Re: [PATCH v2 1/2] dt-bindings: gpio: add gpio-aggregator binding

[Geert Uytterhoeven]

Hi James,

On Wed, 11 Feb 2026 at 18:01, James Hilliard <james.hilliard1@xxxxxxxxx> wrote:
> On Wed, Feb 11, 2026 at 1:44 AM Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
> > On 11/02/2026 09:28, James Hilliard wrote:
> > > virtual gpio driver though so AFAIU it's not hardware specific.
> >
> > You can give example of any hardware where this is useful. You need to
> > make your case with actual arguments.
>
> The sunxi h616 board I have has hundreds of GPIOs, only
> a few of which are needed, I want to map them in device
> tree overlays since there's some minor variants with different
> hardware gpio configurations.
>
> Setting the gpio names on the parent controller is not practical
> since doing so would require setting hundreds of values for
> gpio-line-names, you also can't really combine sets of pin
> names across device tree overlays AFAIU.
>
> > > Use case is I have a device with something like 300 gpio
> > > lines...and I want to name/group a small subset of those
> > > lines for delegation to a userspace app rather than trying
> > > to set 300 or something gpio-line-names values, also I'm
> >
> > So if I change the approach in user-space or use different user-space
> > app then I change the DTS?
>
> The idea is to make it practical to set gpio-line-names for a
> subset of the GPIOs that are wired to peripheral boards.
>
> Say for example I have a control board connected to a few
> different peripheral boards, there may be different mixtures
> of peripheral boards, some of which can be used at the same
> time as they use different GPIOs.
>
> The idea is we load device tree overlays for the detected
> peripheral boards with detection done in uboot based on a
> GPIO pin strapping based detection.

Sounds like the work being done in "[RFC PATCH 00/77] Add support for
dtb metadata and addon device-trees" [1] can be helpful for you, too.

[1] https://lore.kernel.org/20260112142009.1006236-1-herve.codina@xxxxxxxxxxx

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds