[v10,1/3] media: dt-bindings: ov8856: Document YAML bindings

Commit Message

Robert Foss May 5, 2020, 10:01 a.m. UTC

From: Dongchun Zhu <[e-mail]>

This patch adds documentation of device tree in YAML schema for the
OV8856 CMOS image sensor.

Signed-off-by: Dongchun Zhu <[e-mail]>
Signed-off-by: Robert Foss <[e-mail]>
Reviewed-by: Maxime Ripard <[e-mail]>
---

- Changes since v9:
  * Remove remote-endpoint property
  * Marco: Make port property required again
  * Sakari: Remove Ben as a maintainer
  * Sakari: Replace data-lanes with const items
  * Sakari: Remove clock-lanes property
  * Sakari & Rob Herring: Change type of link-frequency
    work around dt-schema bug

- Changes since v8:
  * Maxime: Added r-b

- Changes since v7:
  * Marco: Make 'port' property optional
  * Maxime & Sakari: Add 'link-frequencies' property to dt binding
  * robher: Improve description for 'port' property

- Changes since v6:
  * Marco: remove qcom specifics from DT example
   
- Changes since v5:
  * Add assigned-clocks and assigned-clock-rates
  * robher: dt-schema errors

- 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:

- Changes since v1:
  Fixes comments from Sakari, Tomasz
  * Add clock-frequency and link-frequencies in DT

 .../devicetree/bindings/media/i2c/ov8856.yaml | 142 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 143 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ov8856.yaml

Comments

Dongchun Zhu May 5, 2020, 11:47 a.m. UTC | #1

Hi Robert,

Thanks for the update.

On Tue, 2020-05-05 at 12:01 +0200, Robert Foss wrote:
> From: Dongchun Zhu <[e-mail]>
> 
> This patch adds documentation of device tree in YAML schema for the
> OV8856 CMOS image sensor.
> 
> Signed-off-by: Dongchun Zhu <[e-mail]>
> Signed-off-by: Robert Foss <[e-mail]>
> Reviewed-by: Maxime Ripard <[e-mail]>
> ---
> 
> - Changes since v9:
>   * Remove remote-endpoint property
>   * Marco: Make port property required again
>   * Sakari: Remove Ben as a maintainer
>   * Sakari: Replace data-lanes with const items
>   * Sakari: Remove clock-lanes property
>   * Sakari & Rob Herring: Change type of link-frequency
>     work around dt-schema bug
> 
> - Changes since v8:
>   * Maxime: Added r-b
> 
> - Changes since v7:
>   * Marco: Make 'port' property optional
>   * Maxime & Sakari: Add 'link-frequencies' property to dt binding
>   * robher: Improve description for 'port' property
> 
> - Changes since v6:
>   * Marco: remove qcom specifics from DT example
>    
> - Changes since v5:
>   * Add assigned-clocks and assigned-clock-rates
>   * robher: dt-schema errors
> 
> - 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:
> 
> - Changes since v1:
>   Fixes comments from Sakari, Tomasz
>   * Add clock-frequency and link-frequencies in DT
> 
>  .../devicetree/bindings/media/i2c/ov8856.yaml | 142 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 143 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..d6af685ad3ca
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> @@ -0,0 +1,142 @@
> +# 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:
> +  - Dongchun Zhu <[e-mail]>
> +
> +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 an output port node with an endpoint definition
> +      as documented in
> +      Documentation/devicetree/bindings/media/video-interfaces.txt
> +
> +    properties:
> +      endpoint:
> +        type: object
> +
> +        properties:
> +          data-lanes:
> +            description: |-
> +              The driver only supports four-lane operation.
> +            items:
> +              - const: 1
> +              - const: 2
> +              - const: 3
> +              - const: 4
> +
> +          link-frequencies:
> +            allOf:
> +              - $ref: /schemas/types.yaml#/definitions/uint64-array
> +            description:
> +              Allowed data bus frequencies. 360000000, 180000000 Hz or both
> +              are supported by the driver.
> +
> +
> +        required:
> +          - link-frequencies
> +
> +    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>
> +
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        ov8856: camera@10 {
> +            compatible = "ovti,ov8856";
> +            reg = <0x10>;
> +
> +            reset-gpios = <&pio 111 GPIO_ACTIVE_LOW>;

Apologies for missing to follow the earlier discussion related to this.
I noticed the GPIO flag para and __ov8856_power_on() are aligned using
ACTIVE_LOW.

