net: ti: icss-iep: Add phase offset configuration for perout signal

[ Upstream commit 220cb1b ]

icss_iep_perout_enable_hw() is a common function for generating
both pps and perout signals. When enabling pps, the application needs
to only pass enable/disable argument, whereas for perout it supports
different flags to configure the signal.

In case the app passes a valid phase offset value, the signal should
start toggling after that phase offset, else start immediately or
as soon as possible. ICSS_IEP_SYNC_START_REG register take number of
clock cycles to wait before starting the signal after activation time.
Set appropriate value to this register to support phase offset.

Signed-off-by: Meghana Malladi <m-malladi@ti.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Reviewed-by: Kory Maincent <kory.maincent@bootlin.com>
Link: https://patch.msgid.link/20250304105753.1552159-3-m-malladi@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Stable-dep-of: 7349c9e ("net: ti: icss-iep: Fix possible NULL pointer dereference for perout request")
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit 8b9808b)

Author: MeghanaMalladiTI

drivers/net/ethernet/ti/icssg/icss_iep.c

@@ -477,6 +477,7 @@ static int icss_iep_perout_enable_hw(struct icss_iep *iep,
 				     struct ptp_perout_request *req, int on)
 {
 	struct timespec64 ts;
+	u64 ns_start;
 	u64 ns_width;
 	int ret;
 	u64 cmp;
@@ -486,6 +487,14 @@ static int icss_iep_perout_enable_hw(struct icss_iep *iep,
 	ts.tv_nsec = req->on.nsec;
 	ns_width = timespec64_to_ns(&ts);
 
+	if (req->flags & PTP_PEROUT_PHASE) {
+		ts.tv_sec = req->phase.sec;
+		ts.tv_nsec = req->phase.nsec;
+		ns_start = timespec64_to_ns(&ts);
+	} else {
+		ns_start = 0;
+	}
+
 	if (iep->ops && iep->ops->perout_enable) {
 		ret = iep->ops->perout_enable(iep->clockops_data, req, on, &cmp);
 		if (ret)
@@ -500,7 +509,8 @@ static int icss_iep_perout_enable_hw(struct icss_iep *iep,
 			regmap_write(iep->map, ICSS_IEP_SYNC_PWIDTH_REG,
 				     div_u64(ns_width, iep->def_inc));
 			regmap_write(iep->map, ICSS_IEP_SYNC0_PERIOD_REG, 0);
-			regmap_write(iep->map, ICSS_IEP_SYNC_START_REG, 0);
+			regmap_write(iep->map, ICSS_IEP_SYNC_START_REG,
+				     div_u64(ns_start, iep->def_inc));
 			regmap_write(iep->map, ICSS_IEP_SYNC_CTRL_REG, 0); /* one-shot mode */
 			/* Enable CMP 1 */
 			regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
@@ -527,6 +537,8 @@ static int icss_iep_perout_enable_hw(struct icss_iep *iep,
 
 			regmap_write(iep->map, ICSS_IEP_SYNC_PWIDTH_REG,
 				     div_u64(ns_width, iep->def_inc));
+			regmap_write(iep->map, ICSS_IEP_SYNC_START_REG,
+				     div_u64(ns_start, iep->def_inc));
 			/* Enable Sync in single shot mode  */
 			regmap_write(iep->map, ICSS_IEP_SYNC_CTRL_REG,
 				     IEP_SYNC_CTRL_SYNC_N_EN(0) | IEP_SYNC_CTRL_SYNC_EN);
@@ -557,7 +569,8 @@ static int icss_iep_perout_enable(struct icss_iep *iep,
 	int ret = 0;
 
 	/* Reject requests with unsupported flags */
-	if (req->flags & ~PTP_PEROUT_DUTY_CYCLE)
+	if (req->flags & ~(PTP_PEROUT_DUTY_CYCLE |
+			  PTP_PEROUT_PHASE))
 		return -EOPNOTSUPP;
 
 	mutex_lock(&iep->ptp_clk_mutex);
@@ -607,6 +620,7 @@ static int icss_iep_pps_enable(struct icss_iep *iep, int on)
 	if (on) {
 		ns = icss_iep_gettime(iep, NULL);
 		ts = ns_to_timespec64(ns);
+		rq.perout.flags = 0;
 		rq.perout.period.sec = 1;
 		rq.perout.period.nsec = 0;
 		rq.perout.start.sec = ts.tv_sec + 2;