drivers/net/phy/mdio-bcm-iproc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2015 Broadcom Corporation
   4  */
   5
   6 #include <linux/delay.h>
   7 #include <linux/io.h>
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/of.h>
  11 #include <linux/of_platform.h>
  12 #include <linux/of_mdio.h>
  13 #include <linux/phy.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/sched.h>
  16
  17 #define IPROC_GPHY_MDCDIV    0x1a
  18
  19 #define MII_CTRL_OFFSET      0x000
  20
  21 #define MII_CTRL_DIV_SHIFT   0
  22 #define MII_CTRL_PRE_SHIFT   7
  23 #define MII_CTRL_BUSY_SHIFT  8
  24
  25 #define MII_DATA_OFFSET      0x004
  26 #define MII_DATA_MASK        0xffff
  27 #define MII_DATA_TA_SHIFT    16
  28 #define MII_DATA_TA_VAL      2
  29 #define MII_DATA_RA_SHIFT    18
  30 #define MII_DATA_PA_SHIFT    23
  31 #define MII_DATA_OP_SHIFT    28
  32 #define MII_DATA_OP_WRITE    1
  33 #define MII_DATA_OP_READ     2
  34 #define MII_DATA_SB_SHIFT    30
  35
  36 struct iproc_mdio_priv {
  37         struct mii_bus *mii_bus;
  38         void __iomem *base;
  39 };
  40
  41 static inline int iproc_mdio_wait_for_idle(void __iomem *base)
  42 {
  43         u32 val;
  44         unsigned int timeout = 1000; /* loop for 1s */
  45
  46         do {
  47                 val = readl(base + MII_CTRL_OFFSET);
  48                 if ((val & BIT(MII_CTRL_BUSY_SHIFT)) == 0)
  49                         return 0;
  50
  51                 usleep_range(1000, 2000);
  52         } while (timeout--);
  53
  54         return -ETIMEDOUT;
  55 }
  56
  57 static inline void iproc_mdio_config_clk(void __iomem *base)
  58 {
  59         u32 val;
  60
  61         val = (IPROC_GPHY_MDCDIV << MII_CTRL_DIV_SHIFT) |
  62                   BIT(MII_CTRL_PRE_SHIFT);
  63         writel(val, base + MII_CTRL_OFFSET);
  64 }
  65
  66 static int iproc_mdio_read(struct mii_bus *bus, int phy_id, int reg)
  67 {
  68         struct iproc_mdio_priv *priv = bus->priv;
  69         u32 cmd;
  70         int rc;
  71
  72         rc = iproc_mdio_wait_for_idle(priv->base);
  73         if (rc)
  74                 return rc;
  75
  76         /* Prepare the read operation */
  77         cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
  78                 (reg << MII_DATA_RA_SHIFT) |
  79                 (phy_id << MII_DATA_PA_SHIFT) |
  80                 BIT(MII_DATA_SB_SHIFT) |
  81                 (MII_DATA_OP_READ << MII_DATA_OP_SHIFT);
  82
  83         writel(cmd, priv->base + MII_DATA_OFFSET);
  84
  85         rc = iproc_mdio_wait_for_idle(priv->base);
  86         if (rc)
  87                 return rc;
  88
  89         cmd = readl(priv->base + MII_DATA_OFFSET) & MII_DATA_MASK;
  90
  91         return cmd;
  92 }
  93
  94 static int iproc_mdio_write(struct mii_bus *bus, int phy_id,
  95                             int reg, u16 val)
  96 {
  97         struct iproc_mdio_priv *priv = bus->priv;
  98         u32 cmd;
  99         int rc;
 100
 101         rc = iproc_mdio_wait_for_idle(priv->base);
 102         if (rc)
 103                 return rc;
 104
 105         /* Prepare the write operation */
 106         cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
 107                 (reg << MII_DATA_RA_SHIFT) |
 108                 (phy_id << MII_DATA_PA_SHIFT) |
 109                 BIT(MII_DATA_SB_SHIFT) |
 110                 (MII_DATA_OP_WRITE << MII_DATA_OP_SHIFT) |
 111                 ((u32)(val) & MII_DATA_MASK);
 112
 113         writel(cmd, priv->base + MII_DATA_OFFSET);
 114
 115         rc = iproc_mdio_wait_for_idle(priv->base);
 116         if (rc)
 117                 return rc;
 118
 119         return 0;
 120 }
 121
 122 static int iproc_mdio_probe(struct platform_device *pdev)
 123 {
 124         struct iproc_mdio_priv *priv;
 125         struct mii_bus *bus;
 126         struct resource *res;
 127         int rc;
 128
 129         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 130         if (!priv)
 131                 return -ENOMEM;
 132
 133         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 134         priv->base = devm_ioremap_resource(&pdev->dev, res);
 135         if (IS_ERR(priv->base)) {
 136                 dev_err(&pdev->dev, "failed to ioremap register\n");
 137                 return PTR_ERR(priv->base);
 138         }
 139
 140         priv->mii_bus = mdiobus_alloc();
 141         if (!priv->mii_bus) {
 142                 dev_err(&pdev->dev, "MDIO bus alloc failed\n");
 143                 return -ENOMEM;
 144         }
 145
 146         bus = priv->mii_bus;
 147         bus->priv = priv;
 148         bus->name = "iProc MDIO bus";
 149         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
 150         bus->parent = &pdev->dev;
 151         bus->read = iproc_mdio_read;
 152         bus->write = iproc_mdio_write;
 153
 154         iproc_mdio_config_clk(priv->base);
 155
 156         rc = of_mdiobus_register(bus, pdev->dev.of_node);
 157         if (rc) {
 158                 dev_err(&pdev->dev, "MDIO bus registration failed\n");
 159                 goto err_iproc_mdio;
 160         }
 161
 162         platform_set_drvdata(pdev, priv);
 163
 164         dev_info(&pdev->dev, "Broadcom iProc MDIO bus at 0x%p\n", priv->base);
 165
 166         return 0;
 167
 168 err_iproc_mdio:
 169         mdiobus_free(bus);
 170         return rc;
 171 }
 172
 173 static int iproc_mdio_remove(struct platform_device *pdev)
 174 {
 175         struct iproc_mdio_priv *priv = platform_get_drvdata(pdev);
 176
 177         mdiobus_unregister(priv->mii_bus);
 178         mdiobus_free(priv->mii_bus);
 179
 180         return 0;
 181 }
 182
 183 static const struct of_device_id iproc_mdio_of_match[] = {
 184         { .compatible = "brcm,iproc-mdio", },
 185         { /* sentinel */ },
 186 };
 187 MODULE_DEVICE_TABLE(of, iproc_mdio_of_match);
 188
 189 static struct platform_driver iproc_mdio_driver = {
 190         .driver = {
 191                 .name = "iproc-mdio",
 192                 .of_match_table = iproc_mdio_of_match,
 193         },
 194         .probe = iproc_mdio_probe,
 195         .remove = iproc_mdio_remove,
 196 };
 197
 198 module_platform_driver(iproc_mdio_driver);
 199
 200 MODULE_AUTHOR("Broadcom Corporation");
 201 MODULE_DESCRIPTION("Broadcom iProc MDIO bus controller");
 202 MODULE_LICENSE("GPL v2");
 203 MODULE_ALIAS("platform:iproc-mdio");