Re: [PATCH net-next v2 4/6] net: mvpp2: ptp: add TAI support

[Russell King - ARM Linux admin <linux@armlinux.org.uk>]

On Sun, Sep 06, 2020 at 09:04:02PM +0100, Russell King - ARM Linux admin wrote:
> > > +static void mvpp22_tai_set_tod(struct mvpp2_tai *tai)
> > > +{
> > > +	struct timespec64 now;
> > > +
> > > +	ktime_get_real_ts64(&now);
> > > +	mvpp22_tai_settime64(&tai->caps, &now);
> > > +}
> > > +
> > > +static void mvpp22_tai_init(struct mvpp2_tai *tai)
> > > +{
> > > +	void __iomem *base = tai->base;
> > > +
> > > +	mvpp22_tai_set_step(tai);
> > > +
> > > +	/* Release the TAI reset */
> > > +	mvpp2_tai_modify(base + MVPP22_TAI_CR0, CR0_SW_NRESET, CR0_SW_NRESET);
> > > +
> > > +	mvpp22_tai_set_tod(tai);
> > 
> > The consensus on the list seems to be that new PHCs should start
> > ticking from time zero (1970), although some older drivers do use
> > ktime.  For new clocks, I'd prefer using zero.
> 
> Ok.

Should we always set the TAI counter to zero every time the TAI is
initialised, or just leave it as is (the counter may already be set
by a previous kernel, for example when a kexec has happened).

-- 
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