net: mtk_eth_soc: move trgmii ddr2 check to probe function

If TRGMII mode is not permitted when using DDR2 mode, we should handle
that when setting up phylink's ->supported_interfaces so phylink knows
that this is not supported by the hardware. Move this check to
mtk_add_mac().
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -374,17 +374,6 @@ static int mt7621_gmac0_rgmii_adjust(struct mtk_eth *eth,
 {
 	u32 val;
 
-	/* Check DDR memory type.
-	 * Currently TRGMII mode with DDR2 memory is not supported.
-	 */
-	regmap_read(eth->ethsys, ETHSYS_SYSCFG, &val);
-	if (interface == PHY_INTERFACE_MODE_TRGMII &&
-	    val & SYSCFG_DRAM_TYPE_DDR2) {
-		dev_err(eth->dev,
-			"TRGMII mode with DDR2 memory is not supported!\n");
-		return -EOPNOTSUPP;
-	}
-
 	val = (interface == PHY_INTERFACE_MODE_TRGMII) ?
 		ETHSYS_TRGMII_MT7621_DDR_PLL : 0;
 
@@ -4333,6 +4322,7 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 	struct mtk_mac *mac;
 	int id, err;
 	int txqs = 1;
+	u32 val;
 
 	if (!_id) {
 		dev_err(eth->dev, "missing mac id\n");
@@ -4409,6 +4399,15 @@ static int mtk_add_mac(struct mtk_eth *eth, struct device_node *np)
 		__set_bit(PHY_INTERFACE_MODE_TRGMII,
 			  mac->phylink_config.supported_interfaces);
 
+	/* TRGMII is not permitted on MT7621 if using DDR2 */
+	if (MTK_HAS_CAPS(mac->hw->soc->caps, MTK_GMAC1_TRGMII) &&
+	    MTK_HAS_CAPS(mac->hw->soc->caps, MTK_TRGMII_MT7621_CLK)) {
+		regmap_read(eth->ethsys, ETHSYS_SYSCFG, &val);
+		if (val & SYSCFG_DRAM_TYPE_DDR2)
+			__clear_bit(PHY_INTERFACE_MODE_TRGMII,
+				    mac->phylink_config.supported_interfaces);
+	}
+
 	if (MTK_HAS_CAPS(mac->hw->soc->caps, MTK_SGMII)) {
 		__set_bit(PHY_INTERFACE_MODE_SGMII,
 			  mac->phylink_config.supported_interfaces);