Re: [PATCH v2 07/14] iio: sx9310: Use long instead of int for channel bitmaps

[Daniel Campello]

On Wed, Jul 29, 2020 at 1:00 AM Andy Shevchenko
<andy.shevchenko@xxxxxxxxx> wrote:
>
> On Wed, Jul 29, 2020 at 4:03 AM Stephen Boyd <swboyd@xxxxxxxxxxxx> wrote:
> > Quoting Daniel Campello (2020-07-28 16:05:13)
> > > Uses for_each_set_bit() macro to loop over channel bitmaps.
>
> ...
>
> > > +       unsigned long chan_prox_stat;
> >
> > This can be DECLARE_BITMAP(chan_prox_stat, SX9310_NUM_CHANNELS)
>
> > > +       unsigned long chan_read;
> > > +       unsigned long chan_event;
> >
> > Same for these?
All of these are eventually used by regmap_update_bits() which expects
unsigned int. I believe the extra complexity is not worth it given the
number of channels.
>
> ...
>
> > > +       prox_changed = (data->chan_prox_stat ^ val) & data->chan_event;
> >
> > I was expecting:
> >
> >
> >         bitmap_xor(&prox_changed, &data->chan_prox_stat, &val, SX9310_NUM_CHANNELS);
> >         bitmap_and(&prox_changed, &data->chan_event, SX9310_NUM_CHANNELS);
>
> I agree with this. On a small number of channels (up to 32) it will be
> reduced to simple operations, but will leave a possibility to have
> more with easy redefine.
>
> (though _and() above misses one argument AFAICT)
>
> ...
>
> > > +       unsigned long channels = 0;
> >
> > Use DECLARE_BITMAP(channels, SX9310_NUM_CHANNELS)?
>
>
> --
> With Best Regards,
> Andy Shevchenko