drivers/net/phy/mdio-moxart.c

   1 /* MOXA ART Ethernet (RTL8201CP) MDIO interface driver
   2  *
   3  * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
   4  *
   5  * This file is licensed under the terms of the GNU General Public
   6  * License version 2.  This program is licensed "as is" without any
   7  * warranty of any kind, whether express or implied.
   8  */
   9
  10 #include <linux/delay.h>
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/mutex.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_mdio.h>
  16 #include <linux/phy.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/regulator/consumer.h>
  19
  20 #define REG_PHY_CTRL            0
  21 #define REG_PHY_WRITE_DATA      4
  22
  23 /* REG_PHY_CTRL */
  24 #define MIIWR                   BIT(27) /* init write sequence (auto cleared)*/
  25 #define MIIRD                   BIT(26)
  26 #define REGAD_MASK              0x3e00000
  27 #define PHYAD_MASK              0x1f0000
  28 #define MIIRDATA_MASK           0xffff
  29
  30 /* REG_PHY_WRITE_DATA */
  31 #define MIIWDATA_MASK           0xffff
  32
  33 struct moxart_mdio_data {
  34         void __iomem            *base;
  35 };
  36
  37 static int moxart_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
  38 {
  39         struct moxart_mdio_data *data = bus->priv;
  40         u32 ctrl = 0;
  41         unsigned int count = 5;
  42
  43         dev_dbg(&bus->dev, "%s\n", __func__);
  44
  45         ctrl |= MIIRD | ((mii_id << 16) & PHYAD_MASK) |
  46                 ((regnum << 21) & REGAD_MASK);
  47
  48         writel(ctrl, data->base + REG_PHY_CTRL);
  49
  50         do {
  51                 ctrl = readl(data->base + REG_PHY_CTRL);
  52
  53                 if (!(ctrl & MIIRD))
  54                         return ctrl & MIIRDATA_MASK;
  55
  56                 mdelay(10);
  57                 count--;
  58         } while (count > 0);
  59
  60         dev_dbg(&bus->dev, "%s timed out\n", __func__);
  61
  62         return -ETIMEDOUT;
  63 }
  64
  65 static int moxart_mdio_write(struct mii_bus *bus, int mii_id,
  66                              int regnum, u16 value)
  67 {
  68         struct moxart_mdio_data *data = bus->priv;
  69         u32 ctrl = 0;
  70         unsigned int count = 5;
  71
  72         dev_dbg(&bus->dev, "%s\n", __func__);
  73
  74         ctrl |= MIIWR | ((mii_id << 16) & PHYAD_MASK) |
  75                 ((regnum << 21) & REGAD_MASK);
  76
  77         value &= MIIWDATA_MASK;
  78
  79         writel(value, data->base + REG_PHY_WRITE_DATA);
  80         writel(ctrl, data->base + REG_PHY_CTRL);
  81
  82         do {
  83                 ctrl = readl(data->base + REG_PHY_CTRL);
  84
  85                 if (!(ctrl & MIIWR))
  86                         return 0;
  87
  88                 mdelay(10);
  89                 count--;
  90         } while (count > 0);
  91
  92         dev_dbg(&bus->dev, "%s timed out\n", __func__);
  93
  94         return -ETIMEDOUT;
  95 }
  96
  97 static int moxart_mdio_reset(struct mii_bus *bus)
  98 {
  99         int data, i;
 100
 101         for (i = 0; i < PHY_MAX_ADDR; i++) {
 102                 data = moxart_mdio_read(bus, i, MII_BMCR);
 103                 if (data < 0)
 104                         continue;
 105
 106                 data |= BMCR_RESET;
 107                 if (moxart_mdio_write(bus, i, MII_BMCR, data) < 0)
 108                         continue;
 109         }
 110
 111         return 0;
 112 }
 113
 114 static int moxart_mdio_probe(struct platform_device *pdev)
 115 {
 116         struct device_node *np = pdev->dev.of_node;
 117         struct mii_bus *bus;
 118         struct moxart_mdio_data *data;
 119         struct resource *res;
 120         int ret, i;
 121
 122         bus = mdiobus_alloc_size(sizeof(*data));
 123         if (!bus)
 124                 return -ENOMEM;
 125
 126         bus->name = "MOXA ART Ethernet MII";
 127         bus->read = &moxart_mdio_read;
 128         bus->write = &moxart_mdio_write;
 129         bus->reset = &moxart_mdio_reset;
 130         snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d-mii", pdev->name, pdev->id);
 131         bus->parent = &pdev->dev;
 132
 133         /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
 134          * of_mdiobus_register() sets these PHY_POLL.
 135          * Ideally, the interrupt from MAC controller could be used to
 136          * detect link state changes, not polling, i.e. if there was
 137          * a way phy_driver could set PHY_HAS_INTERRUPT but have that
 138          * interrupt handled in ethernet drivercode.
 139          */
 140         for (i = 0; i < PHY_MAX_ADDR; i++)
 141                 bus->irq[i] = PHY_IGNORE_INTERRUPT;
 142
 143         data = bus->priv;
 144         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 145         data->base = devm_ioremap_resource(&pdev->dev, res);
 146         if (IS_ERR(data->base)) {
 147                 ret = PTR_ERR(data->base);
 148                 goto err_out_free_mdiobus;
 149         }
 150
 151         ret = of_mdiobus_register(bus, np);
 152         if (ret < 0)
 153                 goto err_out_free_mdiobus;
 154
 155         platform_set_drvdata(pdev, bus);
 156
 157         return 0;
 158
 159 err_out_free_mdiobus:
 160         mdiobus_free(bus);
 161         return ret;
 162 }
 163
 164 static int moxart_mdio_remove(struct platform_device *pdev)
 165 {
 166         struct mii_bus *bus = platform_get_drvdata(pdev);
 167
 168         mdiobus_unregister(bus);
 169         mdiobus_free(bus);
 170
 171         return 0;
 172 }
 173
 174 static const struct of_device_id moxart_mdio_dt_ids[] = {
 175         { .compatible = "moxa,moxart-mdio" },
 176         { }
 177 };
 178 MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
 179
 180 static struct platform_driver moxart_mdio_driver = {
 181         .probe = moxart_mdio_probe,
 182         .remove = moxart_mdio_remove,
 183         .driver = {
 184                 .name = "moxart-mdio",
 185                 .of_match_table = moxart_mdio_dt_ids,
 186         },
 187 };
 188
 189 module_platform_driver(moxart_mdio_driver);
 190
 191 MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
 192 MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
 193 MODULE_LICENSE("GPL");