Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Sun, 16 Jul 2017 14:56:46 +0100 | Subject | [PATCH 3.16 117/178] iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values |
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3.16.46-rc1 review patch. If anyone has any objections, please let me know.
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From: Nikolaus Schulz <nikolaus.schulz@avionic-design.de>
commit 7fd6592d1287046f61bfd3cda3c03cd35be490f7 upstream.
Fix formatting of negative values of type IIO_VAL_FRACTIONAL_LOG2 by switching from do_div(), which can't handle negative numbers, to div_s64_rem(). Also use shift_right for shifting, which is safe with negative values.
Signed-off-by: Nikolaus Schulz <nikolaus.schulz@avionic-design.de> Reviewed-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org> [bwh: Backported to 3.16: - Use vals[] instead of tmp{0,1} - Keep using sprintf()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- drivers/iio/industrialio-core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
--- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -406,10 +406,9 @@ ssize_t iio_format_value(char *buf, unsi 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); - vals[0] = tmp; - return sprintf(buf, "%d.%09u\n", vals[0], vals[1]); + tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]); + vals[0] = (int)div_s64_rem(tmp, 1000000000LL, &vals[1]); + return sprintf(buf, "%d.%09u\n", vals[0], abs(vals[1])); case IIO_VAL_INT_MULTIPLE: { int i;
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