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4
5
6#include <linux/device.h>
7#include <linux/mdio-mux.h>
8#include <linux/module.h>
9#include <linux/of_mdio.h>
10#include <linux/phy.h>
11#include <linux/platform_device.h>
12
13#define DRV_DESCRIPTION "MDIO bus multiplexer driver"
14
15struct mdio_mux_child_bus;
16
17struct mdio_mux_parent_bus {
18 struct mii_bus *mii_bus;
19 int current_child;
20 int parent_id;
21 void *switch_data;
22 int (*switch_fn)(int current_child, int desired_child, void *data);
23
24
25 struct mdio_mux_child_bus *children;
26};
27
28struct mdio_mux_child_bus {
29 struct mii_bus *mii_bus;
30 struct mdio_mux_parent_bus *parent;
31 struct mdio_mux_child_bus *next;
32 int bus_number;
33};
34
35
36
37
38static int mdio_mux_read(struct mii_bus *bus, int phy_id, int regnum)
39{
40 struct mdio_mux_child_bus *cb = bus->priv;
41 struct mdio_mux_parent_bus *pb = cb->parent;
42 int r;
43
44 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
45 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
46 if (r)
47 goto out;
48
49 pb->current_child = cb->bus_number;
50
51 r = pb->mii_bus->read(pb->mii_bus, phy_id, regnum);
52out:
53 mutex_unlock(&pb->mii_bus->mdio_lock);
54
55 return r;
56}
57
58
59
60
61static int mdio_mux_write(struct mii_bus *bus, int phy_id,
62 int regnum, u16 val)
63{
64 struct mdio_mux_child_bus *cb = bus->priv;
65 struct mdio_mux_parent_bus *pb = cb->parent;
66
67 int r;
68
69 mutex_lock_nested(&pb->mii_bus->mdio_lock, MDIO_MUTEX_MUX);
70 r = pb->switch_fn(pb->current_child, cb->bus_number, pb->switch_data);
71 if (r)
72 goto out;
73
74 pb->current_child = cb->bus_number;
75
76 r = pb->mii_bus->write(pb->mii_bus, phy_id, regnum, val);
77out:
78 mutex_unlock(&pb->mii_bus->mdio_lock);
79
80 return r;
81}
82
83static int parent_count;
84
85static void mdio_mux_uninit_children(struct mdio_mux_parent_bus *pb)
86{
87 struct mdio_mux_child_bus *cb = pb->children;
88
89 while (cb) {
90 mdiobus_unregister(cb->mii_bus);
91 mdiobus_free(cb->mii_bus);
92 cb = cb->next;
93 }
94}
95
96int mdio_mux_init(struct device *dev,
97 struct device_node *mux_node,
98 int (*switch_fn)(int cur, int desired, void *data),
99 void **mux_handle,
100 void *data,
101 struct mii_bus *mux_bus)
102{
103 struct device_node *parent_bus_node;
104 struct device_node *child_bus_node;
105 int r, ret_val;
106 struct mii_bus *parent_bus;
107 struct mdio_mux_parent_bus *pb;
108 struct mdio_mux_child_bus *cb;
109
110 if (!mux_node)
111 return -ENODEV;
112
113 if (!mux_bus) {
114 parent_bus_node = of_parse_phandle(mux_node,
115 "mdio-parent-bus", 0);
116
117 if (!parent_bus_node)
118 return -ENODEV;
119
120 parent_bus = of_mdio_find_bus(parent_bus_node);
121 if (!parent_bus) {
122 ret_val = -EPROBE_DEFER;
123 goto err_parent_bus;
124 }
125 } else {
126 parent_bus_node = NULL;
127 parent_bus = mux_bus;
128 get_device(&parent_bus->dev);
129 }
130
131 pb = devm_kzalloc(dev, sizeof(*pb), GFP_KERNEL);
132 if (!pb) {
133 ret_val = -ENOMEM;
134 goto err_pb_kz;
135 }
136
137 pb->switch_data = data;
138 pb->switch_fn = switch_fn;
139 pb->current_child = -1;
140 pb->parent_id = parent_count++;
141 pb->mii_bus = parent_bus;
142
143 ret_val = -ENODEV;
144 for_each_available_child_of_node(mux_node, child_bus_node) {
145 int v;
146
147 r = of_property_read_u32(child_bus_node, "reg", &v);
148 if (r) {
149 dev_err(dev,
150 "Error: Failed to find reg for child %pOF\n",
151 child_bus_node);
152 continue;
153 }
154
155 cb = devm_kzalloc(dev, sizeof(*cb), GFP_KERNEL);
156 if (!cb) {
157 ret_val = -ENOMEM;
158 goto err_loop;
159 }
160 cb->bus_number = v;
161 cb->parent = pb;
162
163 cb->mii_bus = mdiobus_alloc();
164 if (!cb->mii_bus) {
165 ret_val = -ENOMEM;
166 goto err_loop;
167 }
168 cb->mii_bus->priv = cb;
169
170 cb->mii_bus->name = "mdio_mux";
171 snprintf(cb->mii_bus->id, MII_BUS_ID_SIZE, "%x.%x",
172 pb->parent_id, v);
173 cb->mii_bus->parent = dev;
174 cb->mii_bus->read = mdio_mux_read;
175 cb->mii_bus->write = mdio_mux_write;
176 r = of_mdiobus_register(cb->mii_bus, child_bus_node);
177 if (r) {
178 mdiobus_free(cb->mii_bus);
179 if (r == -EPROBE_DEFER) {
180 ret_val = r;
181 goto err_loop;
182 }
183 devm_kfree(dev, cb);
184 dev_err(dev,
185 "Error: Failed to register MDIO bus for child %pOF\n",
186 child_bus_node);
187 } else {
188 cb->next = pb->children;
189 pb->children = cb;
190 }
191 }
192 if (pb->children) {
193 *mux_handle = pb;
194 return 0;
195 }
196
197 dev_err(dev, "Error: No acceptable child buses found\n");
198
199err_loop:
200 mdio_mux_uninit_children(pb);
201 of_node_put(child_bus_node);
202err_pb_kz:
203 put_device(&parent_bus->dev);
204err_parent_bus:
205 of_node_put(parent_bus_node);
206 return ret_val;
207}
208EXPORT_SYMBOL_GPL(mdio_mux_init);
209
210void mdio_mux_uninit(void *mux_handle)
211{
212 struct mdio_mux_parent_bus *pb = mux_handle;
213
214 mdio_mux_uninit_children(pb);
215 put_device(&pb->mii_bus->dev);
216}
217EXPORT_SYMBOL_GPL(mdio_mux_uninit);
218
219MODULE_DESCRIPTION(DRV_DESCRIPTION);
220MODULE_AUTHOR("David Daney");
221MODULE_LICENSE("GPL v2");
222
