-----Original Message----- From: Peter Suetterlin <pit@astro.su.se> Sent: 16 September 2021 10:34 To: Guillaume Gardet <Guillaume.Gardet@arm.com> Cc: arm@lists.opensuse.org; Matthias Brugger <mbrugger@suse.com>; nd <nd@arm.com> Subject: Re: GPIO trouble
Guillaume Gardet wrote:
-----Original Message----- From: Guillaume Gardet <Guillaume.Gardet@arm.com>
Did you have a look at https://en.opensuse.org/openSUSE:GPIO for standard packages to access GPIO instead of downstream, RPi specific, software?
Ah no - I saw that there is a different gpio package, and installed it, but had no clue how to use it :(
So I first had a try at the 'basic /sys method'..
You can use 'gpioinfo gpiochip446' and 'gpioinfo gpiochip454' to get info about the gpio available.
Actually 'gpiochip0' and 'gpiochip1'. But yes, that indeed does the trick.
Reading further explains also why I failed with /sys:
Note that the base, which is the N from /sys/class/gpio/gpiochipN, must be added to the GPIO number. This is never mentioned because on Raspbian N is 0.
So indeed a bit irritating with the implementation that it lists /sys/class/gpio/gpiochip446 and /sys/class/gpio/gpiochip454 but refers to them as gpiochip0 and gpiochip1 in gpioinfo whereas the /sys interface requires the 446/454 offsets. I'd assume that is a kernel thing?
The GPIO /sys interface is a deprecated interface provided by the kernel and is not recommended to use anymore.
And latest released Tumbleweed (20210901) test in openQA shows gpiochips 0 and 1: gpiochip0 [pinctrl-bcm2711] (58 lines) gpiochip1 [raspberrypi-exp-gpio] (8 lines)
Indeed, that's what I see here, too :D I'm physically away from the Pi, so I cannot verify that the output actually gets 'high' - but I'm very confident it does.
Thanks for getting me on the right track!
Great! Let us know if it is working, once you will be near to the Pi. Cheers, Guillaume