1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * IIO multiplexer driver
4 *
5 * Copyright (C) 2017 Axentia Technologies AB
6 *
7 * Author: Peter Rosin <peda@axentia.se>
8 */
9
10 #include <linux/err.h>
11 #include <linux/iio/consumer.h>
12 #include <linux/iio/iio.h>
13 #include <linux/mod_devicetable.h>
14 #include <linux/module.h>
15 #include <linux/mutex.h>
16 #include <linux/mux/consumer.h>
17 #include <linux/platform_device.h>
18 #include <linux/property.h>
19
20 struct mux_ext_info_cache {
21 char *data;
22 ssize_t size;
23 };
24
25 struct mux_child {
26 struct mux_ext_info_cache *ext_info_cache;
27 };
28
29 struct mux {
30 int cached_state;
31 struct mux_control *control;
32 struct iio_channel *parent;
33 struct iio_chan_spec *chan;
34 struct iio_chan_spec_ext_info *ext_info;
35 struct mux_child *child;
36 u32 delay_us;
37 };
38
iio_mux_select(struct mux * mux,int idx)39 static int iio_mux_select(struct mux *mux, int idx)
40 {
41 struct mux_child *child = &mux->child[idx];
42 struct iio_chan_spec const *chan = &mux->chan[idx];
43 int ret;
44 int i;
45
46 ret = mux_control_select_delay(mux->control, chan->channel,
47 mux->delay_us);
48 if (ret < 0) {
49 mux->cached_state = -1;
50 return ret;
51 }
52
53 if (mux->cached_state == chan->channel)
54 return 0;
55
56 if (chan->ext_info) {
57 for (i = 0; chan->ext_info[i].name; ++i) {
58 const char *attr = chan->ext_info[i].name;
59 struct mux_ext_info_cache *cache;
60
61 cache = &child->ext_info_cache[i];
62
63 if (cache->size < 0)
64 continue;
65
66 ret = iio_write_channel_ext_info(mux->parent, attr,
67 cache->data,
68 cache->size);
69
70 if (ret < 0) {
71 mux_control_deselect(mux->control);
72 mux->cached_state = -1;
73 return ret;
74 }
75 }
76 }
77 mux->cached_state = chan->channel;
78
79 return 0;
80 }
81
iio_mux_deselect(struct mux * mux)82 static void iio_mux_deselect(struct mux *mux)
83 {
84 mux_control_deselect(mux->control);
85 }
86
mux_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)87 static int mux_read_raw(struct iio_dev *indio_dev,
88 struct iio_chan_spec const *chan,
89 int *val, int *val2, long mask)
90 {
91 struct mux *mux = iio_priv(indio_dev);
92 int idx = chan - mux->chan;
93 int ret;
94
95 ret = iio_mux_select(mux, idx);
96 if (ret < 0)
97 return ret;
98
99 switch (mask) {
100 case IIO_CHAN_INFO_RAW:
101 ret = iio_read_channel_raw(mux->parent, val);
102 break;
103
104 case IIO_CHAN_INFO_SCALE:
105 ret = iio_read_channel_scale(mux->parent, val, val2);
106 break;
107
108 default:
109 ret = -EINVAL;
110 }
111
112 iio_mux_deselect(mux);
113
114 return ret;
115 }
116
mux_read_avail(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)117 static int mux_read_avail(struct iio_dev *indio_dev,
118 struct iio_chan_spec const *chan,
119 const int **vals, int *type, int *length,
120 long mask)
121 {
122 struct mux *mux = iio_priv(indio_dev);
123 int idx = chan - mux->chan;
124 int ret;
125
126 ret = iio_mux_select(mux, idx);
127 if (ret < 0)
128 return ret;
129
130 switch (mask) {
131 case IIO_CHAN_INFO_RAW:
132 *type = IIO_VAL_INT;
133 ret = iio_read_avail_channel_raw(mux->parent, vals, length);
134 break;
135
136 default:
137 ret = -EINVAL;
138 }
139
140 iio_mux_deselect(mux);
141
142 return ret;
143 }
144
mux_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)145 static int mux_write_raw(struct iio_dev *indio_dev,
146 struct iio_chan_spec const *chan,
147 int val, int val2, long mask)
148 {
149 struct mux *mux = iio_priv(indio_dev);
150 int idx = chan - mux->chan;
151 int ret;
152
153 ret = iio_mux_select(mux, idx);
154 if (ret < 0)
155 return ret;
156
157 switch (mask) {
158 case IIO_CHAN_INFO_RAW:
159 ret = iio_write_channel_raw(mux->parent, val);
160 break;
161
162 default:
163 ret = -EINVAL;
164 }
165
166 iio_mux_deselect(mux);
167
168 return ret;
169 }
170
171 static const struct iio_info mux_info = {
172 .read_raw = mux_read_raw,
173 .read_avail = mux_read_avail,
174 .write_raw = mux_write_raw,
