Hi Arm Team,
I have a Wandboard (yeah, I know, OLD Hardware) currently running a project, and I'm trying to add some GPIO inputs to it. In previous GPIO handling (on a different platform) I used the /sys/class/gpio interfaces to set up the GPIO, but I've discovered this is now deprecated and removed from Fedora. So I installed libgpiod and am trying to use it.
I'm using https://download.technexion.com/development_resources/wandboard/wbquad-revb1... as a reference for the board layout. Specifically, on page 27, it shows me that the JP4 header connects to GPIO3_12, GPIO3_27, GPIO6_31, CPIO1_24, GPIO7_8, GPIO3_26, GPIO_18, and GPIO_19.
I figure that GPIO_18 is going to be gpiochip0 line 18, and GPIO3_12 will be gpiochip3 line 12.. Except that gpiodetect only tells me I have gpiochip0 through gpiochip6, so I'm not sure where GPIO7_8 would get mapped. That's the first issue I have.
The second issue is that the kernel does not have any named mappings, so running gpioinfo just displays generic data, like:
gpiochip6 - 32 lines: line 0: unnamed unused input active-high line 1: unnamed unused input active-high
Except, of course, looking at gpiochip3 line 12 shows me:
gpiochip3 - 32 lines: ... line 12: unnamed "scl" output active-high [used open-drain]
Which seems to imply that that GPIO3_12 is actually used for something else -- or my mapping strategy is off.
I'd appreciate any guidance anyone might have on this subject.
Thanks,
-derek