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
| GPIO | PIN | UART0/1 | SPI | JTAG | I2C |
|---|---|---|---|---|---|
| 0 | 6 | CTS0 | SCK | TCK | |
| 1 | 7 | RTS0 | MISO | TDO | |
| 2 | 5 | DSR0 | SCS0 | TMS | |
| 3 | 11 | RI0 | SCL | ||
| 4 | 15 | DCD0/ACT | |||
| 5 | 9 | TNOW0/DTR0 | SCS1 | TRST | |
| 6 | 2 | CTS1 | |||
| 7 | 13 | RTS1 |
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