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iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support

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Some ADCs use IIO_VAL_INT_PLUS_{NANO,MICRO} scale types.
Add support for these to allow using the iio-rescaler with them.

Signed-off-by: Liam Beguin <liambeguin@gmail.com>
Reviewed-by: Peter Rosin <peda@axentia.se>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220213025739.2561834-3-liambeguin@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Liam Beguin 2022-02-12 21:57:31 -05:00 committed by Jonathan Cameron
parent bc437f7515
commit 701ee14da9
1 changed files with 34 additions and 0 deletions
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34
drivers/iio/afe/iio-rescale.c
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@ -23,6 +23,9 @@ int rescale_process_scale(struct rescale *rescale, int scale_type,
int *val, int *val2)
{
s64 tmp;
s32 rem;
u32 mult;
u32 neg;
switch (scale_type) {
case IIO_VAL_FRACTIONAL:
@ -41,6 +44,37 @@ int rescale_process_scale(struct rescale *rescale, int scale_type,
tmp *= rescale->numerator;
tmp = div_s64(tmp, 1000000000LL);
*val = tmp;
return scale_type;
case IIO_VAL_INT_PLUS_NANO:
case IIO_VAL_INT_PLUS_MICRO:
mult = scale_type == IIO_VAL_INT_PLUS_NANO ? 1000000000L : 1000000L;
/*
* 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));
*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;
}
return scale_type;
default:
return -EOPNOTSUPP;