Odroid N2+, Coreelec, GPIO use

[lc625]

Hi
I am running Coreelec (latest stable, 19.3-Matrix) on an Odoroid N2+. At this point a lot of thanks to all of you who are doing such a great job letting us use our SBC’s in our Home cinema, Livingroom or whatever.

I write this post because I wonder if it is possible to use the GPIO`S of the N2+. In order to keep it simple, let’s say I want PIN 29 to put out 3,3V after starting up and switch it off when shut down. I read a lot about this and I feel like being quite close to the solution but missing the last hint:

Modifying the device tree from withing Coreelec is not possible (except blue LED, SPI and DVB GPIO).
Using fdtput to change the dtb.img seems to be a way to get to the point.

@TheCoolest described a way to modify dtb.img redirecting the blue LED to Pin 8 / GPIOX 12 [Odroid-N2 Wake Button - #31 by TheCoolest]. This works apparently only with the former N2 and I want only the pin 29, GPIOX 14 to put out 3,3Volts and not to be connected to the blue LED.

My idea is to do something like this:

mount -o rw,remount /flash

fdtput /flash/dtb.img ??? gpios 26 80 0 #(26 = GPIO, 80 = PIN 29, 0 = active high)

As I mentioned above, there are still remaining questions. That’s why the question marks are not only inside my brain but also inside code.

Perhaps someone can help me in this case. Thanks in advance.

[vpeter]

Sometimes it is possible to use GPIO directly without dtb changes.
Maybe this could work for GPIOX.14 (#490):

# export pin
echo  490 > /sys/class/gpio/export
# set direction
echo out > /sys/class/gpio/gpio490/direction
# set pin high
echo 1 > /sys/class/gpio/gpio490/value
# set pin low
echo 0 > /sys/class/gpio/gpio490/value

[lc625]

Thanks for your reply, but unfortunately there is no effect in this case.