Re: [PATCH v13 06/12] iio: core: add decimal value formatting into 64-bit value

[Rodrigo Alencar]

On 26/05/17 01:16PM, Andy Shevchenko wrote:
> On Sun, May 17, 2026 at 10:14:01AM +0100, Rodrigo Alencar via B4 Relay wrote:
> 
> > Create new format types for iio values (IIO_VAL_DECIMAL64_*), which
> > defines the representation of fixed decimal point values into a single
> > 64-bit number. This new format increases the range of represented values,
> > allowing for integer parts greater than 2^32, as bits are not "wasted"
> > in the fractional part, which can be seen in IIO_VAL_INT_PLUS_MICRO and
> > IIO_VAL_INT_PLUS_NANO. Helpers are created to compose and decompose 64-bit
> > decimals into integer values used in IIO formatting interfaces, which
> > creates consistency and avoid error-prone manual assignments when using
> > wordpart macros. When doing the parsing, kstrtodec64() is used with the
> > scale defined by the specific decimal format type.
> 
> ...
> 
> > +	{
> > +		int scale = type - IIO_VAL_DECIMAL64_BASE;
> 
> > +		int l = 0;
> 
> Perhaps make it global in the function? We have the same in
> IIO_VAL_INT_MULTIPLE case.
> 
> > +		s64 frac;
> > +
> > +		tmp2 = div64_s64_rem(iio_val_s64_from_s32s(vals),
> > +				     int_pow(10, scale), &frac);
> > +		if (tmp2 == 0 && frac < 0)
> > +			l += sysfs_emit_at(buf, offset, "-");
> > +
> > +		l += sysfs_emit_at(buf, offset + l, "%lld.%0*lld", tmp2, scale,
> > +				   abs(frac));
> > +		return l;
> > +	}
> 
> ...
> 
> >  #ifndef _IIO_TYPES_H_
> >  #define _IIO_TYPES_H_
> 
> Also needs types.h now... Which makes me think if the proposed macros are
> placed in the good enough location.

That is a good point. I left it there because they are related to IIO_VAL_INT_64
and IIO_VAL_DECIMAL64_*. I had them as macros initially, but they are not exactly
"types" indeed. 

> 
> (Note, iio/iio.h missing actually types.h, but includes it indirectly.)
> 
> -- 
> With Best Regards,
> Andy Shevchenko
> 
> 

-- 
Kind regards,

Rodrigo Alencar