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