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3a84331d JC |
1 | /** |
2 | * Copyright (c) 2011 Jonathan Cameron | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License version 2 as published by | |
6 | * the Free Software Foundation. | |
7 | * | |
8 | * A reference industrial I/O driver to illustrate the functionality available. | |
9 | * | |
10 | * There are numerous real drivers to illustrate the finer points. | |
11 | * The purpose of this driver is to provide a driver with far more comments | |
12 | * and explanatory notes than any 'real' driver would have. | |
13 | * Anyone starting out writing an IIO driver should first make sure they | |
14 | * understand all of this driver except those bits specifically marked | |
15 | * as being present to allow us to 'fake' the presence of hardware. | |
16 | */ | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/module.h> | |
20 | #include <linux/moduleparam.h> | |
21 | ||
22 | #include "iio.h" | |
e6477000 | 23 | #include "sysfs.h" |
af5046af JC |
24 | #include "events.h" |
25 | #include "buffer.h" | |
e6477000 | 26 | #include "iio_simple_dummy.h" |
3a84331d JC |
27 | |
28 | /* | |
29 | * A few elements needed to fake a bus for this driver | |
30 | * Note instances parmeter controls how many of these | |
31 | * dummy devices are registered. | |
32 | */ | |
33 | static unsigned instances = 1; | |
34 | module_param(instances, int, 0); | |
35 | ||
36 | /* Pointer array used to fake bus elements */ | |
37 | static struct iio_dev **iio_dummy_devs; | |
38 | ||
39 | /* Fake a name for the part number, usually obtained from the id table */ | |
40 | static const char *iio_dummy_part_number = "iio_dummy_part_no"; | |
41 | ||
42 | /** | |
43 | * struct iio_dummy_accel_calibscale - realworld to register mapping | |
44 | * @val: first value in read_raw - here integer part. | |
45 | * @val2: second value in read_raw etc - here micro part. | |
46 | * @regval: register value - magic device specific numbers. | |
47 | */ | |
48 | struct iio_dummy_accel_calibscale { | |
49 | int val; | |
50 | int val2; | |
51 | int regval; /* what would be written to hardware */ | |
52 | }; | |
53 | ||
54 | static const struct iio_dummy_accel_calibscale dummy_scales[] = { | |
55 | { 0, 100, 0x8 }, /* 0.000100 */ | |
56 | { 0, 133, 0x7 }, /* 0.000133 */ | |
57 | { 733, 13, 0x9 }, /* 733.00013 */ | |
58 | }; | |
59 | ||
3a84331d JC |
60 | /* |
61 | * iio_dummy_channels - Description of available channels | |
62 | * | |
63 | * This array of structures tells the IIO core about what the device | |
64 | * actually provides for a given channel. | |
65 | */ | |
66 | static struct iio_chan_spec iio_dummy_channels[] = { | |
67 | /* indexed ADC channel in_voltage0_raw etc */ | |
68 | { | |
69 | .type = IIO_VOLTAGE, | |
70 | /* Channel has a numeric index of 0 */ | |
71 | .indexed = 1, | |
72 | .channel = 0, | |
73 | /* What other information is available? */ | |
74 | .info_mask = | |
75 | /* | |
76 | * in_voltage0_offset | |
77 | * Offset for userspace to apply prior to scale | |
78 | * when converting to standard units (microvolts) | |
79 | */ | |
c8a9f805 | 80 | IIO_CHAN_INFO_OFFSET_SEPARATE_BIT | |
3a84331d JC |
81 | /* |
82 | * in_voltage0_scale | |
83 | * Multipler for userspace to apply post offset | |
