diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index d1fc7955d4227..43222a34cba06 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -599,6 +599,7 @@ void cpts_unregister(struct cpts *cpts)
 
 	ptp_clock_unregister(cpts->clock);
 	cpts->clock = NULL;
+	cpts->phc_index = -1;
 
 	cpts_write32(cpts, 0, int_enable);
 	cpts_write32(cpts, 0, control);
@@ -784,6 +785,7 @@ struct cpts *cpts_create(struct device *dev, void __iomem *regs,
 	cpts->cc.read = cpts_systim_read;
 	cpts->cc.mask = CLOCKSOURCE_MASK(32);
 	cpts->info = cpts_info;
+	cpts->phc_index = -1;
 
 	if (n_ext_ts)
 		cpts->info.n_ext_ts = n_ext_ts;