But from the datasheet, XSHUTDN pin is active-high for OV8856.
It means devm_gpiod_get API (in probe func) should use GPIOD_OUT_LOW to
initialize the GPIO as output with a value of 0.
Otherwise it should use GPIOD_OUT_HIGH.

There is one case for GPIO_ACTIVE_LOW setting:
https://patchwork.linuxtv.org/patch/63460/
https://patchwork.linuxtv.org/patch/63461/

Sakari, Tomasz, am I right?

> +            pinctrl-names = "default";
> +            pinctrl-0 = <&clk_24m_cam>;
> +
> +            clocks = <&cam_osc>;
> +            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>;
> +                    data-lanes = <1 2 3 4>;
> +                    link-frequencies = /bits/ 64 <360000000>;
> +                };
> +            };
> +        };
> +    };
> +...
> \ No newline at end of file
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 26f281d9f32a..84b262afd13d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12489,6 +12489,7 @@ L:	[e-mail]
>  S:	Maintained
>  T:	git git://linuxtv.org/media_tree.git
>  F:	drivers/media/i2c/ov8856.c
> +F:	Documentation/devicetree/bindings/media/i2c/ov8856.yaml
>  

Had you run parse-maintainers.pl?
The new item is supposed to be arranged in alphabetical order.

>  OMNIVISION OV9640 SENSOR DRIVER
>  M:	Petr Cvek <[e-mail]>

Rob Herring May 5, 2020, 3:48 p.m. UTC | #2

On Tue,  5 May 2020 12:01:29 +0200, Robert Foss wrote:
> From: Dongchun Zhu <[e-mail]>
> 
> This patch adds documentation of device tree in YAML schema for the
> OV8856 CMOS image sensor.
> 
> Signed-off-by: Dongchun Zhu <[e-mail]>
> Signed-off-by: Robert Foss <[e-mail]>
> Reviewed-by: Maxime Ripard <[e-mail]>
> ---
> 
> - Changes since v9:
>   * Remove remote-endpoint property
>   * Marco: Make port property required again
>   * Sakari: Remove Ben as a maintainer
>   * Sakari: Replace data-lanes with const items
>   * Sakari: Remove clock-lanes property
>   * Sakari & Rob Herring: Change type of link-frequency
>     work around dt-schema bug
> 
> - Changes since v8:
>   * Maxime: Added r-b
> 
> - Changes since v7:
>   * Marco: Make 'port' property optional
>   * Maxime & Sakari: Add 'link-frequencies' property to dt binding
>   * robher: Improve description for 'port' property
> 
> - Changes since v6:
>   * Marco: remove qcom specifics from DT example
>    
> - Changes since v5:
>   * Add assigned-clocks and assigned-clock-rates
>   * robher: dt-schema errors
> 
> - 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:
> 
> - Changes since v1:
>   Fixes comments from Sakari, Tomasz
>   * Add clock-frequency and link-frequencies in DT
> 
>  .../devicetree/bindings/media/i2c/ov8856.yaml | 142 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 143 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> 

