Let’s say I’m looking at the carrier board description (latest version, May 1, 2017)
Let’s say I see a signal that I’d like to use as a GPIO. For example, ‘GPIO15_AP2MDM_READY’ which is on pin 6 of the 30-pin L26 header.
How do I translate the name “GPIO15_AP2MDM_READY” into the actual GPIO number to use for /sys/class/gpio/export?
If I try to use “15” (as in the “GPIO15” name) I get an error:
nvidia@tegra-ubuntu:~$ sudo bash root@tegra-ubuntu:~# echo 15 > /sys/class/gpio/export bash: echo: write error: Invalid argument
Is there another document that actually documents how to go about this?
Also, is there a C interface or IOCTL interface to the GPIO that may be faster (lower overhead) than the sysfs-based file descriptor interface?