Support Pointing Stick Input for HHKB Studio

[iberianpig]

Input Handling for Pointing Stick Devices Using HIDRAW

We have added new input handling for pointing stick devices using HIDRAW interface.
Now, it can process detailed touch information from pointing stick that libinput and evdev cannot handle.
This means you can map F and D keys to click actions while using the pointing stick.

Currently, this feature only supports HHKB Studio, but we plan to support other devices in the future.

Implementation Details

Handling HIDRAW Devices

• We use IOCTL commands to get information like the device name, bus type, vendor ID, and product ID for the pointing stick device connected through HIDRAW.
• HIDRAW receives data through device files named /dev/hidraw*.
• HHKB Studio can connect either via Bluetooth or USB, and we have implemented the correct processing based on each report descriptor.
• We handle events when switching between USB and Bluetooth, and when the device is connected or disconnected.

Processing Pointing Stick Events

• This feature works as a Fusuma InputPlugin. It creates a thread to wait for HIDRAW events.
• Fusuma analyze byte stream from /dev/hidraw* to determine the state of the pointing stick and generate touch (begin/update/end) events.
• Touch events are produced from PointingStickInput plugin and processed in Fusuma's main thread using IO.select.
• Fusuma's main thread detects touches using existing ThumbsenseDetector.
• It sends requests to change virtual keyboard layer to update key mappings in Fusuma's remap process.
• While using the pointing stick, the click events for the F and D keys are mapped to BTN_LEFT and BTN_RIGHT.

Setting Up Udev Rules

To make PointingStickInput work, users need to set up udev rules like following:

$ sudo vi /etc/udev/rules.d/60-udev-fusuma-thumbsense-hhkb-studio.rules

# /etc/udev/rules.d/60-udev-fusuma-thumbsense-hhkb-studio.rules
# HHKB Studio (USB)
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ATTRS{idVendor}=="04fe", ATTRS{idProduct}=="0016", MODE="0666"
# HHKB Studio (Bluetooth)
KERNEL=="hidraw*", SUBSYSTEM=="hidraw", ENV{DEVPATH}=="/devices/virtual/misc/uhid/*:04FE:0016.*/hidraw*", MODE="0666"

$ sudo udevadm control --reload-rules && sudo udevadm trigger

After this, Fusuma will be able to read the HHKB Studio as a HIDRAW device.

User Configuration Example

Here is an example of how you might configure your ~/.config/fusuma/config.yml . Please add this section to end of config.yml.

---
context:
  thumbsense: true

remap:
  F: BTN_LEFT
  E: BTN_MIDDLE
  D: BTN_RIGHT

  J: BTN_LEFT
  I: BTN_MIDDLE
  K: BTN_RIGHT

  # Translate in Google Chrome
  T: { sendkey: ["LEFTSHIFT+F10", "T", "ENTER", "ESC"] }