Re: using libgpiod to replace sysfs ABI (was Re: [PATCH] gpiolib: Avoid side effects in gpio_is_visible())

From: Bartosz Golaszewski
Date: Thu May 25 2023 - 10:35:41 EST


On Thu, May 25, 2023 at 11:13 AM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
>
> On Thu, May 25, 2023 at 2:53 AM Chris Packham
> <Chris.Packham@xxxxxxxxxxxxxxxxxxx> wrote:
> > On 24/05/23 17:41, Kent Gibson wrote:
>
> ...
>
> > It'd also be great if there was some way of ensuring that a line's state
> > is kept after the application has released the request (i.e. the txdis
> > case I mentioned). But that probably needs work on the kernel side to
> > make such guarantees.
>
> Won't happen. It will require too much of strictness to be added into
> the kernel with likely breakage of the existing code and
> documentation. What is being discussed is a D-Bus (like?) daemon +
> Policy in user space that will allow user / process / cgroup / etc to
> "own" the line and track its state.
>

It's already WiP[1]. I'm trying to keep the footprint minimal with
only GLib and dbus required at run-time.

Bart

[1] https://github.com/brgl/libgpiod-private/tree/topic/dbus