There are 2 repositories under userspace-driver topic.
Open source, cross-platform, user-mode tablet driver
Build userspace NVMe drivers and storage applications with CUDA support
GKey support for Logitech G910 Keyboard on Linux
A faster, lower-latency, userspace touchscreen input driver for the official Raspberry Pi 7" screen.
Virtual OSSv4 compatible digital audio workstation daemon
Allocating physical memory in linux userspace
SoC specific part of the ISO7816 stack
Userspace I/O library for Xilinx AXI S2MM DMA
Userland linux driver for Moga bluetooth gamepads in "A" mode
RGB Cooling HAT advanced utility for YB-EPV02 and it's SSD1306.
Example to integrate Netronome SmartNICs with userspace driver
CLI for managing colors and effects for CosmicByte Firefly Keyboard
ILI9341 TFT screen userspace driver
STM32F4x9 cryptographic accelerator userspace driver
STM32F4xx HASH userspace driver
USART driver for STM32F4xx SoC
Use your smartphone (or tablet) with stylus as a graphics tablet on Linux
Userspace библиотека для работы с портами GPIO Super I/O контроллера VIA VT1211
AD7843 touchscreen userspace driver
STM32F4xx flash memory userspace driver
STM32F4xx SDIO interface userspace driver
STM32F4xx SPI userspace driver
STM32F4xx USB userspace driver for full-speed and high-speed