I’ve added a MAX7320 i2c expander chip to i2c bus 0 on my ARM Linux board. The chip works correctly from userspace with commands such as /usr/sbin/i2cset -y 0 0x5d 0x02 and /usr/sbin/i2cget -y 0 0x5d. There is a drivers/gpio/gpio-max732x.c file in the kernel source, which is compiled into the kernel tha…