0001 # SPDX-License-Identifier: GPL-2.0
0002 %YAML 1.2
0003 ---
0004 $id: http://devicetree.org/schemas/display/simple-framebuffer.yaml#
0005 $schema: http://devicetree.org/meta-schemas/core.yaml#
0006
0007 title: Simple Framebuffer Device Tree Bindings
0008
0009 maintainers:
0010 - Hans de Goede <hdegoede@redhat.com>
0011
0012 description: |+
0013 A simple frame-buffer describes a frame-buffer setup by firmware or
0014 the bootloader, with the assumption that the display hardware has
0015 already been set up to scan out from the memory pointed to by the
0016 reg property.
0017
0018 Since simplefb nodes represent runtime information they must be
0019 sub-nodes of the chosen node (*). Simplefb nodes must be named
0020 framebuffer@<address>.
0021
0022 If the devicetree contains nodes for the display hardware used by a
0023 simplefb, then the simplefb node must contain a property called
0024 display, which contains a phandle pointing to the primary display
0025 hw node, so that the OS knows which simplefb to disable when handing
0026 over control to a driver for the real hardware. The bindings for the
0027 hw nodes must specify which node is considered the primary node.
0028
0029 It is advised to add display# aliases to help the OS determine how
0030 to number things. If display# aliases are used, then if the simplefb
0031 node contains a display property then the /aliases/display# path
0032 must point to the display hw node the display property points to,
0033 otherwise it must point directly to the simplefb node.
0034
0035 If a simplefb node represents the preferred console for user
0036 interaction, then the chosen node stdout-path property should point
0037 to it, or to the primary display hw node, as with display#
0038 aliases. If display aliases are used then it should be set to the
0039 alias instead.
0040
0041 It is advised that devicetree files contain pre-filled, disabled
0042 framebuffer nodes, so that the firmware only needs to update the
0043 mode information and enable them. This way if e.g. later on support
0044 for more display clocks get added, the simplefb nodes will already
0045 contain this info and the firmware does not need to be updated.
0046
0047 If pre-filled framebuffer nodes are used, the firmware may need
0048 extra information to find the right node. In that case an extra
0049 platform specific compatible and platform specific properties should
0050 be used and documented.
0051
0052 properties:
0053 compatible:
0054 oneOf:
0055 - items:
0056 - enum:
0057 - apple,simple-framebuffer
0058 - allwinner,simple-framebuffer
0059 - amlogic,simple-framebuffer
0060 - const: simple-framebuffer
0061 - const: simple-framebuffer
0062
0063 reg:
0064 description: Location and size of the framebuffer memory
0065
0066 clocks:
0067 description: List of clocks used by the framebuffer.
0068
0069 power-domains:
0070 description: List of power domains used by the framebuffer.
0071
0072 width:
0073 $ref: /schemas/types.yaml#/definitions/uint32
0074 description: Width of the framebuffer in pixels
0075
0076 height:
0077 $ref: /schemas/types.yaml#/definitions/uint32
0078 description: Height of the framebuffer in pixels
0079
0080 stride:
0081 $ref: /schemas/types.yaml#/definitions/uint32
0082 description: Number of bytes of a line in the framebuffer
0083
0084 format:
0085 description: >
0086 Format of the framebuffer:
0087 * `a1r5g5b5` - 16-bit pixels, d[15]=a, d[14:10]=r, d[9:5]=g, d[4:0]=b
0088 * `a2r10g10b10` - 32-bit pixels, d[31:30]=a, d[29:20]=r, d[19:10]=g, d[9:0]=b
0089 * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r
0090 * `a8r8g8b8` - 32-bit pixels, d[31:24]=a, d[23:16]=r, d[15:8]=g, d[7:0]=b
0091 * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b
0092 * `r5g5b5a1` - 16-bit pixels, d[15:11]=r, d[10:6]=g, d[5:1]=b d[1:0]=a
0093 * `r8g8b8` - 24-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
0094 * `x1r5g5b5` - 16-bit pixels, d[14:10]=r, d[9:5]=g, d[4:0]=b
0095 * `x2r10g10b10` - 32-bit pixels, d[29:20]=r, d[19:10]=g, d[9:0]=b
0096 * `x8r8g8b8` - 32-bit pixels, d[23:16]=r, d[15:8]=g, d[7:0]=b
0097 enum:
0098 - a1r5g5b5
0099 - a2r10g10b10
0100 - a8b8g8r8
0101 - a8r8g8b8
0102 - r5g6b5
0103 - r5g5b5a1
0104 - r8g8b8
0105 - x1r5g5b5
0106 - x2r10g10b10
0107 - x8r8g8b8
0108
0109 display:
0110 $ref: /schemas/types.yaml#/definitions/phandle
0111 description: Primary display hardware node
0112
0113 allwinner,pipeline:
0114 description: Pipeline used by the framebuffer on Allwinner SoCs
0115 enum:
0116 - de_be0-lcd0
0117 - de_be0-lcd0-hdmi
0118 - de_be0-lcd0-tve0
0119 - de_be1-lcd0
0120 - de_be1-lcd1-hdmi
0121 - de_fe0-de_be0-lcd0
0122 - de_fe0-de_be0-lcd0-hdmi
0123 - de_fe0-de_be0-lcd0-tve0
0124 - mixer0-lcd0
0125 - mixer0-lcd0-hdmi
0126 - mixer1-lcd1-hdmi
0127 - mixer1-lcd1-tve
0128
0129 amlogic,pipeline:
0130 description: Pipeline used by the framebuffer on Amlogic SoCs
0131 enum:
0132 - vpu-cvbs
0133 - vpu-hdmi
0134
0135 patternProperties:
0136 "^[a-zA-Z0-9-]+-supply$":
0137 $ref: /schemas/types.yaml#/definitions/phandle
0138 description:
0139 Regulators used by the framebuffer. These should be named
0140 according to the names in the device design.
0141
0142 required:
0143 # The binding requires also reg, width, height, stride and format,
0144 # but usually they will be filled by the bootloader.
0145 - compatible
0146
0147 allOf:
0148 - if:
0149 properties:
0150 compatible:
0151 contains:
0152 const: allwinner,simple-framebuffer
0153
0154 then:
0155 required:
0156 - allwinner,pipeline
0157
0158 - if:
0159 properties:
0160 compatible:
0161 contains:
0162 const: amlogic,simple-framebuffer
0163
0164 then:
0165 required:
0166 - amlogic,pipeline
0167
0168
0169 additionalProperties: false
0170
0171 examples:
0172 - |
0173 / {
0174 compatible = "foo";
0175 model = "foo";
0176 #address-cells = <1>;
0177 #size-cells = <1>;
0178
0179 chosen {
0180 #address-cells = <1>;
0181 #size-cells = <1>;
0182 framebuffer0: framebuffer@1d385000 {
0183 compatible = "allwinner,simple-framebuffer", "simple-framebuffer";
0184 allwinner,pipeline = "de_be0-lcd0";
0185 reg = <0x1d385000 3840000>;
0186 width = <1600>;
0187 height = <1200>;
0188 stride = <3200>;
0189 format = "r5g6b5";
0190 clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>;
0191 lcd-supply = <®_dc1sw>;
0192 display = <&lcdc0>;
0193 };
0194 };
0195 };
0196
0197 ...
