[PATCH 1/2] net: phy: realtek: add combo mode support for RTL8211FS

[Zhiyuan Wan <kmlinuxm@gmail.com>]

The RTL8211FS chip is an ethernet transceiver with both copper MDIX and
optical (SGMII) port, and it has ability to switch between copper and
optical mode (combo mode).

On Linux kernel v6.12.1, the driver doesn't support negotiation port mode,
which causes optical mode unusable, and copper mode works fine.

This patch solved the issue above by add negotiation phase for this
transceiver chip, allows this transceiver works in combo mode.

Signed-off-by: Yuki Lee <febrieac@outlook.com>
Signed-off-by: Zhiyuan Wan <kmlinuxm@gmail.com>
---
 drivers/net/phy/realtek.c | 67 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 66 insertions(+), 1 deletion(-)

diff --git a/drivers/net/phy/realtek.c b/drivers/net/phy/realtek.c
index f65d7f1f3..10a87d58c 100644
--- a/drivers/net/phy/realtek.c
+++ b/drivers/net/phy/realtek.c
@@ -32,6 +32,11 @@
 #define RTL8211F_PHYCR2				0x19
 #define RTL8211F_INSR				0x1d
 
+#define RTL8211FS_FIBER_ESR			0x0F
+#define RTL8211FS_MODE_MASK			0xC000
+#define RTL8211FS_MODE_COPPER			0
+#define RTL8211FS_MODE_FIBER			1
+
 #define RTL8211F_LEDCR				0x10
 #define RTL8211F_LEDCR_MODE			BIT(15)
 #define RTL8211F_LEDCR_ACT_TXRX			BIT(4)
@@ -110,6 +115,7 @@ struct rtl821x_priv {
 	u16 phycr1;
 	u16 phycr2;
 	bool has_phycr2;
+	int lastmode;
 	struct clk *clk;
 };
 
@@ -163,6 +169,44 @@ static int rtl821x_probe(struct phy_device *phydev)
 	return 0;
 }
 
+static int rtl8211f_mode(struct phy_device *phydev)
+{
+	u16 val;
+
+	val = __phy_read(phydev, RTL8211FS_FIBER_ESR);
+	val &= RTL8211FS_MODE_MASK;
+
+	if (val)
+		return RTL8211FS_MODE_FIBER;
+	else
+		return RTL8211FS_MODE_COPPER;
+}
+
+static int rtl8211f_config_aneg(struct phy_device *phydev)
+{
+	int ret;
+
+	struct rtl821x_priv *priv = phydev->priv;
+
+	ret = genphy_read_abilities(phydev);
+	if (ret < 0)
+		return ret;
+
+	linkmode_copy(phydev->advertising, phydev->supported);
+
+	if (rtl8211f_mode(phydev) == RTL8211FS_MODE_FIBER) {
+		dev_dbg(&phydev->mdio.dev, "fiber link up");
+		priv->lastmode = RTL8211FS_MODE_FIBER;
+		return genphy_c37_config_aneg(phydev);
+	}
+
+	dev_dbg(&phydev->mdio.dev, "copper link up");
+
+	priv->lastmode = RTL8211FS_MODE_COPPER;
+
+	return genphy_config_aneg(phydev);
+}
+
 static int rtl8201_ack_interrupt(struct phy_device *phydev)
 {
 	int err;
@@ -732,6 +776,26 @@ static int rtlgen_read_status(struct phy_device *phydev)
 	return 0;
 }
 
+static int rtl8211f_read_status(struct phy_device *phydev)
+{
+	int ret;
+	struct rtl821x_priv *priv = phydev->priv;
+	bool changed = false;
+
+	if (rtl8211f_mode(phydev) != priv->lastmode) {
+		changed = true;
+		ret = rtl8211f_config_aneg(phydev);
+		if (ret < 0)
+			return ret;
+
+		ret = genphy_restart_aneg(phydev);
+		if (ret < 0)
+			return ret;
+	}
+
+	return genphy_c37_read_status(phydev, &changed);
+}
+
 static int rtlgen_read_mmd(struct phy_device *phydev, int devnum, u16 regnum)
 {
 	int ret;
@@ -1375,7 +1439,8 @@ static struct phy_driver realtek_drvs[] = {
 		.name		= "RTL8211F Gigabit Ethernet",
 		.probe		= rtl821x_probe,
 		.config_init	= &rtl8211f_config_init,
-		.read_status	= rtlgen_read_status,
+		.config_aneg	= rtl8211f_config_aneg,
+		.read_status	= rtl8211f_read_status,
 		.config_intr	= &rtl8211f_config_intr,
 		.handle_interrupt = rtl8211f_handle_interrupt,
 		.suspend	= rtl821x_suspend,
-- 
2.30.2