Documentation/devicetree/bindings/display/simple-framebuffer.yaml

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/display/simple-framebuffer.yaml

File Facts

System
Linux kernel
Corpus path
Documentation/devicetree/bindings/display/simple-framebuffer.yaml
Extension
.yaml
Size
6862 bytes
Lines
213
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: configuration, schema, or hardware description
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

# 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

maintainers:
  - 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.

  If a panel node is given, then the driver uses this to configure the
  physical width and height of the display. If no panel node is given,
  then the driver uses the width and height properties of the simplefb
  node to estimate it.

  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:
    oneOf:
      - items:
          - enum:
              - apple,simple-framebuffer
              - allwinner,simple-framebuffer
              - amlogic,simple-framebuffer
          - const: simple-framebuffer
      - const: simple-framebuffer

  reg:
    description: Location and size of the framebuffer memory

Annotation

Implementation Notes