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50a5ba87 WS |
1 | /* |
2 | * Pinctrl based I2C DeMultiplexer | |
3 | * | |
4 | * Copyright (C) 2015-16 by Wolfram Sang, Sang Engineering <wsa@sang-engineering.com> | |
5 | * Copyright (C) 2015-16 by Renesas Electronics Corporation | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify it | |
8 | * under the terms of the GNU General Public License as published by the | |
9 | * Free Software Foundation; version 2 of the License. | |
10 | * | |
11 | * See the bindings doc for DTS setup and the sysfs doc for usage information. | |
12 | * (look for filenames containing 'i2c-demux-pinctrl' in Documentation/) | |
13 | */ | |
14 | ||
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 | ||
24 | struct i2c_demux_pinctrl_chan { | |
25 | struct device_node *parent_np; | |
26 | struct i2c_adapter *parent_adap; | |
27 | struct of_changeset chgset; | |
28 | }; | |
29 | ||
30 | struct 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 | ||
50a5ba87 WS |
40 | static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) |
41 | { | |
42 | struct i2c_demux_pinctrl_priv *priv = adap->algo_data; | |
43 | struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap; | |
44 | ||
45 | return __i2c_transfer(parent, msgs, num); | |
46 | } | |
47 | ||
48 | static u32 i2c_demux_functionality(struct i2c_adapter *adap) | |
49 | { | |
50 | struct i2c_demux_pinctrl_priv *priv = adap->algo_data; | |
51 | struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap; | |
52 | ||
53 | return parent->algo->functionality(parent); | |
54 | } | |
55 | ||
56 | static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) | |
57 | { | |
58 | struct i2c_adapter *adap; | |
59 | struct pinctrl *p; | |
60 | int ret; | |
61 | ||
62 | ret = of_changeset_apply(&priv->chan[new_chan].chgset); | |
63 | if (ret) | |
64 | goto err; | |
65 | ||
66 | adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np); | |
67 | if (!adap) { | |
68 | ret = -ENODEV; | |
ce8cb803 | 69 | goto err_with_revert; |
50a5ba87 WS |
70 | } |
71 | ||
d052db11 WS |
72 | /* |
73 | * Check if there are pinctrl states at all. Note: we cant' use | |
74 | * devm_pinctrl_get_select() because we need to distinguish between | |
75 | * the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state(). | |
76 | */ | |
77 | p = devm_pinctrl_get(adap->dev.parent); | |
50a5ba87 WS |
78 | if (IS_ERR(p)) { |
79 | ret = PTR_ERR(p); | |
d052db11 WS |
80 | /* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */ |
81 | if (ret != -ENODEV) | |
82 | goto err_with_put; | |
83 | } else { | |
84 | /* there are states. check and use them */ | |
85 | struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name); | |
86 | ||
87 | if (IS_ERR(s)) { | |
88 | ret = PTR_ERR(s); | |
89 | goto err_with_put; | |
90 | } | |
91 | ret = pinctrl_select_state(p, s); | |
92 | if (ret < 0) | |
93 | goto err_with_put; | |
50a5ba87 WS |
94 | } |
95 | ||
96 | priv->chan[new_chan].parent_adap = adap; | |
97 | priv->cur_chan = new_chan; | |
98 | ||
99 | /* Now fill out current adapter structure. cur_chan must be up to date */ | |
100 | priv->algo.master_xfer = i2c_demux_master_xfer; | |
101 | priv->algo.functionality = i2c_demux_functionality; | |
102 | ||
103 | snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name), | |
104 | "i2c-demux (master i2c-%d)", i2c_adapter_id(adap)); | |
105 | priv->cur_adap.owner = THIS_MODULE; | |
106 | priv->cur_adap.algo = &priv->algo; | |
107 | priv->cur_adap.algo_data = priv; | |
108 | priv->cur_adap.dev.parent = priv->dev; | |
109 | priv->cur_adap.class = adap->class; | |