175 };
176
mux_read_ext_info(struct iio_dev * indio_dev,uintptr_t private,struct iio_chan_spec const * chan,char * buf)177 static ssize_t mux_read_ext_info(struct iio_dev *indio_dev, uintptr_t private,
178 struct iio_chan_spec const *chan, char *buf)
179 {
180 struct mux *mux = iio_priv(indio_dev);
181 int idx = chan - mux->chan;
182 ssize_t ret;
183
184 ret = iio_mux_select(mux, idx);
185 if (ret < 0)
186 return ret;
187
188 ret = iio_read_channel_ext_info(mux->parent,
189 mux->ext_info[private].name,
190 buf);
191
192 iio_mux_deselect(mux);
193
194 return ret;
195 }
196
mux_write_ext_info(struct iio_dev * indio_dev,uintptr_t private,struct iio_chan_spec const * chan,const char * buf,size_t len)197 static ssize_t mux_write_ext_info(struct iio_dev *indio_dev, uintptr_t private,
198 struct iio_chan_spec const *chan,
199 const char *buf, size_t len)
200 {
201 struct device *dev = indio_dev->dev.parent;
202 struct mux *mux = iio_priv(indio_dev);
203 int idx = chan - mux->chan;
204 char *new;
205 ssize_t ret;
206
207 if (len >= PAGE_SIZE)
208 return -EINVAL;
209
210 ret = iio_mux_select(mux, idx);
211 if (ret < 0)
212 return ret;
213
214 new = devm_kmemdup(dev, buf, len + 1, GFP_KERNEL);
215 if (!new) {
216 iio_mux_deselect(mux);
217 return -ENOMEM;
218 }
219
220 new[len] = 0;
221
222 ret = iio_write_channel_ext_info(mux->parent,
223 mux->ext_info[private].name,
224 buf, len);
225 if (ret < 0) {
226 iio_mux_deselect(mux);
227 devm_kfree(dev, new);
228 return ret;
229 }
230
231 devm_kfree(dev, mux->child[idx].ext_info_cache[private].data);
232 mux->child[idx].ext_info_cache[private].data = new;
233 mux->child[idx].ext_info_cache[private].size = len;
234
235 iio_mux_deselect(mux);
236
237 return ret;
238 }
239
mux_configure_channel(struct device * dev,struct mux * mux,u32 state,const char * label,int idx)240 static int mux_configure_channel(struct device *dev, struct mux *mux,
241 u32 state, const char *label, int idx)
242 {
243 struct mux_child *child = &mux->child[idx];
244 struct iio_chan_spec *chan = &mux->chan[idx];
245 struct iio_chan_spec const *pchan = mux->parent->channel;
246 char *page = NULL;
247 int num_ext_info;
248 int i;
249 int ret;
250
251 chan->indexed = 1;
252 chan->output = pchan->output;
253 chan->datasheet_name = label;
254 chan->ext_info = mux->ext_info;
255
256 ret = iio_get_channel_type(mux->parent, &chan->type);
257 if (ret < 0) {
258 dev_err(dev, "failed to get parent channel type\n");
259 return ret;
260 }
261
262 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_RAW))
263 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW);
264 if (iio_channel_has_info(pchan, IIO_CHAN_INFO_SCALE))
265 chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE);
266
267 if (iio_channel_has_available(pchan, IIO_CHAN_INFO_RAW))
268 chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW);
269
270 if (state >= mux_control_states(mux->control)) {
271 dev_err(dev, "too many channels\n");
272 return -EINVAL;
273 }
274
275 chan->channel = state;
276
277 num_ext_info = iio_get_channel_ext_info_count(mux->parent);
278 if (num_ext_info) {
279 page = devm_kzalloc(dev, PAGE_SIZE, GFP_KERNEL);
280 if (!page)
281 return -ENOMEM;
282 }
283 child->ext_info_cache = devm_kcalloc(dev,
284 num_ext_info,
285 sizeof(*child->ext_info_cache),
286 GFP_KERNEL);
287 if (!child->ext_info_cache)
288 return -ENOMEM;
289
290 for (i = 0; i < num_ext_info; ++i) {
291 child->ext_info_cache[i].size = -1;
292
293 if (!pchan->ext_info[i].write)
294 continue;
295 if (!pchan->ext_info[i].read)
296 continue;
297
298 ret = iio_read_channel_ext_info(mux->parent,
299 mux->ext_info[i].name,
300 page);
301 if (ret < 0) {
302 dev_err(dev, "failed to get ext_info '%s'\n",
303 pchan->ext_info[i].name);
304 return ret;
305 }
306 if (ret >= PAGE_SIZE) {
307 dev_err(dev, "too large ext_info '%s'\n",
308 pchan->ext_info[i].name);
309 return -EINVAL;
310 }
311
312 child->ext_info_cache[i].data = devm_kmemdup(dev, page, ret + 1,
