On 26.08.2022 12:46:28, Marc Kleine-Budde wrote:
> +void gs_usb_timestamp_init(struct gs_can *dev)
> +{
> + struct cyclecounter *cc = &dev->cc;
> +
> + cc->read = gs_usb_timestamp_read;
> + cc->mask = CYCLECOUNTER_MASK(32);
> + cc->shift = 1;
Using
| cc->shift = 32 - bits_per(NSEC_PER_SEC / GSUSB_TIMESTAMP_TIMER_HZ);
gives the max precision. If you want for example to tune the gs_usb's
clock against the Linux system clock (which needs some extra code
though...).
> + cc->mult = clocksource_hz2mult(GSUSB_TIMESTAMP_TIMER_HZ, cc->shift);
> +
> + timecounter_init(&dev->tc, &dev->cc, ktime_get_real_ns());
> +
> + INIT_DELAYED_WORK(&dev->timestamp, gs_usb_timestamp_work);
> + schedule_delayed_work(&dev->timestamp,
> + GSUSB_TIMESTAMP_WORK_DELAY_SEC * HZ);
> +}
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
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