# SPDX-License-Identifier: GPL-2.0 %YAML 1.2 --- $id: http://devicetree.org/schemas/display/simple-framebuffer.yaml# $schema: http://devicetree.org/meta-schemas/core.yaml# title: Simple Framebuffer Device Tree Bindings maintainers: - Bartlomiej Zolnierkiewicz - Hans de Goede description: |+ A simple frame-buffer describes a frame-buffer setup by firmware or the bootloader, with the assumption that the display hardware has already been set up to scan out from the memory pointed to by the reg property. Since simplefb nodes represent runtime information they must be sub-nodes of the chosen node (*). Simplefb nodes must be named framebuffer@
. If the devicetree contains nodes for the display hardware used by a simplefb, then the simplefb node must contain a property called display, which contains a phandle pointing to the primary display hw node, so that the OS knows which simplefb to disable when handing over control to a driver for the real hardware. The bindings for the hw nodes must specify which node is considered the primary node. It is advised to add display# aliases to help the OS determine how to number things. If display# aliases are used, then if the simplefb node contains a display property then the /aliases/display# path must point to the display hw node the display property points to, otherwise it must point directly to the simplefb node. If a simplefb node represents the preferred console for user interaction, then the chosen node stdout-path property should point to it, or to the primary display hw node, as with display# aliases. If display aliases are used then it should be set to the alias instead. It is advised that devicetree files contain pre-filled, disabled framebuffer nodes, so that the firmware only needs to update the mode information and enable them. This way if e.g. later on support for more display clocks get added, the simplefb nodes will already contain this info and the firmware does not need to be updated. If pre-filled framebuffer nodes are used, the firmware may need extra information to find the right node. In that case an extra platform specific compatible and platform specific properties should be used and documented. properties: compatible: items: - enum: - allwinner,simple-framebuffer - amlogic,simple-framebuffer - const: simple-framebuffer reg: description: Location and size of the framebuffer memory clocks: description: List of clocks used by the framebuffer. power-domains: description: List of power domains used by the framebuffer. width: $ref: /schemas/types.yaml#/definitions/uint32 description: Width of the framebuffer in pixels height: $ref: /schemas/types.yaml#/definitions/uint32 description: Height of the framebuffer in pixels stride: $ref: /schemas/types.yaml#/definitions/uint32 description: Number of bytes of a line in the framebuffer format: description: > Format of the framebuffer: * `a8b8g8r8` - 32-bit pixels, d[31:24]=a, d[23:16]=b, d[15:8]=g, d[7:0]=r * `r5g6b5` - 16-bit pixels, d[15:11]=r, d[10:5]=g, d[4:0]=b enum: - a8b8g8r8 - r5g6b5 display: $ref: /schemas/types.yaml#/definitions/phandle description: Primary display hardware node allwinner,pipeline: description: Pipeline used by the framebuffer on Allwinner SoCs enum: - de_be0-lcd0 - de_be0-lcd0-hdmi - de_be0-lcd0-tve0 - de_be1-lcd0 - de_be1-lcd1-hdmi - de_fe0-de_be0-lcd0 - de_fe0-de_be0-lcd0-hdmi - de_fe0-de_be0-lcd0-tve0 - mixer0-lcd0 - mixer0-lcd0-hdmi - mixer1-lcd1-hdmi - mixer1-lcd1-tve amlogic,pipeline: description: Pipeline used by the framebuffer on Amlogic SoCs enum: - vpu-cvbs - vpu-hdmi patternProperties: "^[a-zA-Z0-9-]+-supply$": $ref: /schemas/types.yaml#/definitions/phandle description: Regulators used by the framebuffer. These should be named according to the names in the device design. required: # The binding requires also reg, width, height, stride and format, # but usually they will be filled by the bootloader. - compatible allOf: - if: properties: compatible: contains: const: allwinner,simple-framebuffer then: required: - allwinner,pipeline - if: properties: compatible: contains: const: amlogic,simple-framebuffer then: required: - amlogic,pipeline additionalProperties: false examples: - | aliases { display0 = &lcdc0; }; chosen { #address-cells = <1>; #size-cells = <1>; stdout-path = "display0"; framebuffer0: framebuffer@1d385000 { compatible = "allwinner,simple-framebuffer", "simple-framebuffer"; allwinner,pipeline = "de_be0-lcd0"; reg = <0x1d385000 3840000>; width = <1600>; height = <1200>; stride = <3200>; format = "r5g6b5"; clocks = <&ahb_gates 36>, <&ahb_gates 43>, <&ahb_gates 44>; lcd-supply = <®_dc1sw>; display = <&lcdc0>; }; }; soc@1c00000 { lcdc0: lcdc@1c0c000 { compatible = "allwinner,sun4i-a10-lcdc"; }; }; ...