Reviewed-by: Rob Herring <[e-mail]>

Rob Herring May 5, 2020, 3:49 p.m. UTC | #3

On Tue,  5 May 2020 12:01:29 +0200, Robert Foss wrote:
> From: Dongchun Zhu <[e-mail]>
> 
> This patch adds documentation of device tree in YAML schema for the
> OV8856 CMOS image sensor.
> 
> Signed-off-by: Dongchun Zhu <[e-mail]>
> Signed-off-by: Robert Foss <[e-mail]>
> Reviewed-by: Maxime Ripard <[e-mail]>
> ---
> 
> - Changes since v9:
>   * Remove remote-endpoint property
>   * Marco: Make port property required again
>   * Sakari: Remove Ben as a maintainer
>   * Sakari: Replace data-lanes with const items
>   * Sakari: Remove clock-lanes property
>   * Sakari & Rob Herring: Change type of link-frequency
>     work around dt-schema bug
> 
> - Changes since v8:
>   * Maxime: Added r-b
> 
> - Changes since v7:
>   * Marco: Make 'port' property optional
>   * Maxime & Sakari: Add 'link-frequencies' property to dt binding
>   * robher: Improve description for 'port' property
> 
> - Changes since v6:
>   * Marco: remove qcom specifics from DT example
>    
> - Changes since v5:
>   * Add assigned-clocks and assigned-clock-rates
>   * robher: dt-schema errors
> 
> - 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:
> 
> - Changes since v1:
>   Fixes comments from Sakari, Tomasz
>   * Add clock-frequency and link-frequencies in DT
> 
>  .../devicetree/bindings/media/i2c/ov8856.yaml | 142 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 143 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> 

Reviewed-by: Rob Herring <[e-mail]>

Robert Foss May 6, 2020, 11:29 a.m. UTC | #4

Hey Dongchun,

Thanks for having a look at this series.

> > +examples:
> > +  - |
> > +    #include <dt-bindings/gpio/gpio.h>
> > +
> > +    i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        ov8856: camera@10 {
> > +            compatible = "ovti,ov8856";
> > +            reg = <0x10>;
> > +
> > +            reset-gpios = <&pio 111 GPIO_ACTIVE_LOW>;
>
> Apologies for missing to follow the earlier discussion related to this.
> I noticed the GPIO flag para and __ov8856_power_on() are aligned using
> ACTIVE_LOW.
>
> But from the datasheet, XSHUTDN pin is active-high for OV8856.
> It means devm_gpiod_get API (in probe func) should use GPIOD_OUT_LOW to
> initialize the GPIO as output with a value of 0.
> Otherwise it should use GPIOD_OUT_HIGH.
>
> There is one case for GPIO_ACTIVE_LOW setting:
> https://patchwork.linuxtv.org/patch/63460/
> https://patchwork.linuxtv.org/patch/63461/

We went back and forth about this a few times, and I switched to this
gpio setting after having worked through the device probing reset gpio
toggling. Semantically it seemed easier to understand in the driver,
since the gpio is called reset and not !shutdown.

Looking into devm_gpiod_get_optional(), the flag argument
GPIOD_OUT_LOW or HIGH for that matter is actually not used initialize
the output, but only used for an exclusivity check.
https://elixir.bootlin.com/linux/latest/source/drivers/gpio/gpiolib-devres.c#L109

If you prefer, I can invert the logic again. To me making the reset
gpio active resulting in the device being actually reset seems like
the most intuitive and easy to understand option.
The different OmniVision drivers seem to have different approaches to
this. The ov9640 driver for example is doing what this series
currently is doing.

>
> Sakari, Tomasz, am I right?
>
> > +            pinctrl-names = "default";
> > +            pinctrl-0 = <&clk_24m_cam>;
> > +
> > +            clocks = <&cam_osc>;
> > +            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>;
> > +                    data-lanes = <1 2 3 4>;
> > +                    link-frequencies = /bits/ 64 <360000000>;
> > +                };
> > +            };
> > +        };
> > +    };
> > +...
> > \ No newline at end of file
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 26f281d9f32a..84b262afd13d 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -12489,6 +12489,7 @@ L:    [e-mail]
> >  S:   Maintained
> >  T:   git git://linuxtv.org/media_tree.git
> >  F:   drivers/media/i2c/ov8856.c
> > +F:   Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> >
>
> Had you run parse-maintainers.pl?
> The new item is supposed to be arranged in alphabetical order.

No, I have not. But upon running it now, it doesn't make suggest any
changes. But let me order the files manually in the next revision.

However, I noticed I removed the wrong person from the maintainers
file in this revision.
So, I'll correct that and add you Dongchun as the maintainer if that's ok.

