1 /*
2 * IIO multiplexer driver
3 *
4 * Copyright (C) 2017 Axentia Technologies AB
5 *
6 * Author: Peter Rosin <peda@axentia.se>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/err.h>
14 #include <linux/iio/consumer.h>
15 #include <linux/iio/iio.h>
16 #include <linux/module.h>
17 #include <linux/mutex.h>
18 #include <linux/mux/consumer.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21
22 struct mux_ext_info_cache {
23 char *data;
24 ssize_t size;
25 };
26
27 struct mux_child {
28 struct mux_ext_info_cache *ext_info_cache;
29 };
30
31 struct mux {
32 int cached_state;
33 struct mux_control *control;
34 struct iio_channel *parent;
35 struct iio_dev *indio_dev;
36 struct iio_chan_spec *chan;
37 struct iio_chan_spec_ext_info *ext_info;
38 struct mux_child *child;
39 };
40
iio_mux_select(struct mux * mux,int idx)41 static int iio_mux_select(struct mux *mux, int idx)
42 {
43 struct mux_child *child = &mux->child[idx];
44 struct iio_chan_spec const *chan = &mux->chan[idx];
45 int ret;
46 int i;
47
48 ret = mux_control_select(mux->control, chan->channel);
49 if (ret < 0) {
50 mux->cached_state = -1;
51 return ret;
52 }
53
54 if (mux->cached_state == chan->channel)
55 return 0;
56
57 if (chan->ext_info) {
58 for (i = 0; chan->ext_info[i].name; ++i) {
59 const char *attr = chan->ext_info[i].name;
60 struct mux_ext_info_cache *cache;
61
62 cache = &child->ext_info_cache[i];
63
64 if (cache->size < 0)
65 continue;
66
67 ret = iio_write_channel_ext_info(mux->parent, attr,
68 cache->data,
69 cache->size);
70
71 if (ret < 0) {
72 mux_control_deselect(mux->control);
73 mux->cached_state = -1;
74 return ret;
75 }
76 }
77 }
78 mux->cached_state = chan->channel;
79
80 return 0;
81 }
82
iio_mux_deselect(struct mux * mux)83 static void iio_mux_deselect(struct mux *mux)
84 {
85 mux_control_deselect(mux->control);
86 }
87
mux_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)88 static int mux_read_raw(struct iio_dev *indio_dev,
89 struct iio_chan_spec const *chan,
90 int *val, int *val2, long mask)
91 {
92 struct mux *mux = iio_priv(indio_dev);
93 int idx = chan - mux->chan;
94 int ret;
95
96 ret = iio_mux_select(mux, idx);
97 if (ret < 0)
98 return ret;
99
100 switch (mask) {
101 case IIO_CHAN_INFO_RAW:
102 ret = iio_read_channel_raw(mux->parent, val);
103 break;
104
105 case IIO_CHAN_INFO_SCALE:
106 ret = iio_read_channel_scale(mux->parent, val, val2);
107 break;
108
109 default:
110 ret = -EINVAL;
111 }
112
113 iio_mux_deselect(mux);
114
115 return ret;
116 }
117
mux_read_avail(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)118 static int mux_read_avail(struct iio_dev *indio_dev,
119 struct iio_chan_spec const *chan,
120 const int **vals, int *type, int *length,
121 long mask)
122 {
123 struct mux *mux = iio_priv(indio_dev);
124 int idx = chan - mux->chan;
125 int ret;
126
127 ret = iio_mux_select(mux, idx);
128 if (ret < 0)
129 return ret;
130
131 switch (mask) {
132 case IIO_CHAN_INFO_RAW:
133 *type = IIO_VAL_INT;
134 ret = iio_read_avail_channel_raw(mux->parent, vals, length);
135 break;
136
137 default:
138 ret = -EINVAL;
139 }
140
141 iio_mux_deselect(mux);
142
143 return ret;
144 }
145
mux_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)146 static int mux_write_raw(struct iio_dev *indio_dev,
147 struct iio_chan_spec const *chan,
148 int val, int val2, long mask)
149 {
150 struct mux *mux = iio_priv(indio_dev);
151 int idx = chan - mux->chan;
152 int ret;
153
154 ret = iio_mux_select(mux, idx);
155 if (ret < 0)
156 return ret;
157
158 switch (mask) {
159 case IIO_CHAN_INFO_RAW:
160 ret = iio_write_channel_raw(mux->parent, val);
161 break;
162
163 default:
164 ret = -EINVAL;
165 }
166
167 iio_mux_deselect(mux);
168
169 return ret;
170 }
171
172 static const struct iio_info mux_info = {
173 .read_raw = mux_read_raw,
174 .read_avail = mux_read_avail,
175 .write_raw = mux_write_raw,
176 };
177
mux_read_ext_info(struct iio_dev * indio_dev,uintptr_t private,struct iio_chan_spec const * chan,char * buf)178 static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private,
179 struct iio_chan_spec const *chan, char *buf)
