xref: /linux/Documentation/devicetree/bindings/display/panel/panel-mipi-dbi-spi.yaml (revision a1ff5a7d78a036d6c2178ee5acd6ba4946243800) 
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 standard defines one pixel format for type C: RGB111. The industry
54  however has decided to provide the type A/B interface pixel formats also on
55  the Type C interface and most common among these are RGB565 and RGB666.
56  The MIPI DCS command set_address_mode (36h) has one bit that controls RGB/BGR
57  order. This gives each supported RGB format a BGR variant.
58
59  The panel resolution is specified using the panel-timing node properties
60  hactive (width) and vactive (height). The other mandatory panel-timing
61  properties should be set to zero except clock-frequency which can be
62  optionally set to inform about the actual pixel clock frequency.
63
64  If the panel is wired to the controller at an offset specify this using
65  hback-porch (x-offset) and vback-porch (y-offset).
66
67allOf:
68  - $ref: panel-common.yaml#
69  - $ref: /schemas/spi/spi-peripheral-props.yaml#
70
71properties:
72  compatible:
73    items:
74      - enum:
75          - saef,sftc154b
76          - sainsmart18
77          - shineworld,lh133k
78      - const: panel-mipi-dbi-spi
79
80  reg:
81    maxItems: 1
82
83  write-only:
84    type: boolean
85    description:
86      Controller is not readable (ie. Din (MISO on the SPI interface) is not
87      wired up).
88
89  dc-gpios:
90    maxItems: 1
91    description: |
92      Controller data/command selection (D/CX) in 4-line SPI mode.
93      If not set, the controller is in 3-line SPI mode.
94
95  io-supply:
96    description: |
97      Logic level supply for interface signals (Vddi).
98      No need to set if this is the same as power-supply.
99
100  spi-3wire: true
101
102  format:
103    description: >
104      Pixel format in bit order as going on the wire:
105        * `x2r1g1b1r1g1b1` - RGB111, 2 pixels per byte
106        * `x2b1g1r1b1g1r1` - BGR111, 2 pixels per byte
107        * `x1r1g1b1x1r1g1b1` - RGB111, 2 pixels per byte
108        * `x1b1g1r1x1b1g1r1` - BGR111, 2 pixels per byte
109        * `r5g6b5` - RGB565, 2 bytes
110        * `b5g6r5` - BGR565, 2 bytes
111        * `r6x2g6x2b6x2` - RGB666, 3 bytes
112        * `b6x2g6x2r6x2` - BGR666, 3 bytes
113    enum:
114      - x2r1g1b1r1g1b1
115      - x2b1g1r1b1g1r1
116      - x1r1g1b1x1r1g1b1
117      - x1b1g1r1x1b1g1r1
118      - r5g6b5
119      - b5g6r5
120      - r6x2g6x2b6x2
121      - b6x2g6x2r6x2
122    default: r5g6b5
123
124required:
125  - compatible
126  - reg
127  - width-mm
128  - height-mm
129  - panel-timing
130
131unevaluatedProperties: false
132
133examples:
134  - |
135    #include <dt-bindings/gpio/gpio.h>
136
137    spi {
138        #address-cells = <1>;
139        #size-cells = <0>;
140
141        display@0{
142            compatible = "sainsmart18", "panel-mipi-dbi-spi";
143            reg = <0>;
144            spi-max-frequency = <40000000>;
145
146            dc-gpios = <&gpio 24 GPIO_ACTIVE_HIGH>;
147            reset-gpios = <&gpio 25 GPIO_ACTIVE_HIGH>;
148            write-only;
149
150            format = "r5g6b5";
151
152            backlight = <&backlight>;
153
154            width-mm = <35>;
155            height-mm = <28>;
156
157            panel-timing {
158                hactive = <160>;
159                vactive = <128>;
160                hback-porch = <0>;
161                vback-porch = <0>;
162                clock-frequency = <0>;
163                hfront-porch = <0>;
164                hsync-len = <0>;
165                vfront-porch = <0>;
166                vsync-len = <0>;
167            };
168        };
169    };
170
171...
172