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159 lines
6.0 KiB
159 lines
6.0 KiB
# 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 <[email protected]> |
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- Laurent Pinchart <[email protected]> |
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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 constitue 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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