Linux PTP driver issue

thousel — Tue, 23 Sep 2025 04:58:00 GMT

Hi. I'm using LinuxPTP on an i.MX7D (on a Compulab module), and I think I've found an issue with the PTP driver in drivers/net/ethernet/freescale/fec_ptp.c (which is still in the current git head at https://github.com/nxp-imx/linux-imx/blob/lf-6.12.y/drivers/net/ethernet/freescale/fec_ptp.c)

The issue is that the ENETx_ATCOR register (called FEC_ATIME_CORR in the driver) is not initialized in fec_ptp_start_cyclecounter. If fec_ptp_adjfine sets it to a weird place, there's no way to fix it, except for rebooting. Since ENETx_ATINC (FEC_ATIME_INC) is reinitialized in fec_ptp_start_cyclecounter, ENETx_ATCOR should be as well (to its reset value of 0 I believe).

Otherwise if ENETx_ATCOR starts at a bad value, LinuxPTP can get into states where it won't converge.

Re: Linux PTP driver issue

pengyong_zhang — Tue, 23 Sep 2025 09:04:38 GMT

Hi @thousel

Thanks for your suggestion, i will contact with our sw team talk about this.

B.R

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