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

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Thu, Jan 22, 2026 at 08:26:33PM +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, as it returns the result directly rather
> than modifying the dividend in-place.
> 
> Issue identified by coccicheck using do_div.cocci.

...

> -	freqreg = (u64)freq * (u64)(1 << 27);
> -	do_div(freqreg, st->mclk_hz / 4);
> +	freqreg = div64_ul((u64)freq * (u64)(1 << 27),
> +			   st->mclk_hz / 4);

It can be one line to begin with.
Then drop that ugly castings and explicit big shifts.

	freqreg = div64_ul(BIT_ULL(27) * freq, st->mclk_hz / 4);

Now you can see That 4 is only 2 bits, so this can be written in
simpler way:

	freqreg = div64_ul(BIT_ULL(29) * freq, st->mclk_hz);

which may give a better precision at the end of the day.

-- 
With Best Regards,
Andy Shevchenko