>
> >  OMNIVISION OV9640 SENSOR DRIVER
> >  M:   Petr Cvek <[e-mail]>
>

Robert Foss May 6, 2020, 11:30 a.m. UTC | #5

Thanks Rob!

On Tue, 5 May 2020 at 17:49, Rob Herring <[e-mail]> wrote:
>
> On Tue,  5 May 2020 12:01:29 +0200, Robert Foss wrote:
> > From: Dongchun Zhu <[e-mail]>
> >
> > This patch adds documentation of device tree in YAML schema for the
> > OV8856 CMOS image sensor.
> >
> > Signed-off-by: Dongchun Zhu <[e-mail]>
> > Signed-off-by: Robert Foss <[e-mail]>
> > Reviewed-by: Maxime Ripard <[e-mail]>
> > ---
> >
> > - Changes since v9:
> >   * Remove remote-endpoint property
> >   * Marco: Make port property required again
> >   * Sakari: Remove Ben as a maintainer
> >   * Sakari: Replace data-lanes with const items
> >   * Sakari: Remove clock-lanes property
> >   * Sakari & Rob Herring: Change type of link-frequency
> >     work around dt-schema bug
> >
> > - Changes since v8:
> >   * Maxime: Added r-b
> >
> > - Changes since v7:
> >   * Marco: Make 'port' property optional
> >   * Maxime & Sakari: Add 'link-frequencies' property to dt binding
> >   * robher: Improve description for 'port' property
> >
> > - Changes since v6:
> >   * Marco: remove qcom specifics from DT example
> >
> > - Changes since v5:
> >   * Add assigned-clocks and assigned-clock-rates
> >   * robher: dt-schema errors
> >
> > - 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:
> >
> > - Changes since v1:
> >   Fixes comments from Sakari, Tomasz
> >   * Add clock-frequency and link-frequencies in DT
> >
> >  .../devicetree/bindings/media/i2c/ov8856.yaml | 142 ++++++++++++++++++
> >  MAINTAINERS                                   |   1 +
> >  2 files changed, 143 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> >
>
> Reviewed-by: Rob Herring <[e-mail]>

Marco Felsch May 6, 2020, 12:26 p.m. UTC | #6

On 20-05-06 13:29, Robert Foss wrote:
> Hey Dongchun,
> 
> Thanks for having a look at this series.
> 
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/gpio/gpio.h>
> > > +
> > > +    i2c {
> > > +        #address-cells = <1>;
> > > +        #size-cells = <0>;
> > > +
> > > +        ov8856: camera@10 {
> > > +            compatible = "ovti,ov8856";
> > > +            reg = <0x10>;
> > > +
> > > +            reset-gpios = <&pio 111 GPIO_ACTIVE_LOW>;
> >
> > Apologies for missing to follow the earlier discussion related to this.
> > I noticed the GPIO flag para and __ov8856_power_on() are aligned using
> > ACTIVE_LOW.
> >
> > But from the datasheet, XSHUTDN pin is active-high for OV8856.
> > It means devm_gpiod_get API (in probe func) should use GPIOD_OUT_LOW to
> > initialize the GPIO as output with a value of 0.
> > Otherwise it should use GPIOD_OUT_HIGH.
> >
> > There is one case for GPIO_ACTIVE_LOW setting:
> > https://patchwork.linuxtv.org/patch/63460/
> > https://patchwork.linuxtv.org/patch/63461/
> 
> We went back and forth about this a few times, and I switched to this
> gpio setting after having worked through the device probing reset gpio
> toggling. Semantically it seemed easier to understand in the driver,
> since the gpio is called reset and not !shutdown.

IMHO you can keep your version. DTs are part of the system integration.
What if one system has a invert logic infront of the gpio input.. The
system integrator needs to read and to understand the schematic
correctly to pick the correct value.

> Looking into devm_gpiod_get_optional(), the flag argument
> GPIOD_OUT_LOW or HIGH for that matter is actually not used initialize

The good think about gpiod is that it care about logic values not
physical/electrical values. If you set GPIOD_OUT_HIGH then the reset is
asserted, whatever asserted means electrical.

