--- /dev/null
+/* MOXA ART Ethernet (RTL8201CP) MDIO interface driver
+ *
+ * Copyright (C) 2013 Jonas Jensen <jonas.jensen@gmail.com>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of_address.h>
+#include <linux/of_mdio.h>
+#include <linux/phy.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#define REG_PHY_CTRL 0
+#define REG_PHY_WRITE_DATA 4
+
+/* REG_PHY_CTRL */
+#define MIIWR BIT(27) /* init write sequence (auto cleared)*/
+#define MIIRD BIT(26)
+#define REGAD_MASK 0x3e00000
+#define PHYAD_MASK 0x1f0000
+#define MIIRDATA_MASK 0xffff
+
+/* REG_PHY_WRITE_DATA */
+#define MIIWDATA_MASK 0xffff
+
+struct moxart_mdio_data {
+ void __iomem *base;
+};
+
+static int moxart_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
+{
+ struct moxart_mdio_data *data = bus->priv;
+ u32 ctrl = 0;
+ unsigned int count = 5;
+
+ dev_dbg(&bus->dev, "%s\n", __func__);
+
+ ctrl |= MIIRD | ((mii_id << 16) & PHYAD_MASK) |
+ ((regnum << 21) & REGAD_MASK);
+
+ writel(ctrl, data->base + REG_PHY_CTRL);
+
+ do {
+ ctrl = readl(data->base + REG_PHY_CTRL);
+
+ if (!(ctrl & MIIRD))
+ return ctrl & MIIRDATA_MASK;
+
+ mdelay(10);
+ count--;
+ } while (count > 0);
+
+ dev_dbg(&bus->dev, "%s timed out\n", __func__);
+
+ return -ETIMEDOUT;
+}
+
+static int moxart_mdio_write(struct mii_bus *bus, int mii_id,
+ int regnum, u16 value)
+{
+ struct moxart_mdio_data *data = bus->priv;
+ u32 ctrl = 0;
+ unsigned int count = 5;
+
+ dev_dbg(&bus->dev, "%s\n", __func__);
+
+ ctrl |= MIIWR | ((mii_id << 16) & PHYAD_MASK) |
+ ((regnum << 21) & REGAD_MASK);
+
+ value &= MIIWDATA_MASK;
+
+ writel(value, data->base + REG_PHY_WRITE_DATA);
+ writel(ctrl, data->base + REG_PHY_CTRL);
+
+ do {
+ ctrl = readl(data->base + REG_PHY_CTRL);
+
+ if (!(ctrl & MIIWR))
+ return 0;
+
+ mdelay(10);
+ count--;
+ } while (count > 0);
+
+ dev_dbg(&bus->dev, "%s timed out\n", __func__);
+
+ return -ETIMEDOUT;
+}
+
+static int moxart_mdio_reset(struct mii_bus *bus)
+{
+ int data, i;
+
+ for (i = 0; i < PHY_MAX_ADDR; i++) {
+ data = moxart_mdio_read(bus, i, MII_BMCR);
+ if (data < 0)
+ continue;
+
+ data |= BMCR_RESET;
+ if (moxart_mdio_write(bus, i, MII_BMCR, data) < 0)
+ continue;
+ }
+
+ return 0;
+}
+
+static int moxart_mdio_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct mii_bus *bus;
+ struct moxart_mdio_data *data;
+ struct resource *res;
+ int ret, i;
+
+ bus = mdiobus_alloc_size(sizeof(*data));
+ if (!bus)
+ return -ENOMEM;
+
+ bus->name = "MOXA ART Ethernet MII";
+ bus->read = &moxart_mdio_read;
+ bus->write = &moxart_mdio_write;
+ bus->reset = &moxart_mdio_reset;
+ snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d-mii", pdev->name, pdev->id);
+ bus->parent = &pdev->dev;
+
+ bus->irq = devm_kzalloc(&pdev->dev, sizeof(int) * PHY_MAX_ADDR,
+ GFP_KERNEL);
+ if (!bus->irq) {
+ ret = -ENOMEM;
+ goto err_out_free_mdiobus;
+ }
+
+ /* Setting PHY_IGNORE_INTERRUPT here even if it has no effect,
+ * of_mdiobus_register() sets these PHY_POLL.
+ * Ideally, the interrupt from MAC controller could be used to
+ * detect link state changes, not polling, i.e. if there was
+ * a way phy_driver could set PHY_HAS_INTERRUPT but have that
+ * interrupt handled in ethernet drivercode.
+ */
+ for (i = 0; i < PHY_MAX_ADDR; i++)
+ bus->irq[i] = PHY_IGNORE_INTERRUPT;
+
+ data = bus->priv;
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ data->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(data->base)) {
+ ret = PTR_ERR(data->base);
+ goto err_out_free_mdiobus;
+ }
+
+ ret = of_mdiobus_register(bus, np);
+ if (ret < 0)
+ goto err_out_free_mdiobus;
+
+ platform_set_drvdata(pdev, bus);
+
+ return 0;
+
+err_out_free_mdiobus:
+ mdiobus_free(bus);
+ return ret;
+}
+
+static int moxart_mdio_remove(struct platform_device *pdev)
+{
+ struct mii_bus *bus = platform_get_drvdata(pdev);
+
+ mdiobus_unregister(bus);
+ mdiobus_free(bus);
+
+ return 0;
+}
+
+static const struct of_device_id moxart_mdio_dt_ids[] = {
+ { .compatible = "moxa,moxart-mdio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, moxart_mdio_dt_ids);
+
+static struct platform_driver moxart_mdio_driver = {
+ .probe = moxart_mdio_probe,
+ .remove = moxart_mdio_remove,
+ .driver = {
+ .name = "moxart-mdio",
+ .of_match_table = moxart_mdio_dt_ids,
+ },
+};
+
+module_platform_driver(moxart_mdio_driver);
+
+MODULE_DESCRIPTION("MOXA ART MDIO interface driver");
+MODULE_AUTHOR("Jonas Jensen <jonas.jensen@gmail.com>");
+MODULE_LICENSE("GPL");