On Wed, 26 Aug 2020 11:14:36 -0700 Anand Ashok Dumbre <[email protected]> wrote:
> Fixes IIO_VAL_FRACTIONAL for case when the result is negative and > exponent is 0. > > example: if the result is -0.75, tmp0 will be 0 and tmp1 = 75 > This causes the output to lose sign because of %d in snprintf > which works for tmp0 <= -1. > > Signed-off-by: Anand Ashok Dumbre <[email protected]> Looks good. Just one last thing. Is this actually hit in an existing driver? I'm just wondering how far back we need to push it in stable etc. Thanks, Jonathan > --- > changes since v1: > Changed -%d to -0 to make the fix clearer. > Removed the email footer. > Updated the commit description with an example > -- > drivers/iio/industrialio-core.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c > index cdcd16f1..a239fa2 100644 > --- a/drivers/iio/industrialio-core.c > +++ b/drivers/iio/industrialio-core.c > @@ -592,6 +592,7 @@ static ssize_t __iio_format_value(char *buf, size_t len, > unsigned int type, > { > unsigned long long tmp; > int tmp0, tmp1; > + s64 tmp2; > bool scale_db = false; > > switch (type) { > @@ -614,10 +615,13 @@ static ssize_t __iio_format_value(char *buf, size_t > len, unsigned int type, > else > return scnprintf(buf, len, "%d.%09u", vals[0], vals[1]); > case IIO_VAL_FRACTIONAL: > - tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]); > + tmp2 = div_s64((s64)vals[0] * 1000000000LL, vals[1]); > tmp1 = vals[1]; > tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1); > - return scnprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); > + if ((tmp2 < 0) && (tmp0 == 0)) > + return snprintf(buf, len, "-0.%09u", abs(tmp1)); > + else > + return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1)); > case IIO_VAL_FRACTIONAL_LOG2: > tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]); > tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
