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_dev *indio_dev; |
34 | struct iio_chan_spec *chan; |
35 | struct iio_chan_spec_ext_info *ext_info; |
36 | struct mux_child *child; |
37 | u32 delay_us; |
38 | }; |
39 | |
40 | static int iio_mux_select(struct mux *mux, int idx) |
41 | { |
42 | struct mux_child *child = &mux->child[idx]; |
43 | struct iio_chan_spec const *chan = &mux->chan[idx]; |
44 | int ret; |
45 | int i; |
46 | |
47 | ret = mux_control_select_delay(mux: mux->control, state: chan->channel, |
48 | delay_us: mux->delay_us); |
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(chan: mux->parent, attr, |
68 | buf: cache->data, |
69 | len: cache->size); |
70 | |
71 | if (ret < 0) { |
72 | mux_control_deselect(mux: 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 | |
83 | static void iio_mux_deselect(struct mux *mux) |
84 | { |
85 | mux_control_deselect(mux: mux->control); |
86 | } |
87 | |
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(chan: mux->parent, val); |
103 | break; |
104 | |
105 | case IIO_CHAN_INFO_SCALE: |
106 | ret = iio_read_channel_scale(chan: 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 | |
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(chan: 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 | |
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(chan: 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 | |
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(chan: mux->parent, |
190 | attr: mux->ext_info[private].name, |
191 | buf); |
192 | |
193 | iio_mux_deselect(mux); |
194 | |
195 | return ret; |
196 | } |
197 | |
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, src: buf, len: 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(chan: mux->parent, |
224 | attr: mux->ext_info[private].name, |
225 | buf, len); |
226 | if (ret < 0) { |
227 | iio_mux_deselect(mux); |
228 | devm_kfree(dev, p: new); |
229 | return ret; |
230 | } |
231 | |
232 | devm_kfree(dev, p: 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 | |
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(channel: mux->parent, type: &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(chan: pchan, type: IIO_CHAN_INFO_RAW)) |
264 | chan->info_mask_separate |= BIT(IIO_CHAN_INFO_RAW); |
265 | if (iio_channel_has_info(chan: pchan, type: IIO_CHAN_INFO_SCALE)) |
266 | chan->info_mask_separate |= BIT(IIO_CHAN_INFO_SCALE); |
267 | |
268 | if (iio_channel_has_available(chan: pchan, type: IIO_CHAN_INFO_RAW)) |
269 | chan->info_mask_separate_available |= BIT(IIO_CHAN_INFO_RAW); |
270 | |
271 | if (state >= mux_control_states(mux: 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(chan: 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 | n: num_ext_info, |
286 | size: 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(chan: mux->parent, |
300 | attr: mux->ext_info[i].name, |
301 | buf: 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, src: page, len: 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, p: page); |
324 | |
325 | return 0; |
326 | } |
327 | |
328 | static int mux_probe(struct platform_device *pdev) |
329 | { |
330 | struct device *dev = &pdev->dev; |
331 | struct iio_dev *indio_dev; |
332 | struct iio_channel *parent; |
333 | struct mux *mux; |
334 | const char **labels; |
335 | int all_children; |
336 | int children; |
337 | u32 state; |
338 | int sizeof_ext_info; |
339 | int sizeof_priv; |
340 | int i; |
341 | int ret; |
342 | |
343 | parent = devm_iio_channel_get(dev, consumer_channel: "parent" ); |
344 | if (IS_ERR(ptr: parent)) |
345 | return dev_err_probe(dev, err: PTR_ERR(ptr: parent), |
346 | fmt: "failed to get parent channel\n" ); |
347 | |
