1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
  2/* Copyright (c) 2015, The Linux Foundation. All rights reserved. */
  3/* Copyright (c) 2020 Sartura Ltd. */
  4
  5#include <linux/delay.h>
  6#include <linux/kernel.h>
  7#include <linux/module.h>
  8#include <linux/io.h>
  9#include <linux/iopoll.h>
 10#include <linux/of_address.h>
 11#include <linux/of_mdio.h>
 12#include <linux/phy.h>
 13#include <linux/platform_device.h>
 14
 15#define MDIO_ADDR_REG				0x44
 16#define MDIO_DATA_WRITE_REG			0x48
 17#define MDIO_DATA_READ_REG			0x4c
 18#define MDIO_CMD_REG				0x50
 19#define MDIO_CMD_ACCESS_BUSY		BIT(16)
 20#define MDIO_CMD_ACCESS_START		BIT(8)
 21#define MDIO_CMD_ACCESS_CODE_READ	0
 22#define MDIO_CMD_ACCESS_CODE_WRITE	1
 23
 24#define ipq4019_MDIO_TIMEOUT	10000
 25#define ipq4019_MDIO_SLEEP		10
 26
 27struct ipq4019_mdio_data {
 28	void __iomem	*membase;
 29};
 30
 31static int ipq4019_mdio_wait_busy(struct mii_bus *bus)
 32{
 33	struct ipq4019_mdio_data *priv = bus->priv;
 34	unsigned int busy;
 35
 36	return readl_poll_timeout(priv->membase + MDIO_CMD_REG, busy,
 37				  (busy & MDIO_CMD_ACCESS_BUSY) == 0,
 38				  ipq4019_MDIO_SLEEP, ipq4019_MDIO_TIMEOUT);
 39}
 40
 41static int ipq4019_mdio_read(struct mii_bus *bus, int mii_id, int regnum)
 42{
 43	struct ipq4019_mdio_data *priv = bus->priv;
 44	unsigned int cmd;
 45
 46	/* Reject clause 45 */
 47	if (regnum & MII_ADDR_C45)
 48		return -EOPNOTSUPP;
 49
 50	if (ipq4019_mdio_wait_busy(bus))
 51		return -ETIMEDOUT;
 52
 53	/* issue the phy address and reg */
 54	writel((mii_id << 8) | regnum, priv->membase + MDIO_ADDR_REG);
 55
 56	cmd = MDIO_CMD_ACCESS_START | MDIO_CMD_ACCESS_CODE_READ;
 57
 58	/* issue read command */
 59	writel(cmd, priv->membase + MDIO_CMD_REG);
 60
 61	/* Wait read complete */
 62	if (ipq4019_mdio_wait_busy(bus))
 63		return -ETIMEDOUT;
 64
 65	/* Read and return data */
 66	return readl(priv->membase + MDIO_DATA_READ_REG);
 67}
 68
 69static int ipq4019_mdio_write(struct mii_bus *bus, int mii_id, int regnum,
 70							 u16 value)
 71{
 72	struct ipq4019_mdio_data *priv = bus->priv;
 73	unsigned int cmd;
 74
 75	/* Reject clause 45 */
 76	if (regnum & MII_ADDR_C45)
 77		return -EOPNOTSUPP;
 78
 79	if (ipq4019_mdio_wait_busy(bus))
 80		return -ETIMEDOUT;
 81
 82	/* issue the phy address and reg */
 83	writel((mii_id << 8) | regnum, priv->membase + MDIO_ADDR_REG);
 84
 85	/* issue write data */
 86	writel(value, priv->membase + MDIO_DATA_WRITE_REG);
 87
 88	cmd = MDIO_CMD_ACCESS_START | MDIO_CMD_ACCESS_CODE_WRITE;
 89	/* issue write command */
 90	writel(cmd, priv->membase + MDIO_CMD_REG);
 91
 92	/* Wait write complete */
 93	if (ipq4019_mdio_wait_busy(bus))
 94		return -ETIMEDOUT;
 95
 96	return 0;
 97}
 98
 99static int ipq4019_mdio_probe(struct platform_device *pdev)
100{
101	struct ipq4019_mdio_data *priv;
102	struct mii_bus *bus;
103	int ret;
104
105	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*priv));
106	if (!bus)
107		return -ENOMEM;
108
109	priv = bus->priv;
110
111	priv->membase = devm_platform_ioremap_resource(pdev, 0);
112	if (IS_ERR(priv->membase))
113		return PTR_ERR(priv->membase);
114
115	bus->name = "ipq4019_mdio";
116	bus->read = ipq4019_mdio_read;
117	bus->write = ipq4019_mdio_write;
118	bus->parent = &pdev->dev;
119	snprintf(bus->id, MII_BUS_ID_SIZE, "%s%d", pdev->name, pdev->id);
120
121	ret = of_mdiobus_register(bus, pdev->dev.of_node);
122	if (ret) {
123		dev_err(&pdev->dev, "Cannot register MDIO bus!\n");
124		return ret;
125	}
126
127	platform_set_drvdata(pdev, bus);
128
129	return 0;
130}
131
132static int ipq4019_mdio_remove(struct platform_device *pdev)
133{
134	struct mii_bus *bus = platform_get_drvdata(pdev);
135
136	mdiobus_unregister(bus);
137
138	return 0;
139}
140
141static const struct of_device_id ipq4019_mdio_dt_ids[] = {
142	{ .compatible = "qcom,ipq4019-mdio" },
143	{ }
144};
145MODULE_DEVICE_TABLE(of, ipq4019_mdio_dt_ids);
146
147static struct platform_driver ipq4019_mdio_driver = {
148	.probe = ipq4019_mdio_probe,
149	.remove = ipq4019_mdio_remove,
150	.driver = {
151		.name = "ipq4019-mdio",
152		.of_match_table = ipq4019_mdio_dt_ids,
153	},
154};
155
156module_platform_driver(ipq4019_mdio_driver);
157
158MODULE_DESCRIPTION("ipq4019 MDIO interface driver");
159MODULE_AUTHOR("Qualcomm Atheros");
160MODULE_LICENSE("Dual BSD/GPL");