[PATCH net-next v3 3/4] net: dsa: mv88e6xxx: extend PTP gettime function to read system clock

[Hubert Feurstein]

From: Hubert Feurstein <h.feurstein@xxxxxxxxx>

This adds support for the PTP_SYS_OFFSET_EXTENDED ioctl.

Signed-off-by: Hubert Feurstein <h.feurstein@xxxxxxxxx>
---
Changes in v3:
 - mv88e6xxx_smi_indirect_write: forward ptp_sts only on the last write
 
 drivers/net/dsa/mv88e6xxx/chip.h |  2 ++
 drivers/net/dsa/mv88e6xxx/ptp.c  | 11 +++++++----
 drivers/net/dsa/mv88e6xxx/smi.c  |  7 ++++++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/net/dsa/mv88e6xxx/chip.h b/drivers/net/dsa/mv88e6xxx/chip.h
index a406be2f5652..1bfde0d8a5a3 100644
--- a/drivers/net/dsa/mv88e6xxx/chip.h
+++ b/drivers/net/dsa/mv88e6xxx/chip.h
@@ -275,6 +275,8 @@ struct mv88e6xxx_chip {
 	struct ptp_clock_info	ptp_clock_info;
 	struct delayed_work	tai_event_work;
 	struct ptp_pin_desc	pin_config[MV88E6XXX_MAX_GPIO];
+	struct ptp_system_timestamp *ptp_sts;
+
 	u16 trig_config;
 	u16 evcap_config;
 	u16 enable_count;
diff --git a/drivers/net/dsa/mv88e6xxx/ptp.c b/drivers/net/dsa/mv88e6xxx/ptp.c
index 073cbd0bb91b..cf6e52ee9e0a 100644
--- a/drivers/net/dsa/mv88e6xxx/ptp.c
+++ b/drivers/net/dsa/mv88e6xxx/ptp.c
@@ -235,14 +235,17 @@ static int mv88e6xxx_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 	return 0;
 }
 
-static int mv88e6xxx_ptp_gettime(struct ptp_clock_info *ptp,
-				 struct timespec64 *ts)
+static int mv88e6xxx_ptp_gettimex(struct ptp_clock_info *ptp,
+				  struct timespec64 *ts,
+				  struct ptp_system_timestamp *sts)
 {
 	struct mv88e6xxx_chip *chip = ptp_to_chip(ptp);
 	u64 ns;
 
 	mv88e6xxx_reg_lock(chip);
+	chip->ptp_sts = sts;
 	ns = timecounter_read(&chip->tstamp_tc);
+	chip->ptp_sts = NULL;
 	mv88e6xxx_reg_unlock(chip);
 
 	*ts = ns_to_timespec64(ns);
@@ -426,7 +429,7 @@ static void mv88e6xxx_ptp_overflow_check(struct work_struct *work)
 	struct mv88e6xxx_chip *chip = dw_overflow_to_chip(dw);
 	struct timespec64 ts;
 
-	mv88e6xxx_ptp_gettime(&chip->ptp_clock_info, &ts);
+	mv88e6xxx_ptp_gettimex(&chip->ptp_clock_info, &ts, NULL);
 
 	schedule_delayed_work(&chip->overflow_work,
 			      MV88E6XXX_TAI_OVERFLOW_PERIOD);
@@ -472,7 +475,7 @@ int mv88e6xxx_ptp_setup(struct mv88e6xxx_chip *chip)
 	chip->ptp_clock_info.max_adj    = MV88E6XXX_MAX_ADJ_PPB;
 	chip->ptp_clock_info.adjfine	= mv88e6xxx_ptp_adjfine;
 	chip->ptp_clock_info.adjtime	= mv88e6xxx_ptp_adjtime;
-	chip->ptp_clock_info.gettime64	= mv88e6xxx_ptp_gettime;
+	chip->ptp_clock_info.gettimex64	= mv88e6xxx_ptp_gettimex;
 	chip->ptp_clock_info.settime64	= mv88e6xxx_ptp_settime;
 	chip->ptp_clock_info.enable	= ptp_ops->ptp_enable;
 	chip->ptp_clock_info.verify	= ptp_ops->ptp_verify;
diff --git a/drivers/net/dsa/mv88e6xxx/smi.c b/drivers/net/dsa/mv88e6xxx/smi.c
index 282fe08db050..1b5f78662158 100644
--- a/drivers/net/dsa/mv88e6xxx/smi.c
+++ b/drivers/net/dsa/mv88e6xxx/smi.c
@@ -45,7 +45,8 @@ static int mv88e6xxx_smi_direct_write(struct mv88e6xxx_chip *chip,
 {
 	int ret;
 
-	ret = mdiobus_write_nested(chip->bus, dev, reg, data);
+	ret = mdiobus_write_sts_nested(chip->bus, dev, reg, data,
+				       chip->ptp_sts);
 	if (ret < 0)
 		return ret;
 
@@ -130,6 +131,7 @@ static int mv88e6xxx_smi_indirect_read(struct mv88e6xxx_chip *chip,
 static int mv88e6xxx_smi_indirect_write(struct mv88e6xxx_chip *chip,
 					int dev, int reg, u16 data)
 {
+	struct ptp_system_timestamp *ptp_sts = chip->ptp_sts;
 	int err;
 
 	err = mv88e6xxx_smi_direct_wait(chip, chip->sw_addr,
@@ -137,11 +139,14 @@ static int mv88e6xxx_smi_indirect_write(struct mv88e6xxx_chip *chip,
 	if (err)
 		return err;
 
+	chip->ptp_sts = NULL;
 	err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr,
 					 MV88E6XXX_SMI_DATA, data);
 	if (err)
 		return err;
 
+	/* Capture the PTP system timestamps only on *this* write operation */
+	chip->ptp_sts = ptp_sts;
 	err = mv88e6xxx_smi_direct_write(chip, chip->sw_addr,
 					 MV88E6XXX_SMI_CMD,
 					 MV88E6XXX_SMI_CMD_BUSY |
-- 
2.22.1