From 0de82310d2b32e78ff79d42c08b1122a6ede3778 Mon Sep 17 00:00:00 2001
From: Daniel Golle <daniel@makrotopia.org>
Date: Sun, 30 Apr 2023 00:15:41 +0100
Subject: [PATCH] net: phy: realtek: detect early version of RTL8221B

Early versions (?) of the RTL8221B PHY cannot be identified in a regular
Clause-45 bus scan as the PHY doesn't report the implemented MMDs
correctly but returns 0 instead.
Implement custom identify function using the PKGID instead of iterating
over the implemented MMDs.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
[forward-port by @namiltd]
Signed-off-by: Mieczyslaw Nalewaj <namiltd@yahoo.com>
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -1085,10 +1085,32 @@ static int rtl8226_match_phy_device(stru
 static int rtlgen_is_c45_match(struct phy_device *phydev, unsigned int id,
 			       bool is_c45)
 {
-	if (phydev->is_c45)
-		return is_c45 && (id == phydev->c45_ids.device_ids[1]);
-	else
+	if (phydev->is_c45) {
+		u32 rid;
+
+		if (!is_c45)
+			return 0;
+
+		rid = phydev->c45_ids.device_ids[1];
+		if ((rid == 0xffffffff) && phydev->mdio.bus->read_c45) {
+			int val;
+
+			val = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_PKGID1);
+			if (val < 0)
+				return 0;
+
+			rid = val << 16;
+			val = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_PKGID2);
+			if (val < 0)
+				return 0;
+
+			rid |= val;
+		}
+
+		return (id == rid);
+	} else {
 		return !is_c45 && (id == phydev->phy_id);
+	}
 }
 
 static int rtl8221b_vb_cg_c22_match_phy_device(struct phy_device *phydev)