diff --git a/drivers/net/dsa/microchip/ksz_ptp.c b/drivers/net/dsa/microchip/ksz_ptp.c
index 35fc21b1ee48..c8bfbe5e2157 100644
--- a/drivers/net/dsa/microchip/ksz_ptp.c
+++ b/drivers/net/dsa/microchip/ksz_ptp.c
@@ -1139,8 +1139,8 @@ int ksz_ptp_irq_setup(struct dsa_switch *ds, u8 p)
 		irq_create_mapping(ptpirq->domain, irq);
 
 	ptpirq->irq_num = irq_find_mapping(port->pirq.domain, PORT_SRC_PTP_INT);
-	if (ptpirq->irq_num < 0) {
-		ret = ptpirq->irq_num;
+	if (!ptpirq->irq_num) {
+		ret = -EINVAL;
 		goto out;
 	}