drivers: gpio: add new driver for STMPE1600 gpio expander

The STMPE1600 is an I2C based GPIO expander. This initial patch
only supports reading from/writing to the pins on the STMPE1600,
and there is currently no support for interrupts.

Signed-off-by: Titouan Christophe <moiandme@gmail.com>
5 files changed