--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/* Airoha AN7583 MDIO interface driver
+ *
+ * Copyright (C) 2025 Christian Marangi <ansuelsmth@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of_mdio.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+
+/* MII address register definitions */
+#define AN7583_MII_BUSY BIT(31)
+#define AN7583_MII_RDY BIT(30) /* RO signal BUS is ready */
+#define AN7583_MII_CL22_REG_ADDR GENMASK(29, 25)
+#define AN7583_MII_CL45_DEV_ADDR AN7583_MII_CL22_REG_ADDR
+#define AN7583_MII_PHY_ADDR GENMASK(24, 20)
+#define AN7583_MII_CMD GENMASK(19, 18)
+#define AN7583_MII_CMD_CL22_WRITE FIELD_PREP_CONST(AN7583_MII_CMD, 0x1)
+#define AN7583_MII_CMD_CL22_READ FIELD_PREP_CONST(AN7583_MII_CMD, 0x2)
+#define AN7583_MII_CMD_CL45_ADDR FIELD_PREP_CONST(AN7583_MII_CMD, 0x0)
+#define AN7583_MII_CMD_CL45_WRITE FIELD_PREP_CONST(AN7583_MII_CMD, 0x1)
+#define AN7583_MII_CMD_CL45_POSTREAD_INCADDR FIELD_PREP_CONST(AN7583_MII_CMD, 0x2)
+#define AN7583_MII_CMD_CL45_READ FIELD_PREP_CONST(AN7583_MII_CMD, 0x3)
+#define AN7583_MII_ST GENMASK(17, 16)
+#define AN7583_MII_ST_CL45 FIELD_PREP_CONST(AN7583_MII_ST, 0x0)
+#define AN7583_MII_ST_CL22 FIELD_PREP_CONST(AN7583_MII_ST, 0x1)
+#define AN7583_MII_RWDATA GENMASK(15, 0)
+#define AN7583_MII_CL45_REG_ADDR AN7583_MII_RWDATA
+
+#define AN7583_MII_MDIO_DELAY_USEC 100
+#define AN7583_MII_MDIO_RETRY_MSEC 100
+
+struct airoha_mdio_data {
+ u32 base_addr;
+ struct regmap *regmap;
+ struct clk *clk;
+ struct reset_control *reset;
+};
+
+static int airoha_mdio_wait_busy(struct airoha_mdio_data *priv)
+{
+ u32 busy;
+
+ return regmap_read_poll_timeout(priv->regmap, priv->base_addr, busy,
+ !(busy & AN7583_MII_BUSY),
+ AN7583_MII_MDIO_DELAY_USEC,
+ AN7583_MII_MDIO_RETRY_MSEC * USEC_PER_MSEC);
+}
+
+static void airoha_mdio_reset(struct airoha_mdio_data *priv)
+{
+ /* There seems to be Hardware bug where AN7583_MII_RWDATA
+ * is not wiped in the context of unconnected PHY and the
+ * previous read value is returned.
+ *
+ * Example: (only one PHY on the BUS at 0x1f)
+ * - read at 0x1f report at 0x2 0x7500
+ * - read at 0x0 report 0x7500 on every address
+ *
+ * To workaround this, we reset the Mdio BUS at every read
+ * to have consistent values on read operation.
+ */
+ reset_control_assert(priv->reset);
+ reset_control_deassert(priv->reset);
+}
+
+static int airoha_mdio_read(struct mii_bus *bus, int addr, int regnum)
+{
+ struct airoha_mdio_data *priv = bus->priv;
+ u32 val;
+ int ret;
+
+ airoha_mdio_reset(priv);
+
+ val = AN7583_MII_BUSY | AN7583_MII_ST_CL22 |
+ AN7583_MII_CMD_CL22_READ;
+ val |= FIELD_PREP(AN7583_MII_PHY_ADDR, addr);
+ val |= FIELD_PREP(AN7583_MII_CL22_REG_ADDR, regnum);
+
+ ret = regmap_write(priv->regmap, priv->base_addr, val);
+ if (ret)
+ return ret;
+
+ ret = airoha_mdio_wait_busy(priv);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(priv->regmap, priv->base_addr, &val);
+ if (ret)
+ return ret;
+
+ return FIELD_GET(AN7583_MII_RWDATA, val);
+}
+
+static int airoha_mdio_write(struct mii_bus *bus, int addr, int regnum,
+ u16 value)
+{
+ struct airoha_mdio_data *priv = bus->priv;
+ u32 val;
+ int ret;
+
+ val = AN7583_MII_BUSY | AN7583_MII_ST_CL22 |
+ AN7583_MII_CMD_CL22_WRITE;
+ val |= FIELD_PREP(AN7583_MII_PHY_ADDR, addr);
+ val |= FIELD_PREP(AN7583_MII_CL22_REG_ADDR, regnum);
+ val |= FIELD_PREP(AN7583_MII_RWDATA, value);
+
+ ret = regmap_write(priv->regmap, priv->base_addr, val);
+ if (ret)
+ return ret;
+
+ ret = airoha_mdio_wait_busy(priv);
+
+ return ret;
+}
+
+static int airoha_mdio_cl45_read(struct mii_bus *bus, int addr, int devnum,
+ int regnum)
+{
+ struct airoha_mdio_data *priv = bus->priv;
+ u32 val;
+ int ret;
+
+ airoha_mdio_reset(priv);
+