84 | * when converting to standard units (microvolts) | |
85 | */ | |
c8a9f805 | 86 | IIO_CHAN_INFO_SCALE_SEPARATE_BIT, |
9ad2e2e1 JC |
87 | /* The ordering of elements in the buffer via an enum */ |
88 | .scan_index = voltage0, | |
89 | .scan_type = { /* Description of storage in buffer */ | |
90 | .sign = 'u', /* unsigned */ | |
91 | .realbits = 13, /* 13 bits */ | |
92 | .storagebits = 16, /* 16 bits used for storage */ | |
93 | .shift = 0, /* zero shift */ | |
94 | }, | |
e6477000 JC |
95 | #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS |
96 | /* | |
97 | * simple event - triggered when value rises above | |
98 | * a threshold | |
99 | */ | |
100 | .event_mask = IIO_EV_BIT(IIO_EV_TYPE_THRESH, | |
101 | IIO_EV_DIR_RISING), | |
102 | #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */ | |
3a84331d JC |
103 | }, |
104 | /* Differential ADC channel in_voltage1-voltage2_raw etc*/ | |
105 | { | |
106 | .type = IIO_VOLTAGE, | |
107 | .differential = 1, | |
108 | /* | |
109 | * Indexing for differential channels uses channel | |
110 | * for the positive part, channel2 for the negative. | |
111 | */ | |
112 | .indexed = 1, | |
113 | .channel = 1, | |
114 | .channel2 = 2, | |
115 | .info_mask = | |
116 | /* | |
117 | * in_voltage-voltage_scale | |
118 | * Shared version of scale - shared by differential | |
119 | * input channels of type IIO_VOLTAGE. | |
120 | */ | |
c8a9f805 | 121 | IIO_CHAN_INFO_SCALE_SHARED_BIT, |
9ad2e2e1 JC |
122 | .scan_index = diffvoltage1m2, |
123 | .scan_type = { /* Description of storage in buffer */ | |
124 | .sign = 's', /* signed */ | |
125 | .realbits = 12, /* 12 bits */ | |
126 | .storagebits = 16, /* 16 bits used for storage */ | |
127 | .shift = 0, /* zero shift */ | |
128 | }, | |
3a84331d JC |
129 | }, |
130 | /* Differential ADC channel in_voltage3-voltage4_raw etc*/ | |
131 | { | |
132 | .type = IIO_VOLTAGE, | |
133 | .differential = 1, | |
134 | .indexed = 1, | |
135 | .channel = 3, | |
136 | .channel2 = 4, | |
137 | .info_mask = | |
c8a9f805 | 138 | IIO_CHAN_INFO_SCALE_SHARED_BIT, |
9ad2e2e1 JC |
139 | .scan_index = diffvoltage3m4, |
140 | .scan_type = { | |
141 | .sign = 's', | |
142 | .realbits = 11, | |
143 | .storagebits = 16, | |
144 | .shift = 0, | |
145 | }, | |
3a84331d JC |
146 | }, |
147 | /* | |
148 | * 'modified' (i.e. axis specified) acceleration channel | |
149 | * in_accel_z_raw | |
150 | */ | |
151 | { | |
152 | .type = IIO_ACCEL, | |
153 | .modified = 1, | |
154 | /* Channel 2 is use for modifiers */ | |
155 | .channel2 = IIO_MOD_X, | |
156 | .info_mask = | |
157 | /* | |
158 | * Internal bias correction value. Applied | |
159 | * by the hardware or driver prior to userspace | |
160 | * seeing the readings. Typically part of hardware | |
161 | * calibration. | |
162 | */ | |
c8a9f805 | 163 | IIO_CHAN_INFO_CALIBBIAS_SEPARATE_BIT, |
9ad2e2e1 JC |
164 | .scan_index = accelx, |
165 | .scan_type = { /* Description of storage in buffer */ | |
166 | .sign = 's', /* signed */ | |
167 | .realbits = 16, /* 12 bits */ | |
168 | .storagebits = 16, /* 16 bits used for storage */ | |
169 | .shift = 0, /* zero shift */ | |
170 | }, | |
171 | }, | |
172 | /* | |
173 | * Convenience macro for timestamps. 4 is the index in | |
