1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2015 Broadcom Corporation
  4 */
  5
  6#include <linux/delay.h>
  7#include <linux/io.h>
  8#include <linux/kernel.h>
  9#include <linux/module.h>
 10#include <linux/of.h>
 11#include <linux/of_platform.h>
 12#include <linux/of_mdio.h>
 13#include <linux/phy.h>
 14#include <linux/platform_device.h>
 15#include <linux/sched.h>
 16
 17#define IPROC_GPHY_MDCDIV    0x1a
 18
 19#define MII_CTRL_OFFSET      0x000
 20
 21#define MII_CTRL_DIV_SHIFT   0
 22#define MII_CTRL_PRE_SHIFT   7
 23#define MII_CTRL_BUSY_SHIFT  8
 24
 25#define MII_DATA_OFFSET      0x004
 26#define MII_DATA_MASK        0xffff
 27#define MII_DATA_TA_SHIFT    16
 28#define MII_DATA_TA_VAL      2
 29#define MII_DATA_RA_SHIFT    18
 30#define MII_DATA_PA_SHIFT    23
 31#define MII_DATA_OP_SHIFT    28
 32#define MII_DATA_OP_WRITE    1
 33#define MII_DATA_OP_READ     2
 34#define MII_DATA_SB_SHIFT    30
 35
 36struct iproc_mdio_priv {
 37	struct mii_bus *mii_bus;
 38	void __iomem *base;
 39};
 40
 41static inline int iproc_mdio_wait_for_idle(void __iomem *base)
 42{
 43	u32 val;
 44	unsigned int timeout = 1000; /* loop for 1s */
 45
 46	do {
 47		val = readl(base + MII_CTRL_OFFSET);
 48		if ((val & BIT(MII_CTRL_BUSY_SHIFT)) == 0)
 49			return 0;
 50
 51		usleep_range(1000, 2000);
 52	} while (timeout--);
 53
 54	return -ETIMEDOUT;
 55}
 56
 57static inline void iproc_mdio_config_clk(void __iomem *base)
 58{
 59	u32 val;
 60
 61	val = (IPROC_GPHY_MDCDIV << MII_CTRL_DIV_SHIFT) |
 62		  BIT(MII_CTRL_PRE_SHIFT);
 63	writel(val, base + MII_CTRL_OFFSET);
 64}
 65
 66static int iproc_mdio_read(struct mii_bus *bus, int phy_id, int reg)
 67{
 68	struct iproc_mdio_priv *priv = bus->priv;
 69	u32 cmd;
 70	int rc;
 71
 72	rc = iproc_mdio_wait_for_idle(priv->base);
 73	if (rc)
 74		return rc;
 75
 76	/* Prepare the read operation */
 77	cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
 78		(reg << MII_DATA_RA_SHIFT) |
 79		(phy_id << MII_DATA_PA_SHIFT) |
 80		BIT(MII_DATA_SB_SHIFT) |
 81		(MII_DATA_OP_READ << MII_DATA_OP_SHIFT);
 82
 83	writel(cmd, priv->base + MII_DATA_OFFSET);
 84
 85	rc = iproc_mdio_wait_for_idle(priv->base);
 86	if (rc)
 87		return rc;
 88
 89	cmd = readl(priv->base + MII_DATA_OFFSET) & MII_DATA_MASK;
 90
 91	return cmd;
 92}
 93
 94static int iproc_mdio_write(struct mii_bus *bus, int phy_id,
 95			    int reg, u16 val)
 96{
 97	struct iproc_mdio_priv *priv = bus->priv;
 98	u32 cmd;
 99	int rc;
100
101	rc = iproc_mdio_wait_for_idle(priv->base);
102	if (rc)
103		return rc;
104
105	/* Prepare the write operation */
106	cmd = (MII_DATA_TA_VAL << MII_DATA_TA_SHIFT) |
107		(reg << MII_DATA_RA_SHIFT) |
108		(phy_id << MII_DATA_PA_SHIFT) |
109		BIT(MII_DATA_SB_SHIFT) |
110		(MII_DATA_OP_WRITE << MII_DATA_OP_SHIFT) |
