Bindings/display/panel/panel-common.yaml

   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
   7 title: Common Properties for Display Panels
   8
   9 maintainers:
  10   - Thierry Reding <thierry.reding@gmail.com>
  11   - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
  12
  13 description: |
  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
  22 properties:
  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     $ref: /schemas/graph.yaml#/properties/port
  72
  73   ddc-i2c-bus:
  74     $ref: /schemas/types.yaml#/definitions/phandle
  75     description:
  76       Some panels expose EDID information through an I2C-compatible
  77       bus such as DDC2 or E-DDC. For such panels the ddc-i2c-bus contains a
  78       phandle to the system I2C controller connected to that bus.
  79
  80   no-hpd:
  81     type: boolean
  82     description:
  83       This panel is supposed to communicate that it's ready via HPD
  84       (hot plug detect) signal, but the signal isn't hooked up so we should
  85       hardcode the max delay from the panel spec when powering up the panel.
  86
  87   hpd-gpios:
  88     maxItems: 1
  89     description:
  90       If Hot Plug Detect (HPD) is connected to a GPIO in the system rather
  91       than a dedicated HPD pin the pin can be specified here.
  92
  93   # Control I/Os
  94
  95   # Many display panels can be controlled through pins driven by GPIOs. The nature
  96   # and timing of those control signals are device-specific and left for panel
  97   # device tree bindings to specify. The following GPIO specifiers can however be
  98   # used for panels that implement compatible control signals.
  99
 100   enable-gpios:
 101     maxItems: 1
 102     description: |
 103       Specifier for a GPIO connected to the panel enable control signal. The
 104       enable signal is active high and enables operation of the panel. This
 105       property can also be used for panels implementing an active low power down
 106       signal, which is a negated version of the enable signal. Active low enable
 107       signals (or active high power down signals) can be supported by inverting
 108       the GPIO specifier polarity flag.
 109
 110       Note that the enable signal control panel operation only and must not be
 111       confused with a backlight enable signal.
 112
 113   reset-gpios:
 114     maxItems: 1
 115     description:
 116       Specifier for a GPIO connected to the panel reset control signal.
 117       The reset signal is active low and resets the panel internal logic
 118       while active. Active high reset signals can be supported by inverting the
 119       GPIO specifier polarity flag.
 120
 121   te-gpios:
 122     maxItems: 1
 123     description:
 124       GPIO spec for the tearing effect synchronization signal.
 125       The tearing effect signal is active high. Active low signals can be
 126       supported by inverting the GPIO specifier polarity flag.
 127
 128   # Power
 129   power-supply:
 130     description:
 131       Display panels require power to be supplied. While several panels need
 132       more than one power supply with panel-specific constraints governing the
 133       order and timings of the power supplies, in many cases a single power
 134       supply is sufficient, either because the panel has a single power rail, or
 135       because all its power rails can be driven by the same supply. In that case
 136       the power-supply property specifies the supply powering the panel as a
 137       phandle to a regulator.
 138
 139   # Backlight
 140
 141   # Most display panels include a backlight. Some of them also include a backlight
 142   # controller exposed through a control bus such as I2C or DSI. Others expose
 143   # backlight control through GPIO, PWM or other signals connected to an external
 144   # backlight controller.
 145
 146   backlight:
 147     $ref: /schemas/types.yaml#/definitions/phandle
 148     description:
 149       For panels whose backlight is controlled by an external backlight
 150       controller, this property contains a phandle that references the
 151       controller.
 152
 153 dependencies:
 154   width-mm: [ height-mm ]
 155   height-mm: [ width-mm ]
 156
 157 additionalProperties: true
 158
 159 ...