174 | * the buffer. | |
175 | */ | |
176 | IIO_CHAN_SOFT_TIMESTAMP(4), | |
177 | /* DAC channel out_voltage0_raw */ | |
178 | { | |
179 | .type = IIO_VOLTAGE, | |
180 | .output = 1, | |
181 | .indexed = 1, | |
182 | .channel = 0, | |
3a84331d JC |
183 | }, |
184 | }; | |
185 | ||
186 | /** | |
187 | * iio_dummy_read_raw() - data read function. | |
188 | * @indio_dev: the struct iio_dev associated with this device instance | |
189 | * @chan: the channel whose data is to be read | |
190 | * @val: first element of returned value (typically INT) | |
191 | * @val2: second element of returned value (typically MICRO) | |
192 | * @mask: what we actually want to read. 0 is the channel, everything else | |
193 | * is as per the info_mask in iio_chan_spec. | |
194 | */ | |
195 | static int iio_dummy_read_raw(struct iio_dev *indio_dev, | |
196 | struct iio_chan_spec const *chan, | |
197 | int *val, | |
198 | int *val2, | |
199 | long mask) | |
200 | { | |
201 | struct iio_dummy_state *st = iio_priv(indio_dev); | |
202 | int ret = -EINVAL; | |
203 | ||
204 | mutex_lock(&st->lock); | |
205 | switch (mask) { | |
206 | case 0: /* magic value - channel value read */ | |
207 | switch (chan->type) { | |
208 | case IIO_VOLTAGE: | |
209 | if (chan->output) { | |
210 | /* Set integer part to cached value */ | |
211 | *val = st->dac_val; | |
212 | ret = IIO_VAL_INT; | |
213 | } else if (chan->differential) { | |
214 | if (chan->channel == 1) | |
215 | *val = st->differential_adc_val[0]; | |
216 | else | |
217 | *val = st->differential_adc_val[1]; | |
218 | ret = IIO_VAL_INT; | |
219 | } else { | |
220 | *val = st->single_ended_adc_val; | |
221 | ret = IIO_VAL_INT; | |
222 | } | |
223 | break; | |
224 | case IIO_ACCEL: | |
225 | *val = st->accel_val; | |
226 | ret = IIO_VAL_INT; | |
227 | break; | |
228 | default: | |
229 | break; | |
230 | } | |
231 | break; | |
c8a9f805 | 232 | case IIO_CHAN_INFO_OFFSET: |
3a84331d JC |
233 | /* only single ended adc -> 7 */ |
234 | *val = 7; | |
235 | ret = IIO_VAL_INT; | |
236 | break; | |
c8a9f805 JC |
237 | case IIO_CHAN_INFO_SCALE: |
238 | switch (chan->differential) { | |
239 | case 0: | |
240 | /* only single ended adc -> 0.001333 */ | |
241 | *val = 0; | |
242 | *val2 = 1333; | |
243 | ret = IIO_VAL_INT_PLUS_MICRO; | |
244 | break; | |
245 | case 1: | |
246 | /* all differential adc channels -> 0.000001344 */ | |
247 | *val = 0; | |
248 | *val2 = 1344; | |
249 | ret = IIO_VAL_INT_PLUS_NANO; | |
250 | } | |
3a84331d | 251 | break; |
c8a9f805 | 252 | case IIO_CHAN_INFO_CALIBBIAS: |
3a84331d JC |
253 | /* only the acceleration axis - read from cache */ |
254 | *val = st->accel_calibbias; | |
255 | ret = IIO_VAL_INT; | |
256 | break; | |
c8a9f805 | 257 | case IIO_CHAN_INFO_CALIBSCALE: |
3a84331d JC |
258 | *val = st->accel_calibscale->val; |
259 | *val2 = st->accel_calibscale->val2; | |
260 | ret = IIO_VAL_INT_PLUS_MICRO; | |
261 | break; | |
262 | default: | |
263 | break; | |
264 | } | |
265 | mutex_unlock(&st->lock); | |
266 | return ret; | |
267 | } | |
268 | ||
269 | /** | |
270 | * iio_dummy_write_raw() - data write function. | |
271 | * @indio_dev: the struct iio_dev associated with this device instance | |
272 | * @chan: the channel whose data is to be read | |
