Controlling the same I2C device from user and kernel space

[Patryk]

Hi, I've got a question. I have an I2C device (FPGA) connected to my
board. This device implements a hardware watchdog and GPIO expander.
My question is - can I control this device from userspace (watchdog
part) using spidev driver and still be able to develop a kernel driver
that controls GPIO expander part without any additional locking
mechanisms?

Best regards
Patryk