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->keep_cs_asserted,
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 data[0] |= sigma_delta->comm;
125 spi_message_add_tail(&t[0], &m);
126 }
127 spi_message_add_tail(&t[1], &m);
128
129 if (sigma_delta->bus_locked)
130 ret = spi_sync_locked(sigma_delta->spi, &m);
131 else
132 ret = spi_sync(sigma_delta->spi, &m);
133
134 return ret;
135 }
136
137 /**
138 * ad_sd_read_reg() - Read a register
139 *
140 * @sigma_delta: The sigma delta device
141 * @reg: Address of the register
142 * @size: Size of the register (1-4)
143 * @val: Read value
144 *
145 * Returns 0 on success, an error code otherwise.
146 **/
ad_sd_read_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int * val)147 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
148 unsigned int reg, unsigned int size, unsigned int *val)
149 {
150 int ret;
151
152 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->data);
153 if (ret < 0)
154 goto out;
155
156 switch (size) {
157 case 4:
158 *val = get_unaligned_be32(sigma_delta->data);
159 break;
160 case 3:
161 *val = (sigma_delta->data[0] << 16) |
162 (sigma_delta->data[1] << 8) |
163 sigma_delta->data[2];
164 break;
165 case 2:
166 *val = get_unaligned_be16(sigma_delta->data);
167 break;
168 case 1:
169 *val = sigma_delta->data[0];
170 break;
171 default:
172 ret = -EINVAL;
173 break;
174 }
175
176 out:
177 return ret;
178 }
179 EXPORT_SYMBOL_GPL(ad_sd_read_reg);
180
181 /**
182 * ad_sd_reset() - Reset the serial interface
183 *
184 * @sigma_delta: The sigma delta device
185 * @reset_length: Number of SCLKs with DIN = 1
186 *
187 * Returns 0 on success, an error code otherwise.
188 **/
ad_sd_reset(struct ad_sigma_delta * sigma_delta,unsigned int reset_length)189 int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
190 unsigned int reset_length)
191 {
192 uint8_t *buf;
193 unsigned int size;
194 int ret;
195
196 size = DIV_ROUND_UP(reset_length, 8);
197 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
198 if (!buf)
199 return -ENOMEM;
200
201 memset(buf, 0xff, size);
202 ret = spi_write(sigma_delta->spi, buf, size);
203 kfree(buf);
204
205 return ret;
206 }
207 EXPORT_SYMBOL_GPL(ad_sd_reset);
208
ad_sd_calibrate(struct ad_sigma_delta * sigma_delta,unsigned int mode,unsigned int channel)209 static int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
210 unsigned int mode, unsigned int channel)
211 {
212 int ret;
213 unsigned long timeout;
214
215 ret = ad_sigma_delta_set_channel(sigma_delta, channel);
216 if (ret)
217 return ret;
218
219 spi_bus_lock(sigma_delta->spi->master);
220 sigma_delta->bus_locked = true;
221 sigma_delta->keep_cs_asserted = true;
222 reinit_completion(&sigma_delta->completion);
223
224 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
225 if (ret < 0)
226 goto out;
227
228 sigma_delta->irq_dis = false;
229 enable_irq(sigma_delta->spi->irq);
230 timeout = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
231 if (timeout == 0) {
232 sigma_delta->irq_dis = true;
233 disable_irq_nosync(sigma_delta->spi->irq);
234 ret = -EIO;
235 } else {
236 ret = 0;
237 }
238 out:
239 sigma_delta->keep_cs_asserted = false;
240 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
241 sigma_delta->bus_locked = false;
242 spi_bus_unlock(sigma_delta->spi->master);
243
244 return ret;
245 }
246
247 /**
248 * ad_sd_calibrate_all() - Performs channel calibration
249 * @sigma_delta: The sigma delta device
250 * @cb: Array of channels and calibration type to perform
251 * @n: Number of items in cb
252 *
253 * Returns 0 on success, an error code otherwise.
254 **/
ad_sd_calibrate_all(struct ad_sigma_delta * sigma_delta,const struct ad_sd_calib_data * cb,unsigned int n)255 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
256 const struct ad_sd_calib_data *cb, unsigned int n)
257 {
258 unsigned int i;
259 int ret;
260
261 for (i = 0; i < n; i++) {
262 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
263 if (ret)
264 return ret;
265 }
266
267 return 0;
268 }
269 EXPORT_SYMBOL_GPL(ad_sd_calibrate_all);
270
271 /**
272 * ad_sigma_delta_single_conversion() - Performs a single data conversion
273 * @indio_dev: The IIO device
274 * @chan: The conversion is done for this channel
275 * @val: Pointer to the location where to store the read value
276 *
277 * Returns: 0 on success, an error value otherwise.
