1 /*
2 * Support code for Analog Devices Sigma-Delta ADCs
3 *
4 * Copyright 2012 Analog Devices Inc.
5 * Author: Lars-Peter Clausen <lars@metafoo.de>
6 *
7 * Licensed under the GPL-2.
8 */
9
10 #include <linux/interrupt.h>
11 #include <linux/device.h>
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/spi/spi.h>
15 #include <linux/err.h>
16 #include <linux/module.h>
17
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20 #include <linux/iio/buffer.h>
21 #include <linux/iio/trigger.h>
22 #include <linux/iio/trigger_consumer.h>
23 #include <linux/iio/triggered_buffer.h>
24 #include <linux/iio/adc/ad_sigma_delta.h>
25
26 #include <asm/unaligned.h>
27
28
29 #define AD_SD_COMM_CHAN_MASK 0x3
30
31 #define AD_SD_REG_COMM 0x00
32 #define AD_SD_REG_DATA 0x03
33
34 /**
35 * ad_sd_set_comm() - Set communications register
36 *
37 * @sigma_delta: The sigma delta device
38 * @comm: New value for the communications register
39 */
ad_sd_set_comm(struct ad_sigma_delta * sigma_delta,uint8_t comm)40 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
41 {
42 /* Some variants use the lower two bits of the communications register
43 * to select the channel */
44 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
45 }
46 EXPORT_SYMBOL_GPL(ad_sd_set_comm);
47
48 /**
49 * ad_sd_write_reg() - Write a register
50 *
51 * @sigma_delta: The sigma delta device
52 * @reg: Address of the register
53 * @size: Size of the register (0-3)
54 * @val: Value to write to the register
55 *
56 * Returns 0 on success, an error code otherwise.
57 **/
ad_sd_write_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int val)58 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
59 unsigned int size, unsigned int val)
60 {
61 uint8_t *data = sigma_delta->data;
62 struct spi_transfer t = {
63 .tx_buf = data,
64 .len = size + 1,
65 .cs_change = sigma_delta->bus_locked,
66 };
67 struct spi_message m;
68 int ret;
69
70 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
71
72 switch (size) {
73 case 3:
74 data[1] = val >> 16;
75 data[2] = val >> 8;
76 data[3] = val;
77 break;
78 case 2:
79 put_unaligned_be16(val, &data[1]);
80 break;
81 case 1:
82 data[1] = val;
83 break;
84 case 0:
85 break;
86 default:
87 return -EINVAL;
88 }
89
90 spi_message_init(&m);
91 spi_message_add_tail(&t, &m);
92
93 if (sigma_delta->bus_locked)
94 ret = spi_sync_locked(sigma_delta->spi, &m);
95 else
96 ret = spi_sync(sigma_delta->spi, &m);
97
98 return ret;
99 }
100 EXPORT_SYMBOL_GPL(ad_sd_write_reg);
101
ad_sd_read_reg_raw(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,uint8_t * val)102 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
103 unsigned int reg, unsigned int size, uint8_t *val)
104 {
105 uint8_t *data = sigma_delta->data;
106 int ret;
107 struct spi_transfer t[] = {
108 {
109 .tx_buf = data,
110 .len = 1,
111 }, {
112 .rx_buf = val,
113 .len = size,
114 .cs_change = sigma_delta->bus_locked,
115 },
116 };
117 struct spi_message m;
118
119 spi_message_init(&m);
120
121 if (sigma_delta->info->has_registers) {
122 data[0] = reg << sigma_delta->info->addr_shift;
123 data[0] |= sigma_delta->info->read_mask;
124 spi_message_add_tail(&t[0], &m);
125 }
126 spi_message_add_tail(&t[1], &m);
127
128 if (sigma_delta->bus_locked)
129 ret = spi_sync_locked(sigma_delta->spi, &m);
130 else
131 ret = spi_sync(sigma_delta->spi, &m);
132
133 return ret;
134 }
135
136 /**
137 * ad_sd_read_reg() - Read a register
138 *
139 * @sigma_delta: The sigma delta device
140 * @reg: Address of the register
141 * @size: Size of the register (1-4)
142 * @val: Read value
143 *
144 * Returns 0 on success, an error code otherwise.
