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
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  If a panel node is given, then the driver uses this to configure the
30  physical width and height of the display. If no panel node is given,
31  then the driver uses the width and height properties of the simplefb
32  node to estimate it.
33
34  It is advised to add display# aliases to help the OS determine how
35  to number things. If display# aliases are used, then if the simplefb
36  node contains a display property then the /aliases/display# path
37  must point to the display hw node the display property points to,
38  otherwise it must point directly to the simplefb node.
39
40  If a simplefb node represents the preferred console for user
41  interaction, then the chosen node stdout-path property should point
42  to it, or to the primary display hw node, as with display#
43  aliases. If display aliases are used then it should be set to the
44  alias instead.
45
46  It is advised that devicetree files contain pre-filled, disabled
47  framebuffer nodes, so that the firmware only needs to update the
48  mode information and enable them. This way if e.g. later on support
49  for more display clocks get added, the simplefb nodes will already
50  contain this info and the firmware does not need to be updated.
51
52  If pre-filled framebuffer nodes are used, the firmware may need
53  extra information to find the right node. In that case an extra
54  platform specific compatible and platform specific properties should
55  be used and documented.
56
57properties:
58  compatible:
59    oneOf:
60      - items:
61          - enum:
62              - apple,simple-framebuffer
63              - allwinner,simple-framebuffer
64              - amlogic,simple-framebuffer
65          - const: simple-framebuffer
66      - const: simple-framebuffer
67
68  reg:
69    description: Location and size of the framebuffer memory
70
71  memory-region:
72    maxItems: 1
73    description: Phandle to a node describing the memory to be used for the
74      framebuffer. If present, overrides the "reg" property (if one exists).
75
76  clocks:
77    description: List of clocks used by the framebuffer.
78
79  power-domains:
80    description: List of power domains used by the framebuffer.
81
82  width:
83    $ref: /schemas/types.yaml#/definitions/uint32
84    description: Width of the framebuffer in pixels
85
86  height:
87    $ref: /schemas/types.yaml#/definitions/uint32
88    description: Height of the framebuffer in pixels
89
90  stride:
91    $ref: /schemas/types.yaml#/definitions/uint32
92    description: Number of bytes of a line in the framebuffer
93
94  format:
95    description: >
96      Format of the framebuffer:
97        * `a1r5g5b5` - 16-bit pixels, d[15]=a, d[14:10]=r, d[9:5]=g, d[4:0]=b
98        * `a2r10g10b10` - 32-bit pixels, d[31:30]=a, d[29:20]=r, d[19:10]=g, d[9:0]=b
99        * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r
100        * `a8r8g8b8` - 32-bit pixels, d[31:24]=a, d[23:16]=r, d[15:8]=g, d[7:0]=b
101        * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b
102        * `r5g5b5a1` - 16-bit pixels, d[15:11]=r, d[10:6]=g, d[5:1]=b d[1:0]=a
103        * `r8g8b8` - 24-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
104        * `x1r5g5b5` - 16-bit pixels, d[14:10]=r, d[9:5]=g, d[4:0]=b
105        * `x2r10g10b10` - 32-bit pixels, d[29:20]=r, d[19:10]=g, d[9:0]=b
106        * `x8r8g8b8` - 32-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
107        * `x8b8g8r8` - 32-bit pixels, d[23:16]=b, d[15:8]=g, d[7:0]=r
108    enum:
109      - a1r5g5b5
110      - a2r10g10b10
111      - a8b8g8r8
112      - a8r8g8b8
113      - r5g6b5
114      - r5g5b5a1
115      - r8g8b8
116      - x1r5g5b5
117      - x2r10g10b10
118      - x8r8g8b8
119      - x8b8g8r8
120
121  display:
122    $ref: /schemas/types.yaml#/definitions/phandle
123    description: Primary display hardware node
124
125  panel:
126    $ref: /schemas/types.yaml#/definitions/phandle
127    description: Display panel node
128
129  allwinner,pipeline:
130    description: Pipeline used by the framebuffer on Allwinner SoCs
131    enum:
132      - de_be0-lcd0
133      - de_be0-lcd0-hdmi
134      - de_be0-lcd0-tve0
135      - de_be1-lcd0
136      - de_be1-lcd1-hdmi
137      - de_fe0-de_be0-lcd0
138      - de_fe0-de_be0-lcd0-hdmi
139      - de_fe0-de_be0-lcd0-tve0
140      - mixer0-lcd0
141      - mixer0-lcd0-hdmi
142      - mixer1-lcd1-hdmi
143      - mixer1-lcd1-tve
144
145  amlogic,pipeline:
146    description: Pipeline used by the framebuffer on Amlogic SoCs
147    enum:
148      - vpu-cvbs
149      - vpu-hdmi
150
151patternProperties:
152  "^[a-zA-Z0-9-]+-supply$":
153    $ref: /schemas/types.yaml#/definitions/phandle
154    description:
155      Regulators used by the framebuffer. These should be named
156      according to the names in the device design.
157
158required:
159  # The binding requires also reg, width, height, stride and format,
160  # but usually they will be filled by the bootloader.
161  - compatible
162
163allOf:
164  - if:
165      properties:
166        compatible:
167          contains:
168            const: allwinner,simple-framebuffer
169
170    then:
171      required:
172        - allwinner,pipeline
173
174  - if:
175      properties:
176        compatible:
177          contains:
178            const: amlogic,simple-framebuffer
179
180    then:
181      required:
182        - amlogic,pipeline
183
184
185additionalProperties: false
186
187examples:
188  - |
189    / {
190        compatible = "foo";
191        model = "foo";
192        #address-cells = <1>;
193        #size-cells = <1>;
194
195        chosen {
196            #address-cells = <1>;
197            #size-cells = <1>;
198            framebuffer0: framebuffer@1d385000 {
199                compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
200                allwinner,pipeline = "de_be0-lcd0";
201                reg = <0x1d385000 3840000>;
202                width = <1600>;
203                height = <1200>;
204                stride = <3200>;
205                format = "r5g6b5";
206                clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
207                lcd-supply = <&reg_dc1sw>;
208                display = <&lcdc0>;
209            };
210        };
211    };
212
213...
214