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    oneOf:
56      - items:
57          - enum:
58              - apple,simple-framebuffer
59              - allwinner,simple-framebuffer
60              - amlogic,simple-framebuffer
61          - const: simple-framebuffer
62      - const: simple-framebuffer
63
64  reg:
65    description: Location and size of the framebuffer memory
66
67  clocks:
68    description: List of clocks used by the framebuffer.
69
70  power-domains:
71    description: List of power domains used by the framebuffer.
72
73  width:
74    $ref: /schemas/types.yaml#/definitions/uint32
75    description: Width of the framebuffer in pixels
76
77  height:
78    $ref: /schemas/types.yaml#/definitions/uint32
79    description: Height of the framebuffer in pixels
80
81  stride:
82    $ref: /schemas/types.yaml#/definitions/uint32
83    description: Number of bytes of a line in the framebuffer
84
85  format:
86    description: >
87      Format of the framebuffer:
88        * `a1r5g5b5` - 16-bit pixels, d[15]=a, d[14:10]=r, d[9:5]=g, d[4:0]=b
89        * `a2r10g10b10` - 32-bit pixels, d[31:30]=a, d[29:20]=r, d[19:10]=g, d[9:0]=b
90        * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r
91        * `a8r8g8b8` - 32-bit pixels, d[31:24]=a, d[23:16]=r, d[15:8]=g, d[7:0]=b
92        * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b
93        * `r5g5b5a1` - 16-bit pixels, d[15:11]=r, d[10:6]=g, d[5:1]=b d[1:0]=a
94        * `r8g8b8` - 24-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
95        * `x1r5g5b5` - 16-bit pixels, d[14:10]=r, d[9:5]=g, d[4:0]=b
96        * `x2r10g10b10` - 32-bit pixels, d[29:20]=r, d[19:10]=g, d[9:0]=b
97        * `x8r8g8b8` - 32-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
98    enum:
99      - a1r5g5b5
100      - a2r10g10b10
101      - a8b8g8r8
102      - a8r8g8b8
103      - r5g6b5
104      - r5g5b5a1
105      - r8g8b8
106      - x1r5g5b5
107      - x2r10g10b10
108      - x8r8g8b8
109
110  display:
111    $ref: /schemas/types.yaml#/definitions/phandle
112    description: Primary display hardware node
113
114  allwinner,pipeline:
115    description: Pipeline used by the framebuffer on Allwinner SoCs
116    enum:
117      - de_be0-lcd0
118      - de_be0-lcd0-hdmi
119      - de_be0-lcd0-tve0
120      - de_be1-lcd0
121      - de_be1-lcd1-hdmi
122      - de_fe0-de_be0-lcd0
123      - de_fe0-de_be0-lcd0-hdmi
124      - de_fe0-de_be0-lcd0-tve0
125      - mixer0-lcd0
126      - mixer0-lcd0-hdmi
127      - mixer1-lcd1-hdmi
128      - mixer1-lcd1-tve
129
130  amlogic,pipeline:
131    description: Pipeline used by the framebuffer on Amlogic SoCs
132    enum:
133      - vpu-cvbs
134      - vpu-hdmi
135
136patternProperties:
137  "^[a-zA-Z0-9-]+-supply$":
138    $ref: /schemas/types.yaml#/definitions/phandle
139    description:
140      Regulators used by the framebuffer. These should be named
141      according to the names in the device design.
142
143required:
144  # The binding requires also reg, width, height, stride and format,
145  # but usually they will be filled by the bootloader.
146  - compatible
147
148allOf:
149  - if:
150      properties:
151        compatible:
152          contains:
153            const: allwinner,simple-framebuffer
154
155    then:
156      required:
157        - allwinner,pipeline
158
159  - if:
160      properties:
161        compatible:
162          contains:
163            const: amlogic,simple-framebuffer
164
165    then:
166      required:
167        - amlogic,pipeline
168
169
170additionalProperties: false
171
172examples:
173  - |
174    / {
175        compatible = "foo";
176        model = "foo";
177        #address-cells = <1>;
178        #size-cells = <1>;
179
180        chosen {
181            #address-cells = <1>;
182            #size-cells = <1>;
183            framebuffer0: framebuffer@1d385000 {
184                compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
185                allwinner,pipeline = "de_be0-lcd0";
186                reg = <0x1d385000 3840000>;
187                width = <1600>;
188                height = <1200>;
189                stride = <3200>;
190                format = "r5g6b5";
191                clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
192                lcd-supply = <&reg_dc1sw>;
193                display = <&lcdc0>;
194            };
195        };
196    };
197
198...
199