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        * `a1r5g5b5` - 16-bit pixels, d[15]=a, d[14:10]=r, d[9:5]=g, d[4:0]=b
87        * `a2r10g10b10` - 32-bit pixels, d[31:30]=a, d[29:20]=r, d[19:10]=g, d[9:0]=b
88        * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r
89        * `a8r8g8b8` - 32-bit pixels, d[31:24]=a, d[23:16]=r, d[15:8]=g, d[7:0]=b
90        * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b
91        * `r5g5b5a1` - 16-bit pixels, d[15:11]=r, d[10:6]=g, d[5:1]=b d[1:0]=a
92        * `r8g8b8` - 24-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
93        * `x1r5g5b5` - 16-bit pixels, d[14:10]=r, d[9:5]=g, d[4:0]=b
94        * `x2r10g10b10` - 32-bit pixels, d[29:20]=r, d[19:10]=g, d[9:0]=b
95        * `x8r8g8b8` - 32-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
96    enum:
97      - a1r5g5b5
98      - a2r10g10b10
99      - a8b8g8r8
100      - a8r8g8b8
101      - r5g6b5
102      - r5g5b5a1
103      - r8g8b8
104      - x1r5g5b5
105      - x2r10g10b10
106      - x8r8g8b8
107
108  display:
109    $ref: /schemas/types.yaml#/definitions/phandle
110    description: Primary display hardware node
111
112  allwinner,pipeline:
113    description: Pipeline used by the framebuffer on Allwinner SoCs
114    enum:
115      - de_be0-lcd0
116      - de_be0-lcd0-hdmi
117      - de_be0-lcd0-tve0
118      - de_be1-lcd0
119      - de_be1-lcd1-hdmi
120      - de_fe0-de_be0-lcd0
121      - de_fe0-de_be0-lcd0-hdmi
122      - de_fe0-de_be0-lcd0-tve0
123      - mixer0-lcd0
124      - mixer0-lcd0-hdmi
125      - mixer1-lcd1-hdmi
126      - mixer1-lcd1-tve
127
128  amlogic,pipeline:
129    description: Pipeline used by the framebuffer on Amlogic SoCs
130    enum:
131      - vpu-cvbs
132      - vpu-hdmi
133
134patternProperties:
135  "^[a-zA-Z0-9-]+-supply$":
136    $ref: /schemas/types.yaml#/definitions/phandle
137    description:
138      Regulators used by the framebuffer. These should be named
139      according to the names in the device design.
140
141required:
142  # The binding requires also reg, width, height, stride and format,
143  # but usually they will be filled by the bootloader.
144  - compatible
145
146allOf:
147  - if:
148      properties:
149        compatible:
150          contains:
151            const: allwinner,simple-framebuffer
152
153    then:
154      required:
155        - allwinner,pipeline
156
157  - if:
158      properties:
159        compatible:
160          contains:
161            const: amlogic,simple-framebuffer
162
163    then:
164      required:
165        - amlogic,pipeline
166
167
168additionalProperties: false
169
170examples:
171  - |
172    / {
173        compatible = "foo";
174        model = "foo";
175        #address-cells = <1>;
176        #size-cells = <1>;
177
178        chosen {
179            #address-cells = <1>;
180            #size-cells = <1>;
181            framebuffer0: framebuffer@1d385000 {
182                compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
183                allwinner,pipeline = "de_be0-lcd0";
184                reg = <0x1d385000 3840000>;
185                width = <1600>;
186                height = <1200>;
187                stride = <3200>;
188                format = "r5g6b5";
189                clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
190                lcd-supply = <&reg_dc1sw>;
191                display = <&lcdc0>;
192            };
193        };
194    };
195
196...
197