On 1/4/2026 6:42 PM, Daniel Golle wrote:

+static int rtl822xb_read_mmd(struct phy_device *phydev, int devnum, u16 reg)
+{
+	int oldpage, ret, read_ret;
+	u16 page;
+
+	/* Use Clause-45 bus access in case it is available */
+	if (phydev->is_c45)
+		return __mdiobus_c45_read(phydev->mdio.bus, phydev->mdio.addr,
+					  devnum, mmdreg);
+

mmdreg is not defined.

+	/* Use indirect access via MII_MMD_CTRL and MII_MMD_DATA for all
+	 * MMDs except MDIO_MMD_VEND2
+	 */
+	if (devnum != MDIO_MMD_VEND2) {
+		__mdiobus_write(phydev->mdio.bus, phydev->mdio.addr,
+				MII_MMD_CTRL, devnum);
+		__mdiobus_write(phydev->mdio.bus, phydev->mdio.addr,
+				MII_MMD_DATA, mmdreg);
+		__mdiobus_write(phydev->mdio.bus, phydev->mdio.addr,
+				MII_MMD_CTRL, devnum | MII_MMD_CTRL_NOINCR);
+
+		return __mdiobus_read(phydev->mdio.bus, phydev->mdio.addr,
+				       MII_MMD_DATA);
+	}
+
+	/* Use paged access for MDIO_MMD_VEND2 over Clause-22 */
+	page = RTL822X_VND2_TO_PAGE(reg);
+	oldpage = __phy_read(phydev, RTL821x_PAGE_SELECT);
+	if (oldpage < 0)
+		return ret;
+
+	if (oldpage != page) {
+		ret = __phy_write(phydev, RTL821x_PAGE_SELECT, page);
+		if (ret < 0)
+			return ret;
+	}
+
+	read_ret = __phy_read(phydev, RTL822X_VND2_TO_PAGE_REG(reg));
+	if (oldpage != page) {
+		ret = __phy_write(phydev, RTL821x_PAGE_SELECT, oldpage);
+		if (ret < 0)
+			return ret;
+	}
+
+	return read_ret;
+}

Thanks,
Alok