net: phy: tja11xx: add interface mode and RMII REF_CLK support

Add below features support for both TJA1100 and TJA1101 cards:
- Add MII and RMII mode support.
- Add REF_CLK input/output support for RMII mode.

Signed-off-by: Wei Fang <wei.fang@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/nxp-tja11xx.c

@@ -10,6 +10,7 @@
 #include <linux/mdio.h>
 #include <linux/mii.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/phy.h>
 #include <linux/hwmon.h>
 #include <linux/bitfield.h>
@@ -34,6 +35,11 @@
 #define MII_CFG1			18
 #define MII_CFG1_MASTER_SLAVE		BIT(15)
 #define MII_CFG1_AUTO_OP		BIT(14)
+#define MII_CFG1_INTERFACE_MODE_MASK	GENMASK(9, 8)
+#define MII_CFG1_MII_MODE				(0x0 << 8)
+#define MII_CFG1_RMII_MODE_REFCLK_IN	BIT(8)
+#define MII_CFG1_RMII_MODE_REFCLK_OUT	BIT(9)
+#define MII_CFG1_REVMII_MODE			GENMASK(9, 8)
 #define MII_CFG1_SLEEP_CONFIRM		BIT(6)
 #define MII_CFG1_LED_MODE_MASK		GENMASK(5, 4)
 #define MII_CFG1_LED_MODE_LINKUP	0
@@ -72,11 +78,15 @@
 #define MII_COMMCFG			27
 #define MII_COMMCFG_AUTO_OP		BIT(15)
 
+/* Configure REF_CLK as input in RMII mode */
+#define TJA110X_RMII_MODE_REFCLK_IN       BIT(0)
+
 struct tja11xx_priv {
 	char		*hwmon_name;
 	struct device	*hwmon_dev;
 	struct phy_device *phydev;
 	struct work_struct phy_register_work;
+	u32 flags;
 };
 
 struct tja11xx_phy_stats {
@@ -251,8 +261,34 @@ static int tja11xx_config_aneg(struct phy_device *phydev)
 	return __genphy_config_aneg(phydev, changed);
 }
 
+static int tja11xx_get_interface_mode(struct phy_device *phydev)
+{
+	struct tja11xx_priv *priv = phydev->priv;
+	int mii_mode;
+
+	switch (phydev->interface) {
+	case PHY_INTERFACE_MODE_MII:
+		mii_mode = MII_CFG1_MII_MODE;
+		break;
+	case PHY_INTERFACE_MODE_REVMII:
+		mii_mode = MII_CFG1_REVMII_MODE;
+		break;
+	case PHY_INTERFACE_MODE_RMII:
+		if (priv->flags & TJA110X_RMII_MODE_REFCLK_IN)
+			mii_mode = MII_CFG1_RMII_MODE_REFCLK_IN;
+		else
+			mii_mode = MII_CFG1_RMII_MODE_REFCLK_OUT;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return mii_mode;
+}
+
 static int tja11xx_config_init(struct phy_device *phydev)
 {
+	u16 reg_mask, reg_val;
 	int ret;
 
 	ret = tja11xx_enable_reg_write(phydev);
@@ -265,15 +301,32 @@ static int tja11xx_config_init(struct phy_device *phydev)
 
 	switch (phydev->phy_id & PHY_ID_MASK) {
 	case PHY_ID_TJA1100:
-		ret = phy_modify(phydev, MII_CFG1,
-				 MII_CFG1_AUTO_OP | MII_CFG1_LED_MODE_MASK |
-				 MII_CFG1_LED_ENABLE,
-				 MII_CFG1_AUTO_OP | MII_CFG1_LED_MODE_LINKUP |
-				 MII_CFG1_LED_ENABLE);
+		reg_mask = MII_CFG1_AUTO_OP | MII_CFG1_LED_MODE_MASK |
+			   MII_CFG1_LED_ENABLE;
+		reg_val = MII_CFG1_AUTO_OP | MII_CFG1_LED_MODE_LINKUP |
+			  MII_CFG1_LED_ENABLE;
+
+		reg_mask |= MII_CFG1_INTERFACE_MODE_MASK;
+		ret = tja11xx_get_interface_mode(phydev);
+		if (ret < 0)
+			return ret;
+
+		reg_val |= (ret & 0xffff);
+		ret = phy_modify(phydev, MII_CFG1, reg_mask, reg_val);
 		if (ret)
 			return ret;
 		break;
 	case PHY_ID_TJA1101:
+		reg_mask = MII_CFG1_INTERFACE_MODE_MASK;
+		ret = tja11xx_get_interface_mode(phydev);
+		if (ret < 0)
+			return ret;
+
+		reg_val = ret & 0xffff;
+		ret = phy_modify(phydev, MII_CFG1, reg_mask, reg_val);
+		if (ret)
+			return ret;
+		fallthrough;
 	case PHY_ID_TJA1102:
 		ret = phy_set_bits(phydev, MII_COMMCFG, MII_COMMCFG_AUTO_OP);
 		if (ret)
@@ -458,16 +511,36 @@ static int tja11xx_hwmon_register(struct phy_device *phydev,
 	return PTR_ERR_OR_ZERO(priv->hwmon_dev);
 }
 
+static int tja11xx_parse_dt(struct phy_device *phydev)
+{
+	struct device_node *node = phydev->mdio.dev.of_node;
+	struct tja11xx_priv *priv = phydev->priv;
+
+	if (!IS_ENABLED(CONFIG_OF_MDIO))
+		return 0;
+
+	if (of_property_read_bool(node, "nxp,rmii-refclk-in"))
+		priv->flags |= TJA110X_RMII_MODE_REFCLK_IN;
+
+	return 0;
+}
+
 static int tja11xx_probe(struct phy_device *phydev)
 {
 	struct device *dev = &phydev->mdio.dev;
 	struct tja11xx_priv *priv;
+	int ret;
 
 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;
 
 	priv->phydev = phydev;
+	phydev->priv = priv;
+
+	ret = tja11xx_parse_dt(phydev);
+	if (ret)
+		return ret;
 
 	return tja11xx_hwmon_register(phydev, priv);
 }