ptp: clockmatrix: dco input-to-output delay is 20 FOD cycles + 8ns

Min Li · NipaLocal · commit 4d6320f54b2c · 2023-12-01T07:00:49.000-08:00
Signed-off-by: Min Li &lt;min.li.xe@renesas.com&gt;
Signed-off-by: NipaLocal &lt;nipa@local&gt;
diff --git 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;
 }

Original file line number	Diff line number	Diff line change
`@@ -2165,7 +2165,7 @@ static int configure_channel_pll(struct idtcm_channel *channel)`
`2165`	`2165`
`2166`	`2166`	`/*`
`2167`	`2167`	`* Compensate for the PTP DCO input-to-output delay.`
`2168`		`- * This delay is 18 FOD cycles.`
	`2168`	`+ * This delay is 20 FOD cycles + 8ns.`
`2169`	`2169`	`*/`
`2170`	`2170`	`static u32 idtcm_get_dco_delay(struct idtcm_channel *channel)`
`2171`	`2171`	`{`
`@@ -2196,7 +2196,7 @@ static u32 idtcm_get_dco_delay(struct idtcm_channel *channel)`
`2196`	`2196`	`fodFreq = (u32)div_u64(m, n);`
`2197`	`2197`
`2198`	`2198`	`if (fodFreq >= 500000000)`
`2199`		`- return (u32)div_u64(18 * (u64)NSEC_PER_SEC, fodFreq);`
	`2199`	`+ return (u32)div_u64(20 * (u64)NSEC_PER_SEC, fodFreq) + 8;`
`2200`	`2200`
`2201`	`2201`	`return 0;`
`2202`	`2202`	`}`