1# SPDX-License-Identifier: GPL-2.0 2%YAML 1.2 3--- 4$id: http://devicetree.org/schemas/display/panel/panel-common.yaml# 5$schema: http://devicetree.org/meta-schemas/core.yaml# 6 7title: Common Properties for Display Panels 8 9maintainers: 10 - Thierry Reding <thierry.reding@gmail.com> 11 - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> 12 13description: | 14 This document defines device tree properties common to several classes of 15 display panels. It doesn't constitute a device tree binding specification by 16 itself but is meant to be referenced by device tree bindings. 17 18 When referenced from panel device tree bindings the properties defined in this 19 document are defined as follows. The panel device tree bindings are 20 responsible for defining whether each property is required or optional. 21 22properties: 23 # Descriptive Properties 24 width-mm: 25 description: 26 Specifies the width of the physical area where images are displayed. This 27 property is expressed in millimeters and rounded to the closest unit. 28 29 height-mm: 30 description: 31 Specifies the height of the physical area where images are displayed. This 32 property is expressed in millimeters and rounded to the closest unit. 33 34 label: 35 description: | 36 The label property specifies a symbolic name for the panel as a 37 string suitable for use by humans. It typically contains a name inscribed 38 on the system (e.g. as an affixed label) or specified in the system's 39 documentation (e.g. in the user's manual). 40 41 If no such name exists, and unless the property is mandatory according to 42 device tree bindings, it shall rather be omitted than constructed of 43 non-descriptive information. For instance an LCD panel in a system that 44 contains a single panel shall not be labelled "LCD" if that name is not 45 inscribed on the system or used in a descriptive fashion in system 46 documentation. 47 48 rotation: 49 description: 50 Display rotation in degrees counter clockwise (0,90,180,270) 51 $ref: /schemas/types.yaml#/definitions/uint32 52 enum: [0, 90, 180, 270] 53 54 flip-horizontal: 55 description: boolean to flip image horizontally 56 type: boolean 57 58 flip-vertical: 59 description: boolean to flip image vertically 60 type: boolean 61 62 # Display Timings 63 panel-timing: 64 description: 65 Most display panels are restricted to a single resolution and 66 require specific display timings. The panel-timing subnode expresses those 67 timings. 68 $ref: panel-timing.yaml# 69 70 display-timings: 71 description: 72 Some display panels support several resolutions with different timings. 73 The display-timings bindings supports specifying several timings and 74 optionally specifying which is the native mode. 75 $ref: display-timings.yaml# 76 77 # Connectivity 78 port: 79 $ref: /schemas/graph.yaml#/properties/port 80 81 ddc-i2c-bus: 82 $ref: /schemas/types.yaml#/definitions/phandle 83 description: 84 Some panels expose EDID information through an I2C-compatible 85 bus such as DDC2 or E-DDC. For such panels the ddc-i2c-bus contains a 86 phandle to the system I2C controller connected to that bus. 87 88 no-hpd: 89 type: boolean 90 description: 91 This panel is supposed to communicate that it's ready via HPD 92 (hot plug detect) signal, but the signal isn't hooked up so we should 93 hardcode the max delay from the panel spec when powering up the panel. 94 95 hpd-gpios: 96 maxItems: 1 97 description: 98 If Hot Plug Detect (HPD) is connected to a GPIO in the system rather 99 than a dedicated HPD pin the pin can be specified here. 100 101 # Control I/Os 102 103 # Many display panels can be controlled through pins driven by GPIOs. The nature 104 # and timing of those control signals are device-specific and left for panel 105 # device tree bindings to specify. The following GPIO specifiers can however be 106 # used for panels that implement compatible control signals. 107 108 enable-gpios: 109 maxItems: 1 110 description: | 111 Specifier for a GPIO connected to the panel enable control signal. The 112 enable signal is active high and enables operation of the panel. This 113 property can also be used for panels implementing an active low power down 114 signal, which is a negated version of the enable signal. Active low enable 115 signals (or active high power down signals) can be supported by inverting 116 the GPIO specifier polarity flag. 117 118 Note that the enable signal control panel operation only and must not be 119 confused with a backlight enable signal. 120 121 reset-gpios: 122 maxItems: 1 123 description: 124 Specifier for a GPIO connected to the panel reset control signal. 125 The reset signal is active low and resets the panel internal logic 126 while active. Active high reset signals can be supported by inverting the 127 GPIO specifier polarity flag. 128 129 te-gpios: 130 maxItems: 1 131 description: 132 GPIO spec for the tearing effect synchronization signal. 133 The tearing effect signal is active high. Active low signals can be 134 supported by inverting the GPIO specifier polarity flag. 135 136 # Power 137 power-supply: 138 description: 139 Display panels require power to be supplied. While several panels need 140 more than one power supply with panel-specific constraints governing the 141 order and timings of the power supplies, in many cases a single power 142 supply is sufficient, either because the panel has a single power rail, or 143 because all its power rails can be driven by the same supply. In that case 144 the power-supply property specifies the supply powering the panel as a 145 phandle to a regulator. 146 147 # Backlight 148 149 # Most display panels include a backlight. Some of them also include a backlight 150 # controller exposed through a control bus such as I2C or DSI. Others expose 151 # backlight control through GPIO, PWM or other signals connected to an external 152 # backlight controller. 153 154 backlight: 155 $ref: /schemas/types.yaml#/definitions/phandle 156 description: 157 For panels whose backlight is controlled by an external backlight 158 controller, this property contains a phandle that references the 159 controller. 160 161dependencies: 162 width-mm: [ height-mm ] 163 height-mm: [ width-mm ] 164 165additionalProperties: true 166 167... 168