net: dsa: microchip: dcb: set default apptrust to PCP only

Before DCB support, the KSZ driver had only PCP as source of packet
priority values. To avoid regressions, make PCP only as default value.
User will need enable DSCP support manually.

This patch do not affect other KSZ8 related quirks. User will still be
warned by setting not support configurations for the port 2.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Acked-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20240510053828.2412516-4-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/dsa/microchip/ksz_dcb.c

@@ -82,10 +82,6 @@ static const u8 ksz_supported_apptrust[] = {
 	IEEE_8021QAZ_APP_SEL_DSCP,
 };
 
-static const u8 ksz8_port2_supported_apptrust[] = {
-	DCB_APP_SEL_PCP,
-};
-
 static const char * const ksz_supported_apptrust_variants[] = {
 	"empty", "dscp", "pcp", "dscp pcp"
 };
@@ -771,9 +767,8 @@ int ksz_port_get_apptrust(struct dsa_switch *ds, int port, u8 *sel, int *nsel)
  */
 int ksz_dcb_init_port(struct ksz_device *dev, int port)
 {
-	const u8 *sel;
+	const u8 ksz_default_apptrust[] = { DCB_APP_SEL_PCP };
 	int ret, ipm;
-	int sel_len;
 
 	if (is_ksz8(dev)) {
 		ipm = ieee8021q_tt_to_tc(IEEE8021Q_TT_BE,
@@ -789,18 +784,8 @@ int ksz_dcb_init_port(struct ksz_device *dev, int port)
 	if (ret)
 		return ret;
 
-	if (ksz_is_ksz88x3(dev) && port == KSZ_PORT_2) {
-		/* KSZ88x3 devices do not support DSCP classification on
-		 * "Port 2.
-		 */
-		sel = ksz8_port2_supported_apptrust;
-		sel_len = ARRAY_SIZE(ksz8_port2_supported_apptrust);
-	} else {
-		sel = ksz_supported_apptrust;
-		sel_len = ARRAY_SIZE(ksz_supported_apptrust);
-	}
-
-	return ksz_port_set_apptrust(dev->ds, port, sel, sel_len);
+	return ksz_port_set_apptrust(dev->ds, port, ksz_default_apptrust,
+				     ARRAY_SIZE(ksz_default_apptrust));
 }
 
 /**