net: phy: microchip_t1s: add support for Microchip LAN867X Rev.D0 PHY

Add support for the LAN8670/1/2 Rev.D0 10BASE-T1S PHYs from Microchip.
The new Rev.D0 silicon requires a specific set of initialization
settings to be configured for optimal performance and compliance with
OPEN Alliance specifications, as described in Microchip Application Note
AN1699 (Revision G, DS60001699G – October 2025).
https://www.microchip.com/en-us/application-notes/an1699

Signed-off-by: Parthiban Veerasooran <parthiban.veerasooran@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20251030102258.180061-2-parthiban.veerasooran@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/Kconfig

@@ -308,7 +308,7 @@ config MICREL_PHY
 config MICROCHIP_T1S_PHY
 	tristate "Microchip 10BASE-T1S Ethernet PHYs"
 	help
-	  Currently supports the LAN8670/1/2 Rev.B1/C1/C2 and
+	  Currently supports the LAN8670/1/2 Rev.B1/C1/C2/D0 and
 	  LAN8650/1 Rev.B0/B1 Internal PHYs.
 
 config MICROCHIP_PHY

drivers/net/phy/microchip_t1s.c

@@ -3,7 +3,7 @@
  * Driver for Microchip 10BASE-T1S PHYs
  *
  * Support: Microchip Phys:
- *  lan8670/1/2 Rev.B1/C1/C2
+ *  lan8670/1/2 Rev.B1/C1/C2/D0
  *  lan8650/1 Rev.B0/B1 Internal PHYs
  */
 
@@ -14,6 +14,7 @@
 #define PHY_ID_LAN867X_REVB1 0x0007C162
 #define PHY_ID_LAN867X_REVC1 0x0007C164
 #define PHY_ID_LAN867X_REVC2 0x0007C165
+#define PHY_ID_LAN867X_REVD0 0x0007C166
 /* Both Rev.B0 and B1 clause 22 PHYID's are same due to B1 chip limitation */
 #define PHY_ID_LAN865X_REVB 0x0007C1B3
 
@@ -109,6 +110,21 @@ static const u16 lan865x_revb_sqi_fixup_cfg_regs[3] = {
 	0x00AD, 0x00AE, 0x00AF,
 };
 
+/* LAN867x Rev.D0 configuration parameters from AN1699
+ * As per the Configuration Application Note AN1699 published in the below link,
+ * https://www.microchip.com/en-us/application-notes/an1699
+ * Revision G (DS60001699G - October 2025)
+ */
+static const u16 lan867x_revd0_fixup_regs[8] = {
+	0x0037, 0x008A, 0x0118, 0x00D6,
+	0x0082, 0x00FD, 0x00FD, 0x0091,
+};
+
+static const u16 lan867x_revd0_fixup_values[8] = {
+	0x0800, 0xBFC0, 0x029C, 0x1001,
+	0x001C, 0x0C0B, 0x8C07, 0x9660,
+};
+
 /* Pulled from AN1760 describing 'indirect read'
  *
  * write_register(0x4, 0x00D8, addr)
@@ -407,6 +423,25 @@ static int lan86xx_plca_set_cfg(struct phy_device *phydev,
 			      COL_DET_CTRL0_ENABLE_BIT_MASK, COL_DET_ENABLE);
 }
 
+static int lan867x_revd0_config_init(struct phy_device *phydev)
+{
+	int ret;
+
+	ret = lan867x_check_reset_complete(phydev);
+	if (ret)
+		return ret;
+
+	for (int i = 0; i < ARRAY_SIZE(lan867x_revd0_fixup_regs); i++) {
+		ret = phy_write_mmd(phydev, MDIO_MMD_VEND2,
+				    lan867x_revd0_fixup_regs[i],
+				    lan867x_revd0_fixup_values[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 static int lan86xx_read_status(struct phy_device *phydev)
 {
 	/* The phy has some limitations, namely:
@@ -481,6 +516,15 @@ static struct phy_driver microchip_t1s_driver[] = {
 		.set_plca_cfg	    = lan86xx_plca_set_cfg,
 		.get_plca_status    = genphy_c45_plca_get_status,
 	},
+	{
+		PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVD0),
+		.name               = "LAN867X Rev.D0",
+		.features           = PHY_BASIC_T1S_P2MP_FEATURES,
+		.config_init        = lan867x_revd0_config_init,
+		.get_plca_cfg	    = genphy_c45_plca_get_cfg,
+		.set_plca_cfg	    = lan86xx_plca_set_cfg,
+		.get_plca_status    = genphy_c45_plca_get_status,
+	},
 	{
 		PHY_ID_MATCH_EXACT(PHY_ID_LAN865X_REVB),
 		.name               = "LAN865X Rev.B0/B1 Internal Phy",
@@ -501,6 +545,7 @@ static const struct mdio_device_id __maybe_unused tbl[] = {
 	{ PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVB1) },
 	{ PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVC1) },
 	{ PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVC2) },
+	{ PHY_ID_MATCH_EXACT(PHY_ID_LAN867X_REVD0) },
 	{ PHY_ID_MATCH_EXACT(PHY_ID_LAN865X_REVB) },
 	{ }
 };