Re: [PATCH 5/6] gpiolib: cdev: consolidate edge detector configuration flags

Kent Gibson
2022-07-13T10:25:09Z

On Wed, Jul 13, 2022 at 12:07:29PM +0200, Andy Shevchenko wrote:
> On Wed, Jul 13, 2022 at 3:39 AM Kent Gibson <warthog618@gmail.com> wrote:
> >
> > Combine the polarity_change flag, struct line eflags, and hte enable
> > flag into a single flag variable.
> >
> > The combination of these flags describes the configuration state
> > of the edge detector, so formalize and clarify that by combining
> > them into a single variable, edflags, in struct line.
> >
> > The edflags is a subset of the GPIO_V2_LINE_FLAGsb relevant to
> > the edge detector, and is also a superset of the eflags it replaces.
> > The eflags name is still used to describe the subset of edflags
> > corresponding to the rising/falling edge flags where edflags is
> > masked down to that subset.
> >
> > This consolidation reduces the number of variables being passed,
> > simplifies state comparisons, and provides a more extensible
> > foundation should additional edge sources be integrated in the
> > future.
>
> I believe that you have checked this from a locking perspective, so we
> won't have worse lock contamination, if any.
>

Yeah, they are used in the same way as the old eflags, so there is no
change in that regard.

> ...
>
> > struct linereq *lr;
> > struct gpio_v2_line_event le;
> > int level;
> > - u64 eflags;
> > + u64 edflags;
>
> I would at the same time move it up before `int level;`.
>

Ok. What is the general rule you want applied, cos I'm not seeing it.

Cheers,
Kent.

> ...
>
> > + int level = -1, diff_seqno;
> > + u64 eflags, edflags = READ_ONCE(line->edflags);
>
> Ditto.
>
> ...
>
> > u32 debounce_period_us;
> > unsigned long irqflags = 0;
> > int irq, ret;
> > + u64 eflags;
>
> Ditto for similarity.
>
> --
> With Best Regards,
> Andy Shevchenko