1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Support code for Analog Devices Sigma-Delta ADCs
4 *
5 * Copyright 2012 Analog Devices Inc.
6 * Author: Lars-Peter Clausen <lars@metafoo.de>
7 */
8
9 #include <linux/align.h>
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 <linux/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_STATUS 0x00
33 #define AD_SD_REG_DATA 0x03
34
35 #define AD_SD_REG_STATUS_RDY 0x80
36
37 /**
38 * ad_sd_set_comm() - Set communications register
39 *
40 * @sigma_delta: The sigma delta device
41 * @comm: New value for the communications register
42 */
ad_sd_set_comm(struct ad_sigma_delta * sigma_delta,uint8_t comm)43 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm)
44 {
45 /* Some variants use the lower two bits of the communications register
46 * to select the channel */
47 sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
48 }
49 EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, "IIO_AD_SIGMA_DELTA");
50
51 /**
52 * ad_sd_write_reg() - Write a register
53 *
54 * @sigma_delta: The sigma delta device
55 * @reg: Address of the register
56 * @size: Size of the register (0-3)
57 * @val: Value to write to the register
58 *
59 * Returns 0 on success, an error code otherwise.
60 **/
ad_sd_write_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int val)61 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
62 unsigned int size, unsigned int val)
63 {
64 uint8_t *data = sigma_delta->tx_buf;
65 struct spi_transfer t = {
66 .tx_buf = data,
67 .len = size + 1,
68 .cs_change = sigma_delta->keep_cs_asserted,
69 };
70 struct spi_message m;
71 int ret;
72
73 data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
74
75 switch (size) {
76 case 3:
77 put_unaligned_be24(val, &data[1]);
78 break;
79 case 2:
80 put_unaligned_be16(val, &data[1]);
81 break;
82 case 1:
83 data[1] = val;
84 break;
85 case 0:
86 break;
87 default:
88 return -EINVAL;
89 }
90
91 spi_message_init(&m);
92 spi_message_add_tail(&t, &m);
93
94 if (sigma_delta->bus_locked)
95 ret = spi_sync_locked(sigma_delta->spi, &m);
96 else
97 ret = spi_sync(sigma_delta->spi, &m);
98
99 return ret;
100 }
101 EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, "IIO_AD_SIGMA_DELTA");
102
ad_sd_read_reg_raw(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,uint8_t * val)103 static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
104 unsigned int reg, unsigned int size, uint8_t *val)
105 {
106 uint8_t *data = sigma_delta->tx_buf;
107 int ret;
108 struct spi_transfer t[] = {
109 {
110 .tx_buf = data,
111 .len = 1,
112 }, {
113 .rx_buf = val,
114 .len = size,
115 .cs_change = sigma_delta->keep_cs_asserted,
116 },
117 };
118 struct spi_message m;
119
120 spi_message_init(&m);
121
122 if (sigma_delta->info->has_registers) {
123 data[0] = reg << sigma_delta->info->addr_shift;
124 data[0] |= sigma_delta->info->read_mask;
125 data[0] |= sigma_delta->comm;
126 spi_message_add_tail(&t[0], &m);
127 }
128 spi_message_add_tail(&t[1], &m);
129
130 if (sigma_delta->bus_locked)
131 ret = spi_sync_locked(sigma_delta->spi, &m);
132 else
133 ret = spi_sync(sigma_delta->spi, &m);
134
135 return ret;
136 }
137
138 /**
139 * ad_sd_read_reg() - Read a register
140 *
141 * @sigma_delta: The sigma delta device
142 * @reg: Address of the register
143 * @size: Size of the register (1-4)
144 * @val: Read value
145 *
146 * Returns 0 on success, an error code otherwise.
