Re: [PATCH v3 02/18] gpio: uapi: define uAPI v2

[Kent Gibson <warthog618@xxxxxxxxx>]

On Tue, Aug 11, 2020 at 09:11:41PM +0200, Bartosz Golaszewski wrote:
> On Sun, Aug 9, 2020 at 3:26 PM Kent Gibson <warthog618@xxxxxxxxx> wrote:
> >
[snip]
> >
> > +/*
> > + * Maximum number of requested lines.
> > + *
> > + * Must be no greater than 64 as bitmaps are limited to 64-bits, and a
> > + * multiple of 2 to ensure 32/64-bit alignment of structs.
> > + */
> > +#define GPIO_V2_LINES_MAX 64
> > +
> 
> If we refer to bitmaps for which helpers are defined in
> include/linux/bitmap.h then they're not limited to 64-bits. I'd just
> say here that we want to fit into 64-bit integers for simplicity.
> 

Strictly speaking, userspace doesn't know about include/linux/bitmap.h,
but I'm happy to remove any ambiguity.

Does this work for you?:

 * Must be no greater than 64, as bitmaps are restricted here to 64-bits
 * for simplicity, and a multiple of 2 to ensure 32/64-bit alignment of
 * structs.

Cheers,
Kent.