Ace that works!
(I've black listed gpio_mcp23s08 as well for good measure!)
Thanks!

Yes its connected correctly - I can control it directly using the /sys filing system. It will happily read and change the output. Either by just simple command line commands or via python. i2c shows this : i2cdetect -y 1 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- -- -- -- -- -- -- -- -- -- -- -- -- 10: ...

Hi All, I have a raspberry B rev2 (revision 000f from /proc/cpuinfo) I'm running Raspbian GNU/Linux 8 (jessie) kernel 4.4.37+ #936 Fri Dec 9 16:53:10 GMT 2016 armv6l /boot/config has dtoverlay=mcp23017 (with or without this the error still occurs) (with the dtoverlay) the MCP23017 device is recognis...