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 constitue 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 # Display Timings 55 panel-timing: 56 description: 57 Most display panels are restricted to a single resolution and 58 require specific display timings. The panel-timing subnode expresses those 59 timings. 60 $ref: panel-timing.yaml# 61 62 display-timings: 63 description: 64 Some display panels support several resolutions with different timings. 65 The display-timings bindings supports specifying several timings and 66 optionally specifying which is the native mode. 67 $ref: display-timings.yaml# 68 69 # Connectivity 70 port: 71 type: object 72 73 ports: 74 type: object 75 description: 76 Panels receive video data through one or multiple connections. While 77 the nature of those connections is specific to the panel type, the 78 connectivity is expressed in a standard fashion using ports as specified 79 in the device graph bindings defined in 80 Documentation/devicetree/bindings/graph.txt. 81 82 ddc-i2c-bus: 83 $ref: /schemas/types.yaml#/definitions/phandle 84 description: 85 Some panels expose EDID information through an I2C-compatible 86 bus such as DDC2 or E-DDC. For such panels the ddc-i2c-bus contains a 87 phandle to the system I2C controller connected to that bus. 88 89 no-hpd: 90 type: boolean 91 description: 92 This panel is supposed to communicate that it's ready via HPD 93 (hot plug detect) signal, but the signal isn't hooked up so we should 94 hardcode the max delay from the panel spec when powering up the panel. 95 96 hpd-gpios: 97 maxItems: 1 98 description: 99 If Hot Plug Detect (HPD) is connected to a GPIO in the system rather 100 than a dedicated HPD pin the pin can be specified here. 101 102 # Control I/Os 103 104 # Many display panels can be controlled through pins driven by GPIOs. The nature 105 # and timing of those control signals are device-specific and left for panel 106 # device tree bindings to specify. The following GPIO specifiers can however be 107 # used for panels that implement compatible control signals. 108 109 enable-gpios: 110 maxItems: 1 111 description: | 112 Specifier for a GPIO connected to the panel enable control signal. The 113 enable signal is active high and enables operation of the panel. This 114 property can also be used for panels implementing an active low power down 115 signal, which is a negated version of the enable signal. Active low enable 116 signals (or active high power down signals) can be supported by inverting 117 the GPIO specifier polarity flag. 118 119 Note that the enable signal control panel operation only and must not be 120 confused with a backlight enable signal. 121 122 reset-gpios: 123 maxItems: 1 124 description: 125 Specifier for a GPIO connected to the panel reset control signal. 126 The reset signal is active low and resets the panel internal logic 127 while active. Active high reset signals can be supported by inverting the 128 GPIO specifier polarity flag. 129 130 te-gpios: 131 maxItems: 1 132 description: 133 GPIO spec for the tearing effect synchronization signal. 134 The tearing effect signal is active high. Active low signals can be 135 supported by inverting the GPIO specifier polarity flag. 136 137 # Power 138 power-supply: 139 description: 140 Display panels require power to be supplied. While several panels need 141 more than one power supply with panel-specific constraints governing the 142 order and timings of the power supplies, in many cases a single power 143 supply is sufficient, either because the panel has a single power rail, or 144 because all its power rails can be driven by the same supply. In that case 145 the power-supply property specifies the supply powering the panel as a 146 phandle to a regulator. 147 148 # Backlight 149 150 # Most display panels include a backlight. Some of them also include a backlight 151 # controller exposed through a control bus such as I2C or DSI. Others expose 152 # backlight control through GPIO, PWM or other signals connected to an external 153 # backlight controller. 154 155 backlight: 156 $ref: /schemas/types.yaml#/definitions/phandle 157 description: 158 For panels whose backlight is controlled by an external backlight 159 controller, this property contains a phandle that references the 160 controller. 161 162dependencies: 163 width-mm: [ height-mm ] 164 height-mm: [ width-mm ] 165 166... 167