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15#include <linux/i2c.h>
16#include <linux/init.h>
17#include <linux/module.h>
18#include <linux/of.h>
19#include <linux/pinctrl/consumer.h>
20#include <linux/platform_device.h>
21#include <linux/slab.h>
22#include <linux/sysfs.h>
23
24struct i2c_demux_pinctrl_chan {
25 struct device_node *parent_np;
26 struct i2c_adapter *parent_adap;
27 struct of_changeset chgset;
28};
29
30struct i2c_demux_pinctrl_priv {
31 int cur_chan;
32 int num_chan;
33 struct device *dev;
34 const char *bus_name;
35 struct i2c_adapter cur_adap;
36 struct i2c_algorithm algo;
37 struct i2c_demux_pinctrl_chan chan[];
38};
39
40static struct property status_okay = { .name = "status", .length = 3, .value = "ok" };
41
42static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
43{
44 struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
45 struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
46
47 return __i2c_transfer(parent, msgs, num);
48}
49
50static u32 i2c_demux_functionality(struct i2c_adapter *adap)
51{
52 struct i2c_demux_pinctrl_priv *priv = adap->algo_data;
53 struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap;
54
55 return parent->algo->functionality(parent);
56}
57
58static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
59{
60 struct i2c_adapter *adap;
61 struct pinctrl *p;
62 int ret;
63
64 ret = of_changeset_apply(&priv->chan[new_chan].chgset);
65 if (ret)
66 goto err;
67
68 adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np);
69 if (!adap) {
70 ret = -ENODEV;
71 goto err;
72 }
73
74 p = devm_pinctrl_get_select(adap->dev.parent, priv->bus_name);
75 if (IS_ERR(p)) {
76 ret = PTR_ERR(p);
77 goto err_with_put;
78 }
79
80 priv->chan[new_chan].parent_adap = adap;
81 priv->cur_chan = new_chan;
82
83
84 priv->algo.master_xfer = i2c_demux_master_xfer;
85 priv->algo.functionality = i2c_demux_functionality;
86
87 snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name),
88 "i2c-demux (master i2c-%d)", i2c_adapter_id(adap));
89 priv->cur_adap.owner = THIS_MODULE;
90 priv->cur_adap.algo = &priv->algo;
91 priv->cur_adap.algo_data = priv;
92 priv->cur_adap.dev.parent = priv->dev;
93 priv->cur_adap.class = adap->class;
94 priv->cur_adap.retries = adap->retries;
95 priv->cur_adap.timeout = adap->timeout;
96 priv->cur_adap.quirks = adap->quirks;
97 priv->cur_adap.dev.of_node = priv->dev->of_node;
98 ret = i2c_add_adapter(&priv->cur_adap);
99 if (ret < 0)
100 goto err_with_put;
101
102 return 0;
103
104 err_with_put:
105 i2c_put_adapter(adap);
106 err:
107 dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret);
108 return ret;
109}
110
111static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv)
112{
113 int ret, cur = priv->cur_chan;
114
115 if (cur < 0)
116 return 0;
117
118 i2c_del_adapter(&priv->cur_adap);
119 i2c_put_adapter(priv->chan[cur].parent_adap);
120
121 ret = of_changeset_revert(&priv->chan[cur].chgset);
122
123 priv->chan[cur].parent_adap = NULL;
124 priv->cur_chan = -EINVAL;
125
126 return ret;
127}
128
129static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan)
130{
131 int ret;
132
133 if (new_chan == priv->cur_chan)
134 return 0;
135
136 ret = i2c_demux_deactivate_master(priv);
137 if (ret)
138 return ret;
139
140 return i2c_demux_activate_master(priv, new_chan);
141}
142
143static ssize_t available_masters_show(struct device *dev,
144 struct device_attribute *attr,
145 char *buf)
146{
147 struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
148 int count = 0, i;
149
150 for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++)
151 count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%s%c",
152 i, priv->chan[i].parent_np->full_name,
153 i == priv->num_chan - 1 ? '\n' : ' ');
154
