Hi Frank, thanks for your patch! I see you already got a bunch of homework from Andy, I will do a more thorough review on the next iteration, just a few things: On Mon, Mar 21, 2022 at 5:21 AM frank zago <frank@xxxxxxxx> wrote: > The GPIO interface offers 16 GPIOs. 6 are read/write, and 10 are > read-only. > > Signed-off-by: frank zago <frank@xxxxxxxx> (...) > +config GPIO_CH341 > + tristate "CH341 USB adapter in GPIO/I2C/SPI mode" > + depends on MFD_CH341 I would add default MFD_CD341 This way it gets selected automatically if the MFD module gets selected. (I suspect you should do the same with the I2C module). > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/mfd/core.h> > +#include <linux/gpio.h> Use <linux/gpio/driver.h> Yours, Linus Walleij