+ val = AN7583_MII_BUSY | AN7583_MII_ST_CL45 |
+ AN7583_MII_CMD_CL45_ADDR;
+ val |= FIELD_PREP(AN7583_MII_PHY_ADDR, addr);
+ val |= FIELD_PREP(AN7583_MII_CL45_DEV_ADDR, devnum);
+ val |= FIELD_PREP(AN7583_MII_CL45_REG_ADDR, regnum);
+
+ ret = regmap_write(priv->regmap, priv->base_addr, val);
+ if (ret)
+ return ret;
+
+ ret = airoha_mdio_wait_busy(priv);
+ if (ret)
+ return ret;
+
+ val = AN7583_MII_BUSY | AN7583_MII_ST_CL45 |
+ AN7583_MII_CMD_CL45_READ;
+ val |= FIELD_PREP(AN7583_MII_PHY_ADDR, addr);
+ val |= FIELD_PREP(AN7583_MII_CL45_DEV_ADDR, devnum);
+
+ ret = regmap_write(priv->regmap, priv->base_addr, val);
+ if (ret)
+ return ret;
+
+ ret = airoha_mdio_wait_busy(priv);
+ if (ret)
+ return ret;
+
+ ret = regmap_read(priv->regmap, priv->base_addr, &val);
+ if (ret)
+ return ret;
+
+ return FIELD_GET(AN7583_MII_RWDATA, val);
+}
+
+static int airoha_mdio_cl45_write(struct mii_bus *bus, int addr, int devnum,
+ int regnum, u16 value)
+{
+ struct airoha_mdio_data *priv = bus->priv;
+ u32 val;
+ int ret;
+
+ val = AN7583_MII_BUSY | AN7583_MII_ST_CL45 |
+ AN7583_MII_CMD_CL45_ADDR;
+ val |= FIELD_PREP(AN7583_MII_PHY_ADDR, addr);
+ val |= FIELD_PREP(AN7583_MII_CL45_DEV_ADDR, devnum);
+ val |= FIELD_PREP(AN7583_MII_CL45_REG_ADDR, regnum);
+
+ ret = regmap_write(priv->regmap, priv->base_addr, val);
+ if (ret)
+ return ret;
+
+ ret = airoha_mdio_wait_busy(priv);
+ if (ret)
+ return ret;
+
+ val = AN7583_MII_BUSY | AN7583_MII_ST_CL45 |
+ AN7583_MII_CMD_CL45_WRITE;
+ val |= FIELD_PREP(AN7583_MII_PHY_ADDR, addr);
+ val |= FIELD_PREP(AN7583_MII_CL45_DEV_ADDR, devnum);
+ val |= FIELD_PREP(AN7583_MII_RWDATA, value);
+
+ ret = regmap_write(priv->regmap, priv->base_addr, val);
+ if (ret)
+ return ret;
+
+ ret = airoha_mdio_wait_busy(priv);
+
+ return ret;
+}
+
+static int airoha_mdio_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct airoha_mdio_data *priv;
+ struct mii_bus *bus;
+ u32 addr, freq;
+ int ret;
+
+ ret = of_property_read_u32(dev->of_node, "reg", &addr);
+ if (ret)
+ return ret;
+
+ bus = devm_mdiobus_alloc_size(dev, sizeof(*priv));
+ if (!bus)
+ return -ENOMEM;
+
+ priv = bus->priv;
+ priv->base_addr = addr;
+ priv->regmap = device_node_to_regmap(dev->parent->of_node);
+
+ priv->clk = devm_clk_get_enabled(dev, NULL);
+ if (IS_ERR(priv->clk))
+ return PTR_ERR(priv->clk);
+
+ priv->reset = devm_reset_control_get_exclusive(dev, NULL);
+ if (IS_ERR(priv->reset))
+ return PTR_ERR(priv->reset);
+
+ reset_control_deassert(priv->reset);
+
+ bus->name = "airoha_mdio_bus";
+ snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(dev));
+ bus->parent = dev;
+ bus->read = airoha_mdio_read;
+ bus->write = airoha_mdio_write;
+ bus->read_c45 = airoha_mdio_cl45_read;
+ bus->write_c45 = airoha_mdio_cl45_write;
+
+ /* Check if a custom frequency is defined in DT or default to 2.5 MHz */
+ if (of_property_read_u32(dev->of_node, "clock-frequency", &freq))
+ freq = 2500000;
+
+ ret = clk_set_rate(priv->clk, freq);
+ if (ret)
+ return ret;
+
+ ret = devm_of_mdiobus_register(dev, bus, dev->of_node);
+ if (ret) {
+ reset_control_assert(priv->reset);
+ return ret;
+ }
+
+ return 0;
+}
+
+static const struct of_device_id airoha_mdio_dt_ids[] = {
+ { .compatible = "airoha,an7583-mdio" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, airoha_mdio_dt_ids);
+
+static struct platform_driver airoha_mdio_driver = {
+ .probe = airoha_mdio_probe,
+ .driver = {
+ .name = "airoha-mdio",
+ .of_match_table = airoha_mdio_dt_ids,
+ },
+};
+
+module_platform_driver(airoha_mdio_driver);
+
+MODULE_DESCRIPTION("Airoha AN7583 MDIO interface driver");
+MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
+MODULE_LICENSE("GPL");
projects / thirdparty / linux.git / commitdiff
