can: rockchip_canfd: rkcanfd_timestamp_init(): rework delay calculation

Rework the delay calculation to only require a single 64-bit division.

Signed-off-by: Arnd Bergmann <[email protected]>
[mkl: port to on-top of existing 32-bit division fix]
Link: https://patch.msgid.link/20240911-can-rockchip_canfd-fixes-v1-1-5ce385b5ab10@pengutronix.de
Signed-off-by: Marc Kleine-Budde <[email protected]>

Author: arndb

drivers/net/can/rockchip/rockchip_canfd-timestamp.c

@@ -71,8 +71,8 @@ void rkcanfd_timestamp_init(struct rkcanfd_priv *priv)
 
 	max_cycles = div_u64(ULLONG_MAX, cc->mult);
 	max_cycles = min(max_cycles, cc->mask);
-	work_delay_ns = div_u64(clocksource_cyc2ns(max_cycles, cc->mult, cc->shift), 3);
-	priv->work_delay_jiffies = nsecs_to_jiffies(work_delay_ns);
+	work_delay_ns = clocksource_cyc2ns(max_cycles, cc->mult, cc->shift);
+	priv->work_delay_jiffies = div_u64(work_delay_ns, 3u * NSEC_PER_SEC / HZ);
 	INIT_DELAYED_WORK(&priv->timestamp, rkcanfd_timestamp_work);
 
 	netdev_dbg(priv->ndev, "clock=%lu.%02luMHz bitrate=%lu.%02luMBit/s div=%u rate=%lu.%02luMHz mult=%u shift=%u delay=%lus\n",