+static int
+mt7531_ind_mmd_phy_read(struct mt7530_priv *priv, int port, int devad,
+			int regnum)
+{
+	struct mii_bus *bus = priv->bus;
+	struct mt7530_dummy_poll p;
+	u32 reg, val;
+	int ret;
+
+	INIT_MT7530_DUMMY_POLL(&p, priv, MT7531_PHY_IAC);
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+
+	ret = readx_poll_timeout(_mt7530_unlocked_read, &p, val,
+				 !(val & PHY_ACS_ST), 20, 100000);
+	if (ret < 0) {
+		dev_err(priv->dev, "poll timeout\n");
+		goto out;
+	}
+
+	reg = MDIO_CL45_ADDR | MDIO_PHY_ADDR(port) | MDIO_DEV_ADDR(devad) |
+	      regnum;

It might be better to call this mt7531_ind_c45_phy_read()

+static int
+mt7531_ind_phy_read(struct dsa_switch *ds, int port, int regnum)
+{
+	struct mt7530_priv *priv = ds->priv;
+	struct mii_bus *bus = priv->bus;
+	struct mt7530_dummy_poll p;
+	int ret;
+	u32 val;
+
+	INIT_MT7530_DUMMY_POLL(&p, priv, MT7531_PHY_IAC);
+
+	mutex_lock_nested(&bus->mdio_lock, MDIO_MUTEX_NESTED);
+
+	ret = readx_poll_timeout(_mt7530_unlocked_read, &p, val,
+				 !(val & PHY_ACS_ST), 20, 100000);
+	if (ret < 0) {
+		dev_err(priv->dev, "poll timeout\n");
+		goto out;
+	}
+
+	val = MDIO_CL22_READ | MDIO_PHY_ADDR(port) | MDIO_REG_ADDR(regnum);

This is then mt7531_ind_c22_phy_read().

And then you can add a wrapper around this to provide

mt7531_phy_read() which can do both C22 and C45.

+	[ID_MT7531] = {
+		.id = ID_MT7531,
+		.setup = mt7531_setup,
+		.phy_read = mt7531_ind_phy_read,

and use it here.

  Andrew