net: dsa: microchip: parse PHY config from device tree

Introduce ksz_parse_dt_phy_config() to validate and parse PHY
configuration from the device tree for KSZ switches. This function
ensures proper setup of internal PHYs by checking `phy-handle`
properties, verifying expected PHY IDs, and handling parent node
mismatches. Sets the PHY mask on the MII bus if validation is
successful. Returns -EINVAL on configuration errors.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Link: https://patch.msgid.link/20241106075942.1636998-7-o.rempel@pengutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 19fb090c09ab7d07db0e7c43cefaa241c12813c4..d57782cdda599ee53cd233974c67bfe305230181 100644 (file)
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -2371,6 +2371,76 @@ static void ksz_irq_phy_free(struct ksz_device *dev)
                        irq_dispose_mapping(ds->user_mii_bus->irq[phy]);
 }
 
+/**
+ * ksz_parse_dt_phy_config - Parse and validate PHY configuration from DT
+ * @dev: pointer to the KSZ device structure
+ * @bus: pointer to the MII bus structure
+ * @mdio_np: pointer to the MDIO node in the device tree
+ *
+ * This function parses and validates PHY configurations for each user port
+ * defined in the device tree for a KSZ switch device. It verifies that the
+ * `phy-handle` properties are correctly set and that the internal PHYs match
+ * expected addresses and parent nodes. Sets up the PHY mask in the MII bus if
+ * all validations pass. Logs error messages for any mismatches or missing data.
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+static int ksz_parse_dt_phy_config(struct ksz_device *dev, struct mii_bus *bus,
+                                  struct device_node *mdio_np)
+{
+       struct device_node *phy_node, *phy_parent_node;
+       bool phys_are_valid = true;
+       struct dsa_port *dp;
+       u32 phy_addr;
+       int ret;
+
+       dsa_switch_for_each_user_port(dp, dev->ds) {
+               if (!dev->info->internal_phy[dp->index])
+                       continue;
+
+               phy_node = of_parse_phandle(dp->dn, "phy-handle", 0);
+               if (!phy_node) {
+                       dev_err(dev->dev, "failed to parse phy-handle for port %d.\n",
+                               dp->index);
+                       phys_are_valid = false;
+                       continue;
+               }
+
+               phy_parent_node = of_get_parent(phy_node);
+               if (!phy_parent_node) {
+                       dev_err(dev->dev, "failed to get PHY-parent node for port %d\n",
+                               dp->index);
+                       phys_are_valid = false;
+               } else if (phy_parent_node != mdio_np) {
+                       dev_err(dev->dev, "PHY-parent node mismatch for port %d, expected %pOF, got %pOF\n",
+                               dp->index, mdio_np, phy_parent_node);
+                       phys_are_valid = false;
+               } else {
+                       ret = of_property_read_u32(phy_node, "reg", &phy_addr);
+                       if (ret < 0) {
+                               dev_err(dev->dev, "failed to read PHY address for port %d. Error %d\n",
+                                       dp->index, ret);
+                               phys_are_valid = false;
+                       } else if (phy_addr != dev->phy_addr_map[dp->index]) {
+                               dev_err(dev->dev, "PHY address mismatch for port %d, expected 0x%x, got 0x%x\n",
+                                       dp->index, dev->phy_addr_map[dp->index],
+                                       phy_addr);
+                               phys_are_valid = false;
+                       } else {
+                               bus->phy_mask |= BIT(phy_addr);
+                       }
+               }
+
+               of_node_put(phy_node);
+               of_node_put(phy_parent_node);
+       }
+
+       if (!phys_are_valid)
+               return -EINVAL;
+
+       return 0;
+}
+
 /**
  * ksz_mdio_register - Register and configure the MDIO bus for the KSZ device.
  * @dev: Pointer to the KSZ device structure.
@@ -2390,7 +2460,6 @@ static int ksz_mdio_register(struct ksz_device *dev)
        struct dsa_switch *ds = dev->ds;
        struct device_node *mdio_np;
        struct mii_bus *bus;
-       struct dsa_port *dp;
        int ret, i;
 
        mdio_np = of_get_child_by_name(dev->dev->of_node, "mdio");
@@ -2449,11 +2518,9 @@ static int ksz_mdio_register(struct ksz_device *dev)
                snprintf(bus->id, MII_BUS_ID_SIZE, "SMI-%d", ds->index);
        }
 
-       dsa_switch_for_each_user_port(dp, dev->ds) {
-               if (dev->info->internal_phy[dp->index] &&
-                   dev->phy_addr_map[dp->index] < PHY_MAX_ADDR)
-                       bus->phy_mask |= BIT(dev->phy_addr_map[dp->index]);
-       }
+       ret = ksz_parse_dt_phy_config(dev, bus, mdio_np);
+       if (ret)
+               goto put_mdio_node;
 
        ds->phys_mii_mask = bus->phy_mask;
        bus->parent = ds->dev;