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");
220