273 | * @val: first element of returned value (typically INT) | |
274 | * @val2: second element of returned value (typically MICRO) | |
275 | * @mask: what we actually want to read. 0 is the channel, everything else | |
276 | * is as per the info_mask in iio_chan_spec. | |
277 | * | |
278 | * Note that all raw writes are assumed IIO_VAL_INT and info mask elements | |
279 | * are assumed to be IIO_INT_PLUS_MICRO unless the callback write_raw_get_fmt | |
280 | * in struct iio_info is provided by the driver. | |
281 | */ | |
282 | static int iio_dummy_write_raw(struct iio_dev *indio_dev, | |
283 | struct iio_chan_spec const *chan, | |
284 | int val, | |
285 | int val2, | |
286 | long mask) | |
287 | { | |
288 | int i; | |
289 | int ret = 0; | |
290 | struct iio_dummy_state *st = iio_priv(indio_dev); | |
291 | ||
292 | switch (mask) { | |
293 | case 0: | |
294 | if (chan->output == 0) | |
295 | return -EINVAL; | |
296 | ||
297 | /* Locking not required as writing single value */ | |
298 | mutex_lock(&st->lock); | |
299 | st->dac_val = val; | |
300 | mutex_unlock(&st->lock); | |
301 | return 0; | |
c8a9f805 | 302 | case IIO_CHAN_INFO_CALIBBIAS: |
3a84331d JC |
303 | mutex_lock(&st->lock); |
304 | /* Compare against table - hard matching here */ | |
305 | for (i = 0; i < ARRAY_SIZE(dummy_scales); i++) | |
306 | if (val == dummy_scales[i].val && | |
307 | val2 == dummy_scales[i].val2) | |
308 | break; | |
309 | if (i == ARRAY_SIZE(dummy_scales)) | |
310 | ret = -EINVAL; | |
311 | else | |
312 | st->accel_calibscale = &dummy_scales[i]; | |
313 | mutex_unlock(&st->lock); | |
314 | return ret; | |
315 | default: | |
316 | return -EINVAL; | |
317 | } | |
318 | } | |
319 | ||
320 | /* | |
321 | * Device type specific information. | |
322 | */ | |
323 | static const struct iio_info iio_dummy_info = { | |
324 | .driver_module = THIS_MODULE, | |
325 | .read_raw = &iio_dummy_read_raw, | |
326 | .write_raw = &iio_dummy_write_raw, | |
e6477000 JC |
327 | #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS |
328 | .read_event_config = &iio_simple_dummy_read_event_config, | |
329 | .write_event_config = &iio_simple_dummy_write_event_config, | |
330 | .read_event_value = &iio_simple_dummy_read_event_value, | |
331 | .write_event_value = &iio_simple_dummy_write_event_value, | |
332 | #endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */ | |
3a84331d JC |
333 | }; |
334 | ||
335 | /** | |
336 | * iio_dummy_init_device() - device instance specific init | |
337 | * @indio_dev: the iio device structure | |
338 | * | |
339 | * Most drivers have one of these to set up default values, | |
340 | * reset the device to known state etc. | |
341 | */ | |
342 | static int iio_dummy_init_device(struct iio_dev *indio_dev) | |
343 | { | |
344 | struct iio_dummy_state *st = iio_priv(indio_dev); | |
345 | ||
346 | st->dac_val = 0; | |
347 | st->single_ended_adc_val = 73; | |
348 | st->differential_adc_val[0] = 33; | |
349 | st->differential_adc_val[1] = -34; | |
350 | st->accel_val = 34; | |
351 | st->accel_calibbias = -7; | |
352 | st->accel_calibscale = &dummy_scales[0]; | |
353 | ||
354 | return 0; | |
355 | } | |
356 | ||
357 | /** | |
358 | * iio_dummy_probe() - device instance probe | |
359 | * @index: an id number for this instance. | |
