drivers/net/mdio/acpi_mdio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * ACPI helpers for the MDIO (Ethernet PHY) API
   4  *
   5  * This file provides helper functions for extracting PHY device information
   6  * out of the ACPI ASL and using it to populate an mii_bus.
   7  */
   8
   9 #include <linux/acpi.h>
  10 #include <linux/acpi_mdio.h>
  11 #include <linux/bits.h>
  12 #include <linux/dev_printk.h>
  13 #include <linux/fwnode_mdio.h>
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16
  17 MODULE_AUTHOR("Calvin Johnson <calvin.johnson@oss.nxp.com>");
  18 MODULE_LICENSE("GPL");
  19 MODULE_DESCRIPTION("ACPI MDIO bus (Ethernet PHY) accessors");
  20
  21 /**
  22  * __acpi_mdiobus_register - Register mii_bus and create PHYs from the ACPI ASL.
  23  * @mdio: pointer to mii_bus structure
  24  * @fwnode: pointer to fwnode of MDIO bus. This fwnode is expected to represent
  25  * @owner: module owning this @mdio object.
  26  * an ACPI device object corresponding to the MDIO bus and its children are
  27  * expected to correspond to the PHY devices on that bus.
  28  *
  29  * This function registers the mii_bus structure and registers a phy_device
  30  * for each child node of @fwnode.
  31  */
  32 int __acpi_mdiobus_register(struct mii_bus *mdio, struct fwnode_handle *fwnode,
  33                             struct module *owner)
  34 {
  35         struct fwnode_handle *child;
  36         u32 addr;
  37         int ret;
  38
  39         /* Mask out all PHYs from auto probing. */
  40         mdio->phy_mask = GENMASK(31, 0);
  41         ret = __mdiobus_register(mdio, owner);
  42         if (ret)
  43                 return ret;
  44
  45         ACPI_COMPANION_SET(&mdio->dev, to_acpi_device_node(fwnode));
  46
  47         /* Loop over the child nodes and register a phy_device for each PHY */
  48         fwnode_for_each_child_node(fwnode, child) {
  49                 ret = acpi_get_local_address(ACPI_HANDLE_FWNODE(child), &addr);
  50                 if (ret || addr >= PHY_MAX_ADDR)
  51                         continue;
  52
  53                 ret = fwnode_mdiobus_register_phy(mdio, child, addr);
  54                 if (ret == -ENODEV)
  55                         dev_err(&mdio->dev,
  56                                 "MDIO device at address %d is missing.\n",
  57                                 addr);
  58         }
  59         return 0;
  60 }
  61 EXPORT_SYMBOL(__acpi_mdiobus_register);