Re: [PATCH v4 00/10] gpio: sysfs: add a per-chip export/unexport attribute pair

[Kent Gibson <warthog618@gmail.com>]

On Sun, Jul 13, 2025 at 10:48:03AM +0200, Bartosz Golaszewski wrote:
> On Fri, Jul 4, 2025 at 2:58 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:
> >
> > Following our discussion[1], here's a proposal for extending the sysfs
> > interface with attributes not referring to GPIO lines by their global
> > numbers in a backward compatible way.
> >
> > Long story short: there is now a new class device for each GPIO chip.
> > It's called chipX where X is the ID of the device as per the driver
> > model and it lives next to the old gpiochipABC where ABC is the GPIO
> > base. Each new chip class device has a pair of export/unexport
> > attributes which work similarly to the global ones under /sys/class/gpio
> > but take hardware offsets within the chip as input, instead of the
> > global numbers. Finally, each exported line appears at the same time as
> > the global /sys/class/gpio/gpioABC as well as per-chip
> > /sys/class/gpio/chipX/gpioY sysfs group except that the latter only
> > implements a minimal subset of the functionality of the former, namely:
> > only the 'direction' and 'value' attributes and it doesn't support event
> > polling.
> >
> > The series contains the implementation of a parallel GPIO chip entry not
> > containing the base GPIO number in the name and the corresponding sysfs
> > attribute group for each exported line that lives under the new chip
> > class device as well as a way to allow to compile out the legacy parts
> > leaving only the new elements of the sysfs ABI.
> >
> > This series passes the compatibility tests I wrote while working on the
> > user-space compatibility layer for sysfs[2].
> >
> > [1] https://lore.kernel.org/all/CAMRc=McUCeZcU6co1aN54rTudo+JfPjjForu4iKQ5npwXk6GXA@mail.gmail.com/
> > [2] https://github.com/brgl/gpio-sysfs-compat-tests
> >
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> > ---
> 
> Alright, so what are we doing about this? Should I queue these patches
> for v6.17? Kent, any additional comments?

Nothing beyond what I've already said.

Cheers,
Kent.