348 | sizeof_ext_info = iio_get_channel_ext_info_count(chan: parent); |
349 | if (sizeof_ext_info) { |
350 | sizeof_ext_info += 1; /* one extra entry for the sentinel */ |
351 | sizeof_ext_info *= sizeof(*mux->ext_info); |
352 | } |
353 | |
354 | all_children = device_property_string_array_count(dev, propname: "channels" ); |
355 | if (all_children < 0) |
356 | return all_children; |
357 | |
358 | labels = devm_kmalloc_array(dev, n: all_children, size: sizeof(*labels), GFP_KERNEL); |
359 | if (!labels) |
360 | return -ENOMEM; |
361 | |
362 | ret = device_property_read_string_array(dev, propname: "channels" , val: labels, nval: all_children); |
363 | if (ret < 0) |
364 | return ret; |
365 | |
366 | children = 0; |
367 | for (state = 0; state < all_children; state++) { |
368 | if (*labels[state]) |
369 | children++; |
370 | } |
371 | if (children <= 0) { |
372 | dev_err(dev, "not even a single child\n" ); |
373 | return -EINVAL; |
374 | } |
375 | |
376 | sizeof_priv = sizeof(*mux); |
377 | sizeof_priv += sizeof(*mux->child) * children; |
378 | sizeof_priv += sizeof(*mux->chan) * children; |
379 | sizeof_priv += sizeof_ext_info; |
380 | |
381 | indio_dev = devm_iio_device_alloc(parent: dev, sizeof_priv); |
382 | if (!indio_dev) |
383 | return -ENOMEM; |
384 | |
385 | mux = iio_priv(indio_dev); |
386 | mux->child = (struct mux_child *)(mux + 1); |
387 | mux->chan = (struct iio_chan_spec *)(mux->child + children); |
388 | |
389 | platform_set_drvdata(pdev, data: indio_dev); |
390 | |
391 | mux->parent = parent; |
392 | mux->cached_state = -1; |
393 | |
394 | mux->delay_us = 0; |
395 | device_property_read_u32(dev, propname: "settle-time-us" , val: &mux->delay_us); |
396 | |
397 | indio_dev->name = dev_name(dev); |
398 | indio_dev->info = &mux_info; |
399 | indio_dev->modes = INDIO_DIRECT_MODE; |
400 | indio_dev->channels = mux->chan; |
401 | indio_dev->num_channels = children; |
402 | if (sizeof_ext_info) { |
403 | mux->ext_info = devm_kmemdup(dev, |
404 | src: parent->channel->ext_info, |
405 | len: sizeof_ext_info, GFP_KERNEL); |
406 | if (!mux->ext_info) |
407 | return -ENOMEM; |
408 | |
409 | for (i = 0; mux->ext_info[i].name; ++i) { |
410 | if (parent->channel->ext_info[i].read) |
411 | mux->ext_info[i].read = mux_read_ext_info; |
412 | if (parent->channel->ext_info[i].write) |
413 | mux->ext_info[i].write = mux_write_ext_info; |
414 | mux->ext_info[i].private = i; |
415 | } |
416 | } |
417 | |
418 | mux->control = devm_mux_control_get(dev, NULL); |
419 | if (IS_ERR(ptr: mux->control)) |
420 | return dev_err_probe(dev, err: PTR_ERR(ptr: mux->control), |
421 | fmt: "failed to get control-mux\n" ); |
422 | |
423 | i = 0; |
424 | for (state = 0; state < all_children; state++) { |
425 | if (!*labels[state]) |
426 | continue; |
427 | |
428 | ret = mux_configure_channel(dev, mux, state, label: labels[state], idx: i++); |
429 | if (ret < 0) |
430 | return ret; |
431 | } |
432 | |
433 | ret = devm_iio_device_register(dev, indio_dev); |
434 | if (ret) { |
435 | dev_err(dev, "failed to register iio device\n" ); |
436 | return ret; |
437 | } |
438 | |
439 | return 0; |
440 | } |
441 | |
442 | static const struct of_device_id mux_match[] = { |
443 | { .compatible = "io-channel-mux" }, |
444 | { /* sentinel */ } |
445 | }; |
446 | MODULE_DEVICE_TABLE(of, mux_match); |
447 | |
448 | static struct platform_driver mux_driver = { |
449 | .probe = mux_probe, |
450 | .driver = { |
451 | .name = "iio-mux" , |
452 | .of_match_table = mux_match, |
453 | }, |
454 | }; |
455 | module_platform_driver(mux_driver); |
456 | |
457 | MODULE_DESCRIPTION("IIO multiplexer driver" ); |
458 | MODULE_AUTHOR("Peter Rosin <peda@axentia.se>" ); |
459 | MODULE_LICENSE("GPL v2" ); |
460 | |