1 # SPDX-License-Identifier: GPL-2.0
4 $id: http://devicetree.org/schemas/display/panel/panel-common.yaml#
5 $schema: http://devicetree.org/meta-schemas/core.yaml#
7 title: Common Properties for Display Panels
10 - Thierry Reding <thierry.reding@gmail.com>
11 - Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
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.
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.
23 # Descriptive Properties
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.
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.
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).
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
50 Display rotation in degrees counter clockwise (0,90,180,270)
51 $ref: /schemas/types.yaml#/definitions/uint32
52 enum: [0, 90, 180, 270]
57 Most display panels are restricted to a single resolution and
58 require specific display timings. The panel-timing subnode expresses those
60 $ref: panel-timing.yaml#
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#
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.
83 $ref: /schemas/types.yaml#/definitions/phandle
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.
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.
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.
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.
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.
119 Note that the enable signal control panel operation only and must not be
120 confused with a backlight enable signal.
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.
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.
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.
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.
156 $ref: /schemas/types.yaml#/definitions/phandle
158 For panels whose backlight is controlled by an external backlight
159 controller, this property contains a phandle that references the
163 width-mm: [ height-mm ]
164 height-mm: [ width-mm ]