net: Add MDIO bus driver for the Allwinner EMAC

This patch adds a separate driver for the MDIO interface of the
Allwinner ethernet controllers.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Tested-by: Richard Genoud <richard.genoud@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 205 insertions, 0 deletions

diff --git a/drivers/net/phy/Kconfig b/drivers/net/phy/Kconfig
index 1e11f2bfd9ce..3a316b30089f 100644
--- a/drivers/net/phy/Kconfig
+++ b/drivers/net/phy/Kconfig
@@ -144,6 +144,16 @@ config MDIO_OCTEON
 
           If in doubt, say Y.
 
+config MDIO_SUN4I
+        tristate "Allwinner sun4i MDIO interface support"
+        depends on ARCH_SUNXI
+        select REGULATOR
+        select REGULATOR_FIXED_VOLTAGE
+        help
+          This driver supports the MDIO interface found in the network
+          interface units of the Allwinner SoC that have an EMAC (A10,
+          A12, A10s, etc.)
+
 config MDIO_BUS_MUX
         tristate
         depends on OF_MDIO
diff --git a/drivers/net/phy/Makefile b/drivers/net/phy/Makefile
index 9645e389a58d..23a2ab2e847e 100644
--- a/drivers/net/phy/Makefile
+++ b/drivers/net/phy/Makefile
@@ -30,3 +30,4 @@ obj-$(CONFIG_AMD_PHY)		+= amd.o
 obj-$(CONFIG_MDIO_BUS_MUX)      += mdio-mux.o
 obj-$(CONFIG_MDIO_BUS_MUX_GPIO) += mdio-mux-gpio.o
 obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) += mdio-mux-mmioreg.o
+obj-$(CONFIG_MDIO_SUN4I)        += mdio-sun4i.o
diff --git a/drivers/net/phy/mdio-sun4i.c b/drivers/net/phy/mdio-sun4i.c
new file mode 100644
index 000000000000..61d3f4ebf52e
--- /dev/null
+++ b/drivers/net/phy/mdio-sun4i.c
@@ -0,0 +1,194 @@
+/*
+ * Allwinner EMAC MDIO interface driver
+ *
+ * Copyright 2012-2013 Stefan Roese <sr@denx.de>
+ * Copyright 2013 Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * Based on the Linux driver provided by Allwinner:
+ * Copyright (C) 1997  Sten Wang
+ *
+ * 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 EMAC_MAC_MCMD_REG       (0x00)
+#define EMAC_MAC_MADR_REG       (0x04)
+#define EMAC_MAC_MWTD_REG       (0x08)
+#define EMAC_MAC_MRDD_REG       (0x0c)
+#define EMAC_MAC_MIND_REG       (0x10)
+#define EMAC_MAC_SSRR_REG       (0x14)
+
+#define MDIO_TIMEOUT            (msecs_to_jiffies(100))
+
+struct sun4i_mdio_data {
+        void __iomem            *membase;
+        struct regulator        *regulator;
+};
+
+static int sun4i_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
+{
+        struct sun4i_mdio_data *data = bus->priv;
+        unsigned long start_jiffies;
+        int value;
+
+        /* issue the phy address and reg */
+        writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
+        /* pull up the phy io line */
+        writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
+
+        /* Wait read complete */
+        start_jiffies = jiffies;
+        while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
+                if (time_after(start_jiffies,
+                               start_jiffies + MDIO_TIMEOUT))
+                        return -ETIMEDOUT;
+                msleep(1);
+        }
+
+        /* push down the phy io line */
+        writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
+        /* and read data */
+        value = readl(data->membase + EMAC_MAC_MRDD_REG);
+
+        return value;
+}
+
+static int sun4i_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
+                            u16 value)
+{
+        struct sun4i_mdio_data *data = bus->priv;
+        unsigned long start_jiffies;
+