110 | priv->cur_adap.retries = adap->retries; | |
111 | priv->cur_adap.timeout = adap->timeout; | |
112 | priv->cur_adap.quirks = adap->quirks; | |
113 | priv->cur_adap.dev.of_node = priv->dev->of_node; | |
114 | ret = i2c_add_adapter(&priv->cur_adap); | |
115 | if (ret < 0) | |
116 | goto err_with_put; | |
117 | ||
118 | return 0; | |
119 | ||
120 | err_with_put: | |
121 | i2c_put_adapter(adap); | |
ce8cb803 WS |
122 | err_with_revert: |
123 | of_changeset_revert(&priv->chan[new_chan].chgset); | |
50a5ba87 WS |
124 | err: |
125 | dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret); | |
9a5382e8 | 126 | priv->cur_chan = -EINVAL; |
50a5ba87 WS |
127 | return ret; |
128 | } | |
129 | ||
130 | static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv) | |
131 | { | |
132 | int ret, cur = priv->cur_chan; | |
133 | ||
134 | if (cur < 0) | |
135 | return 0; | |
136 | ||
137 | i2c_del_adapter(&priv->cur_adap); | |
138 | i2c_put_adapter(priv->chan[cur].parent_adap); | |
139 | ||
140 | ret = of_changeset_revert(&priv->chan[cur].chgset); | |
141 | ||
142 | priv->chan[cur].parent_adap = NULL; | |
143 | priv->cur_chan = -EINVAL; | |
144 | ||
145 | return ret; | |
146 | } | |
147 | ||
148 | static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) | |
149 | { | |
150 | int ret; | |
151 | ||
152 | if (new_chan == priv->cur_chan) | |
153 | return 0; | |
154 | ||
155 | ret = i2c_demux_deactivate_master(priv); | |
156 | if (ret) | |
157 | return ret; | |
158 | ||
159 | return i2c_demux_activate_master(priv, new_chan); | |
160 | } | |
161 | ||
c0c508a4 BH |
162 | static ssize_t available_masters_show(struct device *dev, |
163 | struct device_attribute *attr, | |
164 | char *buf) | |
50a5ba87 WS |
165 | { |
166 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
167 | int count = 0, i; | |
168 | ||
169 | for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++) | |
453a237c RH |
170 | count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%pOF%c", |
171 | i, priv->chan[i].parent_np, | |
c0c508a4 | 172 | i == priv->num_chan - 1 ? '\n' : ' '); |
50a5ba87 WS |
173 | |
174 | return count; | |
175 | } | |
c0c508a4 | 176 | static DEVICE_ATTR_RO(available_masters); |
50a5ba87 | 177 | |
c0c508a4 BH |
178 | static ssize_t current_master_show(struct device *dev, |
179 | struct device_attribute *attr, | |
180 | char *buf) | |
181 | { | |
182 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
183 | ||
184 | return sprintf(buf, "%d\n", priv->cur_chan); | |
185 | } | |
186 | ||
187 | static ssize_t current_master_store(struct device *dev, | |
188 | struct device_attribute *attr, | |
189 | const char *buf, size_t count) | |
50a5ba87 WS |
190 | { |
191 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
192 | unsigned int val; | |
193 | int ret; | |
194 | ||
195 | ret = kstrtouint(buf, 0, &val); | |
196 | if (ret < 0) | |
197 | return ret; | |
198 | ||
199 | if (val >= priv->num_chan) | |
200 | return -EINVAL; | |
201 | ||
202 | ret = i2c_demux_change_master(priv, val); | |
203 | ||
204 | return ret < 0 ? ret : count; | |
205 | } | |
c0c508a4 | 206 | static DEVICE_ATTR_RW(current_master); |
50a5ba87 WS |
207 | |
208 | static int i2c_demux_pinctrl_probe(struct platform_device *pdev) | |
209 | { | |
210 | struct device_node *np = pdev->dev.of_node; | |
211 | struct i2c_demux_pinctrl_priv *priv; | |
e35478ea | 212 | struct property *props; |
50a5ba87 WS |
213 | int num_chan, i, j, err; |
214 | ||
215 | num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL); | |
216 | if (num_chan < 2) { | |
217 | dev_err(&pdev->dev, "Need at least two I2C masters to switch\n"); | |