180 {
181 struct mux *mux = iio_priv(indio_dev);
182 int idx = chan - mux->chan;
183 ssize_t ret;
184
185 ret = iio_mux_select(mux, idx);
186 if (ret < 0)
187 return ret;
188
189 ret = iio_read_channel_ext_info(mux->parent,
190 mux->ext_info[private].name,
191 buf);
192
193 iio_mux_deselect(mux);
194
195 return ret;
196 }
197
mux_write_ext_info(struct iio_dev * indio_dev,uintptr_t private,struct iio_chan_spec const * chan,const char * buf,size_t len)198 static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private,
199 struct iio_chan_spec const *chan,
200 const char *buf, size_t len)
201 {
202 struct device *dev = indio_dev->dev.parent;
203 struct mux *mux = iio_priv(indio_dev);
204 int idx = chan - mux->chan;
205 char *new;
206 ssize_t ret;
207
208 if (len >= PAGE_SIZE)
209 return -EINVAL;
210
211 ret = iio_mux_select(mux, idx);
212 if (ret < 0)
213 return ret;
214
215 new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL);
216 if (!new) {
217 iio_mux_deselect(mux);
218 return -ENOMEM;
219 }
220
221 new[len] = 0;
222
223 ret = iio_write_channel_ext_info(mux->parent,
224 mux->ext_info[private].name,
225 buf, len);
226 if (ret < 0) {
227 iio_mux_deselect(mux);
228 devm_kfree(dev, new);
229 return ret;
230 }
231
232 devm_kfree(dev, mux->child[idx].ext_info_cache[private].data);
233 mux->child[idx].ext_info_cache[private].data = new;
234 mux->child[idx].ext_info_cache[private].size = len;
235
236 iio_mux_deselect(mux);
237
238 return ret;
239 }
240
mux_configure_channel(struct device * dev,struct mux * mux,u32 state,const char * label,int idx)241 static int mux_configure_channel(struct device *dev, struct mux *mux,
242 u32 state, const char *label, int idx)
243 {
244 struct mux_child *child = &mux->child[idx];
245 struct iio_chan_spec *chan = &mux->chan[idx];
246 struct iio_chan_spec const *pchan = mux->parent->channel;
247 char *page = NULL;
248 int num_ext_info;
249 int i;
250 int ret;
251
252 chan->indexed = 1;
253 chan->output = pchan->output;
254 chan->datasheet_name = label;
255 chan->ext_info = mux->ext_info;
256
257 ret = iio_get_channel_type(mux->parent, &chan->type);
258 if (ret < 0) {
259 dev_err(dev, "failed to get parent channel type\n");
260 return ret;
261 }
262
263 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW))
264 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW);
265 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE))
266 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE);
267
268 if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW))
269 chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
270
271 if (state >= mux_control_states(mux->control)) {
272 dev_err(dev, "too many channels\n");
273 return -EINVAL;
274 }
275
276 chan->channel = state;
277
278 num_ext_info = iio_get_channel_ext_info_count(mux->parent);
279 if (num_ext_info) {
280 page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
281 if (!page)
282 return -ENOMEM;
283 }
284 child->ext_info_cache = devm_kcalloc(dev,
285 num_ext_info,
286 sizeof(*child->ext_info_cache),
287 GFP_KERNEL);
288 if (!child->ext_info_cache)
289 return -ENOMEM;
290
291 for (i = 0; i < num_ext_info; ++i) {
292 child->ext_info_cache[i].size = -1;
293
294 if (!pchan->ext_info[i].write)
295 continue;
296 if (!pchan->ext_info[i].read)
297 continue;
298
299 ret = iio_read_channel_ext_info(mux->parent,
300 mux->ext_info[i].name,
301 page);
302 if (ret < 0) {
303 dev_err(dev, "failed to get ext_info '%s'\n",
304 pchan->ext_info[i].name);
305 return ret;
306 }
307 if (ret >= PAGE_SIZE) {
308 dev_err(dev, "too large ext_info '%s'\n",
309 pchan->ext_info[i].name);
310 return -EINVAL;
311 }
312
313 child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1,
314 GFP_KERNEL);
315 if (!child->ext_info_cache[i].data)
316 return -ENOMEM;
317
318 child->ext_info_cache[i].data[ret] = 0;
319 child->ext_info_cache[i].size = ret;
320 }
321
322 if (page)
323 devm_kfree(dev, page);
324
325 return 0;
326 }
327
328 /*
329 * Same as of_property_for_each_string(), but also keeps track of the
330 * index of each string.
