net: phy: realtek: add NBase-T PHY auto-detection

Realtek provided information on how the new NIC-integrated PHY's
expose whether they support 2.5G/5G/10G. This allows to automatically
differentiate 1Gbps and 2.5Gbps PHY's, and therefore allows to
remove the fake PHY ID mechanism for RTL8125.
So far RTL8125 supports 2.5Gbps only, but register layout for faster
modes has been defined already, so let's use this information to be
future-proof.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/phy/realtek.c

@@ -39,11 +39,16 @@
 #define RTL8366RB_POWER_SAVE			0x15
 #define RTL8366RB_POWER_SAVE_ON			BIT(12)
 
+#define RTL_SUPPORTS_5000FULL			BIT(14)
+#define RTL_SUPPORTS_2500FULL			BIT(13)
+#define RTL_SUPPORTS_10000FULL			BIT(0)
 #define RTL_ADV_2500FULL			BIT(7)
 #define RTL_LPADV_10000FULL			BIT(11)
 #define RTL_LPADV_5000FULL			BIT(6)
 #define RTL_LPADV_2500FULL			BIT(5)
 
+#define RTL_GENERIC_PHYID			0x001cc800
+
 MODULE_DESCRIPTION("Realtek PHY driver");
 MODULE_AUTHOR("Johnson Leung");
 MODULE_LICENSE("GPL");
@@ -263,8 +268,18 @@ static int rtl8366rb_config_init(struct phy_device *phydev)
 
 static int rtl8125_get_features(struct phy_device *phydev)
 {
-	linkmode_set_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
-			 phydev->supported);
+	int val;
+
+	val = phy_read_paged(phydev, 0xa61, 0x13);
+	if (val < 0)
+		return val;
+
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_2500baseT_Full_BIT,
+			 phydev->supported, val & RTL_SUPPORTS_2500FULL);
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_5000baseT_Full_BIT,
+			 phydev->supported, val & RTL_SUPPORTS_5000FULL);
+	linkmode_mod_bit(ETHTOOL_LINK_MODE_10000baseT_Full_BIT,
+			 phydev->supported, val & RTL_SUPPORTS_10000FULL);
 
 	return genphy_read_abilities(phydev);
 }
@@ -308,6 +323,29 @@ static int rtl8125_read_status(struct phy_device *phydev)
 	return genphy_read_status(phydev);
 }
 
+static bool rtlgen_supports_2_5gbps(struct phy_device *phydev)
+{
+	int val;
+
+	phy_write(phydev, RTL821x_PAGE_SELECT, 0xa61);
+	val = phy_read(phydev, 0x13);
+	phy_write(phydev, RTL821x_PAGE_SELECT, 0);
+
+	return val >= 0 && val & RTL_SUPPORTS_2500FULL;
+}
+
+static int rtlgen_match_phy_device(struct phy_device *phydev)
+{
+	return phydev->phy_id == RTL_GENERIC_PHYID &&
+	       !rtlgen_supports_2_5gbps(phydev);
+}
+
+static int rtl8125_match_phy_device(struct phy_device *phydev)
+{
+	return phydev->phy_id == RTL_GENERIC_PHYID &&
+	       rtlgen_supports_2_5gbps(phydev);
+}
+
 static struct phy_driver realtek_drvs[] = {
 	{
 		PHY_ID_MATCH_EXACT(0x00008201),
@@ -378,15 +416,15 @@ static struct phy_driver realtek_drvs[] = {
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
 	}, {
-		PHY_ID_MATCH_EXACT(0x001cc800),
-		.name		= "Generic Realtek PHY",
+		.name		= "Generic FE-GE Realtek PHY",
+		.match_phy_device = rtlgen_match_phy_device,
 		.suspend	= genphy_suspend,
 		.resume		= genphy_resume,
 		.read_page	= rtl821x_read_page,
 		.write_page	= rtl821x_write_page,
 	}, {
-		PHY_ID_MATCH_EXACT(0x001cca50),
 		.name		= "RTL8125 2.5Gbps internal",
+		.match_phy_device = rtl8125_match_phy_device,
 		.get_features	= rtl8125_get_features,
 		.config_aneg	= rtl8125_config_aneg,
 		.read_status	= rtl8125_read_status,