iC-JX expander has NINT (not interrupt) pin that goes to logical zero
if interrupt occurs. This commit adds support for iC-JX options settings
that allows to enable the interrupt for defined input pins.
The interrupt is handled in HP worker thread to avoid waiting for SPI
transfers in interrupt context. Board has to configure interrupt event
for GPIO pin connected to NINT.
Signed-off-by: Michal Lenc <michallenc@seznam.cz>
This commit adds basic support for iC-JX expander in SPI mode. The
expander is functional and supports both input and output pins. Further
expander functionalities (filtering, adc, interrupt support) are not
yet implemented.
Signed-off-by: Michal Lenc <michallenc@seznam.cz>