ptp: introduce PTP_CLOCK_EXTOFF event for the measured external offset

This change is for the PHC devices that can measure the phase offset
between PHC signal and the external signal, such as the 1PPS signal of
GNSS. Reporting PTP_CLOCK_EXTOFF to user space will be piggy-backed to
the existing ptp_extts_event so that application such as ts2phc can
poll the external offset the same way as extts. Hence, ts2phc can use
the offset to achieve the alignment between PHC and the external signal
by the help of either SW or HW filters.

Signed-off-by: Min Li <min.li.xe@renesas.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/ptp_clock_kernel.h b/include/linux/ptp_clock_kernel.h
index 1ef4e0f9bd2a..6e4b8206c7d0 100644
--- a/include/linux/ptp_clock_kernel.h
+++ b/include/linux/ptp_clock_kernel.h
@@ -200,6 +200,7 @@ struct ptp_clock;
 enum ptp_clock_events {
 	PTP_CLOCK_ALARM,
 	PTP_CLOCK_EXTTS,
+	PTP_CLOCK_EXTOFF,
 	PTP_CLOCK_PPS,
 	PTP_CLOCK_PPSUSR,
 };
@@ -210,6 +211,7 @@ enum ptp_clock_events {
  * @type:  One of the ptp_clock_events enumeration values.
  * @index: Identifies the source of the event.
  * @timestamp: When the event occurred (%PTP_CLOCK_EXTTS only).
+ * @offset:    When the event occurred (%PTP_CLOCK_EXTOFF only).
  * @pps_times: When the event occurred (%PTP_CLOCK_PPSUSR only).
  */
 
@@ -218,6 +220,7 @@ struct ptp_clock_event {
 	int index;
 	union {
 		u64 timestamp;
+		s64 offset;
 		struct pps_event_time pps_times;
 	};
 };