Re: [PATCH net-next] net: aquantia: Fix build error wihtout CONFIG_PTP_1588_CLOCK

[Simon Horman <simon.horman@netronome.com>]

On Fri, Oct 25, 2019 at 09:37:26PM +0800, YueHaibing wrote:
> If PTP_1588_CLOCK is n, building fails:
> 
> drivers/net/ethernet/aquantia/atlantic/aq_ptp.c: In function aq_ptp_adjfine:
> drivers/net/ethernet/aquantia/atlantic/aq_ptp.c:279:11:
>  error: implicit declaration of function scaled_ppm_to_ppb [-Werror=implicit-function-declaration]
>            scaled_ppm_to_ppb(scaled_ppm));
> 
> Just cp scaled_ppm_to_ppb() from ptp_clock.c to fix this.
> 
> Fixes: 910479a9f793 ("net: aquantia: add basic ptp_clock callbacks")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>

Hi YueHaibing,

thanks for your patch.

What is the motivation for not using the existing copy of this function?

> ---
>  drivers/net/ethernet/aquantia/atlantic/aq_ptp.c | 20 ++++++++++++++++++++
>  1 file changed, 20 insertions(+)
> 
> diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ptp.c b/drivers/net/ethernet/aquantia/atlantic/aq_ptp.c
> index 3ec0841..80c001d 100644
> --- a/drivers/net/ethernet/aquantia/atlantic/aq_ptp.c
> +++ b/drivers/net/ethernet/aquantia/atlantic/aq_ptp.c
> @@ -262,6 +262,26 @@ static void aq_ptp_tx_timeout_check(struct aq_ptp_s *aq_ptp)
>  	}
>  }
>  
> +static s32 scaled_ppm_to_ppb(long ppm)
> +{
> +	/*
> +	 * The 'freq' field in the 'struct timex' is in parts per
> +	 * million, but with a 16 bit binary fractional field.
> +	 *
> +	 * We want to calculate
> +	 *
> +	 *    ppb = scaled_ppm * 1000 / 2^16
> +	 *
> +	 * which simplifies to
> +	 *
> +	 *    ppb = scaled_ppm * 125 / 2^13
> +	 */
> +	s64 ppb = 1 + ppm;
> +	ppb *= 125;
> +	ppb >>= 13;
> +	return (s32) ppb;
> +}
> +
>  /* aq_ptp_adjfine
>   * @ptp: the ptp clock structure
>   * @ppb: parts per billion adjustment from base
> -- 
> 2.7.4
> 
>