generic: 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 to work-around this problem.

Signed-off-by: Daniel Golle <[email protected]>

target/linux/generic/pending-5.15/730-net-phy-realtek-detect-early-version-of-RTL8221B.patch

@@ -0,0 +1,63 @@
+From 0de82310d2b32e78ff79d42c08b1122a6ede3778 Mon Sep 17 00:00:00 2001
+From: Daniel Golle <[email protected]>
+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 <[email protected]>
+
+--- a/drivers/net/phy/realtek.c
++++ b/drivers/net/phy/realtek.c
+@@ -744,6 +744,38 @@ static int rtl8226_match_phy_device(stru
+ 	       rtlgen_supports_2_5gbps(phydev);
+ }
+ 
++static int rtl8221b_vb_cg_match_phy_device(struct phy_device *phydev)
++{
++	int val;
++	u32 id;
++
++	if (phydev->mdio.bus->probe_capabilities >= MDIOBUS_C45) {
++		val = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_PKGID1);
++		if (val < 0)
++			return 0;
++
++		id = val << 16;
++		val = phy_read_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_PKGID2);
++		if (val < 0)
++			return 0;
++
++		id |= val;
++	} else {
++		val = phy_read(phydev, MII_PHYSID1);
++		if (val < 0)
++			return 0;
++
++		id = val << 16;
++		val = phy_read(phydev, MII_PHYSID2);
++		if (val < 0)
++			return 0;
++
++		id |= val;
++	}
++
++	return (id == 0x001cc849);
++}
++
+ static int rtl822x_probe(struct phy_device *phydev)
+ {
+ 	struct device *dev = &phydev->mdio.dev;
+@@ -1084,7 +1116,7 @@ static struct phy_driver realtek_drvs[]
+ 		.write_page     = rtl821x_write_page,
+ 		.soft_reset     = genphy_soft_reset,
+ 	}, {
+-		PHY_ID_MATCH_EXACT(0x001cc849),
++		.match_phy_device = rtl8221b_vb_cg_match_phy_device,
+ 		.name           = "RTL8221B-VB-CG 2.5Gbps PHY",
+ 		.get_features   = rtl822x_get_features,
+ 		.config_init    = rtl8221b_config_init,