Re: [PATCH v2] staging: iio: impedance-analyzer: ad5933: use div64_ul() instead of do_div()
From: Andy Shevchenko
Date: Mon Feb 23 2026 - 03:38:34 EST
On Sun, Feb 22, 2026 at 01:43:26PM +0000, Jonathan Cameron wrote:
> On Wed, 18 Feb 2026 15:51:14 +0200
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> wrote:
> > On Wed, Feb 18, 2026 at 06:23:27PM +0530, Archit Anant wrote:
> > > Replace do_div() with div64_ul() since the remainder is not used.
> > > div64_ul() is the preferred API for 64-bit by 32-bit division when
> > > only the quotient is needed.
> > >
> > > Also replace explicit casting and shifting with the BIT_ULL(27) macro
> > > for clarity.
> > >
> > > Note: A mathematical simplification to `(freq * BIT_ULL(29)) / mclk` was
> > > suggested during review to improve precision. However, as confirmed by
> > > maintainers, the original driver's truncation via `(mclk / 4)` might
> > > be intentional or relied upon by userspace. Since hardware is not
> > > available for verification, this patch preserves the original logic
> > > to avoid regression risk in the absence of testing.
> > >
> > > Issue identified by coccicheck using do_div.cocci.
> >
> > > Changes in v2:
> > > - Replaced explicit `(u64)(1 << 27)` with `BIT_ULL(27)` as suggested by Andy Shevchenko.
> > > - Kept original arithmetic logic `(mclk / 4)` to preserve behavior.
> >
> > The place for changelog (and comments)...
> >
> > > Signed-off-by: Archit Anant <architanant5@xxxxxxxxx>
> > > ---
> >
> > ...is here.
> >
> > But do not resend until maintainers explicitly ask for that.
> >
> Tweaked commit message as Andy pointed out was needed.
>
> Applied to the togreg branch of iio.git
>
> Andy, if you want to give a tag I can role that in for now as need
> to rebase anyway on rc1. This mail felt like an 'almost tag' ;)
I think you are talking about my Rb? Sure
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
--
With Best Regards,
Andy Shevchenko