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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> | |
fca700d6 | 21 | #include <linux/pm_runtime.h> |
50a5ba87 WS |
22 | #include <linux/slab.h> |
23 | #include <linux/sysfs.h> | |
24 | ||
25 | struct i2c_demux_pinctrl_chan { | |
26 | struct device_node *parent_np; | |
27 | struct i2c_adapter *parent_adap; | |
28 | struct of_changeset chgset; | |
29 | }; | |
30 | ||
31 | struct i2c_demux_pinctrl_priv { | |
32 | int cur_chan; | |
33 | int num_chan; | |
34 | struct device *dev; | |
35 | const char *bus_name; | |
36 | struct i2c_adapter cur_adap; | |
37 | struct i2c_algorithm algo; | |
38 | struct i2c_demux_pinctrl_chan chan[]; | |
39 | }; | |
40 | ||
50a5ba87 WS |
41 | static int i2c_demux_master_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) |
42 | { | |
43 | struct i2c_demux_pinctrl_priv *priv = adap->algo_data; | |
44 | struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap; | |
45 | ||
46 | return __i2c_transfer(parent, msgs, num); | |
47 | } | |
48 | ||
49 | static u32 i2c_demux_functionality(struct i2c_adapter *adap) | |
50 | { | |
51 | struct i2c_demux_pinctrl_priv *priv = adap->algo_data; | |
52 | struct i2c_adapter *parent = priv->chan[priv->cur_chan].parent_adap; | |
53 | ||
54 | return parent->algo->functionality(parent); | |
55 | } | |
56 | ||
57 | static int i2c_demux_activate_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) | |
58 | { | |
59 | struct i2c_adapter *adap; | |
60 | struct pinctrl *p; | |
61 | int ret; | |
62 | ||
63 | ret = of_changeset_apply(&priv->chan[new_chan].chgset); | |
64 | if (ret) | |
65 | goto err; | |
66 | ||
67 | adap = of_find_i2c_adapter_by_node(priv->chan[new_chan].parent_np); | |
68 | if (!adap) { | |
69 | ret = -ENODEV; | |
ce8cb803 | 70 | goto err_with_revert; |
50a5ba87 WS |
71 | } |
72 | ||
d052db11 WS |
73 | /* |
74 | * Check if there are pinctrl states at all. Note: we cant' use | |
75 | * devm_pinctrl_get_select() because we need to distinguish between | |
76 | * the -ENODEV from devm_pinctrl_get() and pinctrl_lookup_state(). | |
77 | */ | |
78 | p = devm_pinctrl_get(adap->dev.parent); | |
50a5ba87 WS |
79 | if (IS_ERR(p)) { |
80 | ret = PTR_ERR(p); | |
d052db11 WS |
81 | /* continue if just no pinctrl states (e.g. i2c-gpio), otherwise exit */ |
82 | if (ret != -ENODEV) | |
83 | goto err_with_put; | |
84 | } else { | |
85 | /* there are states. check and use them */ | |
86 | struct pinctrl_state *s = pinctrl_lookup_state(p, priv->bus_name); | |
87 | ||
88 | if (IS_ERR(s)) { | |
89 | ret = PTR_ERR(s); | |
90 | goto err_with_put; | |
91 | } | |
92 | ret = pinctrl_select_state(p, s); | |
93 | if (ret < 0) | |
94 | goto err_with_put; | |
50a5ba87 WS |
95 | } |
96 | ||
97 | priv->chan[new_chan].parent_adap = adap; | |
98 | priv->cur_chan = new_chan; | |
99 | ||
100 | /* Now fill out current adapter structure. cur_chan must be up to date */ | |
101 | priv->algo.master_xfer = i2c_demux_master_xfer; | |
77c1e1e0 WS |
102 | if (adap->algo->master_xfer_atomic) |
103 | priv->algo.master_xfer_atomic = i2c_demux_master_xfer; | |
50a5ba87 WS |
104 | priv->algo.functionality = i2c_demux_functionality; |
105 | ||
106 | snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name), | |
107 | "i2c-demux (master i2c-%d)", i2c_adapter_id(adap)); | |
108 | priv->cur_adap.owner = THIS_MODULE; | |
109 | priv->cur_adap.algo = &priv->algo; | |
110 | priv->cur_adap.algo_data = priv; | |
5a9dcd81 | 111 | priv->cur_adap.dev.parent = &adap->dev; |
50a5ba87 WS |
112 | priv->cur_adap.class = adap->class; |
113 | priv->cur_adap.retries = adap->retries; | |
