1
2
3
4
5
6
7
8
9
10#include <linux/i2c.h>
11#include <linux/i2c-mux.h>
12#include <linux/module.h>
13#include <linux/mux/consumer.h>
14#include <linux/of_device.h>
15#include <linux/platform_device.h>
16
17struct mux {
18 struct mux_control *control;
19
20 bool do_not_deselect;
21};
22
23static int i2c_mux_select(struct i2c_mux_core *muxc, u32 chan)
24{
25 struct mux *mux = i2c_mux_priv(muxc);
26 int ret;
27
28 ret = mux_control_select(mux->control, chan);
29 mux->do_not_deselect = ret < 0;
30
31 return ret;
32}
33
34static int i2c_mux_deselect(struct i2c_mux_core *muxc, u32 chan)
35{
36 struct mux *mux = i2c_mux_priv(muxc);
37
38 if (mux->do_not_deselect)
39 return 0;
40
41 return mux_control_deselect(mux->control);
42}
43
44static struct i2c_adapter *mux_parent_adapter(struct device *dev)
45{
46 struct device_node *np = dev->of_node;
47 struct device_node *parent_np;
48 struct i2c_adapter *parent;
49
50 parent_np = of_parse_phandle(np, "i2c-parent", 0);
51 if (!parent_np) {
52 dev_err(dev, "Cannot parse i2c-parent\n");
53 return ERR_PTR(-ENODEV);
54 }
55 parent = of_find_i2c_adapter_by_node(parent_np);
56 of_node_put(parent_np);
57 if (!parent)
58 return ERR_PTR(-EPROBE_DEFER);
59
60 return parent;
61}
62
63static const struct of_device_id i2c_mux_of_match[] = {
64 { .compatible = "i2c-mux", },
65 {},
66};
67MODULE_DEVICE_TABLE(of, i2c_mux_of_match);
68
69static int i2c_mux_probe(struct platform_device *pdev)
70{
71 struct device *dev = &pdev->dev;
72 struct device_node *np = dev->of_node;
73 struct device_node *child;
74 struct i2c_mux_core *muxc;
75 struct mux *mux;
76 struct i2c_adapter *parent;
77 int children;
78 int ret;
79
80 if (!np)
81 return -ENODEV;
82
83 mux = devm_kzalloc(dev, sizeof(*mux), GFP_KERNEL);
84 if (!mux)
85 return -ENOMEM;
86
87 mux->control = devm_mux_control_get(dev, NULL);
88 if (IS_ERR(mux->control))
89 return dev_err_probe(dev, PTR_ERR(mux->control),
90 "failed to get control-mux\n");
91
92 parent = mux_parent_adapter(dev);
93 if (IS_ERR(parent))
94 return dev_err_probe(dev, PTR_ERR(parent),
95 "failed to get i2c-parent adapter\n");
96
97 children = of_get_child_count(np);
98
99 muxc = i2c_mux_alloc(parent, dev, children, 0, 0,
100 i2c_mux_select, i2c_mux_deselect);
101 if (!muxc) {
102 ret = -ENOMEM;
103 goto err_parent;
104 }
105 muxc->priv = mux;
106
107 platform_set_drvdata(pdev, muxc);
108
109 muxc->mux_locked = of_property_read_bool(np, "mux-locked");
110
111 for_each_child_of_node(np, child) {
112 u32 chan;
113
114 ret = of_property_read_u32(child, "reg", &chan);
115 if (ret < 0) {
116 dev_err(dev, "no reg property for node '%pOFn'\n",
117 child);
118 goto err_children;
119 }
120
121 if (chan >= mux_control_states(mux->control)) {
122 dev_err(dev, "invalid reg %u\n", chan);
123 ret = -EINVAL;
124 goto err_children;
125 }
126
127 ret = i2c_mux_add_adapter(muxc, 0, chan, 0);
128 if (ret)
129 goto err_children;
130 }
131
132 dev_info(dev, "%d-port mux on %s adapter\n", children, parent->name);
133
134 return 0;
135
136err_children:
137 i2c_mux_del_adapters(muxc);
138err_parent:
139 i2c_put_adapter(parent);
140
141 return ret;
142}
143
144static int i2c_mux_remove(struct platform_device *pdev)
145{
146 struct i2c_mux_core *muxc = platform_get_drvdata(pdev);
147
148 i2c_mux_del_adapters(muxc);
149 i2c_put_adapter(muxc->parent);
150
151 return 0;
152}
153
154static struct platform_driver i2c_mux_driver = {
155 .probe = i2c_mux_probe,
156 .remove = i2c_mux_remove,
157 .driver = {
158 .name = "i2c-mux-gpmux",
159 .of_match_table = i2c_mux_of_match,
160 },
161};
162module_platform_driver(i2c_mux_driver);
163
164MODULE_DESCRIPTION("General Purpose I2C multiplexer driver");
165MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
166MODULE_LICENSE("GPL v2");
167