+        /* issue the phy address and reg */
+        writel((mii_id << 8) | regnum, data->membase + EMAC_MAC_MADR_REG);
+        /* pull up the phy io line */
+        writel(0x1, data->membase + EMAC_MAC_MCMD_REG);
+
+        /* Wait read complete */
+        start_jiffies = jiffies;
+        while (readl(data->membase + EMAC_MAC_MIND_REG) & 0x1) {
+                if (time_after(start_jiffies,
+                               start_jiffies + MDIO_TIMEOUT))
+                        return -ETIMEDOUT;
+                msleep(1);
+        }
+
+        /* push down the phy io line */
+        writel(0x0, data->membase + EMAC_MAC_MCMD_REG);
+        /* and write data */
+        writel(value, data->membase + EMAC_MAC_MWTD_REG);
+
+        return 0;
+}
+
+static int sun4i_mdio_reset(struct mii_bus *bus)
+{
+        return 0;
+}
+
+static int sun4i_mdio_probe(struct platform_device *pdev)
+{
+        struct device_node *np = pdev->dev.of_node;
+        struct mii_bus *bus;
+        struct sun4i_mdio_data *data;
+        int ret, i;
+
+        bus = mdiobus_alloc_size(sizeof(*data));
+        if (!bus)
+                return -ENOMEM;
+
+        bus->name = "sun4i_mii_bus";
+        bus->read = &sun4i_mdio_read;
+        bus->write = &sun4i_mdio_write;
+        bus->reset = &sun4i_mdio_reset;
+        snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
+        bus->parent = &pdev->dev;
+
+        bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
+        if (!bus->irq) {
+                ret = -ENOMEM;
+                goto err_out_free_mdiobus;
+        }
+
+        for (i = 0; i < PHY_MAX_ADDR; i++)
+                bus->irq[i] = PHY_POLL;
+
+        data = bus->priv;
+        data->membase = of_iomap(np, 0);
+        if (!data->membase) {
+                ret = -ENOMEM;
+                goto err_out_free_mdio_irq;
+        }
+
+        data->regulator = devm_regulator_get(&pdev->dev, "phy");
+        if (IS_ERR(data->regulator)) {
+                if (PTR_ERR(data->regulator) == -EPROBE_DEFER)
+                        return -EPROBE_DEFER;
+
+                dev_info(&pdev->dev, "no regulator found\n");
+        } else {
+                ret = regulator_enable(data->regulator);
+                if (ret)
+                        goto err_out_free_mdio_irq;
+        }
+
+        ret = of_mdiobus_register(bus, np);
+        if (ret < 0)
+                goto err_out_disable_regulator;
+
+        platform_set_drvdata(pdev, bus);
+
+        return 0;
+
+err_out_disable_regulator:
+        regulator_disable(data->regulator);
+err_out_free_mdio_irq:
+        kfree(bus->irq);
+err_out_free_mdiobus:
+        mdiobus_free(bus);
+        return ret;
+}
+
+static int sun4i_mdio_remove(struct platform_device *pdev)
+{
+        struct mii_bus *bus = platform_get_drvdata(pdev);
+
+        mdiobus_unregister(bus);
+        kfree(bus->irq);
+        mdiobus_free(bus);
+
+        return 0;
+}
+
+static const struct of_device_id sun4i_mdio_dt_ids[] = {
+        { .compatible = "allwinner,sun4i-mdio" },
+        { }
+};
+MODULE_DEVICE_TABLE(of, sun4i_mdio_dt_ids);
+
+static struct platform_driver sun4i_mdio_driver = {
+        .probe = sun4i_mdio_probe,
+        .remove = sun4i_mdio_remove,
+        .driver = {
+                .name = "sun4i-mdio",
+                .of_match_table = sun4i_mdio_dt_ids,
+        },
+};
+
+module_platform_driver(sun4i_mdio_driver);
+
+MODULE_DESCRIPTION("Allwinner EMAC MDIO interface driver");
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_LICENSE("GPL");