diff --git a/drivers/net/ethernet/ti/cpts.c b/drivers/net/ethernet/ti/cpts.c
index 23c953496a0d..9e7e7e8a018d 100644
--- a/drivers/net/ethernet/ti/cpts.c
+++ b/drivers/net/ethernet/ti/cpts.c
@@ -471,6 +471,7 @@ 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);
@@ -572,6 +573,7 @@ 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;
 
 	cpts_calc_mult_shift(cpts);
 	/* save cc.mult original value as it can be modified