Ken Van Hoeylandt c729e8340f
Trackball rewrite (#600)
- Implement generic trackball settings
- Refactor T-Deck trackball driver into generic driver at `Drivers/gpio-trackball-module`
- Automatically bind/unbind trackball devices with LVGL
- Automatically load settings for trackball devices on boot
2026-07-30 13:38:19 +02:00

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# GPIO Trackball
Kernel driver for a 5-way GPIO trackball (4 direction pins + a click button), exposing a
`TRACKBALL_TYPE` device (`tactility/drivers/trackball.h`).
Devicetree binding: `tactility,gpio-trackball` (see `bindings/tactility,gpio-trackball.yaml`).
Each direction pin is wired to a falling-edge interrupt that accumulates a signed delta;
the click pin is active-low and read on any edge. `read_delta()` drains and resets the
accumulated delta on each call.
## Example
```dts
trackball {
compatible = "tactility,gpio-trackball";
pin-right = <&gpio0 1 GPIO_FLAG_NONE>;
pin-up = <&gpio0 2 GPIO_FLAG_NONE>;
pin-left = <&gpio0 3 GPIO_FLAG_NONE>;
pin-down = <&gpio0 4 GPIO_FLAG_NONE>;
pin-click = <&gpio0 5 GPIO_FLAG_NONE>;
};
```
## License
[Apache License Version 2.0](LICENSE-Apache-2.0.md)