> > > -- compatible: Shall be "sony,imx214".
> > > -- reg: I2C bus address of the device. Depending on how the sensor is wired,
> > > -       it shall be <0x10> or <0x1a>;
> > > -- enable-gpios: GPIO descriptor for the enable pin.
> > > -- vdddo-supply: Chip digital IO regulator (1.8V).
> > > -- vdda-supply: Chip analog regulator (2.7V).
> > > -- vddd-supply: Chip digital core regulator (1.12V).
> > > -- clocks: Reference to the xclk clock.
> > > -- clock-frequency: Frequency of the xclk clock.
> > > -
> > > -Optional Properties:
> > > -- flash-leds: See ../video-interfaces.txt
> > > -- lens-focus: See ../video-interfaces.txt
> > > -
> > > -The imx214 device node shall contain one 'port' child node with
> > > -an 'endpoint' subnode. For further reading on port node refer to
> > > -Documentation/devicetree/bindings/media/video-interfaces.txt.
> > > -
> > > -Required Properties on endpoint:
> > > -- data-lanes: check ../video-interfaces.txt
> > > -- link-frequencies: check ../video-interfaces.txt
> > > -- remote-endpoint: check ../video-interfaces.txt
> > > -
> > > -Example:
> > > -
> > > -	camera-sensor@1a {
> > > -		compatible = "sony,imx214";
> > > -		reg = <0x1a>;
> > > -		vdddo-supply = <&pm8994_lvs1>;
> > > -		vddd-supply = <&camera_vddd_1v12>;
> > > -		vdda-supply = <&pm8994_l17>;
> > > -		lens-focus = <&ad5820>;
> > > -		enable-gpios = <&msmgpio 25 GPIO_ACTIVE_HIGH>;
> > > -		clocks = <&mmcc CAMSS_MCLK0_CLK>;
> > > -		clock-frequency = <24000000>;
> > > -		port {
> > > -			imx214_ep: endpoint {
> > > -				data-lanes = <1 2 3 4>;
> > > -				link-frequencies = /bits/ 64 <480000000>;
> > > -				remote-endpoint = <&csiphy0_ep>;
> > > -			};
> > > -		};
> > > -	};
> > > diff --git a/Documentation/devicetree/bindings/media/i2c/sony,imx214.yaml b/Documentation/devicetree/bindings/media/i2c/sony,imx214.yaml
> > > new file mode 100644
> > > index 000000000000..ddd4627214b1
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/media/i2c/sony,imx214.yaml
> > > @@ -0,0 +1,124 @@
> > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/media/i2c/sony,imx214.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Sony 1/3.06-Inch 13.13Mp CMOS Digital Image Sensor
> >
> > s/Mp/MP/
> >
> > > +
> > > +maintainers:
> > > +  - Ricardo Ribalda <ribalda@kernel.org>
> > > +
> > > +description: -|
> > > +  The Sony imx214 is a 1/3.06-inch CMOS active pixel digital image sensor with
> >
> > s/imx214/IMX214/
> >
> > > +  an active array size of 4224H x 3200V. It is programmable through an I2C
> > > +  interface.  Image data is sent through MIPI CSI-2, through 2 or 4 lanes at a
> >
> > s/  Image/ Image/
> >
> > > +  maximum throughput of 1.2Gbps/lane.
> > > +
> > > +properties:
> > > +  compatible:
> > > +    const: sony,imx214
> > > +
> > > +  reg:
> > > +    description: -|
> > > +      I2C device address. Depends on how the sensor is wired.
> >
> > I'd drop the description, it's fairly evident as it's an I2C device,
> > isn't it ?
> >
> > > +    enum:
> > > +      - 0x10
> > > +      - 0x1a
> > > +
> > > +  clocks:
> > > +    description: Reference to the xclk clock.
> > > +    maxItems: 1
> > > +
> > > +  clock-frequency:
> > > +    description: Frequency of the xclk clock in Hz.
> > > +
> > > +  enable-gpios:
> > > +    description: GPIO descriptor for the enable pin.
> > > +    maxItems: 1
> > > +
> > > +  vdddo-supply:
> > > +    description: Chip digital IO regulator (1.8V).
> > > +    maxItems: 1
> > > +
> > > +  vdda-supply:
> > > +    description: Chip analog regulator (2.7V).
> > > +    maxItems: 1
> > > +
> > > +  vddd-supply:
> > > +    description: Chip digital core regulator (1.12V).
> > > +    maxItems: 1
> > > +
> > > +  flash-leds:
> > > +    description: See ../video-interfaces.txt
> > > +
> > > +  lens-focus:
> > > +    description: See ../video-interfaces.txt
> > > +
> > > +  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.
> >
> > I'd drop this, the port node is already described as required below.
> >
> > > +
> > > +    properties:
> > > +      endpoint:
> > > +        type: object
> > > +        properties:
> > > +          remote-endpoint:
> > > +            description: See ../video-interfaces.txt
> > > +
> > > +          data-lanes:
> > > +            description: See ../video-interfaces.txt
> >
> > Shouldn't this also express that only 2 or 4 data lanes are allowed ?
> 
> I can't tell. I don't have the device manual, nor I'm the maintainer
> of the driver, so I barely translated the existing bindings into yaml.
> Spelling improvements apart, I won't modify the existing in this
> patch, but possibly on top.
> 
> That' said, in this case the device description reports "supports 2 or
> 4 lanes" so that's probably the case and this could be done already ?
> 
> >
> >             $ref: /schemas/types.yaml#/definitions/uint32-array
> >             description: See ../video-interfaces.txt
> >             anyOf:
> >               - items:
> >                   - const: 1
> >                   - const: 2
> >               - items:
> >                   - const: 1
> >                   - const: 2
> >                   - const: 3
> >                   - const: 4
> >
> > Maybe someone more experienced with YAML schemas could propose a better
> > way to express this ? I initially tried to express it with enum instead
> > of anyOf but couldn't get it to work.
> 
> FWIW I can trick the validator to work with
> 
>           data-lanes:
>             description: See ../video-interfaces.txt
>             enum:
>               - [[1, 2]]
>               - [[1, 2, 3, 4]]
> 
> If I drop the ugly double [[ ]] I get a complaint for:
> camera-sensor@1a: port:endpoint:data-lanes: [[1, 2, 3, 4]] is not one of [[1, 2], [1, 2, 3, 4]]

That exposes that the data encoding is an array of an array which I 
don't really want to do in schemas. To fix this, we would need to 
rework the fix-ups for this case and they are fairly fragile code 
(which I've rewritten like 3 times now). 

I'd stick with Laurent's suggestion for now and put supporting this on 
my todo.

> which makes me think the way we express the property makes the
> validator parse it as an array of arrays of uint32_t.

In case you're curious, the reason why everything is an array of arrays 
is because dtc has no way of knowing if a given property is an array 
with a single element or always a scalar. And then we treat the 
bracketing in dts as significant. 

Rob