Commit 821a1f71 authored by Rob Herring's avatar Rob Herring
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dt-bindings: display: Convert common panel bindings to DT schema 



Convert the common panel bindings to DT schema consolidating scattered
definitions to a single schema file.

The 'simple-panel' binding just a collection of properties and not a
complete binding itself. All of the 'simple-panel' properties are
covered by the panel-common.txt binding with the exception of the
'no-hpd' property, so add that to the schema.

As there are lots of references to simple-panel.txt, just keep the file
with a reference to common.yaml for now until all the bindings are
converted.

Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: dri-devel@lists.freedesktop.org
Acked-by: default avatarSam Ravnborg <sam@ravnborg.org>
Reviewed-by: default avatarMaxime Ripard <maxime.ripard@bootlin.com>
Reviewed-by: default avatarThierry Reding <treding@nvidia.com>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190705164221.4462-2-robh@kernel.org
parent 67b58793

Documentation/devicetree/bindings/display/panel/arm,versatile-tft-panel.txt

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@@ -10,7 +10,7 @@ Required properties: 
- compatible: should be "arm,versatile-tft-panel"



Required subnodes:

- port: see display/panel/panel-common.txt, graph.txt

- port: see display/panel/panel-common.yaml, graph.txt





Example:

Documentation/devicetree/bindings/display/panel/panel-common.txt

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Common Properties for Display Panel

===================================



This document defines device tree properties common to several classes of

display panels. It doesn't constitue a device tree binding specification by

itself but is meant to be referenced by device tree bindings.



When referenced from panel device tree bindings the properties defined in this

document are defined as follows. The panel device tree bindings are

responsible for defining whether each property is required or optional.





Descriptive Properties

----------------------



- width-mm,

- height-mm: The width-mm and height-mm specify the width and height of the

  physical area where images are displayed. These properties are expressed in

  millimeters and rounded to the closest unit.



- label: The label property specifies a symbolic name for the panel as a

  string suitable for use by humans. It typically contains a name inscribed on

  the system (e.g. as an affixed label) or specified in the system's

  documentation (e.g. in the user's manual).



  If no such name exists, and unless the property is mandatory according to

  device tree bindings, it shall rather be omitted than constructed of

  non-descriptive information. For instance an LCD panel in a system that

  contains a single panel shall not be labelled "LCD" if that name is not

  inscribed on the system or used in a descriptive fashion in system

  documentation.





Display Timings

---------------



- panel-timing: Most display panels are restricted to a single resolution and

  require specific display timings. The panel-timing subnode expresses those

  timings as specified in the timing subnode section of the display timing

  bindings defined in

  Documentation/devicetree/bindings/display/panel/display-timing.txt.





Connectivity

------------



- ports: Panels receive video data through one or multiple connections. While

  the nature of those connections is specific to the panel type, the

  connectivity is expressed in a standard fashion using ports as specified in

  the device graph bindings defined in

  Documentation/devicetree/bindings/graph.txt.



- ddc-i2c-bus: Some panels expose EDID information through an I2C-compatible

  bus such as DDC2 or E-DDC. For such panels the ddc-i2c-bus contains a

  phandle to the system I2C controller connected to that bus.





Control I/Os

------------



Many display panels can be controlled through pins driven by GPIOs. The nature

and timing of those control signals are device-specific and left for panel

device tree bindings to specify. The following GPIO specifiers can however be

used for panels that implement compatible control signals.



- enable-gpios: Specifier for a GPIO connected to the panel enable control

  signal. The enable signal is active high and enables operation of the panel.

  This property can also be used for panels implementing an active low power

  down signal, which is a negated version of the enable signal. Active low

  enable signals (or active high power down signals) can be supported by

  inverting the GPIO specifier polarity flag.



  Note that the enable signal control panel operation only and must not be

  confused with a backlight enable signal.



- reset-gpios: Specifier for a GPIO coonnected to the panel reset control

  signal. The reset signal is active low and resets the panel internal logic

  while active. Active high reset signals can be supported by inverting the

  GPIO specifier polarity flag.



Power

-----



- power-supply: display panels require power to be supplied. While several

  panels need more than one power supply with panel-specific constraints

  governing the order and timings of the power supplies, in many cases a single

  power supply is sufficient, either because the panel has a single power rail,

  or because all its power rails can be driven by the same supply. In that case

  the power-supply property specifies the supply powering the panel as a phandle

  to a regulator.



Backlight

---------



Most display panels include a backlight. Some of them also include a backlight

controller exposed through a control bus such as I2C or DSI. Others expose

backlight control through GPIO, PWM or other signals connected to an external

backlight controller.



- backlight: For panels whose backlight is controlled by an external backlight

  controller, this property contains a phandle that references the controller.

Documentation/devicetree/bindings/display/panel/panel-common.yaml

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# SPDX-License-Identifier: GPL-2.0

%YAML 1.2

---

$id: http://devicetree.org/schemas/display/panel/panel-common.yaml#

$schema: http://devicetree.org/meta-schemas/core.yaml#



title: Common Properties for Display Panels



maintainers:

  - Thierry Reding <thierry.reding@gmail.com>

  - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>



description: |

  This document defines device tree properties common to several classes of

  display panels. It doesn't constitue a device tree binding specification by

  itself but is meant to be referenced by device tree bindings.



