I'm using Tumbleweed JeOS (20190308, aarch64) on a RaspberryPI 3B+,
which works astonishingly good and stable.
During my attempts to use the GPIOs with libgpiod, i've found that the
GPIOs are not named as they should be. Also setting GPIOs does not seem
to work, if they are changed with gpioset.
Regarding the naming of the GPIOs, all of them are unnamed:
# gpioinfo pinctrl-bcm2835
gpiochip0 - 54 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 29: unnamed "led0" output active-high [used]
line 30: unnamed unused output active-high
line 31: unnamed unused output active-high
...
line 47: unnamed unused output active-high
...
There are references for Raspian, that the 'unnamed' entries should
contain the GPIO names, e.g. at
https://www.beyondlogic.org/an-introduction-to-chardev-gpio-and-libgpiod-on-the-raspberry-pi/
.
Also the "led0" and other output-GPIOs do not match in their position.
It seems that there is a mismatch in the device tree and I think the
Tumbleweed kernel uses a generic .dts config file, whereas Raspian uses
an adapted one.
I have checked the mailing list and found, that the problem is not new:
https://lists.opensuse.org/opensuse-arm/2018-09/msg00000.html
I also have found an article in the opensuse wiki, which describes the
functionality, but does not help with the mapping:
https://en.opensuse.org/openSUSE:GPIO
Additionally, I have tried setting all possible GPIOs with libgpiod's
gpioset (some of them crashed the system), but it was not possible to
change the GPIO output (I've connected a LED). However, with the
deprecated sysfs GPIO subsystem this worked instantly without any
problems (with offset N=458).
Question: did anyone here succeeded in using libgpiod for setting GPIOs
in Tumbleweed yet?
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