Re: [PATCH RFC 3/3] iio: core: use kstrtodec64() to parse fixed-point values

[Rodrigo Alencar]

On 02/10/26 11:00, Andy Shevchenko wrote:
> On Thu, Oct 01, 2026 at 12:34:58PM -0300, Rodrigo Alencar via B4 Relay wrote:
> 
> ...
> 
> > +	/* fract_mult = 10^n, so ffs(10^n) = ffs(2^n * 5^n) = n + 1 */
> > +	unsigned int scale = ffs(fract_mult);
> 
> Hmm... It's not obvious. Maybe you want to use int_log() instead?

hence the comment. intlog10() from int_log.h returns log10(x) * 2^24.
It could be used with a correction:

	DIV_ROUND_CLOSEST(intlog10(x), 1 << 24)

because the header warns the result "might be not exactly n·2²⁴".
Assuming that the fract_mult is a power of 10, ffs is the most straight
forward way of doing this.

-- 
Kind regards,

Rodrigo Alencar