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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; | |
102 | priv->algo.functionality = i2c_demux_functionality; | |
103 | ||
104 | snprintf(priv->cur_adap.name, sizeof(priv->cur_adap.name), | |
105 | "i2c-demux (master i2c-%d)", i2c_adapter_id(adap)); | |
106 | priv->cur_adap.owner = THIS_MODULE; | |
107 | priv->cur_adap.algo = &priv->algo; | |
108 | priv->cur_adap.algo_data = priv; | |
5a9dcd81 | 109 | priv->cur_adap.dev.parent = &adap->dev; |
50a5ba87 WS |
110 | priv->cur_adap.class = adap->class; |
111 | priv->cur_adap.retries = adap->retries; | |
112 | priv->cur_adap.timeout = adap->timeout; | |
113 | priv->cur_adap.quirks = adap->quirks; | |
114 | priv->cur_adap.dev.of_node = priv->dev->of_node; | |
115 | ret = i2c_add_adapter(&priv->cur_adap); | |
116 | if (ret < 0) | |
117 | goto err_with_put; | |
118 | ||
119 | return 0; | |
120 | ||
121 | err_with_put: | |
122 | i2c_put_adapter(adap); | |
ce8cb803 WS |
123 | err_with_revert: |
124 | of_changeset_revert(&priv->chan[new_chan].chgset); | |
50a5ba87 WS |
125 | err: |
126 | dev_err(priv->dev, "failed to setup demux-adapter %d (%d)\n", new_chan, ret); | |
9a5382e8 | 127 | priv->cur_chan = -EINVAL; |
50a5ba87 WS |
128 | return ret; |
129 | } | |
130 | ||
131 | static int i2c_demux_deactivate_master(struct i2c_demux_pinctrl_priv *priv) | |
132 | { | |
133 | int ret, cur = priv->cur_chan; | |
134 | ||
135 | if (cur < 0) | |
136 | return 0; | |
137 | ||
138 | i2c_del_adapter(&priv->cur_adap); | |
139 | i2c_put_adapter(priv->chan[cur].parent_adap); | |
140 | ||
141 | ret = of_changeset_revert(&priv->chan[cur].chgset); | |
142 | ||
143 | priv->chan[cur].parent_adap = NULL; | |
144 | priv->cur_chan = -EINVAL; | |
145 | ||
146 | return ret; | |
147 | } | |
148 | ||
149 | static int i2c_demux_change_master(struct i2c_demux_pinctrl_priv *priv, u32 new_chan) | |
150 | { | |
151 | int ret; | |
152 | ||
153 | if (new_chan == priv->cur_chan) | |
154 | return 0; | |
155 | ||
156 | ret = i2c_demux_deactivate_master(priv); | |
157 | if (ret) | |
158 | return ret; | |
159 | ||
160 | return i2c_demux_activate_master(priv, new_chan); | |
161 | } | |
162 | ||
c0c508a4 BH |
163 | static ssize_t available_masters_show(struct device *dev, |
164 | struct device_attribute *attr, | |
165 | char *buf) | |
50a5ba87 WS |
166 | { |
167 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
168 | int count = 0, i; | |
169 | ||
170 | for (i = 0; i < priv->num_chan && count < PAGE_SIZE; i++) | |
453a237c RH |
171 | count += scnprintf(buf + count, PAGE_SIZE - count, "%d:%pOF%c", |
172 | i, priv->chan[i].parent_np, | |
c0c508a4 | 173 | i == priv->num_chan - 1 ? '\n' : ' '); |
50a5ba87 WS |
174 | |
175 | return count; | |
176 | } | |
c0c508a4 | 177 | static DEVICE_ATTR_RO(available_masters); |
50a5ba87 | 178 | |
c0c508a4 BH |
179 | static ssize_t current_master_show(struct device *dev, |
180 | struct device_attribute *attr, | |
181 | char *buf) | |
182 | { | |
183 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
184 | ||
185 | return sprintf(buf, "%d\n", priv->cur_chan); | |
186 | } | |
187 | ||
188 | static ssize_t current_master_store(struct device *dev, | |
189 | struct device_attribute *attr, | |
190 | const char *buf, size_t count) | |
50a5ba87 WS |
191 | { |
192 | struct i2c_demux_pinctrl_priv *priv = dev_get_drvdata(dev); | |
193 | unsigned int val; | |
194 | int ret; | |
195 | ||
196 | ret = kstrtouint(buf, 0, &val); | |
197 | if (ret < 0) | |
198 | return ret; | |
199 | ||
200 | if (val >= priv->num_chan) | |
201 | return -EINVAL; | |
202 | ||
203 | ret = i2c_demux_change_master(priv, val); | |
204 | ||
205 | return ret < 0 ? ret : count; | |
206 | } | |
c0c508a4 | 207 | static DEVICE_ATTR_RW(current_master); |
50a5ba87 WS |
208 | |
209 | static int i2c_demux_pinctrl_probe(struct platform_device *pdev) | |
210 | { | |
211 | struct device_node *np = pdev->dev.of_node; | |
212 | struct i2c_demux_pinctrl_priv *priv; | |