147 **/
ad_sd_read_reg(struct ad_sigma_delta * sigma_delta,unsigned int reg,unsigned int size,unsigned int * val)148 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
149 unsigned int reg, unsigned int size, unsigned int *val)
150 {
151 int ret;
152
153 ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf);
154 if (ret < 0)
155 goto out;
156
157 switch (size) {
158 case 4:
159 *val = get_unaligned_be32(sigma_delta->rx_buf);
160 break;
161 case 3:
162 *val = get_unaligned_be24(sigma_delta->rx_buf);
163 break;
164 case 2:
165 *val = get_unaligned_be16(sigma_delta->rx_buf);
166 break;
167 case 1:
168 *val = sigma_delta->rx_buf[0];
169 break;
170 default:
171 ret = -EINVAL;
172 break;
173 }
174
175 out:
176 return ret;
177 }
178 EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, "IIO_AD_SIGMA_DELTA");
179
180 /**
181 * ad_sd_reset() - Reset the serial interface
182 *
183 * @sigma_delta: The sigma delta device
184 *
185 * Returns 0 on success, an error code otherwise.
186 **/
ad_sd_reset(struct ad_sigma_delta * sigma_delta)187 int ad_sd_reset(struct ad_sigma_delta *sigma_delta)
188 {
189 unsigned int reset_length = sigma_delta->info->num_resetclks;
190 uint8_t *buf;
191 unsigned int size;
192 int ret;
193
194 size = DIV_ROUND_UP(reset_length, 8);
195 buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
196 if (!buf)
197 return -ENOMEM;
198
199 memset(buf, 0xff, size);
200 ret = spi_write(sigma_delta->spi, buf, size);
201 kfree(buf);
202
203 return ret;
204 }
205 EXPORT_SYMBOL_NS_GPL(ad_sd_reset, "IIO_AD_SIGMA_DELTA");
206
ad_sd_disable_irq(struct ad_sigma_delta * sigma_delta)207 static bool ad_sd_disable_irq(struct ad_sigma_delta *sigma_delta)
208 {
209 guard(spinlock_irqsave)(&sigma_delta->irq_lock);
210
211 /* It's already off, return false to indicate nothing was changed */
212 if (sigma_delta->irq_dis)
213 return false;
214
215 sigma_delta->irq_dis = true;
216 disable_irq_nosync(sigma_delta->irq_line);
217 return true;
218 }
219
ad_sd_enable_irq(struct ad_sigma_delta * sigma_delta)220 static void ad_sd_enable_irq(struct ad_sigma_delta *sigma_delta)
221 {
222 guard(spinlock_irqsave)(&sigma_delta->irq_lock);
223
224 sigma_delta->irq_dis = false;
225 enable_irq(sigma_delta->irq_line);
226 }
227
228 #define AD_SD_CLEAR_DATA_BUFLEN 9
229
230 /* Called with `sigma_delta->bus_locked == true` only. */
ad_sigma_delta_clear_pending_event(struct ad_sigma_delta * sigma_delta)231 static int ad_sigma_delta_clear_pending_event(struct ad_sigma_delta *sigma_delta)
232 {
233 bool pending_event;
234 unsigned int data_read_len = BITS_TO_BYTES(sigma_delta->info->num_resetclks);
235 u8 *data;
236 struct spi_transfer t[] = {
237 {
238 .len = 1,
239 }, {
240 .len = data_read_len,
241 }
242 };
243 struct spi_message m;
244 int ret;
245
246 /*
247 * Read R̅D̅Y̅ pin (if possible) or status register to check if there is an
248 * old event.
249 */
250 if (sigma_delta->rdy_gpiod) {
251 pending_event = gpiod_get_value(sigma_delta->rdy_gpiod);
252 } else {
253 unsigned int status_reg;
254
255 ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_STATUS, 1, &status_reg);
256 if (ret)
257 return ret;
258
259 pending_event = !(status_reg & AD_SD_REG_STATUS_RDY);
260 }
261
262 if (!pending_event)
263 return 0;
264
265 /*
266 * In general the size of the data register is unknown. It varies from
267 * device to device, might be one byte longer if CONTROL.DATA_STATUS is
268 * set and even varies on some devices depending on which input is
269 * selected. So send one byte to start reading the data register and
270 * then just clock for some bytes with DIN (aka MOSI) high to not
271 * confuse the register access state machine after the data register was
272 * completely read. Note however that the sequence length must be
273 * shorter than the reset procedure.
