Re: [PATCH v1 5/5] gpiolib: cdev: Utilize more bitmap APIs

From: Andy Shevchenko
Date: Mon Oct 02 2023 - 05:05:25 EST


On Wed, Sep 27, 2023 at 10:23:12PM +0800, Kent Gibson wrote:
> On Wed, Sep 27, 2023 at 04:59:34PM +0300, Andy Shevchenko wrote:
> > On Wed, Sep 27, 2023 at 09:49:35PM +0800, Kent Gibson wrote:
> > > On Wed, Sep 27, 2023 at 03:17:06PM +0300, Andy Shevchenko wrote:
> > > > On Wed, Sep 27, 2023 at 09:32:11AM +0800, Kent Gibson wrote:

...

> > > > Yet, it opens a way to scale this in case we might have v3 ABI that let's say
> > > > allows to work with 512 GPIOs at a time. With your code it will be much harder
> > > > to achieve and see what you wrote about maintenance (in that case).
> > >
> > > v3 ABI?? libgpiod v2 is barely out the door!
> > > Do you have any cases where 64 lines per request is limiting?
> >
> > IIRC it was SO question where the OP asks exactly about breaking the 64 lines
> > limitation in the current ABI.
> >
> > > If that sort of speculation isn't premature optimisation then I don't know
> > > what is.
> >
> > No, based on the real question / discussion, just have no link at hand.
> > But it's quite a niche, I can agree.
>
> Let me know if you find a ref to that discussion - I'm curious.

Here it is (read comments as well):
https://stackoverflow.com/questions/76307370/control-gpio-from-linux-userspace-with-linux-gpio-h

--
With Best Regards,
Andy Shevchenko