This kernel driver reads the status of a Wii Nunchuk and exports this data to the relevant kernel subsystems. Input events are exported via evdev and accelerometer data via Industrial I/O.
The driver is part of my experimental BeagleBone Black buildroot project.
It was initially based on bootlin's Linux kernel and driver development training.
User input of the Nunchuk is exported via an input_polled_dev.
The evdev driver exports the input events via a char device (e.g. /dev/input/event0) to user space.
The input device used by the evdev driver is called Wii Nunchuk.
The Nunchuk has the following inputs:
- Button C and Button Z
Event Type
EV_KEY
Codes
BTN_CandBTN_Z
- Joystick-Axis X and Joystick-Axis Y
Event Type
EV_ABS,
Codes
ABS_XandABS_Y)
Acceleration data of the Nunchuk is exported via an iio_dev.
It uses three channels of type IIO_ACCEL, one for each of the accelerometer's three axis.
They are exported by the iio driver at /sys/bus/iio/devices/iio\:device0/in_accel_{x,y,z}_raw.
The iio device is called Nunchuk Accel.