1# SPDX-License-Identifier: GPL-2.0
2%YAML 1.2
3---
4$id: http://devicetree.org/schemas/display/simple-framebuffer.yaml#
5$schema: http://devicetree.org/meta-schemas/core.yaml#
6
7title: Simple Framebuffer Device Tree Bindings
8
9maintainers:
10  - Hans de Goede <hdegoede@redhat.com>
11
12description: |+
13  A simple frame-buffer describes a frame-buffer setup by firmware or
14  the bootloader, with the assumption that the display hardware has
15  already been set up to scan out from the memory pointed to by the
16  reg property.
17
18  Since simplefb nodes represent runtime information they must be
19  sub-nodes of the chosen node (*). Simplefb nodes must be named
20  framebuffer@<address>.
21
22  If the devicetree contains nodes for the display hardware used by a
23  simplefb, then the simplefb node must contain a property called
24  display, which contains a phandle pointing to the primary display
25  hw node, so that the OS knows which simplefb to disable when handing
26  over control to a driver for the real hardware. The bindings for the
27  hw nodes must specify which node is considered the primary node.
28
29  It is advised to add display# aliases to help the OS determine how
30  to number things. If display# aliases are used, then if the simplefb
31  node contains a display property then the /aliases/display# path
32  must point to the display hw node the display property points to,
33  otherwise it must point directly to the simplefb node.
34
35  If a simplefb node represents the preferred console for user
36  interaction, then the chosen node stdout-path property should point
37  to it, or to the primary display hw node, as with display#
38  aliases. If display aliases are used then it should be set to the
39  alias instead.
40
41  It is advised that devicetree files contain pre-filled, disabled
42  framebuffer nodes, so that the firmware only needs to update the
43  mode information and enable them. This way if e.g. later on support
44  for more display clocks get added, the simplefb nodes will already
45  contain this info and the firmware does not need to be updated.
46
47  If pre-filled framebuffer nodes are used, the firmware may need
48  extra information to find the right node. In that case an extra
49  platform specific compatible and platform specific properties should
50  be used and documented.
51
52properties:
53  compatible:
54    oneOf:
55      - items:
56          - enum:
57              - apple,simple-framebuffer
58              - allwinner,simple-framebuffer
59              - amlogic,simple-framebuffer
60          - const: simple-framebuffer
61      - const: simple-framebuffer
62
63  reg:
64    description: Location and size of the framebuffer memory
65
66  clocks:
67    description: List of clocks used by the framebuffer.
68
69  power-domains:
70    description: List of power domains used by the framebuffer.
71
72  width:
73    $ref: /schemas/types.yaml#/definitions/uint32
74    description: Width of the framebuffer in pixels
75
76  height:
77    $ref: /schemas/types.yaml#/definitions/uint32
78    description: Height of the framebuffer in pixels
79
80  stride:
81    $ref: /schemas/types.yaml#/definitions/uint32
82    description: Number of bytes of a line in the framebuffer
83
84  format:
85    description: >
86      Format of the framebuffer:
87        * `a1r5g5b5` - 16-bit pixels, d[15]=a, d[14:10]=r, d[9:5]=g, d[4:0]=b
88        * `a2r10g10b10` - 32-bit pixels, d[31:30]=a, d[29:20]=r, d[19:10]=g, d[9:0]=b
89        * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r
90        * `a8r8g8b8` - 32-bit pixels, d[31:24]=a, d[23:16]=r, d[15:8]=g, d[7:0]=b
91        * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b
92        * `r5g5b5a1` - 16-bit pixels, d[15:11]=r, d[10:6]=g, d[5:1]=b d[1:0]=a
93        * `r8g8b8` - 24-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
94        * `x1r5g5b5` - 16-bit pixels, d[14:10]=r, d[9:5]=g, d[4:0]=b
95        * `x2r10g10b10` - 32-bit pixels, d[29:20]=r, d[19:10]=g, d[9:0]=b
96        * `x8r8g8b8` - 32-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
97    enum:
98      - a1r5g5b5
99      - a2r10g10b10
100      - a8b8g8r8
101      - a8r8g8b8
102      - r5g6b5
103      - r5g5b5a1
104      - r8g8b8
105      - x1r5g5b5
106      - x2r10g10b10
107      - x8r8g8b8
108
109  display:
110    $ref: /schemas/types.yaml#/definitions/phandle
111    description: Primary display hardware node
112
113  allwinner,pipeline:
114    description: Pipeline used by the framebuffer on Allwinner SoCs
115    enum:
116      - de_be0-lcd0
117      - de_be0-lcd0-hdmi
118      - de_be0-lcd0-tve0
119      - de_be1-lcd0
120      - de_be1-lcd1-hdmi
121      - de_fe0-de_be0-lcd0
122      - de_fe0-de_be0-lcd0-hdmi
123      - de_fe0-de_be0-lcd0-tve0
124      - mixer0-lcd0
125      - mixer0-lcd0-hdmi
126      - mixer1-lcd1-hdmi
127      - mixer1-lcd1-tve
128
129  amlogic,pipeline:
130    description: Pipeline used by the framebuffer on Amlogic SoCs
131    enum:
132      - vpu-cvbs
133      - vpu-hdmi
134
135patternProperties:
136  "^[a-zA-Z0-9-]+-supply$":
137    $ref: /schemas/types.yaml#/definitions/phandle
138    description:
139      Regulators used by the framebuffer. These should be named
140      according to the names in the device design.
141
142required:
143  # The binding requires also reg, width, height, stride and format,
144  # but usually they will be filled by the bootloader.
145  - compatible
146
147allOf:
148  - if:
149      properties:
150        compatible:
151          contains:
152            const: allwinner,simple-framebuffer
153
154    then:
155      required:
156        - allwinner,pipeline
157
158  - if:
159      properties:
160        compatible:
161          contains:
162            const: amlogic,simple-framebuffer
163
164    then:
165      required:
166        - amlogic,pipeline
167
168
169additionalProperties: false
170
171examples:
172  - |
173    / {
174        compatible = "foo";
175        model = "foo";
176        #address-cells = <1>;
177        #size-cells = <1>;
178
179        chosen {
180            #address-cells = <1>;
181            #size-cells = <1>;
182            framebuffer0: framebuffer@1d385000 {
183                compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
184                allwinner,pipeline = "de_be0-lcd0";
185                reg = <0x1d385000 3840000>;
186                width = <1600>;
187                height = <1200>;
188                stride = <3200>;
189                format = "r5g6b5";
190                clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
191                lcd-supply = <&reg_dc1sw>;
192                display = <&lcdc0>;
193            };
194        };
195    };
196
197...
198