160 lines
6.0 KiB
YAML
160 lines
6.0 KiB
YAML
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# SPDX-License-Identifier: GPL-2.0
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%YAML 1.2
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---
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$id: http://devicetree.org/schemas/display/panel/panel-common.yaml#
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$schema: http://devicetree.org/meta-schemas/core.yaml#
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title: Common Properties for Display Panels
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maintainers:
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- Thierry Reding <thierry.reding@gmail.com>
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- Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
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description: |
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This document defines device tree properties common to several classes of
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display panels. It doesn't constitute a device tree binding specification by
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itself but is meant to be referenced by device tree bindings.
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When referenced from panel device tree bindings the properties defined in this
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document are defined as follows. The panel device tree bindings are
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responsible for defining whether each property is required or optional.
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properties:
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# Descriptive Properties
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width-mm:
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description:
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Specifies the width of the physical area where images are displayed. This
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property is expressed in millimeters and rounded to the closest unit.
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height-mm:
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description:
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Specifies the height of the physical area where images are displayed. This
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property is expressed in millimeters and rounded to the closest unit.
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label:
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description: |
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The label property specifies a symbolic name for the panel as a
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string suitable for use by humans. It typically contains a name inscribed
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on the system (e.g. as an affixed label) or specified in the system's
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documentation (e.g. in the user's manual).
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If no such name exists, and unless the property is mandatory according to
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device tree bindings, it shall rather be omitted than constructed of
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non-descriptive information. For instance an LCD panel in a system that
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contains a single panel shall not be labelled "LCD" if that name is not
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inscribed on the system or used in a descriptive fashion in system
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documentation.
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rotation:
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description:
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Display rotation in degrees counter clockwise (0,90,180,270)
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$ref: /schemas/types.yaml#/definitions/uint32
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enum: [0, 90, 180, 270]
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# Display Timings
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panel-timing:
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description:
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Most display panels are restricted to a single resolution and
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require specific display timings. The panel-timing subnode expresses those
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timings.
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$ref: panel-timing.yaml#
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display-timings:
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description:
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Some display panels support several resolutions with different timings.
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The display-timings bindings supports specifying several timings and
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optionally specifying which is the native mode.
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$ref: display-timings.yaml#
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# Connectivity
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port:
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$ref: /schemas/graph.yaml#/properties/port
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ddc-i2c-bus:
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$ref: /schemas/types.yaml#/definitions/phandle
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description:
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Some panels expose EDID information through an I2C-compatible
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bus such as DDC2 or E-DDC. For such panels the ddc-i2c-bus contains a
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phandle to the system I2C controller connected to that bus.
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no-hpd:
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type: boolean
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description:
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This panel is supposed to communicate that it's ready via HPD
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(hot plug detect) signal, but the signal isn't hooked up so we should
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hardcode the max delay from the panel spec when powering up the panel.
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hpd-gpios:
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maxItems: 1
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description:
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If Hot Plug Detect (HPD) is connected to a GPIO in the system rather
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than a dedicated HPD pin the pin can be specified here.
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# Control I/Os
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# Many display panels can be controlled through pins driven by GPIOs. The nature
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# and timing of those control signals are device-specific and left for panel
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# device tree bindings to specify. The following GPIO specifiers can however be
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# used for panels that implement compatible control signals.
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enable-gpios:
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maxItems: 1
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description: |
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Specifier for a GPIO connected to the panel enable control signal. The
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enable signal is active high and enables operation of the panel. This
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property can also be used for panels implementing an active low power down
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signal, which is a negated version of the enable signal. Active low enable
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signals (or active high power down signals) can be supported by inverting
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the GPIO specifier polarity flag.
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Note that the enable signal control panel operation only and must not be
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confused with a backlight enable signal.
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reset-gpios:
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maxItems: 1
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description:
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Specifier for a GPIO connected to the panel reset control signal.
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The reset signal is active low and resets the panel internal logic
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while active. Active high reset signals can be supported by inverting the
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GPIO specifier polarity flag.
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te-gpios:
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maxItems: 1
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description:
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GPIO spec for the tearing effect synchronization signal.
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The tearing effect signal is active high. Active low signals can be
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supported by inverting the GPIO specifier polarity flag.
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# Power
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power-supply:
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description:
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Display panels require power to be supplied. While several panels need
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more than one power supply with panel-specific constraints governing the
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order and timings of the power supplies, in many cases a single power
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supply is sufficient, either because the panel has a single power rail, or
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because all its power rails can be driven by the same supply. In that case
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the power-supply property specifies the supply powering the panel as a
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phandle to a regulator.
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# Backlight
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# Most display panels include a backlight. Some of them also include a backlight
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# controller exposed through a control bus such as I2C or DSI. Others expose
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# backlight control through GPIO, PWM or other signals connected to an external
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# backlight controller.
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backlight:
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$ref: /schemas/types.yaml#/definitions/phandle
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description:
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For panels whose backlight is controlled by an external backlight
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controller, this property contains a phandle that references the
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controller.
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dependencies:
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width-mm: [ height-mm ]
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height-mm: [ width-mm ]
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additionalProperties: true
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...
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