Wandboard Quad GPIO mapping

[Edward Sandberg]

I'm working with the imx6 GPIO driver on Wandboard Quad, using the
gpio_led run file as a smoke test.  Unfortunately, I've had only limited
success controlling the GPIO pins exported to the Wandboard's JP-4.  It
is unclear where these pins map in the Genode  imx6 driver (18.05,
nova). In Linux, I can successfully toggle them all via /sys/class/gpio.

The imx6 driver allows for 32 pins to be set to high or low and I have
modified the run file and the main.cc file to blink sets of pins rather
than just a single pin.  If I set all 32 pins as output with an initial
value of "0" in the run file and then blink the following sets of pins I
see these results:

0-31: I read 3 pins blinking with a voltage meter
0-15: I read 2 pins blinking
0-6: I read no pins blinking
7-15: I read no pins blinking

It seems as though it takes combinations of pins set to high and low at
the same time to get a reading of high or low off of a particular pin,
but I cannot divine the pattern. This leads me to think that there is a
step missing in the initial configuration.

Does anyone have a suggestion of what step I am missing to get
predictable results?

-- 
Edward Sandberg
Adventium Labs
111 3rd Avenue S. Suite #100
Minneapolis, MN 55401
ed.sandberg at adventiumlabs.com