linux-kernel - Re: [RFC Patch net-next v2 8/8] net: dsa: microchip: ptp: add periodic output signal

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Date:   Tue, 22 Nov 2022 06:38:53 -0800
From:   Richard Cochran <richardcochran@...il.com>
To:     Arun Ramadoss <arun.ramadoss@...rochip.com>
Cc:     linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        woojung.huh@...rochip.com, UNGLinuxDriver@...rochip.com,
        andrew@...n.ch, vivien.didelot@...il.com, f.fainelli@...il.com,
        olteanv@...il.com, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, linux@...linux.org.uk,
        Tristram.Ha@...rochip.com
Subject: Re: [RFC Patch net-next v2 8/8] net: dsa: microchip: ptp: add
 periodic output signal

On Mon, Nov 21, 2022 at 09:11:50PM +0530, Arun Ramadoss wrote:

> +static int ksz_ptp_restart_perout(struct ksz_device *dev)
> +{
> +	struct ksz_ptp_data *ptp_data = &dev->ptp_data;
> +	s64 now_ns, first_ns, period_ns, next_ns;
> +	struct timespec64 now;
> +	unsigned int count;
> +	int ret;
> +
> +	ret = _ksz_ptp_gettime(dev, &now);
> +	if (ret)
> +		return ret;
> +
> +	now_ns = timespec64_to_ns(&now);
> +	first_ns = timespec64_to_ns(&ptp_data->perout_target_time_first);
> +
> +	/* Calculate next perout event based on start time and period */
> +	period_ns = timespec64_to_ns(&ptp_data->perout_period);
> +
> +	if (first_ns < now_ns) {
> +		count = div_u64(now_ns - first_ns, period_ns);
> +		next_ns = first_ns + count * period_ns;
> +	} else {
> +		next_ns = first_ns;
> +	}
> +
> +	/* Ensure 100 ms guard time prior next event */
> +	while (next_ns < now_ns + 100000000)
> +		next_ns += period_ns;
> +
> +	/* Restart periodic output signal */
> +	{

CodingStyle: avoid anonymous blocks.  Move to helper function instead?

Thanks,
Richard


> +		struct timespec64 next = ns_to_timespec64(next_ns);
> +		struct ptp_perout_request perout_request = {
> +			.start = {
> +				.sec  = next.tv_sec,
> +				.nsec = next.tv_nsec
> +			},
> +			.period = {
> +				.sec  = ptp_data->perout_period.tv_sec,
> +				.nsec = ptp_data->perout_period.tv_nsec
> +			},
> +			.index = 0,
> +			.flags = 0,  /* keep current values */
> +		};
> +		ret = ksz_ptp_enable_perout(dev, &perout_request, 1);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
> +}