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Diffstat (limited to 'Documentation/devicetree/bindings/display/simple-framebuffer.yaml')
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diff --git a/Documentation/devicetree/bindings/display/simple-framebuffer.yaml b/Documentation/devicetree/bindings/display/simple-framebuffer.yaml new file mode 100644 index 000000000000..b052d76cf8b6 --- /dev/null +++ b/Documentation/devicetree/bindings/display/simple-framebuffer.yaml @@ -0,0 +1,160 @@ +# 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 <b.zolnierkie@samsung.com> + - Hans de Goede <hdegoede@redhat.com> + +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@<address>. + + 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 + +additionalProperties: false + +examples: + - | + aliases { + display0 = &lcdc0; + }; + + chosen { + #address-cells = <1>; + #size-cells = <1>; + stdout-path = "display0"; + framebuffer0: framebuffer@1d385000 { + compatible = "simple-framebuffer"; + 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"; + }; + }; + +... |