Hi,

Am 14.06.2016 um 17:55 schrieb Freek de Kruijf:
> On the Tumbleweed system for the Raspberry Pi 1B (armv6l) support for the 
> device /dev/gpiomem is missing. It provides access to GPIO registers by a 
> normal user. Otherwise only root is allowed to access these registers via 
> /dev/mem
> 
> It is available on Tumbleweed for the Raspberry Pi 2B (armv7l).
> 
> I searched build.opensuse.org for the software of its driver but failed to 
> find it.

Kernel features are usually not separate packages on build.opensuse.org
but kernel config files on kernel.opensuse.org that end up as a
config.tar.bz2 in "kernel-source" packages in OBS.

Let's check master branch for ARMv6 kernel-default:

http://kernel.opensuse.org/cgit/kernel-source/tree/config/armv6hl/default

Neither GPIOMEM nor GPIO_MEM turn up any search hits there.

The Raspberry Pi 2 is not yet in Tumbleweed (USB not working in 4.6.2,
thus no network), so you probably mean the Contrib project which is
using the Raspberry Pi Foundation's 4.1.19 kernel.

I happen to have a Raspberry Pi 2 running today and a quick `grep
GPIOMEM /boot/config-4.1.19-1-rpi2` shows this candidate:

CONFIG_BCM2835_DEVGPIOMEM=m

`git grep BCM2835_DEVGPIOMEM` shows no results in linux-next.git,
hinting that this is one of those features that no one bothered to
submit to the official mainline kernel (or that the submission didn't
get accepted). Google indeed finds no patch submission.

So once we switch the Raspberry Pi 2 to a Tumbleweed kernel you will
lose that feature there too, unless you nag the Raspberry Pi people to
submit their patches...

raspi2:/boot # grep GPIOMEM config-4.6.2-1-default
raspi2:/boot # grep GPIOMEM config-4.6.2-1-lpae
raspi2:/boot # uname -r
4.6.2-1-default
raspi2:/boot # ll /dev/gpiomem
ls: cannot access '/dev/gpiomem': No such file or directory

Theoretically you could try repackaging the driver as a KMP, but
maintaining that is no fun really.

Regards,
Andreas

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