145 **/
ad_sd_read_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int * val)146 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
147 unsigned int reg, unsigned int size, unsigned int *val)
148 {
149 int ret;
150
151 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data);
152 if (ret < 0)
153 goto out;
154
155 switch (size) {
156 case 4:
157 *val = get_unaligned_be32(sigma_delta->data);
158 break;
159 case 3:
160 *val = (sigma_delta->data[0] << 16) |
161 (sigma_delta->data[1] << 8) |
162 sigma_delta->data[2];
163 break;
164 case 2:
165 *val = get_unaligned_be16(sigma_delta->data);
166 break;
167 case 1:
168 *val = sigma_delta->data[0];
169 break;
170 default:
171 ret = -EINVAL;
172 break;
173 }
174
175 out:
176 return ret;
177 }
178 EXPORT_SYMBOL_GPL(ad_sd_read_reg);
179
ad_sd_calibrate(struct ad_sigma_delta * sigma_delta,unsigned int mode,unsigned int channel)180 static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
181 unsigned int mode, unsigned int channel)
182 {
183 int ret;
184
185 ret = ad_sigma_delta_set_channel(sigma_delta, channel);
186 if (ret)
187 return ret;
188
189 spi_bus_lock(sigma_delta->spi->master);
190 sigma_delta->bus_locked = true;
191 INIT_COMPLETION(sigma_delta->completion);
192
193 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
194 if (ret < 0)
195 goto out;
196
197 sigma_delta->irq_dis = false;
198 enable_irq(sigma_delta->spi->irq);
199 ret = wait_for_completion_timeout(&sigma_delta->completion, 2*HZ);
200 if (ret == 0) {
201 sigma_delta->irq_dis = true;
202 disable_irq_nosync(sigma_delta->spi->irq);
203 ret = -EIO;
204 } else {
205 ret = 0;
206 }
207 out:
208 sigma_delta->bus_locked = false;
209 spi_bus_unlock(sigma_delta->spi->master);
210 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
211
212 return ret;
213 }
214
215 /**
216 * ad_sd_calibrate_all() - Performs channel calibration
217 * @sigma_delta: The sigma delta device
218 * @cb: Array of channels and calibration type to perform
219 * @n: Number of items in cb
220 *
221 * Returns 0 on success, an error code otherwise.
222 **/
ad_sd_calibrate_all(struct ad_sigma_delta * sigma_delta,const struct ad_sd_calib_data * cb,unsigned int n)223 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
224 const struct ad_sd_calib_data *cb, unsigned int n)
225 {
226 unsigned int i;
227 int ret;
228
229 for (i = 0; i < n; i++) {
230 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
231 if (ret)
232 return ret;
233 }
234
235 return 0;
236 }
237 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
238
239 /**
240 * ad_sigma_delta_single_conversion() - Performs a single data conversion
241 * @indio_dev: The IIO device
242 * @chan: The conversion is done for this channel
243 * @val: Pointer to the location where to store the read value
244 *
245 * Returns: 0 on success, an error value otherwise.