Regards,
  Marco

> the output, but only used for an exclusivity check.
> https://elixir.bootlin.com/linux/latest/source/drivers/gpio/gpiolib-devres.c#L109
> 
> If you prefer, I can invert the logic again. To me making the reset
> gpio active resulting in the device being actually reset seems like
> the most intuitive and easy to understand option.
> The different OmniVision drivers seem to have different approaches to
> this. The ov9640 driver for example is doing what this series
> currently is doing.
> 
> >
> > Sakari, Tomasz, am I right?
> >
> > > +            pinctrl-names = "default";
> > > +            pinctrl-0 = <&clk_24m_cam>;
> > > +
> > > +            clocks = <&cam_osc>;
> > > +            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>;
> > > +                    data-lanes = <1 2 3 4>;
> > > +                    link-frequencies = /bits/ 64 <360000000>;
> > > +                };
> > > +            };
> > > +        };
> > > +    };
> > > +...
> > > \ No newline at end of file
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 26f281d9f32a..84b262afd13d 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -12489,6 +12489,7 @@ L:    [e-mail]
> > >  S:   Maintained
> > >  T:   git git://linuxtv.org/media_tree.git
> > >  F:   drivers/media/i2c/ov8856.c
> > > +F:   Documentation/devicetree/bindings/media/i2c/ov8856.yaml
> > >
> >
> > Had you run parse-maintainers.pl?
> > The new item is supposed to be arranged in alphabetical order.
> 
> No, I have not. But upon running it now, it doesn't make suggest any
> changes. But let me order the files manually in the next revision.
> 
> However, I noticed I removed the wrong person from the maintainers
> file in this revision.
> So, I'll correct that and add you Dongchun as the maintainer if that's ok.
> 
> >
> > >  OMNIVISION OV9640 SENSOR DRIVER
> > >  M:   Petr Cvek <[e-mail]>
> >
>

Patch

diff --git a/Documentation/devicetree/bindings/media/i2c/ov8856.yaml b/Documentation/devicetree/bindings/media/i2c/ov8856.yaml
new file mode 100644
index 000000000000..d6af685ad3ca
--- /dev/null
+++ b/Documentation/devicetree/bindings/media/i2c/ov8856.yaml
@@ -0,0 +1,142 @@ 
+# 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:
+  - Dongchun Zhu <[e-mail]>
+
+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 an output port node with an endpoint definition
+      as documented in
+      Documentation/devicetree/bindings/media/video-interfaces.txt
+
+    properties:
+      endpoint:
+        type: object
+
+        properties:
+          data-lanes:
+            description: |-
+              The driver only supports four-lane operation.
+            items:
+              - const: 1
+              - const: 2
+              - const: 3
+              - const: 4
+
+          link-frequencies:
+            allOf:
+              - $ref: /schemas/types.yaml#/definitions/uint64-array
+            description:
+              Allowed data bus frequencies. 360000000, 180000000 Hz or both
+              are supported by the driver.
+
+
+        required:
+          - link-frequencies
+
+    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>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        ov8856: camera@10 {
+            compatible = "ovti,ov8856";
+            reg = <0x10>;
+
+            reset-gpios = <&pio 111 GPIO_ACTIVE_LOW>;
+            pinctrl-names = "default";
+            pinctrl-0 = <&clk_24m_cam>;
+
+            clocks = <&cam_osc>;
+            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>;
+                    data-lanes = <1 2 3 4>;
+                    link-frequencies = /bits/ 64 <360000000>;
+                };
+            };
+        };
+    };
+...
\ No newline at end of file
diff --git a/MAINTAINERS b/MAINTAINERS
index 26f281d9f32a..84b262afd13d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12489,6 +12489,7 @@  L:	[e-mail]
 S:	Maintained
 T:	git git://linuxtv.org/media_tree.git
 F:	drivers/media/i2c/ov8856.c
+F:	Documentation/devicetree/bindings/media/i2c/ov8856.yaml
 
 OMNIVISION OV9640 SENSOR DRIVER
 M:	Petr Cvek <[e-mail]>