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

Andy Shevchenko
2022-07-13T10:08:10Z

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.

...

> 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;`.

...

> + 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