From: Iain Hunter <iain@xxxxxxxxxxxxxxxxxxxx>
That change adds an error check to avoid saturation during multiplication
to calculate nano seconds in timespec64_to_ns().
In ina2xx_capture_thread() a timespec64 structure is used to calculate
the delta time until the next sample time. This delta can be negative if
the next sample time was in the past. In the -1 case timespec64_to_ns()
now clamps the -1 second value to KTIME_MAX. This essentially puts ina2xx
thread to sleep forever.
Proposed patch is to replace the call to timespec64_to_ns() with the
contents of that function without the overflow test introduced by the
commit (ie revert to pre kernel 5.4 behaviour)
Signed-off-by: Iain Hunter <iain@xxxxxxxxxxxxxxxxxxxx>
---
drivers/iio/adc/ina2xx-adc.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
index a4b2ff9e0..ba3e98fde 100644
--- a/drivers/iio/adc/ina2xx-adc.c
+++ b/drivers/iio/adc/ina2xx-adc.c
@@ -777,6 +777,7 @@ static int ina2xx_capture_thread(void *data)
int ret;
struct timespec64 next, now, delta;
s64 delay_us;
+ s64 delta_ns;
/*
* Poll a bit faster than the chip internal Fs, in case
@@ -818,7 +819,8 @@ static int ina2xx_capture_thread(void *data)
do {
timespec64_add_ns(&next, 1000 * sampling_us);
delta = timespec64_sub(next, now);
- delay_us = div_s64(timespec64_to_ns(&delta), 1000);
+ delta_ns = (((s64)delta.tv_sec) * NSEC_PER_SEC)+delta.tv_nsec;
+ delay_us = div_s64(delta_ns, 1000);
} while (delay_us <= 0);
usleep_range(delay_us, (delay_us * 3) >> 1);
--
2.17.1