360 | * | |
361 | * Arguments are bus type specific. | |
362 | * I2C: iio_dummy_probe(struct i2c_client *client, | |
363 | * const struct i2c_device_id *id) | |
364 | * SPI: iio_dummy_probe(struct spi_device *spi) | |
365 | */ | |
366 | static int __devinit iio_dummy_probe(int index) | |
367 | { | |
368 | int ret; | |
369 | struct iio_dev *indio_dev; | |
370 | struct iio_dummy_state *st; | |
371 | ||
372 | /* | |
373 | * Allocate an IIO device. | |
374 | * | |
375 | * This structure contains all generic state | |
376 | * information about the device instance. | |
377 | * It also has a region (accessed by iio_priv() | |
378 | * for chip specific state information. | |
379 | */ | |
380 | indio_dev = iio_allocate_device(sizeof(*st)); | |
381 | if (indio_dev == NULL) { | |
382 | ret = -ENOMEM; | |
383 | goto error_ret; | |
384 | } | |
385 | ||
386 | st = iio_priv(indio_dev); | |
387 | mutex_init(&st->lock); | |
388 | ||
389 | iio_dummy_init_device(indio_dev); | |
390 | /* | |
391 | * With hardware: Set the parent device. | |
392 | * indio_dev->dev.parent = &spi->dev; | |
393 | * indio_dev->dev.parent = &client->dev; | |
394 | */ | |
395 | ||
396 | /* | |
397 | * Make the iio_dev struct available to remove function. | |
398 | * Bus equivalents | |
399 | * i2c_set_clientdata(client, indio_dev); | |
400 | * spi_set_drvdata(spi, indio_dev); | |
401 | */ | |
402 | iio_dummy_devs[index] = indio_dev; | |
403 | ||
404 | ||
405 | /* | |
406 | * Set the device name. | |
407 | * | |
408 | * This is typically a part number and obtained from the module | |
409 | * id table. | |
410 | * e.g. for i2c and spi: | |
411 | * indio_dev->name = id->name; | |
412 | * indio_dev->name = spi_get_device_id(spi)->name; | |
413 | */ | |
414 | indio_dev->name = iio_dummy_part_number; | |
415 | ||
416 | /* Provide description of available channels */ | |
417 | indio_dev->channels = iio_dummy_channels; | |
418 | indio_dev->num_channels = ARRAY_SIZE(iio_dummy_channels); | |
419 | ||
420 | /* | |
421 | * Provide device type specific interface functions and | |
422 | * constant data. | |
423 | */ | |
424 | indio_dev->info = &iio_dummy_info; | |
425 | ||
426 | /* Specify that device provides sysfs type interfaces */ | |
427 | indio_dev->modes = INDIO_DIRECT_MODE; | |
428 | ||
e6477000 | 429 | ret = iio_simple_dummy_events_register(indio_dev); |
3a84331d JC |
430 | if (ret < 0) |
431 | goto error_free_device; | |
9ad2e2e1 JC |
432 | |
433 | /* Configure buffered capture support. */ | |
434 | ret = iio_simple_dummy_configure_buffer(indio_dev); | |
e6477000 JC |
435 | if (ret < 0) |
436 | goto error_unregister_events; | |
3a84331d | 437 | |
9ad2e2e1 JC |
438 | /* |
439 | * Register the channels with the buffer, but avoid the output | |
440 | * channel being registered by reducing the number of channels by 1. | |
441 | */ | |
442 | ret = iio_buffer_register(indio_dev, iio_dummy_channels, 5); | |
443 | if (ret < 0) | |
444 | goto error_unconfigure_buffer; | |
445 | ||
446 | ret = iio_device_register(indio_dev); | |
447 | if (ret < 0) | |
448 | goto error_unregister_buffer; | |
449 | ||
3a84331d | 450 | return 0; |
9ad2e2e1 JC |
451 | error_unregister_buffer: |
452 | iio_buffer_unregister(indio_dev); | |
453 | error_unconfigure_buffer: | |
