Re: [V9, 1/2] media: dt-bindings: media: i2c: Document OV02A10 bindings

[Dongchun Zhu <dongchun.zhu@mediatek.com>]

Hi Rob,

Thanks for the review. Please see my replies below.

On Tue, 2020-05-26 at 12:28 -0600, Rob Herring wrote:
> On Sat, May 23, 2020 at 04:41:02PM +0800, Dongchun Zhu wrote:
> > Add DT bindings documentation for Omnivision OV02A10 image sensor.
> > 
> > Signed-off-by: Dongchun Zhu <dongchun.zhu@mediatek.com>
> > ---
> >  .../bindings/media/i2c/ovti,ov02a10.yaml           | 172 +++++++++++++++++++++
> >  MAINTAINERS                                        |   7 +
> >  2 files changed, 179 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > new file mode 100644
> > index 0000000..56f31b5
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > @@ -0,0 +1,172 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +# Copyright (c) 2020 MediaTek Inc.
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/media/i2c/ovti,ov02a10.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Omnivision OV02A10 CMOS Sensor Device Tree Bindings
> > +
> > +maintainers:
> > +  - Dongchun Zhu <dongchun.zhu@mediatek.com>
> > +
> > +description: |-
> > +  The Omnivision OV02A10 is a low-cost, high performance, 1/5-inch, 2 megapixel
> > +  image sensor, which is the latest production derived from Omnivision's CMOS
> > +  image sensor technology. Ihis chip supports high frame rate speeds up to 30fps
> > +  @ 1600x1200 (UXGA) resolution transferred over a 1-lane MIPI interface. The
> > +  sensor output is available via CSI-2 serial data output.
> > +
> > +properties:
> > +  compatible:
> > +    const: ovti,ov02a10
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    items:
> > +      - description: top mux camtg clock
> > +      - description: divider clock
> > +
> > +  clock-names:
> > +    items:
> > +      - const: eclk
> > +      - const: freq_mux
> > +
> > +  clock-frequency:
> > +    description:
> > +      Frequency of the eclk clock in Hertz.
> > +

Rob, shall we use 'maxItems: 1' to constrain property: clock-frequency?
Or could we adopt 'clock-frequency: true' directly here?

> > +  dovdd-supply:
> > +    description:
> > +      Definition of the regulator used as Digital I/O voltage supply.
> > +

Shall we add 'maxItems: 1' here?

> > +  avdd-supply:
> > +    description:
> > +      Definition of the regulator used as Analog voltage supply.
> > +

Ditto.

> > +  dvdd-supply:
> > +    description:
> > +      Definition of the regulator used as Digital core voltage supply.
> > +

Ditto.

> > +  powerdown-gpios:
> > +    description:
> > +      Must be the device tree identifier of the GPIO connected to the
> > +      PD_PAD pin. This pin is used to place the OV02A10 into Standby mode
> > +      or Shutdown mode. As the line is active low, it should be
> > +      marked GPIO_ACTIVE_LOW.
> 
> Need to define how many GPIOs ('maxItems: 1')
> 

It would be fixed like this in next release.
powerdown-gpios:
  maxItems: 1
  description:
    Must be the device tree identifier of the GPIO connected to the
    PD_PAD pin. This pin is used to place the OV02A10 into Standby mode
    or Shutdown mode. As the line is active low, it should be
    marked GPIO_ACTIVE_LOW.

> > +
> > +  reset-gpios:
> > +    description:
> > +      Must be the device tree identifier of the GPIO connected to the
> > +      RST_PD pin. If specified, it will be asserted during driver probe.
> > +      As the line is active high, it should be marked GPIO_ACTIVE_HIGH.
> 
> Here too.
> 

Similar as 'powerdown-gpios'.
Fixed in next release.

