Add aux button

Add support for external button.

Signed-off-by: Paul Brook <paul@nowt.org>
Remove old RFID code

Remove bitrotten code for other RFID readers

Signed-off-by: Paul Brook <paul@nowt.org>
Tag scanout

Add scanout tag reader

Signed-off-by: Paul Brook <paul@nowt.org>
Better debug message

Include device name in timout error.

Signed-off-by: Paul Brook <paul@nowt.org>
Reset IO expander

Reset IO expander on startup.

Signed-off-by: Paul Brook <paul@nowt.org>