278 */
ad_sigma_delta_single_conversion(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val)279 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
280 const struct iio_chan_spec *chan, int *val)
281 {
282 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
283 unsigned int sample, raw_sample;
284 int ret = 0;
285
286 if (iio_buffer_enabled(indio_dev))
287 return -EBUSY;
288
289 mutex_lock(&indio_dev->mlock);
290 ad_sigma_delta_set_channel(sigma_delta, chan->address);
291
292 spi_bus_lock(sigma_delta->spi->master);
293 sigma_delta->bus_locked = true;
294 sigma_delta->keep_cs_asserted = true;
295 reinit_completion(&sigma_delta->completion);
296
297 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
298
299 sigma_delta->irq_dis = false;
300 enable_irq(sigma_delta->spi->irq);
301 ret = wait_for_completion_interruptible_timeout(
302 &sigma_delta->completion, HZ);
303
304 if (ret == 0)
305 ret = -EIO;
306 if (ret < 0)
307 goto out;
308
309 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_DATA,
310 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
311 &raw_sample);
312
313 out:
314 if (!sigma_delta->irq_dis) {
315 disable_irq_nosync(sigma_delta->spi->irq);
316 sigma_delta->irq_dis = true;
317 }
318
319 sigma_delta->keep_cs_asserted = false;
320 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
321 sigma_delta->bus_locked = false;
322 spi_bus_unlock(sigma_delta->spi->master);
323 mutex_unlock(&indio_dev->mlock);
324
325 if (ret)
326 return ret;
327
328 sample = raw_sample >> chan->scan_type.shift;
329 sample &= (1 << chan->scan_type.realbits) - 1;
330 *val = sample;
331
332 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
333 if (ret)
334 return ret;
335
336 return IIO_VAL_INT;
337 }
338 EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
339
ad_sd_buffer_postenable(struct iio_dev * indio_dev)340 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
341 {
342 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
343 unsigned int channel;
344 int ret;
345
346 ret = iio_triggered_buffer_postenable(indio_dev);
347 if (ret < 0)
348 return ret;
349
350 channel = find_first_bit(indio_dev->active_scan_mask,
351 indio_dev->masklength);
352 ret = ad_sigma_delta_set_channel(sigma_delta,
353 indio_dev->channels[channel].address);
354 if (ret)
355 goto err_predisable;
356
357 spi_bus_lock(sigma_delta->spi->master);
358 sigma_delta->bus_locked = true;
359 sigma_delta->keep_cs_asserted = true;
360
361 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
362 if (ret)
363 goto err_unlock;
364
365 sigma_delta->irq_dis = false;
366 enable_irq(sigma_delta->spi->irq);
367
368 return 0;
369
370 err_unlock:
371 spi_bus_unlock(sigma_delta->spi->master);
372 err_predisable:
373
374 return ret;
375 }
376
ad_sd_buffer_postdisable(struct iio_dev * indio_dev)377 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
378 {
379 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
380
381 reinit_completion(&sigma_delta->completion);
382 wait_for_completion_timeout(&sigma_delta->completion, HZ);
383
384 if (!sigma_delta->irq_dis) {
385 disable_irq_nosync(sigma_delta->spi->irq);
386 sigma_delta->irq_dis = true;
387 }
388
389 sigma_delta->keep_cs_asserted = false;
390 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
391
392 sigma_delta->bus_locked = false;
393 return spi_bus_unlock(sigma_delta->spi->master);
394 }
395
ad_sd_trigger_handler(int irq,void * p)396 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
397 {
398 struct iio_poll_func *pf = p;
399 struct iio_dev *indio_dev = pf->indio_dev;
400 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
401 unsigned int reg_size;
402 uint8_t data[16];
403 int ret;
404
405 memset(data, 0x00, 16);
406
407 reg_size = indio_dev->channels[0].scan_type.realbits +
408 indio_dev->channels[0].scan_type.shift;
409 reg_size = DIV_ROUND_UP(reg_size, 8);
410
411 switch (reg_size) {
412 case 4:
413 case 2:
414 case 1:
415 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
416 reg_size, &data[0]);
417 break;
418 case 3:
419 /* We store 24 bit samples in a 32 bit word. Keep the upper
420 * byte set to zero. */
421 ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
422 reg_size, &data[1]);
423 break;
424 }
425
426 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
427
428 iio_trigger_notify_done(indio_dev->trig);
429 sigma_delta->irq_dis = false;
430 enable_irq(sigma_delta->spi->irq);
431
432 return IRQ_HANDLED;
433 }
434
435 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
436 .postenable = &ad_sd_buffer_postenable,
437 .predisable = &iio_triggered_buffer_predisable,
438 .postdisable = &ad_sd_buffer_postdisable,
439 .validate_scan_mask = &iio_validate_scan_mask_onehot,
440 };
441
ad_sd_data_rdy_trig_poll(int irq,void * private)442 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
443 {
444 struct ad_sigma_delta *sigma_delta = private;
445
446 complete(&sigma_delta->completion);
447 disable_irq_nosync(irq);
448 sigma_delta->irq_dis = true;
449 iio_trigger_poll(sigma_delta->trig);
450
451 return IRQ_HANDLED;
452 }
453
454 /**
455 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
456 * @indio_dev: The IIO device
457 * @trig: The new trigger
458 *
459 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
460 * device, -EINVAL otherwise.
