Re: [PATCH v2 02/14] dt-bindings: display: Add Solomon SSD16xx e-paper controller binding

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:
- [Medium] dt-bindings: redefined standard rotation property semantics (clockwise vs CCW)
- [Medium] dt-bindings: missing panel-common.yaml reference incorrectly rejects panel properties
- [Medium] dt-bindings: missing spi-3wire property definition breaks validation for 3-wire mode
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commit 504b4d897333eddd3593a4ba35eae49d79d7d739
Author: Devarsh Thakkar <devarsht@ti.com>
dt-bindings: display: Add Solomon SSD16xx e-paper controller binding

This commit adds a device tree binding for the Solomon Systech SSD16xx e-Paper
display controllers. It covers the 4-wire SPI interface and required GPIO pins
while also noting optional 3-wire mode support.

Link: https://www.crystalfontz.com/controllers/SolomonSystech/SSD1683
Link: https://files.seeedstudio.com/wiki/Other_Display/42-epaper/GDEY042T81.pdf
Link: https://www.crystalfontz.com/controllers/SolomonSystech/SSD1673
Link: https://www.crystalfontz.com/controllers/SolomonSystech/SSD1680
Link: https://www.crystalfontz.com/controllers/SolomonSystech/SSD1681

> diff --git a/Documentation/devicetree/bindings/display/solomon,ssd16xx.yaml b/Documentation/devicetree/bindings/display/solomon,ssd16xx.yaml
> new file mode 100644
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/solomon,ssd16xx.yaml
[ ... ]
> +allOf:
> +  - $ref: /schemas/spi/spi-peripheral-props.yaml#

[Severity: Medium]
Is this missing a reference to /schemas/display/panel/panel-common.yaml#?

Because this schema acts as a display panel node and sets
unevaluatedProperties: false later in the file, omitting the panel-common
reference strictly forbids standard panel properties like power-supply or
port. This might prevent valid hardware board configurations from passing
schema validation.

> +
> +properties:
> +  compatible:

[Severity: Medium]
Should spi-3wire: true be explicitly declared here in the properties section?

The commit message notes that the controller supports 3-wire mode, but neither
this schema nor the referenced spi-peripheral-props.yaml define spi-3wire.
Because unevaluatedProperties is set to false, configuring a peripheral in
3-wire mode with the standard spi-3wire property will erroneously fail schema
validation.

[ ... ]
> +  rotation:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    enum: [0, 90, 180, 270]
> +    description:
> +      Display rotation in degrees clockwise.

[Severity: Medium]
Does defining rotation as clockwise conflict with standard device tree
semantics?

The device tree standard for displays (panel-common.yaml) explicitly defines
rotation as counter-clockwise. Defining it as clockwise here creates a
semantic mismatch that could lead to inverted rotation at runtime if the DRM
driver or generic kernel helpers parse it assuming the standard CCW semantics.

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260927182329.4193961-1-devarsht@ti.com?part=2