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iio: core: Fix IIO_VAL_FRACTIONAL calculation for negative values 

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.

Reported-by: kernel test robot <lkp@intel.com> #error: uninitialized symbol tmp
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@xilinx.com>
Link: https://lore.kernel.org/r/1601910316-24111-1-git-send-email-anand.ashok.dumbre@xilinx.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Anand Ashok Dumbre 2020-10-05 08:05:16 -07:00 committed by Jonathan Cameron
parent c5bf4d645f
commit 0e7a3978a4
1 changed files with 7 additions and 3 deletions
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10
drivers/iio/industrialio-core.c
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@ -594,6 +594,7 @@ 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) {
@ -616,10 +617,13 @@ 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));
tmp0 = (int)div_s64_rem(tmp2, 1000000000, &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);