[PATCH net 2/2] net: ti: icssg-prueth: Fix clearing of IEP_CMP_CFG registers during iep_init

[Meghana Malladi <m-malladi@ti.com>]

When ICSSG interfaces are brought down and brought up again, the
pru cores are shut down and booted again, flushing out all the memories
and start again in a clean state. Hence it is expected that the
IEP_CMP_CFG register needs to be flushed during iep_init() to ensure
that the existing residual configuration doesn't cause any unusual
behavior. If the register is not cleared, existing IEP_CMP_CFG set for
CMP1 will result in SYNC0_OUT signal based on the SYNC_OUT register values.

After bringing the interface up, calling PPS enable doesn't work as
the driver believes PPS is already enabled, (iep->pps_enabled is not
cleared during interface bring down) and driver  will just return true
even though there is no signal. Fix this by setting the iep->pps_enable
and iep->perout_enable flags to false during the link down.

Fixes: c1e0230eeaab ("net: ti: icss-iep: Add IEP driver")
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
---
 drivers/net/ethernet/ti/icssg/icss_iep.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/ti/icssg/icss_iep.c b/drivers/net/ethernet/ti/icssg/icss_iep.c
index 5d6d1cf78e93..03abc25ced12 100644
--- a/drivers/net/ethernet/ti/icssg/icss_iep.c
+++ b/drivers/net/ethernet/ti/icssg/icss_iep.c
@@ -195,6 +195,12 @@ static void icss_iep_enable_shadow_mode(struct icss_iep *iep)
 
 	icss_iep_disable(iep);
 
+	/* clear compare config */
+	for (cmp = IEP_MIN_CMP; cmp < IEP_MAX_CMP; cmp++) {
+		regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
+				   IEP_CMP_CFG_CMP_EN(cmp), 0);
+	}
+
 	/* disable shadow mode */
 	regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
 			   IEP_CMP_CFG_SHADOW_EN, 0);
@@ -778,6 +784,10 @@ int icss_iep_exit(struct icss_iep *iep)
 		ptp_clock_unregister(iep->ptp_clock);
 		iep->ptp_clock = NULL;
 	}
+
+	iep->pps_enabled = false;
+	iep->perout_enabled = false;
+
 	icss_iep_disable(iep);
 
 	return 0;
-- 
2.25.1