331 */
332 #define of_property_for_each_string_index(np, propname, prop, s, i) \
333 for (prop = of_find_property(np, propname, NULL), \
334 s = of_prop_next_string(prop, NULL), \
335 i = 0; \
336 s; \
337 s = of_prop_next_string(prop, s), \
338 i++)
339
mux_probe(struct platform_device * pdev)340 static int mux_probe(struct platform_device *pdev)
341 {
342 struct device *dev = &pdev->dev;
343 struct device_node *np = pdev->dev.of_node;
344 struct iio_dev *indio_dev;
345 struct iio_channel *parent;
346 struct mux *mux;
347 struct property *prop;
348 const char *label;
349 u32 state;
350 int sizeof_ext_info;
351 int children;
352 int sizeof_priv;
353 int i;
354 int ret;
355
356 if (!np)
357 return -ENODEV;
358
359 parent = devm_iio_channel_get(dev, "parent");
360 if (IS_ERR(parent)) {
361 if (PTR_ERR(parent) != -EPROBE_DEFER)
362 dev_err(dev, "failed to get parent channel\n");
363 return PTR_ERR(parent);
364 }
365
366 sizeof_ext_info = iio_get_channel_ext_info_count(parent);
367 if (sizeof_ext_info) {
368 sizeof_ext_info += 1; /* one extra entry for the sentinel */
369 sizeof_ext_info *= sizeof(*mux->ext_info);
370 }
371
372 children = 0;
373 of_property_for_each_string(np, "channels", prop, label) {
374 if (*label)
375 children++;
376 }
377 if (children <= 0) {
378 dev_err(dev, "not even a single child\n");
379 return -EINVAL;
380 }
381
382 sizeof_priv = sizeof(*mux);
383 sizeof_priv += sizeof(*mux->child) * children;
384 sizeof_priv += sizeof(*mux->chan) * children;
385 sizeof_priv += sizeof_ext_info;
386
387 indio_dev = devm_iio_device_alloc(dev, sizeof_priv);
388 if (!indio_dev)
389 return -ENOMEM;
390
391 mux = iio_priv(indio_dev);
392 mux->child = (struct mux_child *)(mux + 1);
393 mux->chan = (struct iio_chan_spec *)(mux->child + children);
394
395 platform_set_drvdata(pdev, indio_dev);
396
397 mux->parent = parent;
398 mux->cached_state = -1;
399
400 indio_dev->name = dev_name(dev);
401 indio_dev->dev.parent = dev;
402 indio_dev->info = &mux_info;
403 indio_dev->modes = INDIO_DIRECT_MODE;
404 indio_dev->channels = mux->chan;
405 indio_dev->num_channels = children;
406 if (sizeof_ext_info) {
407 mux->ext_info = devm_kmemdup(dev,
408 parent->channel->ext_info,
409 sizeof_ext_info, GFP_KERNEL);
410 if (!mux->ext_info)
411 return -ENOMEM;
412
413 for (i = 0; mux->ext_info[i].name; ++i) {
414 if (parent->channel->ext_info[i].read)
415 mux->ext_info[i].read = mux_read_ext_info;
416 if (parent->channel->ext_info[i].write)
417 mux->ext_info[i].write = mux_write_ext_info;
418 mux->ext_info[i].private = i;
419 }
420 }
421
422 mux->control = devm_mux_control_get(dev, NULL);
423 if (IS_ERR(mux->control)) {
424 if (PTR_ERR(mux->control) != -EPROBE_DEFER)
425 dev_err(dev, "failed to get control-mux\n");
426 return PTR_ERR(mux->control);
427 }
428
429 i = 0;
430 of_property_for_each_string_index(np, "channels", prop, label, state) {
431 if (!*label)
432 continue;
433
434 ret = mux_configure_channel(dev, mux, state, label, i++);
435 if (ret < 0)
436 return ret;
437 }
438
439 ret = devm_iio_device_register(dev, indio_dev);
440 if (ret) {
441 dev_err(dev, "failed to register iio device\n");
442 return ret;
443 }
444
445 return 0;
446 }
447
448 static const struct of_device_id mux_match[] = {
449 { .compatible = "io-channel-mux" },
450 { /* sentinel */ }
451 };
452 MODULE_DEVICE_TABLE(of, mux_match);
453
454 static struct platform_driver mux_driver = {
455 .probe = mux_probe,
456 .driver = {
457 .name = "iio-mux",
458 .of_match_table = mux_match,
459 },
460 };
461 module_platform_driver(mux_driver);
462
463 MODULE_DESCRIPTION("IIO multiplexer driver");
464 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
465 MODULE_LICENSE("GPL v2");
466
