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Subject[PATCH 4.10 014/110] iio: core: Fix IIO_VAL_FRACTIONAL_LOG2 for negative values
Date
4.10-stable review patch.  If anyone has any objections, please let me know.

------------------

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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
@@ -608,10 +608,9 @@ static ssize_t __iio_format_value(char *
tmp0 = (int)div_s64_rem(tmp, 1000000000, &tmp1);
return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
case IIO_VAL_FRACTIONAL_LOG2:
- tmp = (s64)vals[0] * 1000000000LL >> vals[1];
- tmp1 = do_div(tmp, 1000000000LL);
- tmp0 = tmp;
- return snprintf(buf, len, "%d.%09u", tmp0, tmp1);
+ tmp = shift_right((s64)vals[0] * 1000000000LL, vals[1]);
+ tmp0 = (int)div_s64_rem(tmp, 1000000000LL, &tmp1);
+ return snprintf(buf, len, "%d.%09u", tmp0, abs(tmp1));
case IIO_VAL_INT_MULTIPLE:
{
int i;

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