linux/drivers/net/phy/mdio-moxart.c
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   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
  33struct moxart_mdio_data {
  34        void __iomem            *base;
  35};
  36
  37static 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
  65static 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
  97static 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
 114static 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        bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
 134                        GFP_KERNEL);
 135        if (!bus->irq) {
 136                ret = -ENOMEM;
 137                goto err_out_free_mdiobus;
 138        }
 139
 140        /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
 141         * of_mdiobus_register() sets these PHY_POLL.
 142         * Ideally, the interrupt from MAC controller could be used to
 143         * detect link state changes, not polling, i.e. if there was
 144         * a way phy_driver could set PHY_HAS_INTERRUPT but have that
 145         * interrupt handled in ethernet drivercode.
 146         */
 147        for (i = 0; i < PHY_MAX_ADDR; i++)
 148                bus->irq[i] = PHY_IGNORE_INTERRUPT;
 149
 150        data = bus->priv;
 151        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 152        data->base = devm_ioremap_resource(&pdev->dev, res);
 153        if (IS_ERR(data->base)) {
 154                ret = PTR_ERR(data->base);
 155                goto err_out_free_mdiobus;
 156        }
 157
 158        ret = of_mdiobus_register(bus, np);
 159        if (ret < 0)
 160                goto err_out_free_mdiobus;
 161
 162        platform_set_drvdata(pdev, bus);
 163
 164        return 0;
 165
 166err_out_free_mdiobus:
 167        mdiobus_free(bus);
 168        return ret;
 169}
 170
 171static int moxart_mdio_remove(struct platform_device *pdev)
 172{
 173        struct mii_bus *bus = platform_get_drvdata(pdev);
 174
 175        mdiobus_unregister(bus);
 176        mdiobus_free(bus);
 177
 178        return 0;
 179}
 180
 181static const struct of_device_id moxart_mdio_dt_ids[] = {
 182        { .compatible = "moxa,moxart-mdio" },
 183        { }
 184};
 185MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
 186
 187static struct platform_driver moxart_mdio_driver = {
 188        .probe = moxart_mdio_probe,
 189        .remove = moxart_mdio_remove,
 190        .driver = {
 191                .name = "moxart-mdio",
 192                .of_match_table = moxart_mdio_dt_ids,
 193        },
 194};
 195
 196module_platform_driver(moxart_mdio_driver);
 197
 198MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
 199MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
 200MODULE_LICENSE("GPL");
 201
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