114 | priv->cur_adap.timeout = adap->timeout; | |
115 | priv->cur_adap.quirks = adap->quirks; | |
116 | priv->cur_adap.dev.of_node = priv->dev->of_node; | |
117 | ret = i2c_add_adapter(&priv->cur_adap); | |
118 | if (ret < 0) | |
119 | goto err_with_put; | |
120 | ||
121 | return 0; | |
122 | ||
123 | err_with_put: | |
124 | i2c_put_adapter(adap); | |
ce8cb803 WS |
125 | err_with_revert: |
126 | of_changeset_revert(&priv->chan[new_chan].chgset); | |
50a5ba87 WS |
127 | err: |
128 | dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret); | |
9a5382e8 | 129 | priv->cur_chan = -EINVAL; |
50a5ba87 WS |
130 | return ret; |
131 | } | |
132 | ||
133 | static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv) | |
134 | { | |
135 | int ret, cur = priv->cur_chan; | |
136 | ||
137 | if (cur < 0) | |
138 | return 0; | |
139 | ||
140 | i2c_del_adapter(&priv->cur_adap); | |
141 | i2c_put_adapter(priv->chan[cur].parent_adap); | |
142 | ||
143 | ret = of_changeset_revert(&priv->chan[cur].chgset); | |
144 | ||
145 | priv->chan[cur].parent_adap = NULL; | |
146 | priv->cur_chan = -EINVAL; | |
147 | ||
148 | return ret; | |
149 | } | |
150 | ||
151 | static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) | |
152 | { | |
153 | int ret; | |
154 | ||
155 | if (new_chan == priv->cur_chan) | |
156 | return 0; | |
157 | ||
158 | ret = i2c_demux_deactivate_master(priv); | |
159 | if (ret) | |
160 | return ret; | |
161 | ||
162 | return i2c_demux_activate_master(priv, new_chan); | |
163 | } | |
164 | ||
c0c508a4 BH |
165 | static ssize_t available_masters_show(struct device *dev, |
166 | struct device_attribute *attr, | |
167 | char *buf) | |
50a5ba87 WS |
168 | { |
169 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
170 | int count = 0, i; | |
171 | ||
172 | for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++) | |
453a237c RH |
173 | count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%pOF%c", |
174 | i, priv->chan[i].parent_np, | |
c0c508a4 | 175 | i == priv->num_chan - 1 ? '\n' : ' '); |
50a5ba87 WS |
176 | |
177 | return count; | |
178 | } | |
c0c508a4 | 179 | static DEVICE_ATTR_RO(available_masters); |
50a5ba87 | 180 | |
c0c508a4 BH |
181 | static ssize_t current_master_show(struct device *dev, |
182 | struct device_attribute *attr, | |
183 | char *buf) | |
184 | { | |
185 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
186 | ||
187 | return sprintf(buf, "%d\n", priv->cur_chan); | |
188 | } | |
189 | ||
190 | static ssize_t current_master_store(struct device *dev, | |
191 | struct device_attribute *attr, | |
192 | const char *buf, size_t count) | |
50a5ba87 WS |
193 | { |
194 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
195 | unsigned int val; | |
196 | int ret; | |
197 | ||
198 | ret = kstrtouint(buf, 0, &val); | |
199 | if (ret < 0) | |
200 | return ret; | |
201 | ||
202 | if (val >= priv->num_chan) | |
203 | return -EINVAL; | |
204 | ||
205 | ret = i2c_demux_change_master(priv, val); | |
206 | ||
207 | return ret < 0 ? ret : count; | |
208 | } | |
c0c508a4 | 209 | static DEVICE_ATTR_RW(current_master); |
50a5ba87 WS |
210 | |
211 | static int i2c_demux_pinctrl_probe(struct platform_device *pdev) | |
212 | { | |
213 | struct device_node *np = pdev->dev.of_node; | |
214 | struct i2c_demux_pinctrl_priv *priv; | |
e35478ea | 215 | struct property *props; |
50a5ba87 WS |
216 | int num_chan, i, j, err; |
217 | ||
218 | num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL); | |
219 | if (num_chan < 2) { | |
220 | dev_err(&pdev->dev, "Need at least two I2C masters to switch\n"); | |
221 | return -EINVAL; | |
222 | } | |
223 | ||
d5984d2a GS |