246 */
ad_sigma_delta_single_conversion(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val)247 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
248 const struct iio_chan_spec *chan, int *val)
249 {
250 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
251 unsigned int sample, raw_sample;
252 int ret = 0;
253
254 if (iio_buffer_enabled(indio_dev))
255 return -EBUSY;
256
257 mutex_lock(&indio_dev->mlock);
258 ad_sigma_delta_set_channel(sigma_delta, chan->address);
259
260 spi_bus_lock(sigma_delta->spi->master);
261 sigma_delta->bus_locked = true;
262 INIT_COMPLETION(sigma_delta->completion);
263
264 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
265
266 sigma_delta->irq_dis = false;
267 enable_irq(sigma_delta->spi->irq);
268 ret = wait_for_completion_interruptible_timeout(
269 &sigma_delta->completion, HZ);
270
271 sigma_delta->bus_locked = false;
272 spi_bus_unlock(sigma_delta->spi->master);
273
274 if (ret == 0)
275 ret = -EIO;
276 if (ret < 0)
277 goto out;
278
279 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
280 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
281 &raw_sample);
282
283 out:
284 if (!sigma_delta->irq_dis) {
285 disable_irq_nosync(sigma_delta->spi->irq);
286 sigma_delta->irq_dis = true;
287 }
288
289 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
290 mutex_unlock(&indio_dev->mlock);
291
292 if (ret)
293 return ret;
294
295 sample = raw_sample >> chan->scan_type.shift;
296 sample &= (1 << chan->scan_type.realbits) - 1;
297 *val = sample;
298
299 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
300 if (ret)
301 return ret;
302
303 return IIO_VAL_INT;
304 }
305 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
306
ad_sd_buffer_postenable(struct iio_dev * indio_dev)307 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
308 {
309 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
310 unsigned int channel;
311 int ret;
312
313 ret = iio_triggered_buffer_postenable(indio_dev);
314 if (ret < 0)
315 return ret;
316
317 channel = find_first_bit(indio_dev->active_scan_mask,
318 indio_dev->masklength);
319 ret = ad_sigma_delta_set_channel(sigma_delta,
320 indio_dev->channels[channel].address);
321 if (ret)
322 goto err_predisable;
323
324 spi_bus_lock(sigma_delta->spi->master);
325 sigma_delta->bus_locked = true;
326 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
327 if (ret)
328 goto err_unlock;
329
330 sigma_delta->irq_dis = false;
331 enable_irq(sigma_delta->spi->irq);
332
333 return 0;
334
335 err_unlock:
336 spi_bus_unlock(sigma_delta->spi->master);
337 err_predisable:
338
339 return ret;
340 }
341
ad_sd_buffer_postdisable(struct iio_dev * indio_dev)342 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
343 {
344 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
345
346 INIT_COMPLETION(sigma_delta->completion);
347 wait_for_completion_timeout(&sigma_delta->completion, HZ);
348
349 if (!sigma_delta->irq_dis) {
350 disable_irq_nosync(sigma_delta->spi->irq);
351 sigma_delta->irq_dis = true;
352 }
353
354 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
355
356 sigma_delta->bus_locked = false;
357 return spi_bus_unlock(sigma_delta->spi->master);
358 }
359
ad_sd_trigger_handler(int irq,void * p)360 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
361 {
362 struct iio_poll_func *pf = p;
363 struct iio_dev *indio_dev = pf->indio_dev;
364 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
365 unsigned int reg_size;
366 uint8_t data[16];
367 int ret;
368
369 memset(data, 0x00, 16);
370
371 /* Guaranteed to be aligned with 8 byte boundary */
372 if (indio_dev->scan_timestamp)
373 ((s64 *)data)[1] = pf->timestamp;
374
375 reg_size = indio_dev->channels[0].scan_type.realbits +
376 indio_dev->channels[0].scan_type.shift;
377 reg_size = DIV_ROUND_UP(reg_size, 8);
378
379 switch (reg_size) {
380 case 4:
381 case 2:
382 case 1:
383 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
384 reg_size, &data[0]);
385 break;
386 case 3:
387 /* We store 24 bit samples in a 32 bit word. Keep the upper
388 * byte set to zero. */
389 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
390 reg_size, &data[1]);
391 break;
392 }
393
394 iio_push_to_buffers(indio_dev, (uint8_t *)data);
395
396 iio_trigger_notify_done(indio_dev->trig);
397 sigma_delta->irq_dis = false;
398 enable_irq(sigma_delta->spi->irq);
399
400 return IRQ_HANDLED;
401 }
402
403 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
404 .preenable = &iio_sw_buffer_preenable,
405 .postenable = &ad_sd_buffer_postenable,
406 .predisable = &iio_triggered_buffer_predisable,
407 .postdisable = &ad_sd_buffer_postdisable,
408 .validate_scan_mask = &iio_validate_scan_mask_onehot,
409 };
410
ad_sd_data_rdy_trig_poll(int irq,void * private)411 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
412 {
413 struct ad_sigma_delta *sigma_delta = private;
414
415 complete(&sigma_delta->completion);
416 disable_irq_nosync(irq);
417 sigma_delta->irq_dis = true;
418 iio_trigger_poll(sigma_delta->trig, iio_get_time_ns());
419
420 return IRQ_HANDLED;
421 }
422
423 /**
424 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
425 * @indio_dev: The IIO device
426 * @trig: The new trigger
427 *
428 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
429 * device, -EINVAL otherwise.
