Here is a list of all documented enum values with links to the documentation:

• HID_API_BUS_BLUETOOTH : hidapi.h
• HID_API_BUS_I2C : hidapi.h
• HID_API_BUS_SPI : hidapi.h
• HID_API_BUS_UNKNOWN : hidapi.h
• HID_API_BUS_USB : hidapi.h