Re: [net-next 11/14] ptp: ravb: convert to .adjfine and adjust_by_scaled_ppm

[Sergey Shtylyov <s.shtylyov@omp.ru>]

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@intel.com>
> Cc: Sergey Shtylyov <s.shtylyov@omp.ru>
> Cc: Biju Das <biju.das.jz@bp.renesas.com>
> Cc: Phil Edworthy <phil.edworthy@renesas.com>
> Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> 
> 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...

> -	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