drivers/net/mdio/mdio-mux-bcm6368.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Broadcom BCM6368 mdiomux bus controller driver
   4  *
   5  * Copyright (C) 2021 Álvaro Fernández Rojas <noltari@gmail.com>
   6  */
   7
   8 #include <linux/delay.h>
   9 #include <linux/io.h>
  10 #include <linux/kernel.h>
  11 #include <linux/mdio-mux.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/of_platform.h>
  15 #include <linux/of_mdio.h>
  16 #include <linux/phy.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/sched.h>
  19
  20 #define MDIOC_REG               0x0
  21 #define MDIOC_EXT_MASK          BIT(16)
  22 #define MDIOC_REG_SHIFT         20
  23 #define MDIOC_PHYID_SHIFT       25
  24 #define MDIOC_RD_MASK           BIT(30)
  25 #define MDIOC_WR_MASK           BIT(31)
  26
  27 #define MDIOD_REG               0x4
  28
  29 struct bcm6368_mdiomux_desc {
  30         void *mux_handle;
  31         void __iomem *base;
  32         struct device *dev;
  33         struct mii_bus *mii_bus;
  34         int ext_phy;
  35 };
  36
  37 static int bcm6368_mdiomux_read(struct mii_bus *bus, int phy_id, int loc)
  38 {
  39         struct bcm6368_mdiomux_desc *md = bus->priv;
  40         uint32_t reg;
  41         int ret;
  42
  43         __raw_writel(0, md->base + MDIOC_REG);
  44
  45         reg = MDIOC_RD_MASK |
  46               (phy_id << MDIOC_PHYID_SHIFT) |
  47               (loc << MDIOC_REG_SHIFT);
  48         if (md->ext_phy)
  49                 reg |= MDIOC_EXT_MASK;
  50
  51         __raw_writel(reg, md->base + MDIOC_REG);
  52         udelay(50);
  53         ret = __raw_readw(md->base + MDIOD_REG);
  54
  55         return ret;
  56 }
  57
  58 static int bcm6368_mdiomux_write(struct mii_bus *bus, int phy_id, int loc,
  59                                  uint16_t val)
  60 {
  61         struct bcm6368_mdiomux_desc *md = bus->priv;
  62         uint32_t reg;
  63
  64         __raw_writel(0, md->base + MDIOC_REG);
  65
  66         reg = MDIOC_WR_MASK |
  67               (phy_id << MDIOC_PHYID_SHIFT) |
  68               (loc << MDIOC_REG_SHIFT);
  69         if (md->ext_phy)
  70                 reg |= MDIOC_EXT_MASK;
  71         reg |= val;
  72
  73         __raw_writel(reg, md->base + MDIOC_REG);
  74         udelay(50);
  75
  76         return 0;
  77 }
  78
  79 static int bcm6368_mdiomux_switch_fn(int current_child, int desired_child,
  80                                      void *data)
  81 {
  82         struct bcm6368_mdiomux_desc *md = data;
  83
  84         md->ext_phy = desired_child;
  85
  86         return 0;
  87 }
  88
  89 static int bcm6368_mdiomux_probe(struct platform_device *pdev)
  90 {
  91         struct bcm6368_mdiomux_desc *md;
  92         struct mii_bus *bus;
  93         struct resource *res;
  94         int rc;
  95
  96         md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
  97         if (!md)
  98                 return -ENOMEM;
  99         md->dev = &pdev->dev;
 100
 101         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 102         if (!res)
 103                 return -EINVAL;
 104
 105         /*
 106          * Just ioremap, as this MDIO block is usually integrated into an
 107          * Ethernet MAC controller register range
 108          */
 109         md->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 110         if (!md->base) {
 111                 dev_err(&pdev->dev, "failed to ioremap register\n");
 112                 return -ENOMEM;
 113         }
 114
 115         md->mii_bus = devm_mdiobus_alloc(&pdev->dev);
 116         if (!md->mii_bus) {
 117                 dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
 118                 return -ENOMEM;
 119         }
 120
 121         bus = md->mii_bus;
 122         bus->priv = md;
 123         bus->name = "BCM6368 MDIO mux bus";
 124         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
 125         bus->parent = &pdev->dev;
 126         bus->read = bcm6368_mdiomux_read;
 127         bus->write = bcm6368_mdiomux_write;
 128         bus->phy_mask = 0x3f;
 129         bus->dev.of_node = pdev->dev.of_node;
 130
 131         rc = mdiobus_register(bus);
 132         if (rc) {
 133                 dev_err(&pdev->dev, "mdiomux registration failed\n");
 134                 return rc;
 135         }
 136
 137         platform_set_drvdata(pdev, md);
 138
 139         rc = mdio_mux_init(md->dev, md->dev->of_node,
 140                            bcm6368_mdiomux_switch_fn, &md->mux_handle, md,
 141                            md->mii_bus);
 142         if (rc) {
 143                 dev_info(md->dev, "mdiomux initialization failed\n");
 144                 goto out_register;
 145         }
 146
 147         dev_info(&pdev->dev, "Broadcom BCM6368 MDIO mux bus\n");
 148
 149         return 0;
 150
 151 out_register:
 152         mdiobus_unregister(bus);
 153         return rc;
 154 }
 155
 156 static void bcm6368_mdiomux_remove(struct platform_device *pdev)
 157 {
 158         struct bcm6368_mdiomux_desc *md = platform_get_drvdata(pdev);
 159
 160         mdio_mux_uninit(md->mux_handle);
 161         mdiobus_unregister(md->mii_bus);
 162 }
 163
 164 static const struct of_device_id bcm6368_mdiomux_ids[] = {
 165         { .compatible = "brcm,bcm6368-mdio-mux", },
 166         { /* sentinel */ }
 167 };
 168 MODULE_DEVICE_TABLE(of, bcm6368_mdiomux_ids);
 169
 170 static struct platform_driver bcm6368_mdiomux_driver = {
 171         .driver = {
 172                 .name = "bcm6368-mdio-mux",
 173                 .of_match_table = bcm6368_mdiomux_ids,
 174         },
 175         .probe  = bcm6368_mdiomux_probe,
 176         .remove = bcm6368_mdiomux_remove,
 177 };
 178 module_platform_driver(bcm6368_mdiomux_driver);
 179
 180 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
 181 MODULE_DESCRIPTION("BCM6368 mdiomux bus controller driver");
 182 MODULE_LICENSE("GPL v2");