how do I change the value of a GPIO?

[arrow53]

I'm working with a Jetson Orin Nano and scarthgap.

Previously i've used /sys/class/gpio to set GPIO values. But, that seems to be missing.

Can anyone provide some general guidance on setting GPIO02 and GPIO03 which are GPIO0_PP.06 and GPIO3_PCC.00 respectively.

I'm pretty unclear to where to start.
thanks!

[dwalkes]

@arrow53 I'd start by mining the content in https://github.com/search?q=org%3AOE4T+gpio&type=discussions and possibly also referencing the wiki content in https://github.com/search?q=org%3AOE4T+gpio&type=wikis. We do have a page on GPIO control at https://github.com/OE4T/meta-tegra/wiki/Controlling-Jetson-TX2-pin-states but I think it's out of date and in need of a refresh/update.

[madisongh]

Also, some Google searching for "GPIO sysfs vs libgpiod" will also give you some pointers to info on the years-long transition away from the old sysfs interface for manipulating GPIOs, too. You should still be able to add CONFIG_GPIO_SYSFS=y to your kernel config to enable the old interface, though.

[arrow53]

thanks guys. the CONFIG_GPIO_SYSFS is nice

[arrow53]

For posterity in case anyone else runs across this discussion, this is what I did

1. Grab the pinmux spreadsheet and configure the pins the way you need then generate the new files https://developer.nvidia.com/downloads/jetson-orin-nx-and-orin-nano-series-pinmux-config-template.
2. This will give you three new dtsi files. You need to match up what these are with your machine and meld them to get the changes you need from the machine. The relevant recipe is tegra-bootfiles
3. Build in these recipes libgpiod libgpiod-tools libgpiod-dev
4. Back at the command line run gpioinfo and grep on your gpio you want. For my case I wanted GGPIO3_PCC.00
5. Take the controller name (0 or 1 for me) and the line and you should now be able to gpioset -c 1 12=1 to set. where the c is the controller number and 12 is the line number.

Good reference https://docs.nvidia.com/jetson/archives/r35.3.1/DeveloperGuide/text/HR/JetsonModuleAdaptationAndBringUp/JetsonOrinNxNanoSeries.html#generating-the-pinmux-dtsi-files

[dwalkes]

Thanks for sharing! I've copied to https://github.com/OE4T/meta-tegra/wiki/Controlling-Jetson-pin-states so we can find this link in wiki searches going forward.