[fedora-arm] Re: Nvidia Jetson Nano GPIO?

On Tue, Mar 30, 2021 at 6:51 AM Peter Robinson <pbrobinson@gmail.com> wrote:

On Tue, Mar 30, 2021 at 12:31 PM Richard Shaw <hobbes1069@gmail.com> wrote:
>
> I have a Jetso Nano running Fedora 33 following this guide:

Which guide, could you provide a link?

Whoops!

https://nullr0ute.com/2020/11/installing-fedora-on-the-nvidia-jetson-nano/

 

> I want to use it to play with home automation and I have node-red installed and have hacked together a node based on the Rpi GPIO node for the Jetson.
>
> I have copied the udev rules into /etc/udev/rules.d but I don't see the devices, there is no /sys/class/gpio. I changed the udev loglevel to info and see:

<snip> please only include relevant logs.

We don't support the gpio sysfs means of accessing GPIO, it's been
deprecated since around the 4.8 kernel.

Interesting... I'm assuming that Nvidia based theirs on Debian which may still be using this method?

 

> Any tips? Or am I stuck running Nvidia's linux for it to work?

The replacement mechanism is the GPIO character interface where the
GPIO is available via /dev/gpiochip* or through the libgpiod userspace
utils and python3 bindings in the python3-libgpiod package. I've not
looked but I would guess there's support for this interface on NodeRED
as it's been around for some time.

Yes, I do see a /dev/gpiochip{0,1}

I'll take a look. Thanks!

Richard