Re: [PATCH v2] staging: iio: impedance-analyzer: ad5933: use div64_ul() instead of do_div()

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 18 Feb 2026 15:51:14 +0200
Andy Shevchenko <andriy.shevchenko@intel.com> 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@gmail.com>
> > ---  
> 
> ...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' ;)

Thanks,

Jonathan