Linux kernel drivers for vendor class protocols of CH347

Set has four drivers -- base is MFD (mfd-ch347.ko), and on top of it are I2C, GPIO and SPI drivers (Modes 1 and 3).

CH347 can also do UART(s), which are handled independently (in parallel to these drivers) by either standard USB CDC driver or by common W-CH driver for all their UARTs.

JTAG support is handled in userspace via openFPGALoader (open source) or binary driver for OpenOCD released by W-CH.

Driver behaves as an ordinary I2C master controller, e.g. i2c-tools work with it and it is possible to add slave devices via usual methods.

Driver controls 8 pins, there is no check if these pins are used by any other protocol

Driver adds new SPI master controller with speeds up to 60MHz and 2 slaves. If your setup does not support such frequencies (think "dupont" wires), decrease frequency when adding slave devices.

To add a slave device you should send string containing device driver name, chip select number and optionally frequency into "new_device" file in sysfs directory of the driver.

echo "spi-nor 0 15000" > /sys/class/.../spi2/new_device