Re: [PATCH RFC libgpiod 3/3] tools: implement gpioctl

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Fri, Oct 16, 2026 at 08:00:38PM +0200, Linus Walleij wrote:
> On Fri, Oct 16, 2026 at 4:21 PM Bartosz Golaszewski
> <bartosz.golaszewski@oss.qualcomm.com> wrote:
> 
> > Provide gpioctl, a new command-line tool for persistent GPIO line control.
> > Unlike gpioget and gpioset which release lines on exit, gpioctl holds
> > requested lines in a background daemon so their state survives across
> > multiple client invocations.
> >
> > The client auto-spawns the daemon on first use. Communication uses a
> > per-user abstract Unix-domain socket, providing automatic cleanup and
> > per-user isolation without filesystem artifacts.
> >
> > Each set of lines requested through the tool is assigned a unique ID and
> > referred to as a "request". The following sub-commands are provided:
> >
> >   request      - Request a set of GPIO lines by offset or name. The daemon
> >                  holds them after the client exits.
> >   release      - Release a previously made request by ID.
> >   requests     - List all requests currently held by the daemon.
> >   get          - Read values of requested lines.
> >   set          - Set the output values of requested lines.
> >   monitor      - Subscribe to edge events on a held request.
> >   reconfigure  - Change the settings of a held request in-place without
> >                  releasing it (e.g. switch direction, add edge detection).
> >
> > There are also "hidden" sub-commands that are not documented in the help
> > text but can be used for debugging purposes:
> >
> >   ping         - Verify the daemon is running (spawns it if not).
> >   stop         - Ask the daemon to exit, releasing all held lines.
> >   debug        - Run the daemon in the foreground with logging enabled.
> >
> > The wire protocol is intentionally private and unstable: only gpioctl
> > itself speaks it, so no ABI commitment is made.
> >
> > Also add test-cases covering all sub-commands and configuration options.
> > Update documentation, man page generation (main page plus one page per
> > sub-command), and mark the persistent-daemon TODO item as complete.
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
> 
> A big Acked-by: Linus Walleij <linusw@kernel.org> for the entire
> idea and approach.

Seconded here. But the amount is simply unreviewable by a human.

> I can't claim to have read the code in any detail, because it
> is quite a lot. I can run it through Sashiko if you want, hehe :D
> 
> I think this will be very helpful when doing automation using
> different AI tools, but also for pretty elaborate scripting.

-- 
With Best Regards,
Andy Shevchenko