On Sat, Jan 8, 2022 at 10:53 PM Liam Beguin <liambeguin@xxxxxxxxx> wrote:
>
> Some ADCs use IIO_VAL_INT_PLUS_{NANO,MICRO} scale types.
> Add support for these to allow using the iio-rescaler with them.
...
> + mult = scale_type == IIO_VAL_INT_PLUS_NANO ? GIGA : MEGA;
> +
> + /*
> + * For IIO_VAL_INT_PLUS_{MICRO,NANO} scale types if either *val
> + * OR *val2 is negative the schan scale is negative, i.e.
> + * *val = 1 and *val2 = -0.5 yields -1.5 not -0.5.
> + */
> + neg = *val < 0 || *val2 < 0;
> +
> + tmp = (s64)abs(*val) * abs(rescale->numerator);
> + *val = div_s64_rem(tmp, abs(rescale->denominator), &rem);
> +
> + tmp = (s64)rem * mult + (s64)abs(*val2) * abs(rescale->numerator);
> + tmp = div_s64(tmp, abs(rescale->denominator));
Isn't it too many repetitive abs() calls?
What about
// Create a macro and use for u16 (struct rn5t618_channel_ratios), s16
(struct twl4030_prescale_divider_ratios), s32 (can be reused in struct
rescale)
struct u32_fract {
u32 numerator;
u32 denominator;
};
// (potential reuse in struct hclge_ptp_cycle) and so on...
struct u32_fract fract = {
.numerator = abs(rescale->numerator),
.denominator = abs(rescale->denominator),
};
// obviously we can add a macro/inliner to abs() the fract struct and
return original sign
and reuse fract.numerator, fract.denominator?
> + *val += div_s64_rem(tmp, mult, val2);
> +
> + /*
> + * If only one of the rescaler elements or the schan scale is
> + * negative, the combined scale is negative.
> + */
> + if (neg ^ ((rescale->numerator < 0) ^ (rescale->denominator < 0))) {
> + if (*val)
> + *val = -*val;
> + else
> + *val2 = -*val2;
> + }
--
With Best Regards,
Andy Shevchenko