e35478ea | 213 | struct property *props; |
50a5ba87 WS |
214 | int num_chan, i, j, err; |
215 | ||
216 | num_chan = of_count_phandle_with_args(np, "i2c-parent", NULL); | |
217 | if (num_chan < 2) { | |
218 | dev_err(&pdev->dev, "Need at least two I2C masters to switch\n"); | |
219 | return -EINVAL; | |
220 | } | |
221 | ||
222 | priv = devm_kzalloc(&pdev->dev, sizeof(*priv) | |
223 | + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL); | |
e35478ea WS |
224 | |
225 | props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL); | |
226 | ||
227 | if (!priv || !props) | |
50a5ba87 WS |
228 | return -ENOMEM; |
229 | ||
230 | err = of_property_read_string(np, "i2c-bus-name", &priv->bus_name); | |
231 | if (err) | |
232 | return err; | |
233 | ||
234 | for (i = 0; i < num_chan; i++) { | |
235 | struct device_node *adap_np; | |
236 | ||
237 | adap_np = of_parse_phandle(np, "i2c-parent", i); | |
238 | if (!adap_np) { | |
239 | dev_err(&pdev->dev, "can't get phandle for parent %d\n", i); | |
240 | err = -ENOENT; | |
241 | goto err_rollback; | |
242 | } | |
243 | priv->chan[i].parent_np = adap_np; | |
244 | ||
e35478ea WS |
245 | props[i].name = devm_kstrdup(&pdev->dev, "status", GFP_KERNEL); |
246 | props[i].value = devm_kstrdup(&pdev->dev, "ok", GFP_KERNEL); | |
247 | props[i].length = 3; | |
248 | ||
50a5ba87 | 249 | of_changeset_init(&priv->chan[i].chgset); |
e35478ea | 250 | of_changeset_update_property(&priv->chan[i].chgset, adap_np, &props[i]); |
50a5ba87 WS |
251 | } |
252 | ||
253 | priv->num_chan = num_chan; | |
254 | priv->dev = &pdev->dev; | |
255 | ||
256 | platform_set_drvdata(pdev, priv); | |
257 | ||
fca700d6 WS |
258 | pm_runtime_no_callbacks(&pdev->dev); |
259 | ||
50a5ba87 WS |
260 | /* switch to first parent as active master */ |
261 | i2c_demux_activate_master(priv, 0); | |
262 | ||
c0c508a4 | 263 | err = device_create_file(&pdev->dev, &dev_attr_available_masters); |
50a5ba87 WS |
264 | if (err) |
265 | goto err_rollback; | |
266 | ||
c0c508a4 BH |
267 | err = device_create_file(&pdev->dev, &dev_attr_current_master); |
268 | if (err) | |
269 | goto err_rollback_available; | |
270 | ||
50a5ba87 WS |
271 | return 0; |
272 | ||
c0c508a4 BH |
273 | err_rollback_available: |
274 | device_remove_file(&pdev->dev, &dev_attr_available_masters); | |
50a5ba87 WS |
275 | err_rollback: |
276 | for (j = 0; j < i; j++) { | |
277 | of_node_put(priv->chan[j].parent_np); | |
278 | of_changeset_destroy(&priv->chan[j].chgset); | |
279 | } | |
280 | ||
281 | return err; | |
282 | } | |
283 | ||
284 | static int i2c_demux_pinctrl_remove(struct platform_device *pdev) | |
285 | { | |
286 | struct i2c_demux_pinctrl_priv *priv = platform_get_drvdata(pdev); | |
287 | int i; | |
288 | ||
c0c508a4 BH |
289 | device_remove_file(&pdev->dev, &dev_attr_current_master); |
290 | device_remove_file(&pdev->dev, &dev_attr_available_masters); | |
50a5ba87 WS |
291 | |
292 | i2c_demux_deactivate_master(priv); | |
293 | ||
294 | for (i = 0; i < priv->num_chan; i++) { | |
295 | of_node_put(priv->chan[i].parent_np); | |
296 | of_changeset_destroy(&priv->chan[i].chgset); | |
297 | } | |
298 | ||
299 | return 0; | |
300 | } | |
301 | ||
302 | static const struct of_device_id i2c_demux_pinctrl_of_match[] = { | |
303 | { .compatible = "i2c-demux-pinctrl", }, | |
304 | {}, | |
305 | }; | |
306 | MODULE_DEVICE_TABLE(of, i2c_demux_pinctrl_of_match); | |
307 | ||
308 | static struct platform_driver i2c_demux_pinctrl_driver = { | |
309 | .driver = { | |
310 | .name = "i2c-demux-pinctrl", | |
311 | .of_match_table = i2c_demux_pinctrl_of_match, | |
312 | }, | |
313 | .probe = i2c_demux_pinctrl_probe, | |
314 | .remove = i2c_demux_pinctrl_remove, | |
315 | }; | |
316 | module_platform_driver(i2c_demux_pinctrl_driver); | |
317 | ||
318 | MODULE_DESCRIPTION("pinctrl-based I2C demux driver"); | |
319 | MODULE_AUTHOR("Wolfram Sang <wsa@sang-engineering.com>"); | |
320 | MODULE_LICENSE("GPL v2"); | |
321 | MODULE_ALIAS("platform:i2c-demux-pinctrl"); |