430 */
ad_sd_validate_trigger(struct iio_dev * indio_dev,struct iio_trigger * trig)431 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
432 {
433 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
434
435 if (sigma_delta->trig != trig)
436 return -EINVAL;
437
438 return 0;
439 }
440 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
441
442 static const struct iio_trigger_ops ad_sd_trigger_ops = {
443 .owner = THIS_MODULE,
444 };
445
ad_sd_probe_trigger(struct iio_dev * indio_dev)446 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
447 {
448 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
449 int ret;
450
451 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
452 indio_dev->id);
453 if (sigma_delta->trig == NULL) {
454 ret = -ENOMEM;
455 goto error_ret;
456 }
457 sigma_delta->trig->ops = &ad_sd_trigger_ops;
458 init_completion(&sigma_delta->completion);
459
460 ret = request_irq(sigma_delta->spi->irq,
461 ad_sd_data_rdy_trig_poll,
462 IRQF_TRIGGER_LOW,
463 indio_dev->name,
464 sigma_delta);
465 if (ret)
466 goto error_free_trig;
467
468 if (!sigma_delta->irq_dis) {
469 sigma_delta->irq_dis = true;
470 disable_irq_nosync(sigma_delta->spi->irq);
471 }
472 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
473 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
474
475 ret = iio_trigger_register(sigma_delta->trig);
476 if (ret)
477 goto error_free_irq;
478
479 /* select default trigger */
480 indio_dev->trig = sigma_delta->trig;
481
482 return 0;
483
484 error_free_irq:
485 free_irq(sigma_delta->spi->irq, sigma_delta);
486 error_free_trig:
487 iio_trigger_free(sigma_delta->trig);
488 error_ret:
489 return ret;
490 }
491
ad_sd_remove_trigger(struct iio_dev * indio_dev)492 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
493 {
494 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
495
496 iio_trigger_unregister(sigma_delta->trig);
497 free_irq(sigma_delta->spi->irq, sigma_delta);
498 iio_trigger_free(sigma_delta->trig);
499 }
500
501 /**
502 * ad_sd_setup_buffer_and_trigger() -
503 * @indio_dev: The IIO device
504 */
ad_sd_setup_buffer_and_trigger(struct iio_dev * indio_dev)505 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
506 {
507 int ret;
508
509 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
510 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
511 if (ret)
512 return ret;
513
514 ret = ad_sd_probe_trigger(indio_dev);
515 if (ret) {
516 iio_triggered_buffer_cleanup(indio_dev);
517 return ret;
518 }
519
520 return 0;
521 }
522 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
523
524 /**
525 * ad_sd_cleanup_buffer_and_trigger() -
526 * @indio_dev: The IIO device
527 */
ad_sd_cleanup_buffer_and_trigger(struct iio_dev * indio_dev)528 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
529 {
530 ad_sd_remove_trigger(indio_dev);
531 iio_triggered_buffer_cleanup(indio_dev);
532 }
533 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
534
535 /**
536 * ad_sd_init() - Initializes a ad_sigma_delta struct
537 * @sigma_delta: The ad_sigma_delta device
538 * @indio_dev: The IIO device which the Sigma Delta device is used for
539 * @spi: The SPI device for the ad_sigma_delta device
540 * @info: Device specific callbacks and options
541 *
542 * This function needs to be called before any other operations are performed on
543 * the ad_sigma_delta struct.
544 */
ad_sd_init(struct ad_sigma_delta * sigma_delta,struct iio_dev * indio_dev,struct spi_device * spi,const struct ad_sigma_delta_info * info)545 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
546 struct spi_device *spi, const struct ad_sigma_delta_info *info)
547 {
548 sigma_delta->spi = spi;
549 sigma_delta->info = info;
550 iio_device_set_drvdata(indio_dev, sigma_delta);
551
552 return 0;
553 }
554 EXPORT_SYMBOL_GPL(ad_sd_init);
555
556 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
557 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
558 MODULE_LICENSE("GPL v2");
559