[PATCH net] net: ethernet: ti: am65-cpts: fix support for PTP_EXTTS_REQUEST2 ioctl

[James Clark <jjc@jclark.com>]

Commit 7c571ac57d9d ("net: ptp: introduce .supported_extts_flags to
ptp_clock_info") modified the PTP core to validate the supported flags
of external timestamp requests, rather than relying on each driver to
check them.

am65_cpts_extts_enable() ignores the flags, and am65-cpts was not given
any .supported_extts_flags. Since PTP_EXTTS_REQUEST2 always implies
PTP_STRICT_FLAGS, the core now rejects every PTP_EXTTS_REQUEST2 for this
driver with -EOPNOTSUPP, where before that commit the same requests
succeeded. Only the PTP_EXTTS_REQUEST ioctl still works.

Tests on a BeagleY-AI (J722S) show that the CPTS hardware timestamp push
inputs timestamp just the rising edge. Encode this in
.supported_extts_flags. A PTP_EXTTS_REQUEST2 for the rising edge then
succeeds, and one for the falling edge or for both edges fails with
-EOPNOTSUPP.

Fixes: 7c571ac57d9d ("net: ptp: introduce .supported_extts_flags to ptp_clock_info")
Signed-off-by: James Clark <jjc@jclark.com>
---
 drivers/net/ethernet/ti/am65-cpts.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/ti/am65-cpts.c b/drivers/net/ethernet/ti/am65-cpts.c
index efbf2ef976a..df5659ead72 100644
--- a/drivers/net/ethernet/ti/am65-cpts.c
+++ b/drivers/net/ethernet/ti/am65-cpts.c
@@ -779,6 +779,7 @@ static long am65_cpts_ts_work(struct ptp_clock_info *ptp);
 static struct ptp_clock_info am65_ptp_info = {
 	.owner		= THIS_MODULE,
 	.name		= "CTPS timer",
+	.supported_extts_flags = PTP_RISING_EDGE | PTP_STRICT_FLAGS,
 	.adjfine	= am65_cpts_ptp_adjfine,
 	.adjtime	= am65_cpts_ptp_adjtime,
 	.gettimex64	= am65_cpts_ptp_gettimex,
-- 
2.56.0