1// SPDX-License-Identifier: GPL-2.0
  2/* Qualcomm IPQ8064 MDIO interface driver
  3 *
  4 * Copyright (C) 2019 Christian Lamparter <chunkeey@gmail.com>
  5 * Copyright (C) 2020 Ansuel Smith <ansuelsmth@gmail.com>
  6 */
  7
  8#include <linux/delay.h>
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/regmap.h>
 12#include <linux/of_mdio.h>
 13#include <linux/phy.h>
 14#include <linux/platform_device.h>
 15#include <linux/mfd/syscon.h>
 16
 17/* MII address register definitions */
 18#define MII_ADDR_REG_ADDR                       0x10
 19#define MII_BUSY                                BIT(0)
 20#define MII_WRITE                               BIT(1)
 21#define MII_CLKRANGE_60_100M                    (0 << 2)
 22#define MII_CLKRANGE_100_150M                   (1 << 2)
 23#define MII_CLKRANGE_20_35M                     (2 << 2)
 24#define MII_CLKRANGE_35_60M                     (3 << 2)
 25#define MII_CLKRANGE_150_250M                   (4 << 2)
 26#define MII_CLKRANGE_250_300M                   (5 << 2)
 27#define MII_CLKRANGE_MASK			GENMASK(4, 2)
 28#define MII_REG_SHIFT				6
 29#define MII_REG_MASK				GENMASK(10, 6)
 30#define MII_ADDR_SHIFT				11
 31#define MII_ADDR_MASK				GENMASK(15, 11)
 32
 33#define MII_DATA_REG_ADDR                       0x14
 34
 35#define MII_MDIO_DELAY_USEC                     (1000)
 36#define MII_MDIO_RETRY_MSEC                     (10)
 37
 38struct ipq8064_mdio {
 39	struct regmap *base; /* NSS_GMAC0_BASE */
 40};
 41
 42static int
 43ipq8064_mdio_wait_busy(struct ipq8064_mdio *priv)
 44{
 45	u32 busy;
 46
 47	return regmap_read_poll_timeout(priv->base, MII_ADDR_REG_ADDR, busy,
 48					!(busy & MII_BUSY), MII_MDIO_DELAY_USEC,
 49					MII_MDIO_RETRY_MSEC * USEC_PER_MSEC);
 50}
 51
 52static int
 53ipq8064_mdio_read(struct mii_bus *bus, int phy_addr, int reg_offset)
 54{
 55	u32 miiaddr = MII_BUSY | MII_CLKRANGE_250_300M;
 56	struct ipq8064_mdio *priv = bus->priv;
 57	u32 ret_val;
 58	int err;
 59
 60	/* Reject clause 45 */
 61	if (reg_offset & MII_ADDR_C45)
 62		return -EOPNOTSUPP;
 63
 64	miiaddr |= ((phy_addr << MII_ADDR_SHIFT) & MII_ADDR_MASK) |
 65		   ((reg_offset << MII_REG_SHIFT) & MII_REG_MASK);
 66
 67	regmap_write(priv->base, MII_ADDR_REG_ADDR, miiaddr);
 68	usleep_range(8, 10);
 69
 70	err = ipq8064_mdio_wait_busy(priv);
 71	if (err)
 72		return err;
 73
 74	regmap_read(priv->base, MII_DATA_REG_ADDR, &ret_val);
 75	return (int)ret_val;
 76}
 77
 78static int
 79ipq8064_mdio_write(struct mii_bus *bus, int phy_addr, int reg_offset, u16 data)
 80{
 81	u32 miiaddr = MII_WRITE | MII_BUSY | MII_CLKRANGE_250_300M;
 82	struct ipq8064_mdio *priv = bus->priv;
 83
 84	/* Reject clause 45 */
 85	if (reg_offset & MII_ADDR_C45)
 86		return -EOPNOTSUPP;
 87
 88	regmap_write(priv->base, MII_DATA_REG_ADDR, data);
 89
 90	miiaddr |= ((phy_addr << MII_ADDR_SHIFT) & MII_ADDR_MASK) |
 91		   ((reg_offset << MII_REG_SHIFT) & MII_REG_MASK);
 92
 93	regmap_write(priv->base, MII_ADDR_REG_ADDR, miiaddr);
 94	usleep_range(8, 10);
 95
 96	return ipq8064_mdio_wait_busy(priv);
 97}
 98
 99static int
100ipq8064_mdio_probe(struct platform_device *pdev)
101{
102	struct device_node *np = pdev->dev.of_node;
103	struct ipq8064_mdio *priv;
104	struct mii_bus *bus;
105	int ret;
106
107	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*priv));
108	if (!bus)
109		return -ENOMEM;
110
111	bus->name = "ipq8064_mdio_bus";
112	bus->read = ipq8064_mdio_read;
113	bus->write = ipq8064_mdio_write;
114	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
115	bus->parent = &pdev->dev;
116
117	priv = bus->priv;
118	priv->base = device_node_to_regmap(np);
119	if (IS_ERR(priv->base)) {
120		if (priv->base == ERR_PTR(-EPROBE_DEFER))
121			return -EPROBE_DEFER;
122
123		dev_err(&pdev->dev, "error getting device regmap, error=%pe\n",
124			priv->base);
125		return PTR_ERR(priv->base);
126	}
127
128	ret = of_mdiobus_register(bus, np);
129	if (ret)
130		return ret;
131
132	platform_set_drvdata(pdev, bus);
133	return 0;
134}
135
136static int
137ipq8064_mdio_remove(struct platform_device *pdev)
138{
139	struct mii_bus *bus = platform_get_drvdata(pdev);
140
141	mdiobus_unregister(bus);
142
143	return 0;
144}
145
146static const struct of_device_id ipq8064_mdio_dt_ids[] = {
147	{ .compatible = "qcom,ipq8064-mdio" },
148	{ }
149};
150MODULE_DEVICE_TABLE(of, ipq8064_mdio_dt_ids);
151
152static struct platform_driver ipq8064_mdio_driver = {
153	.probe = ipq8064_mdio_probe,
154	.remove = ipq8064_mdio_remove,
155	.driver = {
156		.name = "ipq8064-mdio",
157		.of_match_table = ipq8064_mdio_dt_ids,
158	},
159};
160
161module_platform_driver(ipq8064_mdio_driver);
162
163MODULE_DESCRIPTION("Qualcomm IPQ8064 MDIO interface driver");
164MODULE_AUTHOR("Christian Lamparter <chunkeey@gmail.com>");
165MODULE_AUTHOR("Ansuel Smith <ansuelsmth@gmail.com>");
166MODULE_LICENSE("GPL");