Re: [PATCH v3 2/7] dt-bindings: display: add a device tree supplied boot logo

On Wed, 23 Sep 2026 22:10:30 +0200, Max Pedraza wrote:

Embedded products frequently need a product specific boot logo. Today that
means pointing CONFIG_LOGO_LINUX_CLUT224_FILE at a different image, which
bakes it into the kernel image: a change of branding, or a second product
sharing the same board support package, requires a separate kernel build,
and requalifying that kernel for what is a cosmetic change.

Add a binding for a "boot-logo-clut224" node, which carries the logo
in the same paletted format the built-in CLUT224 logos already use, plus a
few optional properties describing where on the screen it is drawn.

The node lives under /chosen because a logo is configuration handed over by
firmware rather than a description of the hardware. Open Firmware, which
the device tree descends from, carried a boot logo in the same spirit as
the oem-logo variable under /options, and simple-framebuffer nodes live
under /chosen today for the same reason.

The palette size is derived from the length of the "clut" property rather
than spelled out separately, and "data" holds plain palette indices; the
32 entry offset the frame buffer layer reserves for the console is an
implementation detail and is applied by the kernel, not by the binding.

"logo-position" takes -1 on an axis to mean centre on that axis rather than
carrying a separate boolean for it. A boolean can only centre both axes or
neither, and next to explicit coordinates it would have to override them
silently when a device tree gave both.

A rotation turns the logo, not the screen. "logo-position" and
"logo-offset" are screen pixels whatever "logo-rotation" says, and a
quarter turn only changes how much room the logo takes up. Placing the
logo in a frame that turns with it would make the same pair of
coordinates mean different places on the same panel, decided by a
property that is meant to describe the image.

Every coordinate is bounded. The kernel clamps them anyway, since it cannot
trust a device tree, but a value that cannot possibly be meant is worth
catching in dtbs_check rather than on the panel.

Signed-off-by: Max Pedraza <redacted>
---
 .../bindings/display/boot-logo-clut224.yaml   | 135 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 136 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/boot-logo-clut224.yaml

My bot found errors running 'make dt_binding_check' on your patch:

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/display/boot-logo-clut224.example.dtb: chosen: 'logo' does not match any of the regexes: '^framebuffer', '^pinctrl-[0-9]+$'
	from schema $id: http://devicetree.org/schemas/chosen.yaml

doc reference errors (make refcheckdocs):

See https://patchwork.kernel.org/project/devicetree/patch/20260923201035.51007-3-maximpedraza@gmail.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.