[PATCH net-next v6 4/6] ptp: clockmatrix: dco input-to-output delay is 20 FOD cycles + 8ns

Min Li
2023-11-30T18:47:12Z

drivers/ptp/ptp_clockmatrix.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/ptp/ptp_clockmatrix.c b/drivers/ptp/ptp_clockmatrix.c
index d069b6e451ef..21f3a2c179f5 100644
--- a/drivers/ptp/ptp_clockmatrix.c
+++ b/drivers/ptp/ptp_clockmatrix.c
@@ -2165,7 +2165,7 @@ static int configure_channel_pll(struct idtcm_channel *channel)

/*
* Compensate for the PTP DCO input-to-output delay.
- * This delay is 18 FOD cycles.
+ * This delay is 20 FOD cycles + 8ns.
*/
static u32 idtcm_get_dco_delay(struct idtcm_channel *channel)
{
@@ -2196,7 +2196,7 @@ static u32 idtcm_get_dco_delay(struct idtcm_channel *channel)
fodFreq = (u32)div_u64(m, n);

if (fodFreq >= 500000000)
- return (u32)div_u64(18 * (u64)NSEC_PER_SEC, fodFreq);
+ return (u32)div_u64(20 * (u64)NSEC_PER_SEC, fodFreq) + 8;

return 0;
}
--
2.39.2