Documentation/devicetree/bindings/display/panel/panel-common.yaml - linux - Git at Google

 # 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)
     $ref: /schemas/types.yaml#/definitions/uint32
     enum: [0, 90, 180, 270]

   # Display Timings
   panel-timing:
     description:
       Most display panels are restricted to a single resolution and
       require specific display timings. The panel-timing subnode expresses those
       timings.
     $ref: panel-timing.yaml#

   display-timings:
     description:
       Some display panels support several resolutions with different timings.
       The display-timings bindings supports specifying several timings and
       optionally specifying which is the native mode.
     $ref: display-timings.yaml#

   # 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.

   hpd-gpios:
     maxItems: 1
     description:
       If Hot Plug Detect (HPD) is connected to a GPIO in the system rather
       than a dedicated HPD pin the pin can be specified here.

   # 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.

   te-gpios:
     maxItems: 1
     description:
       GPIO spec for the tearing effect synchronization signal.
       The tearing effect signal is active high. Active low 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 ]

 ...
	# 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)
	$ref: /schemas/types.yaml#/definitions/uint32
	enum: [0, 90, 180, 270]

	# Display Timings
	panel-timing:
	description:
	Most display panels are restricted to a single resolution and
	require specific display timings. The panel-timing subnode expresses those
	timings.
	$ref: panel-timing.yaml#

	display-timings:
	description:
	Some display panels support several resolutions with different timings.
	The display-timings bindings supports specifying several timings and
	optionally specifying which is the native mode.
	$ref: display-timings.yaml#

	# 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.

	hpd-gpios:
	maxItems: 1
	description:
	If Hot Plug Detect (HPD) is connected to a GPIO in the system rather
	than a dedicated HPD pin the pin can be specified here.

	# 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.

	te-gpios:
	maxItems: 1
	description:
	GPIO spec for the tearing effect synchronization signal.
	The tearing effect signal is active high. Active low 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 ]

	...