Re: [RFC] GPIO User I/O

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Mon, Jul 6, 2020 at 5:33 PM Rodolfo Giometti <giometti@xxxxxxxxxxxx> wrote:

> > With Geert's GPIO aggregator userspace and device tree can conjure
> > special per-usecase gpio chips as pointed out by Drew: this is
> > very useful when you want some kernel-managed yet
> > usecase-specific GPIO lines in a special "container" chip.
> > To me this is the best of two worlds. (Kernelspace and userspace.)
>
> Maybe this is the "best of two worlds" as you say but the problem is that board
> manufactures need a way to well-define how a GPIO line must be used for within
> the device-tree and without the need of patches! In this point of view neither
> the "driver_override" way nor adding a compatible value to
> gpio_aggregator_dt_ids[] can help (this last solution requires a patch for each
> board!). That's why at the moment they prefer not specify these GPIO lines at
> all or (improperly) use the gpio-leds and gpio-uinput interfaces to keep it
> simple...

I think the idea is to add a very generic DT compatible to the
gpio_aggregator_dt_ids[]. That way, any DT can use the aggregator
to create a new chip with named lines etc.

But Geert can speak of that.

Yours,
Linus Walleij