454 | iio_simple_dummy_unconfigure_buffer(indio_dev); | |
e6477000 JC |
455 | error_unregister_events: |
456 | iio_simple_dummy_events_unregister(indio_dev); | |
3a84331d JC |
457 | error_free_device: |
458 | /* Note free device should only be called, before registration | |
459 | * has succeeded. */ | |
460 | iio_free_device(indio_dev); | |
461 | error_ret: | |
462 | return ret; | |
463 | } | |
464 | ||
465 | /** | |
466 | * iio_dummy_remove() - device instance removal function | |
467 | * @index: device index. | |
468 | * | |
469 | * Parameters follow those of iio_dummy_probe for buses. | |
470 | */ | |
471 | static int iio_dummy_remove(int index) | |
472 | { | |
e6477000 | 473 | int ret; |
3a84331d JC |
474 | /* |
475 | * Get a pointer to the device instance iio_dev structure | |
476 | * from the bus subsystem. E.g. | |
477 | * struct iio_dev *indio_dev = i2c_get_clientdata(client); | |
478 | * struct iio_dev *indio_dev = spi_get_drvdata(spi); | |
479 | */ | |
480 | struct iio_dev *indio_dev = iio_dummy_devs[index]; | |
481 | ||
e6477000 | 482 | |
3a84331d JC |
483 | /* Unregister the device */ |
484 | iio_device_unregister(indio_dev); | |
485 | ||
486 | /* Device specific code to power down etc */ | |
487 | ||
9ad2e2e1 JC |
488 | /* Buffered capture related cleanup */ |
489 | iio_buffer_unregister(indio_dev); | |
490 | iio_simple_dummy_unconfigure_buffer(indio_dev); | |
e6477000 JC |
491 | |
492 | ret = iio_simple_dummy_events_unregister(indio_dev); | |
493 | if (ret) | |
494 | goto error_ret; | |
495 | ||
3a84331d JC |
496 | /* Free all structures */ |
497 | iio_free_device(indio_dev); | |
498 | ||
e6477000 JC |
499 | error_ret: |
500 | return ret; | |
3a84331d JC |
501 | } |
502 | ||
503 | /** | |
504 | * iio_dummy_init() - device driver registration | |
505 | * | |
506 | * Varies depending on bus type of the device. As there is no device | |
507 | * here, call probe directly. For information on device registration | |
508 | * i2c: | |
509 | * Documentation/i2c/writing-clients | |
510 | * spi: | |
511 | * Documentation/spi/spi-summary | |
512 | */ | |
513 | static __init int iio_dummy_init(void) | |
514 | { | |
515 | int i, ret; | |
516 | if (instances > 10) { | |
517 | instances = 1; | |
518 | return -EINVAL; | |
519 | } | |
520 | /* Fake a bus */ | |
521 | iio_dummy_devs = kzalloc(sizeof(*iio_dummy_devs)*instances, GFP_KERNEL); | |
522 | /* Here we have no actual device so call probe */ | |
523 | for (i = 0; i < instances; i++) { | |
524 | ret = iio_dummy_probe(i); | |
525 | if (ret < 0) | |
526 | return ret; | |
527 | } | |
528 | return 0; | |
529 | } | |
530 | module_init(iio_dummy_init); | |
531 | ||
532 | /** | |
533 | * iio_dummy_exit() - device driver removal | |
534 | * | |
535 | * Varies depending on bus type of the device. | |
536 | * As there is no device here, call remove directly. | |
537 | */ | |
538 | static __exit void iio_dummy_exit(void) | |
539 | { | |
540 | int i; | |
541 | for (i = 0; i < instances; i++) | |
542 | iio_dummy_remove(i); | |
543 | kfree(iio_dummy_devs); | |
544 | } | |
545 | module_exit(iio_dummy_exit); | |
546 | ||
547 | MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>"); | |
548 | MODULE_DESCRIPTION("IIO dummy driver"); | |
549 | MODULE_LICENSE("GPL v2"); |