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authorGregor Boirie <gregor.boirie@parrot.com>2016-09-02 20:27:46 +0200
committerJonathan Cameron <jic23@kernel.org>2016-09-05 21:21:32 +0100
commit171c0091837c81ed5c949fec6966bb5afff2d1cf (patch)
treea1d5f5ac471ef9c9a224632479e00623fd4c4a7e /drivers/iio
parent5dba4b14bafe801083d01e1f400816df7e5a8f2e (diff)
downloadlinux-171c0091837c81ed5c949fec6966bb5afff2d1cf.tar.bz2
iio:core: fix IIO_VAL_FRACTIONAL sign handling
7985e7c100 ("iio: Introduce a new fractional value type") introduced a new IIO_VAL_FRACTIONAL value type meant to represent rational type numbers expressed by a numerator and denominator combination. Formating of IIO_VAL_FRACTIONAL values relies upon do_div() usage. This fails handling negative values properly since parameters are reevaluated as unsigned values. Fix this by using div_s64_rem() instead. Computed integer part will carry properly signed value. Formatted fractional part will always be positive. Fixes: 7985e7c100 ("iio: Introduce a new fractional value type") Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio')
-rw-r--r--drivers/iio/industrialio-core.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index f914d5d140e4..d2b889918c3e 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -613,9 +613,8 @@ ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
case IIO_VAL_FRACTIONAL:
tmp = div_s64((s64)vals[0] * 1000000000LL, vals[1]);
- vals[1] = do_div(tmp, 1000000000LL);
- vals[0] = tmp;
- return sprintf(buf, "%d.%09u\n", vals[0], vals[1]);
+ vals[0] = (int)div_s64_rem(tmp, 1000000000, &vals[1]);
+ return sprintf(buf, "%d.%09u\n", vals[0], abs(vals[1]));
case IIO_VAL_FRACTIONAL_LOG2:
tmp = (s64)vals[0] * 1000000000LL >> vals[1];
vals[1] = do_div(tmp, 1000000000LL);