Some more digging on my end…
I am trying to use libgpiod, which accesses the gpio pins through a character device. The sysfs method is deprecated and removed in newer kernels, so everybody is going to have to adjust anyway.
See https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/about/
So, what I am now essentially asking is…What is the correlation between the physical pin number and the line number? 4 gpiochips show up, and 0 and 1 both have 80 lines.
# gpiodetect
gpiochip0 [INT3453:00] (80 lines)
gpiochip1 [INT3453:01] (80 lines)
gpiochip2 [INT3453:02] (20 lines)
gpiochip3 [INT3453:03] (35 lines)
Which gpiochip is the 40 pin setup on the board?
gpioinfo
gpiochip0 - 80 lines:
line 0: unnamed unused input active-high
line 1: unnamed unused input active-high
line 2: unnamed unused input active-high
line 3: unnamed unused input active-high
line 4: unnamed unused input active-high
line 5: unnamed unused input active-high
line 6: unnamed unused input active-high
line 7: unnamed unused input active-high
line 8: unnamed unused input active-high
line 9: unnamed unused input active-high
line 10: unnamed unused output active-high
line 11: unnamed unused output active-high
line 12: unnamed unused output active-high
line 13: unnamed unused input active-high
From other pages I’ve seed, the broadcom chips have labels. And there is no correlation between pin number and line number. I’ve already caused a crash and reboot by setting line 47 to high.