> -----Original Message-----
> From: Sergey Shtylyov <s.shtylyov@xxxxxx>
> Sent: Saturday, August 20, 2022 12:34 PM
> To: Keller, Jacob E <jacob.e.keller@xxxxxxxxx>; netdev@xxxxxxxxxxxxxxx
> Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang
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> Subject: Re: [net-next 11/14] ptp: ravb: convert to .adjfine and
> adjust_by_scaled_ppm
>
> Hello!
>
> On 8/19/22 1:27 AM, Jacob Keller wrote:
>
> > The ravb implementation of .adjfreq is implemented in terms of a
> > straight forward "base * ppb / 1 billion" calculation.
> >
> > Convert this driver to .adjfine and use the adjust_by_scaled_ppm helper
> > function to calculate the new addend.
> >
> > Signed-off-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
> > Cc: Sergey Shtylyov <s.shtylyov@xxxxxx>
> > Cc: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > Cc: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
> > Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > Cc: linux-renesas-soc@xxxxxxxxxxxxxxx
> > ---
> >
> > I do not have this hardware, and have only compile tested the change.
> >
> > drivers/net/ethernet/renesas/ravb_ptp.c | 16 +++++-----------
> > 1 file changed, 5 insertions(+), 11 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/renesas/ravb_ptp.c
> b/drivers/net/ethernet/renesas/ravb_ptp.c
> > index 87c4306d66ec..941aa3b0e8a0 100644
> > --- a/drivers/net/ethernet/renesas/ravb_ptp.c
> > +++ b/drivers/net/ethernet/renesas/ravb_ptp.c
> > @@ -88,24 +88,18 @@ static int ravb_ptp_update_compare(struct
> ravb_private *priv, u32 ns)
> > }
> >
> > /* PTP clock operations */
> > -static int ravb_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
> > +static int ravb_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
> > {
> > struct ravb_private *priv = container_of(ptp, struct ravb_private,
> > ptp.info);
> > struct net_device *ndev = priv->ndev;
> > unsigned long flags;
> > - u32 diff, addend;
> > - bool neg_adj = false;
> > + u32 addend;
> > u32 gccr;
> >
> > - if (ppb < 0) {
> > - neg_adj = true;
> > - ppb = -ppb;
> > - }
> > addend = priv->ptp.default_addend;
>
> I don't think we should keep this line -- it has no effect now...
>
Yea this can be dropped.
> > - diff = div_u64((u64)addend * ppb, NSEC_PER_SEC);
> > -
> > - addend = neg_adj ? addend - diff : addend + diff;
> > + addend = (u32)adjust_by_scaled_ppm(priv->ptp.default_addend,
> > + scaled_ppm);
> >
> > spin_lock_irqsave(&priv->lock, flags);
> >
> [...]
>
> MBR, Sergey
