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22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/i2c.h>
26#include <linux/i2c-mux.h>
27#include <linux/of.h>
28#include <linux/of_i2c.h>
29
30
31struct i2c_mux_priv {
32 struct i2c_adapter adap;
33 struct i2c_algorithm algo;
34
35 struct i2c_adapter *parent;
36 void *mux_priv;
37 u32 chan_id;
38
39 int (*select)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
40 int (*deselect)(struct i2c_adapter *, void *mux_priv, u32 chan_id);
41};
42
43static int i2c_mux_master_xfer(struct i2c_adapter *adap,
44 struct i2c_msg msgs[], int num)
45{
46 struct i2c_mux_priv *priv = adap->algo_data;
47 struct i2c_adapter *parent = priv->parent;
48 int ret;
49
50
51
52 ret = priv->select(parent, priv->mux_priv, priv->chan_id);
53 if (ret >= 0)
54 ret = parent->algo->master_xfer(parent, msgs, num);
55 if (priv->deselect)
56 priv->deselect(parent, priv->mux_priv, priv->chan_id);
57
58 return ret;
59}
60
61static int i2c_mux_smbus_xfer(struct i2c_adapter *adap,
62 u16 addr, unsigned short flags,
63 char read_write, u8 command,
64 int size, union i2c_smbus_data *data)
65{
66 struct i2c_mux_priv *priv = adap->algo_data;
67 struct i2c_adapter *parent = priv->parent;
68 int ret;
69
70
71
72 ret = priv->select(parent, priv->mux_priv, priv->chan_id);
73 if (ret >= 0)
74 ret = parent->algo->smbus_xfer(parent, addr, flags,
75 read_write, command, size, data);
76 if (priv->deselect)
77 priv->deselect(parent, priv->mux_priv, priv->chan_id);
78
79 return ret;
80}
81
82
83static u32 i2c_mux_functionality(struct i2c_adapter *adap)
84{
85 struct i2c_mux_priv *priv = adap->algo_data;
86 struct i2c_adapter *parent = priv->parent;
87
88 return parent->algo->functionality(parent);
89}
90
91struct i2c_adapter *i2c_add_mux_adapter(struct i2c_adapter *parent,
92 struct device *mux_dev,
93 void *mux_priv, u32 force_nr, u32 chan_id,
94 int (*select) (struct i2c_adapter *,
95 void *, u32),
96 int (*deselect) (struct i2c_adapter *,
97 void *, u32))
98{
99 struct i2c_mux_priv *priv;
100 int ret;
101
102 priv = kzalloc(sizeof(struct i2c_mux_priv), GFP_KERNEL);
103 if (!priv)
104 return NULL;
105
106
107 priv->parent = parent;
108 priv->mux_priv = mux_priv;
109 priv->chan_id = chan_id;
110 priv->select = select;
111 priv->deselect = deselect;
112
113
114
115
116 if (parent->algo->master_xfer)
117 priv->algo.master_xfer = i2c_mux_master_xfer;
118 if (parent->algo->smbus_xfer)
119 priv->algo.smbus_xfer = i2c_mux_smbus_xfer;
120 priv->algo.functionality = i2c_mux_functionality;
121
122
123 snprintf(priv->adap.name, sizeof(priv->adap.name),
124 "i2c-%d-mux (chan_id %d)", i2c_adapter_id(parent), chan_id);
125 priv->adap.owner = THIS_MODULE;
126 priv->adap.algo = &priv->algo;
127 priv->adap.algo_data = priv;
128 priv->adap.dev.parent = &parent->dev;
129
130
131
132
133
134 if (mux_dev->of_node) {
135 struct device_node *child;
136 u32 reg;
137
138 for_each_child_of_node(mux_dev->of_node, child) {
139 ret = of_property_read_u32(child, "reg", ®);
140 if (ret)
141 continue;
142 if (chan_id == reg) {
143 priv->adap.dev.of_node = child;
144 break;
145 }
146 }
147 }
148
149 if (force_nr) {
150 priv->adap.nr = force_nr;
151 ret = i2c_add_numbered_adapter(&priv->adap);
152 } else {
153 ret = i2c_add_adapter(&priv->adap);
154 }
155 if (ret < 0) {
156 dev_err(&parent->dev,
157 "failed to add mux-adapter (error=%d)\n",
158 ret);
159 kfree(priv);
160 return NULL;
161 }
162
163 dev_info(&parent->dev, "Added multiplexed i2c bus %d\n",
164 i2c_adapter_id(&priv->adap));
165
166 of_i2c_register_devices(&priv->adap);
167
168 return &priv->adap;
169}
170EXPORT_SYMBOL_GPL(i2c_add_mux_adapter);
171
172int i2c_del_mux_adapter(struct i2c_adapter *adap)
173{
174 struct i2c_mux_priv *priv = adap->algo_data;
175 int ret;
176
177 ret = i2c_del_adapter(adap);
178 if (ret < 0)
179 return ret;
180 kfree(priv);
181
182 return 0;
183}
184EXPORT_SYMBOL_GPL(i2c_del_mux_adapter);
185
186MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
187MODULE_DESCRIPTION("I2C driver for multiplexed I2C busses");
188MODULE_LICENSE("GPL v2");
189