> > +
> > +  rotation:
> > +    description:
> > +      Definition of the sensor's placement.
> > +    allOf:
> > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > +      - enum:
> > +          - 0    # Sensor Mounted Upright
> > +          - 180  # Sensor Mounted Upside Down
> > +        default: 0
> > +
> > +  ovti,mipi-tx-speed:
> > +    description:
> > +      Indication of MIPI transmission speed select, which is to control D-PHY
> > +      timing setting by adjusting MIPI clock voltage to improve the clock
> > +      driver capability.
> > +    allOf:
> > +      - $ref: "/schemas/types.yaml#/definitions/uint32"
> > +      - enum:
> > +          - 0    #  20MHz -  30MHz
> > +          - 1    #  30MHz -  50MHz
> > +          - 2    #  50MHz -  75MHz
> > +          - 3    #  75MHz - 100MHz
> > +          - 4    # 100MHz - 130MHz
> > +        default: 3
> > +
> > +  # See ../video-interfaces.txt for details
> > +  port:
> > +    type: object
> > +    additionalProperties: false
> 
> Should have a description of what data the port has.
> 

It would be updated as below in next release.
port:
  type: object
  additionalProperties: false
  description:
    Input port node, single endpoint describing the CSI-2 transmitter.

> > +
> > +    properties:
> > +      endpoint:
> > +        type: object
> > +        additionalProperties: false
> > +
> > +        properties:

Actually I wonder whether we need to declare 'clock-lanes' here?

> > +          data-lanes:
> > +            maxItems: 1
> > +
> > +          link-frequencies: true
> > +          remote-endpoint: true
> > +
> > +        required:

Ditto.

> > +          - data-lanes
> > +          - link-frequencies
> > +          - remote-endpoint
> > +
> > +    required:
> > +      - endpoint
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - clocks
> > +  - clock-names
> > +  - clock-frequency
> > +  - dovdd-supply
> > +  - avdd-supply
> > +  - dvdd-supply
> > +  - powerdown-gpios
> > +  - reset-gpios
> > +  - port
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +
> > +    #include <dt-bindings/clock/mt8183-clk.h>
> > +    #include <dt-bindings/gpio/gpio.h>
> > +
> > +    i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        ov02a10: camera-sensor@3d {
> > +            compatible = "ovti,ov02a10";
> > +            reg = <0x3d>;
> > +            pinctrl-names = "default";
> > +            pinctrl-0 = <&clk_24m_cam>;
> > +
> > +            clocks = <&topckgen CLK_TOP_MUX_CAMTG>,
> > +                     <&topckgen CLK_TOP_UNIVP_192M_D8>;
> > +            clock-names = "eclk", "freq_mux";
> > +            clock-frequency = <24000000>;
> > +
> > +            rotation = <180>;
> > +            ovti,mipi-tx-speed = <4>;
> > +
> > +            dovdd-supply = <&mt6358_vcamio_reg>;
> > +            avdd-supply = <&mt6358_vcama1_reg>;
> > +            dvdd-supply = <&mt6358_vcn18_reg>;
> > +
> > +            powerdown-gpios = <&pio 107 GPIO_ACTIVE_LOW>;
> > +            reset-gpios = <&pio 109 GPIO_ACTIVE_HIGH>;
> > +
> > +            port {
> > +                wcam_out: endpoint {
> > +                    data-lanes = <1>;
> > +                    link-frequencies = /bits/ 64 <390000000>;
> > +                    remote-endpoint = <&mipi_in_wcam>;
> > +                };
> > +            };
> > +        };
> > +    };
> > +
> > +...
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index e64e5db..63a2335 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12389,6 +12389,13 @@ M:	Harald Welte <laforge@gnumonks.org>
> >  S:	Maintained
> >  F:	drivers/char/pcmcia/cm4040_cs.*
> >  
> > +OMNIVISION OV02A10 SENSOR DRIVER
> > +M:	Dongchun Zhu <dongchun.zhu@mediatek.com>
> > +L:	linux-media@vger.kernel.org
> > +S:	Maintained
> > +T:	git git://linuxtv.org/media_tree.git
> > +F:	Documentation/devicetree/bindings/media/i2c/ovti,ov02a10.yaml
> > +
> >  OMNIVISION OV13858 SENSOR DRIVER
> >  M:	Sakari Ailus <sakari.ailus@linux.intel.com>
> >  L:	linux-media@vger.kernel.org
> > -- 
> > 2.9.2