224 | priv = devm_kzalloc(&pdev->dev, struct_size(priv, chan, num_chan), |
225 | GFP_KERNEL); | |
e35478ea WS |
226 | |
227 | props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL); | |
228 | ||
229 | if (!priv || !props) | |
50a5ba87 WS |
230 | return -ENOMEM; |
231 | ||
232 | err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name); | |
233 | if (err) | |
234 | return err; | |
235 | ||
236 | for (i = 0; i < num_chan; i++) { | |
237 | struct device_node *adap_np; | |
238 | ||
239 | adap_np = of_parse_phandle(np, "i2c-parent", i); | |
240 | if (!adap_np) { | |
241 | dev_err(&pdev->dev, "can't get phandle for parent %d\n", i); | |
242 | err = -ENOENT; | |
243 | goto err_rollback; | |
244 | } | |
245 | priv->chan[i].parent_np = adap_np; | |
246 | ||
e35478ea WS |
247 | props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL); |
248 | props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL); | |
249 | props[i].length = 3; | |
250 | ||
50a5ba87 | 251 | of_changeset_init(&priv->chan[i].chgset); |
e35478ea | 252 | of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]); |
50a5ba87 WS |
253 | } |
254 | ||
255 | priv->num_chan = num_chan; | |
256 | priv->dev = &pdev->dev; | |
257 | ||
258 | platform_set_drvdata(pdev, priv); | |
259 | ||
fca700d6 WS |
260 | pm_runtime_no_callbacks(&pdev->dev); |
261 | ||
50a5ba87 WS |
262 | /* switch to first parent as active master */ |
263 | i2c_demux_activate_master(priv, 0); | |
264 | ||
c0c508a4 | 265 | err = device_create_file(&pdev->dev, &dev_attr_available_masters); |
50a5ba87 WS |
266 | if (err) |
267 | goto err_rollback; | |
268 | ||
c0c508a4 BH |
269 | err = device_create_file(&pdev->dev, &dev_attr_current_master); |
270 | if (err) | |
271 | goto err_rollback_available; | |
272 | ||
50a5ba87 WS |
273 | return 0; |
274 | ||
c0c508a4 BH |
275 | err_rollback_available: |
276 | device_remove_file(&pdev->dev, &dev_attr_available_masters); | |
50a5ba87 WS |
277 | err_rollback: |
278 | for (j = 0; j < i; j++) { | |
279 | of_node_put(priv->chan[j].parent_np); | |
280 | of_changeset_destroy(&priv->chan[j].chgset); | |
281 | } | |
282 | ||
283 | return err; | |
284 | } | |
285 | ||
286 | static int i2c_demux_pinctrl_remove(struct platform_device *pdev) | |
287 | { | |
288 | struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev); | |
289 | int i; | |
290 | ||
c0c508a4 BH |
291 | device_remove_file(&pdev->dev, &dev_attr_current_master); |
292 | device_remove_file(&pdev->dev, &dev_attr_available_masters); | |
50a5ba87 WS |
293 | |
294 | i2c_demux_deactivate_master(priv); | |
295 | ||
296 | for (i = 0; i < priv->num_chan; i++) { | |
297 | of_node_put(priv->chan[i].parent_np); | |
298 | of_changeset_destroy(&priv->chan[i].chgset); | |
299 | } | |
300 | ||
301 | return 0; | |
302 | } | |
303 | ||
304 | static const struct of_device_id i2c_demux_pinctrl_of_match[] = { | |
305 | { .compatible = "i2c-demux-pinctrl", }, | |
306 | {}, | |
307 | }; | |
308 | MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match); | |
309 | ||
310 | static struct platform_driver i2c_demux_pinctrl_driver = { | |
311 | .driver = { | |
312 | .name = "i2c-demux-pinctrl", | |
313 | .of_match_table = i2c_demux_pinctrl_of_match, | |
314 | }, | |
315 | .probe = i2c_demux_pinctrl_probe, | |
316 | .remove = i2c_demux_pinctrl_remove, | |
317 | }; | |
318 | module_platform_driver(i2c_demux_pinctrl_driver); | |
319 | ||
320 | MODULE_DESCRIPTION("pinctrl-based I2C demux driver"); | |
321 | MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>"); | |
322 | MODULE_LICENSE("GPL v2"); | |
323 | MODULE_ALIAS("platform:i2c-demux-pinctrl"); |