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 
36 struct iproc_mdio_priv {
37 	struct mii_bus *mii_bus;
38 	void __iomem *base;
39 };
40 
41 static 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 
57 static 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 
66 static 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 
94 static 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 
122 static 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 
166 err_iproc_mdio:
167 	mdiobus_free(bus);
168 	return rc;
169 }
170 
171 static int 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 	return 0;
179 }
180 
181 #ifdef CONFIG_PM_SLEEP
182 static int iproc_mdio_resume(struct device *dev)
183 {
184 	struct platform_device *pdev = to_platform_device(dev);
185 	struct iproc_mdio_priv *priv = platform_get_drvdata(pdev);
186 
187 	/* restore the mii clock configuration */
188 	iproc_mdio_config_clk(priv->base);
189 
190 	return 0;
191 }
192 
193 static const struct dev_pm_ops iproc_mdio_pm_ops = {
194 	.resume = iproc_mdio_resume
195 };
196 #endif /* CONFIG_PM_SLEEP */
197 
198 static const struct of_device_id iproc_mdio_of_match[] = {
199 	{ .compatible = "brcm,iproc-mdio", },
200 	{ /* sentinel */ },
201 };
202 MODULE_DEVICE_TABLE(of, iproc_mdio_of_match);
203 
204 static struct platform_driver iproc_mdio_driver = {
205 	.driver = {
206 		.name = "iproc-mdio",
207 		.of_match_table = iproc_mdio_of_match,
208 #ifdef CONFIG_PM_SLEEP
209 		.pm = &iproc_mdio_pm_ops,
210 #endif
211 	},
212 	.probe = iproc_mdio_probe,
213 	.remove = iproc_mdio_remove,
214 };
215 
216 module_platform_driver(iproc_mdio_driver);
217 
218 MODULE_AUTHOR("Broadcom Corporation");
219 MODULE_DESCRIPTION("Broadcom iProc MDIO bus controller");
220 MODULE_LICENSE("GPL v2");
221 MODULE_ALIAS("platform:iproc-mdio");
222