218 | return -EINVAL; | |
219 | } | |
220 | ||
221 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv) | |
222 | + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL); | |
e35478ea WS |
223 | |
224 | props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL); | |
225 | ||
226 | if (!priv || !props) | |
50a5ba87 WS |
227 | return -ENOMEM; |
228 | ||
229 | err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name); | |
230 | if (err) | |
231 | return err; | |
232 | ||
233 | for (i = 0; i < num_chan; i++) { | |
234 | struct device_node *adap_np; | |
235 | ||
236 | adap_np = of_parse_phandle(np, "i2c-parent", i); | |
237 | if (!adap_np) { | |
238 | dev_err(&pdev->dev, "can't get phandle for parent %d\n", i); | |
239 | err = -ENOENT; | |
240 | goto err_rollback; | |
241 | } | |
242 | priv->chan[i].parent_np = adap_np; | |
243 | ||
e35478ea WS |
244 | props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL); |
245 | props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL); | |
246 | props[i].length = 3; | |
247 | ||
50a5ba87 | 248 | of_changeset_init(&priv->chan[i].chgset); |
e35478ea | 249 | of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]); |
50a5ba87 WS |
250 | } |
251 | ||
252 | priv->num_chan = num_chan; | |
253 | priv->dev = &pdev->dev; | |
254 | ||
255 | platform_set_drvdata(pdev, priv); | |
256 | ||
257 | /* switch to first parent as active master */ | |
258 | i2c_demux_activate_master(priv, 0); | |
259 | ||
c0c508a4 | 260 | err = device_create_file(&pdev->dev, &dev_attr_available_masters); |
50a5ba87 WS |
261 | if (err) |
262 | goto err_rollback; | |
263 | ||
c0c508a4 BH |
264 | err = device_create_file(&pdev->dev, &dev_attr_current_master); |
265 | if (err) | |
266 | goto err_rollback_available; | |
267 | ||
50a5ba87 WS |
268 | return 0; |
269 | ||
c0c508a4 BH |
270 | err_rollback_available: |
271 | device_remove_file(&pdev->dev, &dev_attr_available_masters); | |
50a5ba87 WS |
272 | err_rollback: |
273 | for (j = 0; j < i; j++) { | |
274 | of_node_put(priv->chan[j].parent_np); | |
275 | of_changeset_destroy(&priv->chan[j].chgset); | |
276 | } | |
277 | ||
278 | return err; | |
279 | } | |
280 | ||
281 | static int i2c_demux_pinctrl_remove(struct platform_device *pdev) | |
282 | { | |
283 | struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev); | |
284 | int i; | |
285 | ||
c0c508a4 BH |
286 | device_remove_file(&pdev->dev, &dev_attr_current_master); |
287 | device_remove_file(&pdev->dev, &dev_attr_available_masters); | |
50a5ba87 WS |
288 | |
289 | i2c_demux_deactivate_master(priv); | |
290 | ||
291 | for (i = 0; i < priv->num_chan; i++) { | |
292 | of_node_put(priv->chan[i].parent_np); | |
293 | of_changeset_destroy(&priv->chan[i].chgset); | |
294 | } | |
295 | ||
296 | return 0; | |
297 | } | |
298 | ||
299 | static const struct of_device_id i2c_demux_pinctrl_of_match[] = { | |
300 | { .compatible = "i2c-demux-pinctrl", }, | |
301 | {}, | |
302 | }; | |
303 | MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match); | |
304 | ||
305 | static struct platform_driver i2c_demux_pinctrl_driver = { | |
306 | .driver = { | |
307 | .name = "i2c-demux-pinctrl", | |
308 | .of_match_table = i2c_demux_pinctrl_of_match, | |
309 | }, | |
310 | .probe = i2c_demux_pinctrl_probe, | |
311 | .remove = i2c_demux_pinctrl_remove, | |
312 | }; | |
313 | module_platform_driver(i2c_demux_pinctrl_driver); | |
314 | ||
315 | MODULE_DESCRIPTION("pinctrl-based I2C demux driver"); | |
316 | MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>"); | |
317 | MODULE_LICENSE("GPL v2"); | |
318 | MODULE_ALIAS("platform:i2c-demux-pinctrl"); |