1# SPDX-License-Identifier: (GPL-2.0-only or BSD-2-Clause)
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/display/panel/panel-mipi-dbi-spi.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: MIPI DBI SPI Panel
8
9maintainers:
10  - Noralf Trønnes <noralf@tronnes.org>
11
12description: |
13  This binding is for display panels using a MIPI DBI compatible controller
14  in SPI mode.
15
16  The MIPI Alliance Standard for Display Bus Interface defines the electrical
17  and logical interfaces for display controllers historically used in mobile
18  phones. The standard defines 4 display architecture types and this binding is
19  for type 1 which has full frame memory. There are 3 interface types in the
20  standard and type C is the serial interface.
21
22  The standard defines the following interface signals for type C:
23  - Power:
24    - Vdd: Power supply for display module
25      Called power-supply in this binding.
26    - Vddi: Logic level supply for interface signals
27      Called io-supply in this binding.
28  - Interface:
29    - CSx: Chip select
30    - SCL: Serial clock
31    - Dout: Serial out
32    - Din: Serial in
33    - SDA: Bidrectional in/out
34    - D/CX: Data/command selection, high=data, low=command
35      Called dc-gpios in this binding.
36    - RESX: Reset when low
37      Called reset-gpios in this binding.
38
39  The type C interface has 3 options:
40
41    - Option 1: 9-bit mode and D/CX as the 9th bit
42      |              Command              |  the next command or following data  |
43      |<0><D7><D6><D5><D4><D3><D2><D1><D0>|<D/CX><D7><D6><D5><D4><D3><D2><D1><D0>|
44
45    - Option 2: 16-bit mode and D/CX as a 9th bit
46      |              Command or data                              |
47      |<X><X><X><X><X><X><X><D/CX><D7><D6><D5><D4><D3><D2><D1><D0>|
48
49    - Option 3: 8-bit mode and D/CX as a separate interface line
50      |        Command or data         |
51      |<D7><D6><D5><D4><D3><D2><D1><D0>|
52
53  The panel resolution is specified using the panel-timing node properties
54  hactive (width) and vactive (height). The other mandatory panel-timing
55  properties should be set to zero except clock-frequency which can be
56  optionally set to inform about the actual pixel clock frequency.
57
58  If the panel is wired to the controller at an offset specify this using
59  hback-porch (x-offset) and vback-porch (y-offset).
60
61allOf:
62  - $ref: panel-common.yaml#
63  - $ref: /schemas/spi/spi-peripheral-props.yaml#
64
65properties:
66  compatible:
67    items:
68      - enum:
69          - sainsmart18
70      - const: panel-mipi-dbi-spi
71
72  write-only:
73    type: boolean
74    description:
75      Controller is not readable (ie. Din (MISO on the SPI interface) is not
76      wired up).
77
78  dc-gpios:
79    maxItems: 1
80    description: |
81      Controller data/command selection (D/CX) in 4-line SPI mode.
82      If not set, the controller is in 3-line SPI mode.
83
84  io-supply:
85    description: |
86      Logic level supply for interface signals (Vddi).
87      No need to set if this is the same as power-supply.
88
89required:
90  - compatible
91  - reg
92  - width-mm
93  - height-mm
94  - panel-timing
95
96unevaluatedProperties: false
97
98examples:
99  - |
100    #include <dt-bindings/gpio/gpio.h>
101
102    spi {
103        #address-cells = <1>;
104        #size-cells = <0>;
105
106        display@0{
107            compatible = "sainsmart18", "panel-mipi-dbi-spi";
108            reg = <0>;
109            spi-max-frequency = <40000000>;
110
111            dc-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
112            reset-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>;
113            write-only;
114
115            backlight = <&backlight>;
116
117            width-mm = <35>;
118            height-mm = <28>;
119
120            panel-timing {
121                hactive = <160>;
122                vactive = <128>;
123                hback-porch = <0>;
124                vback-porch = <0>;
125                clock-frequency = <0>;
126                hfront-porch = <0>;
127                hsync-len = <0>;
128                vfront-porch = <0>;
129                vsync-len = <0>;
130            };
131        };
132    };
133
134...
135