Re: [PATCH v3 1/5] gpiolib: cdev: relocate debounce_period_us from struct gpio_desc

Kent Gibson
2023-12-15T23:33:42Z

On Fri, Dec 15, 2023 at 06:35:14PM +0200, Andy Shevchenko wrote:
> On Fri, Dec 15, 2023 at 10:38:01AM +0800, Kent Gibson wrote:
> > Store the debounce period for a requested line locally, rather than in
> > the debounce_period_us field in the gpiolib struct gpio_desc.
> >
> > Add a global tree of lines containing supplemental line information
> > to make the debounce period available to be reported by the
> > GPIO_V2_GET_LINEINFO_IOCTL and the line change notifier.
>
> LGTM, a few minor comments below.
>
> ...
>
> > +/*
>
> (now you can have a kernel doc :-)
>

Maybe you can, but I can't.

> > + * a rbtree of the struct lines containing supplemental info.
> > + * Used to populate gpio_v2_line_info with cdev specific fields not contained
> > + * in the struct gpio_desc.
> > + * A line is determined to contain supplemental information by
> > + * line_is_supplemental().
> > + */
> > +static struct rb_root supinfo_tree = RB_ROOT;
> > +/* covers supinfo_tree */
> > +DEFINE_SPINLOCK(supinfo_lock);
>
> Shouldn't this also be static?
>

Indeed.

> ...
>
> > + guard(spinlock)(&supinfo_lock);
>
> + cleanup.h ?
>

Bah, I could've sworn I added that in, but it isn't evident in any of
the patches all the way back to v1, so apparently not.

> ...
>
> > +static void supinfo_to_lineinfo(struct gpio_desc *desc,
> > + struct gpio_v2_line_info *info)
> > +{
> > + struct gpio_v2_line_attribute *attr;
> > + struct line *line;
> > +
> > + guard(spinlock)(&supinfo_lock);
> > +
> > + line = supinfo_find(desc);
> > + if (line) {
>
> if (!line)
> return;
>
> ?

Will do.

>
> > + attr = &info->attrs[info->num_attrs];
> > + attr->id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
> > + attr->debounce_period_us = READ_ONCE(line->debounce_period_us);
> > + info->num_attrs++;
> > + }
> > +}
>

Cheers,
Kent.

> --
> With Best Regards,
> Andy Shevchenko
>
>