The ole power-off button using gpio question - AML-S905X-CC

[pezmaker]

Hello.  I've searched here, the Libre computer forums, even tried "cheating" with asking chatgpt.  Using a "Le Potato" AML-S905X-CC with Armbian Jammy 22.04.2 LTS.

I've gotten far enough to be able to read the switch on the GPIO with pulled to 0 reading as 1.
 

button untouched:
~$ sudo gpioget --active-low gpiochip1 97
0
button pressed:
:~$ sudo gpioget --active-low gpiochip1 97
1

 

From here though, I can't seem to figure out what to do next.  I've seen suggestions to use a python script with a sleep to using device overlays.  The device overlay examples I see using armbian are typically for orange Pis and I can't seem to extrapolate to the le potato gpio, or are Libre's support saying how to do it with their custom kernels and device tree overlay tools, which I (in my foolishness? long term wisdom?) chose not to use over Armbian.

If anyone has some input on what to throw at this next I'd love it.  I am using this le potato as a klipper server with Fluidd and would love to be able to hit my pretty led backed power button to power down the server board and a second led lit power switch to power down the printer.  In the end it's no big deal if I can't get this working, I can just shutdown the pi via Klipperscreen and then use the modified power switch on the 3d printer.  But that's not as much fun as changing everything.

 

Thank you!

[usual user]

On 7/10/2023 at 9:05 PM, pezmaker said:

If anyone has some input on what to throw at this next I'd love it. 

gpiomon is your friend, e.g.:

sudo gpiomon --num-events=1 gpiochip1 97 && poweroff

 

[pezmaker]

Good input.  I did have to add  option " -B pull-down" or it gave me syntax errors.

 

sudo gpiomon --num-events=1 -B pull-down -f gpiochip0 9 && halt

 

I also couldn't get it to register the button press immediately.  I'd need to do more testing but it seemed I needed to hold it down for seconds before it'd register.  I also wasn't sure how to get a wall message and 5 second wait in there, so in the end I went with a script that loads on startup. 

 

That said, what you said was a perfectly solid answer so you get the solution.

 

Thank you for the response!

[usual user]

7 hours ago, pezmaker said:

I did have to add  option " -B pull-down"

 

7 hours ago, pezmaker said:

I also couldn't get it to register the button press immediately.  I'd need to do more testing but it seemed I needed to hold it down for seconds before it'd register.

The necessity of the "-B" parameter with the observed gpio behavior is probably due to how the gpio is wired up in the DT and how its pin control is set up there.

 

7 hours ago, pezmaker said:

I also wasn't sure how to get a wall message and 5 second wait in there, so in the end I went with a script that loads on startup. 

Since I didn't know the exact use case, I only presented the basic command and left it to the user's imagination how it would ultimately be used. It's general shell usage, and if I understand the use case correctly, I'd have e.g. used something like this in a script that loads on startup:

gpiomon --num-events=1 -B pull-down -f gpiochip0 9 && wall power off initiated && sleep 5 && halt

 

7 hours ago, pezmaker said:

Thank you for the response!

You're welcome.