On Sun, 26 Sep 2021 23:18:42 +0200
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> 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
Thanks Thomas.
Iain could you test this approach?
Thanks,
Jonathan
> ---
> --- 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());
>
>
