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

   1 /*
   2  * Copyright (C) 2015 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation version 2.
   7  *
   8  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
   9  * kind, whether express or implied; without even the implied warranty
  10  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #include <linux/delay.h>
  15 #include <linux/io.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/of.h>
  19 #include <linux/of_platform.h>
  20 #include <linux/of_mdio.h>
  21 #include <linux/phy.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/sched.h>
  24
  25 #define IPROC_GPHY_MDCDIV    0x1a
  26
  27 #define MII_CTRL_OFFSET      0x000
  28
  29 #define MII_CTRL_DIV_SHIFT   0
  30 #define MII_CTRL_PRE_SHIFT   7
  31 #define MII_CTRL_BUSY_SHIFT  8
  32
  33 #define MII_DATA_OFFSET      0x004
  34 #define MII_DATA_MASK        0xffff
  35 #define MII_DATA_TA_SHIFT    16
  36 #define MII_DATA_TA_VAL      2
  37 #define MII_DATA_RA_SHIFT    18
  38 #define MII_DATA_PA_SHIFT    23
  39 #define MII_DATA_OP_SHIFT    28
  40 #define MII_DATA_OP_WRITE    1
  41 #define MII_DATA_OP_READ     2
  42 #define MII_DATA_SB_SHIFT    30
  43
  44 struct iproc_mdio_priv {
  45         struct mii_bus *mii_bus;
  46         void __iomem *base;
  47 };
  48
  49 static inline int iproc_mdio_wait_for_idle(void __iomem *base)
  50 {
  51         u32 val;
  52         unsigned int timeout = 1000; /* loop for 1s */
  53
  54         do {
  55                 val = readl(base + MII_CTRL_OFFSET);
  56                 if ((val & BIT(MII_CTRL_BUSY_SHIFT)) == 0)
  57                         return 0;
  58
  59                 usleep_range(1000, 2000);
  60         } while (timeout--);
  61
  62         return -ETIMEDOUT;
  63 }
  64
  65 static inline void iproc_mdio_config_clk(void __iomem *base)
  66 {
  67         u32 val;
  68
  69         val = (IPROC_GPHY_MDCDIV << MII_CTRL_DIV_SHIFT) |
  70                   BIT(MII_CTRL_PRE_SHIFT);
  71         writel(val, base + MII_CTRL_OFFSET);
  72 }
  73
  74 static int iproc_mdio_read(struct mii_bus *bus, int phy_id, int reg)
  75 {
  76         struct iproc_mdio_priv *priv = bus->priv;
  77         u32 cmd;
  78         int rc;
  79
  80         rc = iproc_mdio_wait_for_idle(priv->base);
  81         if (rc)
  82                 return rc;
  83
  84         iproc_mdio_config_clk(priv->base);
  85
  86         /* Prepare the read operation */
  87         cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
  88                 (reg << MII_DATA_RA_SHIFT) |
  89                 (phy_id << MII_DATA_PA_SHIFT) |
  90                 BIT(MII_DATA_SB_SHIFT) |
  91                 (MII_DATA_OP_READ << MII_DATA_OP_SHIFT);
  92
  93         writel(cmd, priv->base + MII_DATA_OFFSET);
  94
  95         rc = iproc_mdio_wait_for_idle(priv->base);
  96         if (rc)
  97                 return rc;
  98
  99         cmd = readl(priv->base + MII_DATA_OFFSET) & MII_DATA_MASK;
 100
 101         return cmd;
 102 }
 103
 104 static int iproc_mdio_write(struct mii_bus *bus, int phy_id,
 105                             int reg, u16 val)
 106 {
 107         struct iproc_mdio_priv *priv = bus->priv;
 108         u32 cmd;
 109         int rc;
 110
 111         rc = iproc_mdio_wait_for_idle(priv->base);
 112         if (rc)
 113                 return rc;
 114
 115         iproc_mdio_config_clk(priv->base);
 116
 117         /* Prepare the write operation */
 118         cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
 119                 (reg << MII_DATA_RA_SHIFT) |
 120                 (phy_id << MII_DATA_PA_SHIFT) |
 121                 BIT(MII_DATA_SB_SHIFT) |
 122                 (MII_DATA_OP_WRITE << MII_DATA_OP_SHIFT) |
 123                 ((u32)(val) & MII_DATA_MASK);
 124
 125         writel(cmd, priv->base + MII_DATA_OFFSET);
 126
 127         rc = iproc_mdio_wait_for_idle(priv->base);
 128         if (rc)
 129                 return rc;
 130
 131         return 0;
 132 }
 133
 134 static int iproc_mdio_probe(struct platform_device *pdev)
 135 {
 136         struct iproc_mdio_priv *priv;
 137         struct mii_bus *bus;
 138         struct resource *res;
 139         int rc;
 140
 141         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 142         if (!priv)
 143                 return -ENOMEM;
 144
 145         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 146         priv->base = devm_ioremap_resource(&pdev->dev, res);
 147         if (IS_ERR(priv->base)) {
 148                 dev_err(&pdev->dev, "failed to ioremap register\n");
 149                 return PTR_ERR(priv->base);
 150         }
 151
 152         priv->mii_bus = mdiobus_alloc();
 153         if (!priv->mii_bus) {
 154                 dev_err(&pdev->dev, "MDIO bus alloc failed\n");
 155                 return -ENOMEM;
 156         }
 157
 158         bus = priv->mii_bus;
 159         bus->priv = priv;
 160         bus->name = "iProc MDIO bus";
 161         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
 162         bus->parent = &pdev->dev;
 163         bus->read = iproc_mdio_read;
 164         bus->write = iproc_mdio_write;
 165
 166         rc = of_mdiobus_register(bus, pdev->dev.of_node);
 167         if (rc) {
 168                 dev_err(&pdev->dev, "MDIO bus registration failed\n");
 169                 goto err_iproc_mdio;
 170         }
 171
 172         platform_set_drvdata(pdev, priv);
 173
 174         dev_info(&pdev->dev, "Broadcom iProc MDIO bus at 0x%p\n", priv->base);
 175
 176         return 0;
 177
 178 err_iproc_mdio:
 179         mdiobus_free(bus);
 180         return rc;
 181 }
 182
 183 static int iproc_mdio_remove(struct platform_device *pdev)
 184 {
 185         struct iproc_mdio_priv *priv = platform_get_drvdata(pdev);
 186
 187         mdiobus_unregister(priv->mii_bus);
 188         mdiobus_free(priv->mii_bus);
 189
 190         return 0;
 191 }
 192
 193 static const struct of_device_id iproc_mdio_of_match[] = {
 194         { .compatible = "brcm,iproc-mdio", },
 195         { /* sentinel */ },
 196 };
 197 MODULE_DEVICE_TABLE(of, iproc_mdio_of_match);
 198
 199 static struct platform_driver iproc_mdio_driver = {
 200         .driver = {
 201                 .name = "iproc-mdio",
 202                 .of_match_table = iproc_mdio_of_match,
 203         },
 204         .probe = iproc_mdio_probe,
 205         .remove = iproc_mdio_remove,
 206 };
 207
 208 module_platform_driver(iproc_mdio_driver);
 209
 210 MODULE_AUTHOR("Broadcom Corporation");
 211 MODULE_DESCRIPTION("Broadcom iProc MDIO bus controller");
 212 MODULE_LICENSE("GPL v2");
 213 MODULE_ALIAS("platform:iproc-mdio");