155 return count;
156}
157static DEVICE_ATTR_RO(available_masters);
158
159static ssize_t current_master_show(struct device *dev,
160 struct device_attribute *attr,
161 char *buf)
162{
163 struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
164
165 return sprintf(buf, "%d\n", priv->cur_chan);
166}
167
168static ssize_t current_master_store(struct device *dev,
169 struct device_attribute *attr,
170 const char *buf, size_t count)
171{
172 struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev);
173 unsigned int val;
174 int ret;
175
176 ret = kstrtouint(buf, 0, &val);
177 if (ret < 0)
178 return ret;
179
180 if (val >= priv->num_chan)
181 return -EINVAL;
182
183 ret = i2c_demux_change_master(priv, val);
184
185 return ret < 0 ? ret : count;
186}
187static DEVICE_ATTR_RW(current_master);
188
189static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
190{
191 struct device_node *np = pdev->dev.of_node;
192 struct i2c_demux_pinctrl_priv *priv;
193 int num_chan, i, j, err;
194
195 num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL);
196 if (num_chan < 2) {
197 dev_err(&pdev->dev, "Need at least two I2C masters to switch\n");
198 return -EINVAL;
199 }
200
201 priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
202 + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
203 if (!priv)
204 return -ENOMEM;
205
206 err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name);
207 if (err)
208 return err;
209
210 for (i = 0; i < num_chan; i++) {
211 struct device_node *adap_np;
212
213 adap_np = of_parse_phandle(np, "i2c-parent", i);
214 if (!adap_np) {
215 dev_err(&pdev->dev, "can't get phandle for parent %d\n", i);
216 err = -ENOENT;
217 goto err_rollback;
218 }
219 priv->chan[i].parent_np = adap_np;
220
221 of_changeset_init(&priv->chan[i].chgset);
222 of_changeset_update_property(&priv->chan[i].chgset, adap_np, &status_okay);
223 }
224
225 priv->num_chan = num_chan;
226 priv->dev = &pdev->dev;
227
228 platform_set_drvdata(pdev, priv);
229
230
231 i2c_demux_activate_master(priv, 0);
232
233 err = device_create_file(&pdev->dev, &dev_attr_available_masters);
234 if (err)
235 goto err_rollback;
236
237 err = device_create_file(&pdev->dev, &dev_attr_current_master);
238 if (err)
239 goto err_rollback_available;
240
241 return 0;
242
243err_rollback_available:
244 device_remove_file(&pdev->dev, &dev_attr_available_masters);
245err_rollback:
246 for (j = 0; j < i; j++) {
247 of_node_put(priv->chan[j].parent_np);
248 of_changeset_destroy(&priv->chan[j].chgset);
249 }
250
251 return err;
252}
253
254static int i2c_demux_pinctrl_remove(struct platform_device *pdev)
255{
256 struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev);
257 int i;
258
259 device_remove_file(&pdev->dev, &dev_attr_current_master);
260 device_remove_file(&pdev->dev, &dev_attr_available_masters);
261
262 i2c_demux_deactivate_master(priv);
263
264 for (i = 0; i < priv->num_chan; i++) {
265 of_node_put(priv->chan[i].parent_np);
266 of_changeset_destroy(&priv->chan[i].chgset);
267 }
268
269 return 0;
270}
271
272static const struct of_device_id i2c_demux_pinctrl_of_match[] = {
273 { .compatible = "i2c-demux-pinctrl", },
274 {},
275};
276MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match);
277
278static struct platform_driver i2c_demux_pinctrl_driver = {
279 .driver = {
280 .name = "i2c-demux-pinctrl",
281 .of_match_table = i2c_demux_pinctrl_of_match,
282 },
283 .probe = i2c_demux_pinctrl_probe,
284 .remove = i2c_demux_pinctrl_remove,
285};
286module_platform_driver(i2c_demux_pinctrl_driver);
287
288MODULE_DESCRIPTION("pinctrl-based I2C demux driver");
289MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>");
290MODULE_LICENSE("GPL v2");
291MODULE_ALIAS("platform:i2c-demux-pinctrl");
292