461 */
ad_sd_validate_trigger(struct iio_dev * indio_dev,struct iio_trigger * trig)462 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
463 {
464 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
465
466 if (sigma_delta->trig != trig)
467 return -EINVAL;
468
469 return 0;
470 }
471 EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
472
473 static const struct iio_trigger_ops ad_sd_trigger_ops = {
474 };
475
ad_sd_probe_trigger(struct iio_dev * indio_dev)476 static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
477 {
478 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
479 int ret;
480
481 sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
482 indio_dev->id);
483 if (sigma_delta->trig == NULL) {
484 ret = -ENOMEM;
485 goto error_ret;
486 }
487 sigma_delta->trig->ops = &ad_sd_trigger_ops;
488 init_completion(&sigma_delta->completion);
489
490 ret = request_irq(sigma_delta->spi->irq,
491 ad_sd_data_rdy_trig_poll,
492 IRQF_TRIGGER_LOW,
493 indio_dev->name,
494 sigma_delta);
495 if (ret)
496 goto error_free_trig;
497
498 if (!sigma_delta->irq_dis) {
499 sigma_delta->irq_dis = true;
500 disable_irq_nosync(sigma_delta->spi->irq);
501 }
502 sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
503 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
504
505 ret = iio_trigger_register(sigma_delta->trig);
506 if (ret)
507 goto error_free_irq;
508
509 /* select default trigger */
510 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
511
512 return 0;
513
514 error_free_irq:
515 free_irq(sigma_delta->spi->irq, sigma_delta);
516 error_free_trig:
517 iio_trigger_free(sigma_delta->trig);
518 error_ret:
519 return ret;
520 }
521
ad_sd_remove_trigger(struct iio_dev * indio_dev)522 static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
523 {
524 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
525
526 iio_trigger_unregister(sigma_delta->trig);
527 free_irq(sigma_delta->spi->irq, sigma_delta);
528 iio_trigger_free(sigma_delta->trig);
529 }
530
531 /**
532 * ad_sd_setup_buffer_and_trigger() -
533 * @indio_dev: The IIO device
534 */
ad_sd_setup_buffer_and_trigger(struct iio_dev * indio_dev)535 int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
536 {
537 int ret;
538
539 ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
540 &ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
541 if (ret)
542 return ret;
543
544 ret = ad_sd_probe_trigger(indio_dev);
545 if (ret) {
546 iio_triggered_buffer_cleanup(indio_dev);
547 return ret;
548 }
549
550 return 0;
551 }
552 EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
553
554 /**
555 * ad_sd_cleanup_buffer_and_trigger() -
556 * @indio_dev: The IIO device
557 */
ad_sd_cleanup_buffer_and_trigger(struct iio_dev * indio_dev)558 void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
559 {
560 ad_sd_remove_trigger(indio_dev);
561 iio_triggered_buffer_cleanup(indio_dev);
562 }
563 EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
564
565 /**
566 * ad_sd_init() - Initializes a ad_sigma_delta struct
567 * @sigma_delta: The ad_sigma_delta device
568 * @indio_dev: The IIO device which the Sigma Delta device is used for
569 * @spi: The SPI device for the ad_sigma_delta device
570 * @info: Device specific callbacks and options
571 *
572 * This function needs to be called before any other operations are performed on
573 * the ad_sigma_delta struct.
574 */
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)575 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
576 struct spi_device *spi, const struct ad_sigma_delta_info *info)
577 {
578 sigma_delta->spi = spi;
579 sigma_delta->info = info;
580 iio_device_set_drvdata(indio_dev, sigma_delta);
581
582 return 0;
583 }
584 EXPORT_SYMBOL_GPL(ad_sd_init);
585
586 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
587 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
588 MODULE_LICENSE("GPL v2");
589