/sys/class/gpio/export will unexport a pin if accessed twice. Is this a bug?
$ echo 13 > /sys/class/gpio/export $ ls /sys/class/gpio/gpio13 active_low device direction edge label power subsystem uevent value $ echo 13 > /sys/class/gpio/export -bash: echo: write error: Operation not permitted $ ls /sys/class/gpio/gpio13 ls: cannot access '/sys/class/gpio/gpio13': No such file or directory Expected behavior: gpio13 should still be there after the second export. Observed behavior: gpio13 disappears after the second export. This is with the latest Debian kernel (4.14.71-ti-r80). Is there a recommended way to export a gpio pin if it may already exist? I want to write a script to set up the pins. I could check if each pin already exists, but that's a recipe for race conditions as well as being inconvenient. Ken -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/62a49479-026b-455b-bd02-312065a78bc5%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
