On Sun, Sep 26 2021 at 18:16, Iain Hunter wrote: > --- a/drivers/iio/adc/ina2xx-adc.c > +++ b/drivers/iio/adc/ina2xx-adc.c > @@ -817,10 +817,10 @@ 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); > - } while (delay_us <= 0); > + } while (timespec64_compare(&next, &now) < 0); > > + delta = timespec64_sub(next, now); > + delay_us = div_s64(timespec64_to_ns(&delta), 1000); This whole timespec dance does not make any sense and can be completely avoided by using just scalar nanoseconds. Untested patch below. Thanks, tglx --- --- a/drivers/iio/adc/ina2xx-adc.c +++ b/drivers/iio/adc/ina2xx-adc.c @@ -775,7 +775,7 @@ static int ina2xx_capture_thread(void *d struct ina2xx_chip_info *chip = iio_priv(indio_dev); int sampling_us = SAMPLING_PERIOD(chip); int ret; - struct timespec64 next, now, delta; + ktime_t next, now, delta; s64 delay_us; /* @@ -785,7 +785,7 @@ static int ina2xx_capture_thread(void *d if (!chip->allow_async_readout) sampling_us -= 200; - ktime_get_ts64(&next); + next = ktime_get(); do { while (!chip->allow_async_readout) { @@ -798,7 +798,7 @@ static int ina2xx_capture_thread(void *d * reset the reference timestamp. */ if (ret == 0) - ktime_get_ts64(&next); + next = ktime_get(); else break; } @@ -807,7 +807,7 @@ static int ina2xx_capture_thread(void *d if (ret < 0) return ret; - ktime_get_ts64(&now); + now = ktime_get(); /* * Advance the timestamp for the next poll by one sampling @@ -816,11 +816,10 @@ static int ina2xx_capture_thread(void *d * multiple times, i.e. samples are dropped. */ do { - timespec64_add_ns(&next, 1000 * sampling_us); - delta = timespec64_sub(next, now); - delay_us = div_s64(timespec64_to_ns(&delta), 1000); - } while (delay_us <= 0); + next = ktime_add_us(next, sampling_us); + } while (next <= now); + delay_us = ktime_to_us(ktime_sub(next, now)); usleep_range(delay_us, (delay_us * 3) >> 1); } while (!kthread_should_stop());