split_micro_fraction() scales the remainder to micro units by multiplying it by 10^(6 - exp). The unit exponent of a HID field goes down to -8, so exp can be 7 or 8 here. Then the argument of int_pow() is negative, which the unsigned parameter turns into a huge power of ten: 0 modulo 2^64. As a result, the fractional part of a value read from the hysteresis attributes is always reported as 0. Divide by 10^(exp - 6) in these two cases. This matches the reverse conversion in convert_to_vtf_format(). Fixes: 73c6768b710a ("iio: hid-sensors: Common attribute and trigger") Cc: stable@vger.kernel.org Signed-off-by: Srinivas Pandruvada --- v2: - Fix __udivdi3 link error on 32-bit by using a 32-bit divisor - Address Andy's comment: Keep no % divisor in a temporary variable next to no / divisor drivers/iio/common/hid-sensors/hid-sensor-attributes.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c index 9e7c26e37880..d44091faf122 100644 --- a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c +++ b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c @@ -96,9 +96,14 @@ static void simple_div(int dividend, int divisor, int *whole, int *micro_frac) static void split_micro_fraction(unsigned int no, int exp, int *val1, int *val2) { int divisor = int_pow(10, exp); + unsigned int rem; *val1 = no / divisor; - *val2 = no % divisor * int_pow(10, 6 - exp); + rem = no % divisor; + if (exp > 6) + *val2 = rem / (unsigned int)int_pow(10, exp - 6); + else + *val2 = rem * int_pow(10, 6 - exp); } /* -- 2.56.0