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| author | Liam Beguin <liambeguin@gmail.com> | 2022-02-13 03:57:31 +0100 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2022-02-27 14:38:05 +0100 |
| commit | 701ee14da95dcd25c1bf20dea7c8335b70d73124 (patch) | |
| tree | f74fb1a4cf79da94265f03cc191ea92912b34e6e /drivers/iio | |
| parent | iio: afe: rescale: expose scale processing function (diff) | |
| download | linux-701ee14da95dcd25c1bf20dea7c8335b70d73124.tar.xz linux-701ee14da95dcd25c1bf20dea7c8335b70d73124.zip | |
iio: afe: rescale: add INT_PLUS_{MICRO,NANO} support
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>
Diffstat (limited to 'drivers/iio')
| -rw-r--r-- | drivers/iio/afe/iio-rescale.c | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/drivers/iio/afe/iio-rescale.c b/drivers/iio/afe/iio-rescale.c index 65832dd09249..e67d9a9e6135 100644 --- a/drivers/iio/afe/iio-rescale.c +++ b/drivers/iio/afe/iio-rescale.c @@ -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: @@ -42,6 +45,37 @@ int rescale_process_scale(struct rescale *rescale, int scale_type, 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; } |