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
7 title: Simple Framebuffer
8
9 maintainers:
10 - Hans de Goede <hdegoede@redhat.com>
11
12 description: |+
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
57 properties:
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 $ref: /schemas/types.yaml#/definitions/phandle
127 description: Display panel node
128
129 allwinner,pipeline:
130 description: Pipeline used by the framebuffer on Allwinner SoCs
131 enum:
132 - de_be0-lcd0
133 - de_be0-lcd0-hdmi
134 - de_be0-lcd0-tve0
135 - de_be1-lcd0
136 - de_be1-lcd1-hdmi
137 - de_fe0-de_be0-lcd0
138 - de_fe0-de_be0-lcd0-hdmi
139 - de_fe0-de_be0-lcd0-tve0
140 - mixer0-lcd0
141 - mixer0-lcd0-hdmi
142 - mixer1-lcd1-hdmi
143 - mixer1-lcd1-tve
144
145 amlogic,pipeline:
146 description: Pipeline used by the framebuffer on Amlogic SoCs
147 enum:
148 - vpu-cvbs
149 - vpu-hdmi
150
151 patternProperties:
152 "^[a-zA-Z0-9-]+-supply$":
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
158 required:
159 # The binding requires also reg, width, height, stride and format,
160 # but usually they will be filled by the bootloader.
161 - compatible
162
163 allOf:
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
185 additionalProperties: false
186
187 examples:
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 = <®_dc1sw>;
208 display = <&lcdc0>;
209 };
210 };
211 };
212
213 ...
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