net: ptp: introduce .supported_perout_flags to ptp_clock_info

The PTP_PEROUT_REQUEST2 ioctl has gained support for flags specifying
specific output behavior including PTP_PEROUT_ONE_SHOT,
PTP_PEROUT_DUTY_CYCLE, PTP_PEROUT_PHASE.

Driver authors are notorious for not checking the flags of the request.
This results in misinterpreting the request, generating an output signal
that does not match the requested value. It is anticipated that even more
flags will be added in the future, resulting in even more broken requests.

Expecting these issues to be caught during review or playing whack-a-mole
after the fact is not a great solution.

Instead, introduce the supported_perout_flags field in the ptp_clock_info
structure. Update the core character device logic to explicitly reject any
request which has a flag not on this list.

This ensures that drivers must 'opt in' to the flags they support. Drivers
which don't set the .supported_perout_flags field will not need to check
that unsupported flags aren't passed, as the core takes care of this.

Update the drivers which do support flags to set this new field.

Note the following driver files set n_per_out to a non-zero value but did
not check the flags at all:

 • drivers/ptp/ptp_clockmatrix.c
 • drivers/ptp/ptp_idt82p33.c
 • drivers/ptp/ptp_fc3.c
 • drivers/net/ethernet/ti/am65-cpts.c
 • drivers/net/ethernet/aquantia/atlantic/aq_ptp.c
 • drivers/net/ethernet/broadcom/bnxt/bnxt_ptp.c
 • drivers/net/dsa/sja1105/sja1105_ptp.c
 • drivers/net/ethernet/freescale/dpaa2/dpaa2-ptp.c
 • drivers/net/ethernet/mscc/ocelot_vsc7514.c
 • drivers/net/ethernet/intel/i40e/i40e_ptp.c

Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20250414-jk-supported-perout-flags-v2-2-f6b17d15475c@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 3 insertions, 8 deletions

diff --git a/drivers/net/ethernet/microchip/lan743x_ptp.c b/drivers/net/ethernet/microchip/lan743x_ptp.c
index b171c893175b..b07f5b099a2b 100644
--- a/drivers/net/ethernet/microchip/lan743x_ptp.c
+++ b/drivers/net/ethernet/microchip/lan743x_ptp.c
@@ -463,10 +463,6 @@ static int lan743x_ptp_perout(struct lan743x_adapter *adapter, int on,
 	struct lan743x_ptp_perout *perout = &ptp->perout[index];
 	int ret = 0;
 
-	/* Reject requests with unsupported flags */
-	if (perout_request->flags & ~PTP_PEROUT_DUTY_CYCLE)
-		return -EOPNOTSUPP;
-
 	if (on) {
 		perout_pin = ptp_find_pin(ptp->ptp_clock, PTP_PF_PEROUT,
 					  perout_request->index);
@@ -1540,6 +1536,7 @@ int lan743x_ptp_open(struct lan743x_adapter *adapter)
 	ptp->ptp_clock_info.supported_extts_flags = PTP_RISING_EDGE |
 						    PTP_FALLING_EDGE |
 						    PTP_STRICT_FLAGS;
+	ptp->ptp_clock_info.supported_perout_flags = PTP_PEROUT_DUTY_CYCLE;
 	ptp->ptp_clock_info.pin_config = ptp->pin_config;
 	ptp->ptp_clock_info.adjfine = lan743x_ptpci_adjfine;
 	ptp->ptp_clock_info.adjtime = lan743x_ptpci_adjtime;
diff --git a/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c b/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c
index 8cf41b0977b2..098406e2e5bb 100644
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c
+++ b/drivers/net/ethernet/microchip/lan966x/lan966x_ptp.c
@@ -815,10 +815,6 @@ static int lan966x_ptp_perout(struct ptp_clock_info *ptp,
 	bool pps = false;
 	int pin;
 
-	if (rq->perout.flags & ~(PTP_PEROUT_DUTY_CYCLE |
-				 PTP_PEROUT_PHASE))
-		return -EOPNOTSUPP;
-
 	pin = ptp_find_pin(phc->clock, PTP_PF_PEROUT, rq->perout.index);
 	if (pin == -1 || pin >= LAN966X_PHC_PINS_NUM)
 		return -EINVAL;
@@ -974,6 +970,8 @@ static struct ptp_clock_info lan966x_ptp_clock_info = {
 	.n_pins		= LAN966X_PHC_PINS_NUM,
 	.supported_extts_flags = PTP_RISING_EDGE |
 				 PTP_STRICT_FLAGS,
+	.supported_perout_flags = PTP_PEROUT_DUTY_CYCLE |
+				  PTP_PEROUT_PHASE,
 };
 
 static int lan966x_ptp_phc_init(struct lan966x *lan966x,