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I'm trying to create gpio22 and gpio27 in sys/class/gpio/ and enable them, I'm using following command for the same:

echo "22" | sudo tee /sys/class/gpio/export
echo "27" | sudo tee /sys/class/gpio/export

Using the above commands I'm able to add/configure the pins, But every time I restart the system Gpio22 and Gpio27 disappear from the directory.

Droidverine
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  • *"But every time I restart the system ..."* -- That's how it is designed to work. Sysfs is a pseudo-filesystem; sysfs is simply not a permanent filesystem, and is regenerated on each boot. Learn how to use the newer gpiolib. –  Nov 24 '21 at 10:02
  • @sawdust thanks for your answer. I'm not using any libraries currently to enable these pins and I don't prefer installing any new libraries onto the system I'm working on. Can you please suggest any other way to permanently enable these pins? – Droidverine Nov 24 '21 at 11:34
  • @sawdust why not make that an answer? – joan Nov 24 '21 at 11:35
  • create a systemd service – Bravo Nov 24 '21 at 11:36
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    @Droidverine Arch is intended for experts. You might be better off using the standard Raspberry OS. – joan Nov 24 '21 at 11:36

2 Answers2

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The easiest way to run a program at boot is to edit the file rc.local. This is a file which contains lines of code to be run at boot time. Run sudo nano /etc/rc.local. Right before the line exit 0 in the file paste your code:

echo "22" | sudo tee /sys/class/gpio/export
echo "27" | sudo tee /sys/class/gpio/export

Save the file by pressing Ctrl-x then Y. Finally press Enter. Your lines of code will run every time at boot. If for some reason this does not work, here are a few other ways of doing it: https://www.dexterindustries.com/howto/run-a-program-on-your-raspberry-pi-at-startup/.

Quizzer515SY
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The gpio directive allows GPIO pins to be set to specific modes and values at boot time. See https://www.raspberrypi.com/documentation/computers/config_txt.html#gpio

NOTE this is not using the deprecated sysfs interface, so if you want to subsequently change pins you will need another method.

https://raspberrypi.stackexchange.com/a/133252/8697 shows options

Milliways
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