1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Broadcom BCM6368 mdiomux bus controller driver
4 *
5 * Copyright (C) 2021 Álvaro Fernández Rojas <noltari@gmail.com>
6 */
7
8 #include <linux/delay.h>
9 #include <linux/io.h>
10 #include <linux/kernel.h>
11 #include <linux/mdio-mux.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/of_platform.h>
15 #include <linux/of_mdio.h>
16 #include <linux/phy.h>
17 #include <linux/platform_device.h>
18 #include <linux/sched.h>
19
20 #define MDIOC_REG 0x0
21 #define MDIOC_EXT_MASK BIT(16)
22 #define MDIOC_REG_SHIFT 20
23 #define MDIOC_PHYID_SHIFT 25
24 #define MDIOC_RD_MASK BIT(30)
25 #define MDIOC_WR_MASK BIT(31)
26
27 #define MDIOD_REG 0x4
28
29 struct bcm6368_mdiomux_desc {
30 void *mux_handle;
31 void __iomem *base;
32 struct device *dev;
33 struct mii_bus *mii_bus;
34 int ext_phy;
35 };
36
bcm6368_mdiomux_read(struct mii_bus * bus,int phy_id,int loc)37 static int bcm6368_mdiomux_read(struct mii_bus *bus, int phy_id, int loc)
38 {
39 struct bcm6368_mdiomux_desc *md = bus->priv;
40 uint32_t reg;
41 int ret;
42
43 __raw_writel(0, md->base + MDIOC_REG);
44
45 reg = MDIOC_RD_MASK |
46 (phy_id << MDIOC_PHYID_SHIFT) |
47 (loc << MDIOC_REG_SHIFT);
48 if (md->ext_phy)
49 reg |= MDIOC_EXT_MASK;
50
51 __raw_writel(reg, md->base + MDIOC_REG);
52 udelay(50);
53 ret = __raw_readw(md->base + MDIOD_REG);
54
55 return ret;
56 }
57
bcm6368_mdiomux_write(struct mii_bus * bus,int phy_id,int loc,uint16_t val)58 static int bcm6368_mdiomux_write(struct mii_bus *bus, int phy_id, int loc,
59 uint16_t val)
60 {
61 struct bcm6368_mdiomux_desc *md = bus->priv;
62 uint32_t reg;
63
64 __raw_writel(0, md->base + MDIOC_REG);
65
66 reg = MDIOC_WR_MASK |
67 (phy_id << MDIOC_PHYID_SHIFT) |
68 (loc << MDIOC_REG_SHIFT);
69 if (md->ext_phy)
70 reg |= MDIOC_EXT_MASK;
71 reg |= val;
72
73 __raw_writel(reg, md->base + MDIOC_REG);
74 udelay(50);
75
76 return 0;
77 }
78
bcm6368_mdiomux_switch_fn(int current_child,int desired_child,void * data)79 static int bcm6368_mdiomux_switch_fn(int current_child, int desired_child,
80 void *data)
81 {
82 struct bcm6368_mdiomux_desc *md = data;
83
84 md->ext_phy = desired_child;
85
86 return 0;
87 }
88
bcm6368_mdiomux_probe(struct platform_device * pdev)89 static int bcm6368_mdiomux_probe(struct platform_device *pdev)
90 {
91 struct bcm6368_mdiomux_desc *md;
92 struct mii_bus *bus;
93 struct resource *res;
94 int rc;
95
96 md = devm_kzalloc(&pdev->dev, sizeof(*md), GFP_KERNEL);
97 if (!md)
98 return -ENOMEM;
99 md->dev = &pdev->dev;
100
101 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
102 if (!res)
103 return -EINVAL;
104
105 /*
106 * Just ioremap, as this MDIO block is usually integrated into an
107 * Ethernet MAC controller register range
108 */
109 md->base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
110 if (!md->base) {
111 dev_err(&pdev->dev, "failed to ioremap register\n");
112 return -ENOMEM;
113 }
114
115 md->mii_bus = devm_mdiobus_alloc(&pdev->dev);
116 if (!md->mii_bus) {
117 dev_err(&pdev->dev, "mdiomux bus alloc failed\n");
118 return -ENOMEM;
119 }
120
121 bus = md->mii_bus;
122 bus->priv = md;
123 bus->name = "BCM6368 MDIO mux bus";
124 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-%d", pdev->name, pdev->id);
125 bus->parent = &pdev->dev;
126 bus->read = bcm6368_mdiomux_read;
127 bus->write = bcm6368_mdiomux_write;
128 bus->phy_mask = 0x3f;
129 bus->dev.of_node = pdev->dev.of_node;
130
131 rc = mdiobus_register(bus);
132 if (rc) {
133 dev_err(&pdev->dev, "mdiomux registration failed\n");
134 return rc;
135 }
136
137 platform_set_drvdata(pdev, md);
138
139 rc = mdio_mux_init(md->dev, md->dev->of_node,
140 bcm6368_mdiomux_switch_fn, &md->mux_handle, md,
141 md->mii_bus);
142 if (rc) {
143 dev_info(md->dev, "mdiomux initialization failed\n");
144 goto out_register;
145 }
146
147 dev_info(&pdev->dev, "Broadcom BCM6368 MDIO mux bus\n");
148
149 return 0;
150
151 out_register:
152 mdiobus_unregister(bus);
153 return rc;
154 }
155
bcm6368_mdiomux_remove(struct platform_device * pdev)156 static void bcm6368_mdiomux_remove(struct platform_device *pdev)
157 {
158 struct bcm6368_mdiomux_desc *md = platform_get_drvdata(pdev);
159
160 mdio_mux_uninit(md->mux_handle);
161 mdiobus_unregister(md->mii_bus);
162 }
163
164 static const struct of_device_id bcm6368_mdiomux_ids[] = {
165 { .compatible = "brcm,bcm6368-mdio-mux", },
166 { /* sentinel */ }
167 };
168 MODULE_DEVICE_TABLE(of, bcm6368_mdiomux_ids);
169
170 static struct platform_driver bcm6368_mdiomux_driver = {
171 .driver = {
172 .name = "bcm6368-mdio-mux",
173 .of_match_table = bcm6368_mdiomux_ids,
174 },
175 .probe = bcm6368_mdiomux_probe,
176 .remove_new = bcm6368_mdiomux_remove,
177 };
178 module_platform_driver(bcm6368_mdiomux_driver);
179
180 MODULE_AUTHOR("Álvaro Fernández Rojas <noltari@gmail.com>");
181 MODULE_DESCRIPTION("BCM6368 mdiomux bus controller driver");
182 MODULE_LICENSE("GPL v2");
183