Message ID | 1433496128-3102-1-git-send-email-B38611@freescale.com |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: Fugang Duan <B38611@freescale.com> Date: Fri, 5 Jun 2015 17:22:08 +0800 > From: Fugang Duan <b38611@freescale.com> > > The current driver adjust freq formula is: > fe * diff = ppb * pc > Note: > fe: ENET ref clock frequency in Hz > diff = inc_corr - inc: difference between default increment and correction increment > ppb: parts per billion adjustment from base > pc: correction period (in number of fe clock cycles) > > The correction increment will be used after N cycles of regular increments, > not every N cycles (with N being the correction period). For example, set ENET_ATCOR=4, > INC=8, INC_CORR=9, there will be 4 increments of 8 (ENET_ATINC[INC]) , followed by 1 > increment of 9 (ENET_ATINC[INC_CORR]). > > So, the correct formula is: > fe * diff = ppb * (pc + 1) > > For ENET_ATCOR, a value 0 disables the correction counter and no corrections occur. > So base on the origin formula, set pc = pc > 1 ? pc - 1 : pc. > > Signed-off-by: Fugang Duan <B38611@freescale.com> > Signed-off-by: Frank Li <Frank.Li@freescale.com> Applied, thank you. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/freescale/fec_ptp.c b/drivers/net/ethernet/freescale/fec_ptp.c index 2daf42e..9eb81fa 100644 --- a/drivers/net/ethernet/freescale/fec_ptp.c +++ b/drivers/net/ethernet/freescale/fec_ptp.c @@ -353,6 +353,7 @@ static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb) tmp = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK; tmp |= corr_ns << FEC_T_INC_CORR_OFFSET; writel(tmp, fep->hwp + FEC_ATIME_INC); + corr_period = corr_period > 1 ? corr_period - 1 : corr_period; writel(corr_period, fep->hwp + FEC_ATIME_CORR); /* dummy read to update the timer. */ timecounter_read(&fep->tc);