111		((u32)(val) & MII_DATA_MASK);
112
113	writel(cmd, priv->base + MII_DATA_OFFSET);
114
115	rc = iproc_mdio_wait_for_idle(priv->base);
116	if (rc)
117		return rc;
118
119	return 0;
120}
121
122static int iproc_mdio_probe(struct platform_device *pdev)
123{
124	struct iproc_mdio_priv *priv;
125	struct mii_bus *bus;
126	int rc;
127
128	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
129	if (!priv)
130		return -ENOMEM;
131
132	priv->base = devm_platform_ioremap_resource(pdev, 0);
133	if (IS_ERR(priv->base)) {
134		dev_err(&pdev->dev, "failed to ioremap register\n");
135		return PTR_ERR(priv->base);
136	}
137
138	priv->mii_bus = mdiobus_alloc();
139	if (!priv->mii_bus) {
140		dev_err(&pdev->dev, "MDIO bus alloc failed\n");
141		return -ENOMEM;
142	}
143
144	bus = priv->mii_bus;
145	bus->priv = priv;
146	bus->name = "iProc MDIO bus";
147	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
148	bus->parent = &pdev->dev;
149	bus->read = iproc_mdio_read;
150	bus->write = iproc_mdio_write;
151
152	iproc_mdio_config_clk(priv->base);
153
154	rc = of_mdiobus_register(bus, pdev->dev.of_node);
155	if (rc) {
156		dev_err(&pdev->dev, "MDIO bus registration failed\n");
157		goto err_iproc_mdio;
158	}
159
160	platform_set_drvdata(pdev, priv);
161
162	dev_info(&pdev->dev, "Broadcom iProc MDIO bus registered\n");
163
164	return 0;
165
166err_iproc_mdio:
167	mdiobus_free(bus);
168	return rc;
169}
170
171static void iproc_mdio_remove(struct platform_device *pdev)
172{
173	struct iproc_mdio_priv *priv = platform_get_drvdata(pdev);
174
175	mdiobus_unregister(priv->mii_bus);
176	mdiobus_free(priv->mii_bus);
177}
178
179#ifdef CONFIG_PM_SLEEP
180static int iproc_mdio_resume(struct device *dev)
181{
182	struct platform_device *pdev = to_platform_device(dev);
183	struct iproc_mdio_priv *priv = platform_get_drvdata(pdev);
184
185	/* restore the mii clock configuration */
186	iproc_mdio_config_clk(priv->base);
187
188	return 0;
189}
190
191static const struct dev_pm_ops iproc_mdio_pm_ops = {
192	.resume = iproc_mdio_resume
193};
194#endif /* CONFIG_PM_SLEEP */
195
196static const struct of_device_id iproc_mdio_of_match[] = {
197	{ .compatible = "brcm,iproc-mdio", },
198	{ /* sentinel */ },
199};
200MODULE_DEVICE_TABLE(of, iproc_mdio_of_match);
201
202static struct platform_driver iproc_mdio_driver = {
203	.driver = {
204		.name = "iproc-mdio",
205		.of_match_table = iproc_mdio_of_match,
206#ifdef CONFIG_PM_SLEEP
207		.pm = &iproc_mdio_pm_ops,
208#endif
209	},
210	.probe = iproc_mdio_probe,
211	.remove_new = iproc_mdio_remove,
212};
213
214module_platform_driver(iproc_mdio_driver);
215
216MODULE_AUTHOR("Broadcom Corporation");
217MODULE_DESCRIPTION("Broadcom iProc MDIO bus controller");
218MODULE_LICENSE("GPL v2");
219MODULE_ALIAS("platform:iproc-mdio");