[PATCH RFC 0/9] gpio: improve support for shared GPIOs

[Bartosz Golaszewski]

On Mon, Oct 6, 2025 at 5:43 PM Manivannan Sadhasivam <mani at kernel.org> wrote:
>
> On Wed, Sep 24, 2025 at 11:25:12AM -0700, Dmitry Torokhov wrote:
> > Hi Bartosz,
> >
> > >
> > > The practical use-case for this are the powerdown GPIOs shared by
> > > speakers on Qualcomm db845c platform, however I have also extensively
> > > tested it using gpio-virtuser on arm64 qemu with various DT
> > > configurations.
> >
> > How is this different from the existing gpio-backed regulator/supply?
> > IMO GPIOs are naturally exclusive-use resources (in cases when you need
> > to control them, not simply read their state), and when there is a need
> > to share them there are more appropriate abstractions that are built on
> > top of GPIOs...
> >
>
> Not always... For something like shared reset line, consumers request the line
> as GPIO and expect gpiolib to do resource manangement.
>

They could use the reset API and it would implicitly create a virtual
device that requests the reset GPIO and controls its enable count.
Except that some devices also do a specific reset sequence with delays
etc. That would require some additional logic in reset-gpio.

Bart