diff --git a/net/dsa/tag_rtl4_a.c b/net/dsa/tag_rtl4_a.c
index 57c46b4ab2b3..e34b80fa52e1 100644
--- a/net/dsa/tag_rtl4_a.c
+++ b/net/dsa/tag_rtl4_a.c
@@ -54,9 +54,10 @@ static struct sk_buff *rtl4a_tag_xmit(struct sk_buff *skb,
 	p = (__be16 *)tag;
 	*p = htons(RTL4_A_ETHERTYPE);
 
-	out = (RTL4_A_PROTOCOL_RTL8366RB << 12) | (2 << 8);
-	/* The lower bits is the port number */
-	out |= (u8)dp->index;
+	out = (RTL4_A_PROTOCOL_RTL8366RB << RTL4_A_PROTOCOL_SHIFT) | (2 << 8);
+	/* The lower bits indicate the port number */
+	out |= BIT(dp->index);
+
 	p = (__be16 *)(tag + 2);
 	*p = htons(out);