  When referenced from panel device tree bindings the properties defined in this

  document are defined as follows. The panel device tree bindings are

  responsible for defining whether each property is required or optional.



properties:

  # Descriptive Properties

  width-mm:

    description:

      Specifies the width of the physical area where images are displayed. This

      property is expressed in millimeters and rounded to the closest unit.



  height-mm:

    description:

      Specifies the height of the physical area where images are displayed. This

      property is expressed in millimeters and rounded to the closest unit.



  label:

    description: |

      The label property specifies a symbolic name for the panel as a

      string suitable for use by humans. It typically contains a name inscribed

      on the system (e.g. as an affixed label) or specified in the system's

      documentation (e.g. in the user's manual).



      If no such name exists, and unless the property is mandatory according to

      device tree bindings, it shall rather be omitted than constructed of

      non-descriptive information. For instance an LCD panel in a system that

      contains a single panel shall not be labelled "LCD" if that name is not

      inscribed on the system or used in a descriptive fashion in system

      documentation.



  rotation:

    description:

      Display rotation in degrees counter clockwise (0,90,180,270)

    allOf:

      - $ref: /schemas/types.yaml#/definitions/uint32

      - enum: [ 0, 90, 180, 270 ]



  # Display Timings

  panel-timing:

    type: object

    description:

      Most display panels are restricted to a single resolution and

      require specific display timings. The panel-timing subnode expresses those

      timings as specified in the timing subnode section of the display timing

      bindings defined in

      Documentation/devicetree/bindings/display/panel/display-timing.txt.



  # Connectivity

  port:

    type: object



  ports:

    type: object

    description:

      Panels receive video data through one or multiple connections. While

      the nature of those connections is specific to the panel type, the

      connectivity is expressed in a standard fashion using ports as specified

      in the device graph bindings defined in

      Documentation/devicetree/bindings/graph.txt.



  ddc-i2c-bus:

    $ref: /schemas/types.yaml#/definitions/phandle

    description:

      Some panels expose EDID information through an I2C-compatible

      bus such as DDC2 or E-DDC. For such panels the ddc-i2c-bus contains a

      phandle to the system I2C controller connected to that bus.



  no-hpd:

    type: boolean

    description:

      This panel is supposed to communicate that it's ready via HPD

      (hot plug detect) signal, but the signal isn't hooked up so we should

      hardcode the max delay from the panel spec when powering up the panel.



  # Control I/Os



  # Many display panels can be controlled through pins driven by GPIOs. The nature

  # and timing of those control signals are device-specific and left for panel

  # device tree bindings to specify. The following GPIO specifiers can however be

  # used for panels that implement compatible control signals.



  enable-gpios:

    maxItems: 1

    description: |

      Specifier for a GPIO connected to the panel enable control signal. The

      enable signal is active high and enables operation of the panel. This

      property can also be used for panels implementing an active low power down

      signal, which is a negated version of the enable signal. Active low enable

      signals (or active high power down signals) can be supported by inverting

      the GPIO specifier polarity flag.



      Note that the enable signal control panel operation only and must not be

      confused with a backlight enable signal.



  reset-gpios:

    maxItems: 1

    description:

      Specifier for a GPIO connected to the panel reset control signal.

      The reset signal is active low and resets the panel internal logic

      while active. Active high reset signals can be supported by inverting the

      GPIO specifier polarity flag.



  # Power

  power-supply:

    description:

      Display panels require power to be supplied. While several panels need

      more than one power supply with panel-specific constraints governing the

      order and timings of the power supplies, in many cases a single power

      supply is sufficient, either because the panel has a single power rail, or

      because all its power rails can be driven by the same supply. In that case

      the power-supply property specifies the supply powering the panel as a

      phandle to a regulator.



  # Backlight



  # Most display panels include a backlight. Some of them also include a backlight

  # controller exposed through a control bus such as I2C or DSI. Others expose

  # backlight control through GPIO, PWM or other signals connected to an external

  # backlight controller.



  backlight:

    $ref: /schemas/types.yaml#/definitions/phandle

    description:

      For panels whose backlight is controlled by an external backlight

      controller, this property contains a phandle that references the

      controller.



dependencies:

  width-mm: [ height-mm ]

  height-mm: [ width-mm ]



...

Documentation/devicetree/bindings/display/panel/panel.txt

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Common display properties

-------------------------



- rotation:	Display rotation in degrees counter clockwise (0,90,180,270)

Documentation/devicetree/bindings/display/panel/simple-panel.txt

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Simple display panel

====================



panel node

----------



Required properties:

- power-supply: See panel-common.txt



Optional properties:

- ddc-i2c-bus: phandle of an I2C controller used for DDC EDID probing

- enable-gpios: GPIO pin to enable or disable the panel

- backlight: phandle of the backlight device attached to the panel

- no-hpd: This panel is supposed to communicate that it's ready via HPD

  (hot plug detect) signal, but the signal isn't hooked up so we should

  hardcode the max delay from the panel spec when powering up the panel.



Example:



	panel: panel {

		compatible = "cptt,claa101wb01";

		ddc-i2c-bus = <&panelddc>;



		power-supply = <&vdd_pnl_reg>;

		enable-gpios = <&gpio 90 0>;



		backlight = <&backlight>;

	};
 
See panel-common.yaml in this directory.

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