313 GFP_KERNEL);
314 if (!child->ext_info_cache[i].data)
315 return -ENOMEM;
316
317 child->ext_info_cache[i].data[ret] = 0;
318 child->ext_info_cache[i].size = ret;
319 }
320
321 if (page)
322 devm_kfree(dev, page);
323
324 return 0;
325 }
326
mux_probe(struct platform_device * pdev)327 static int mux_probe(struct platform_device *pdev)
328 {
329 struct device *dev = &pdev->dev;
330 struct iio_dev *indio_dev;
331 struct iio_channel *parent;
332 struct mux *mux;
333 const char **labels;
334 int all_children;
335 int children;
336 u32 state;
337 int sizeof_ext_info;
338 int sizeof_priv;
339 int i;
340 int ret;
341
342 parent = devm_iio_channel_get(dev, "parent");
343 if (IS_ERR(parent))
344 return dev_err_probe(dev, PTR_ERR(parent),
345 "failed to get parent channel\n");
346
347 sizeof_ext_info = iio_get_channel_ext_info_count(parent);
348 if (sizeof_ext_info) {
349 sizeof_ext_info += 1; /* one extra entry for the sentinel */
350 sizeof_ext_info *= sizeof(*mux->ext_info);
351 }
352
353 all_children = device_property_string_array_count(dev, "channels");
354 if (all_children < 0)
355 return all_children;
356
357 labels = devm_kmalloc_array(dev, all_children, sizeof(*labels), GFP_KERNEL);
358 if (!labels)
359 return -ENOMEM;
360
361 ret = device_property_read_string_array(dev, "channels", labels, all_children);
362 if (ret < 0)
363 return ret;
364
365 children = 0;
366 for (state = 0; state < all_children; state++) {
367 if (*labels[state])
368 children++;
369 }
370 if (children <= 0) {
371 dev_err(dev, "not even a single child\n");
372 return -EINVAL;
373 }
374
375 sizeof_priv = sizeof(*mux);
376 sizeof_priv += sizeof(*mux->child) * children;
377 sizeof_priv += sizeof(*mux->chan) * children;
378 sizeof_priv += sizeof_ext_info;
379
380 indio_dev = devm_iio_device_alloc(dev, sizeof_priv);
381 if (!indio_dev)
382 return -ENOMEM;
383
384 mux = iio_priv(indio_dev);
385 mux->child = (struct mux_child *)(mux + 1);
386 mux->chan = (struct iio_chan_spec *)(mux->child + children);
387
388 platform_set_drvdata(pdev, indio_dev);
389
390 mux->parent = parent;
391 mux->cached_state = -1;
392
393 mux->delay_us = 0;
394 device_property_read_u32(dev, "settle-time-us", &mux->delay_us);
395
396 indio_dev->name = dev_name(dev);
397 indio_dev->info = &mux_info;
398 indio_dev->modes = INDIO_DIRECT_MODE;
399 indio_dev->channels = mux->chan;
400 indio_dev->num_channels = children;
401 if (sizeof_ext_info) {
402 mux->ext_info = devm_kmemdup(dev,
403 parent->channel->ext_info,
404 sizeof_ext_info, GFP_KERNEL);
405 if (!mux->ext_info)
406 return -ENOMEM;
407
408 for (i = 0; mux->ext_info[i].name; ++i) {
409 if (parent->channel->ext_info[i].read)
410 mux->ext_info[i].read = mux_read_ext_info;
411 if (parent->channel->ext_info[i].write)
412 mux->ext_info[i].write = mux_write_ext_info;
413 mux->ext_info[i].private = i;
414 }
415 }
416
417 mux->control = devm_mux_control_get(dev, NULL);
418 if (IS_ERR(mux->control))
419 return dev_err_probe(dev, PTR_ERR(mux->control),
420 "failed to get control-mux\n");
421
422 i = 0;
423 for (state = 0; state < all_children; state++) {
424 if (!*labels[state])
425 continue;
426
427 ret = mux_configure_channel(dev, mux, state, labels[state], i++);
428 if (ret < 0)
429 return ret;
430 }
431
432 ret = devm_iio_device_register(dev, indio_dev);
433 if (ret) {
434 dev_err(dev, "failed to register iio device\n");
435 return ret;
436 }
437
438 return 0;
439 }
440
441 static const struct of_device_id mux_match[] = {
442 { .compatible = "io-channel-mux" },
443 { /* sentinel */ }
444 };
445 MODULE_DEVICE_TABLE(of, mux_match);
446
447 static struct platform_driver mux_driver = {
448 .probe = mux_probe,
449 .driver = {
450 .name = "iio-mux",
451 .of_match_table = mux_match,
452 },
453 };
454 module_platform_driver(mux_driver);
455
456 MODULE_DESCRIPTION("IIO multiplexer driver");
457 MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
458 MODULE_LICENSE("GPL v2");
459