274 */
275
276 data = kzalloc(data_read_len + 1, GFP_KERNEL);
277 if (!data)
278 return -ENOMEM;
279
280 spi_message_init(&m);
281 if (sigma_delta->info->has_registers) {
282 unsigned int data_reg = sigma_delta->info->data_reg ?: AD_SD_REG_DATA;
283
284 data[0] = data_reg << sigma_delta->info->addr_shift;
285 data[0] |= sigma_delta->info->read_mask;
286 data[0] |= sigma_delta->comm;
287 t[0].tx_buf = data;
288 spi_message_add_tail(&t[0], &m);
289 }
290
291 /*
292 * The first transferred byte is part of the real data register,
293 * so this doesn't need to be 0xff. In the remaining
294 * `data_read_len - 1` bytes are less than $num_resetclks ones.
295 */
296 t[1].tx_buf = data + 1;
297 data[1] = 0x00;
298 memset(data + 2, 0xff, data_read_len - 1);
299 spi_message_add_tail(&t[1], &m);
300
301 ret = spi_sync_locked(sigma_delta->spi, &m);
302
303 kfree(data);
304
305 return ret;
306 }
307
ad_sd_calibrate(struct ad_sigma_delta * sigma_delta,unsigned int mode,unsigned int channel)308 int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
309 unsigned int mode, unsigned int channel)
310 {
311 int ret;
312 unsigned long time_left;
313
314 ret = ad_sigma_delta_set_channel(sigma_delta, channel);
315 if (ret)
316 return ret;
317
318 spi_bus_lock(sigma_delta->spi->controller);
319 sigma_delta->bus_locked = true;
320 sigma_delta->keep_cs_asserted = true;
321 reinit_completion(&sigma_delta->completion);
322
323 ret = ad_sigma_delta_clear_pending_event(sigma_delta);
324 if (ret)
325 goto out;
326
327 ret = ad_sigma_delta_set_mode(sigma_delta, mode);
328 if (ret < 0)
329 goto out;
330
331 ad_sd_enable_irq(sigma_delta);
332 time_left = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
333 if (time_left == 0) {
334 ad_sd_disable_irq(sigma_delta);
335 ret = -EIO;
336 } else {
337 ret = 0;
338 }
339 out:
340 sigma_delta->keep_cs_asserted = false;
341 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
342 ad_sigma_delta_disable_one(sigma_delta, channel);
343 sigma_delta->bus_locked = false;
344 spi_bus_unlock(sigma_delta->spi->controller);
345
346 return ret;
347 }
348 EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, "IIO_AD_SIGMA_DELTA");
349
350 /**
351 * ad_sd_calibrate_all() - Performs channel calibration
352 * @sigma_delta: The sigma delta device
353 * @cb: Array of channels and calibration type to perform
354 * @n: Number of items in cb
355 *
356 * Returns 0 on success, an error code otherwise.
357 **/
ad_sd_calibrate_all(struct ad_sigma_delta * sigma_delta,const struct ad_sd_calib_data * cb,unsigned int n)358 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
359 const struct ad_sd_calib_data *cb, unsigned int n)
360 {
361 unsigned int i;
362 int ret;
363
364 for (i = 0; i < n; i++) {
365 ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
366 if (ret)
367 return ret;
368 }
369
370 return 0;
371 }
372 EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, "IIO_AD_SIGMA_DELTA");
373
374 /**
375 * ad_sigma_delta_single_conversion() - Performs a single data conversion
376 * @indio_dev: The IIO device
377 * @chan: The conversion is done for this channel
378 * @val: Pointer to the location where to store the read value
379 *
380 * Returns: 0 on success, an error value otherwise.
381 */
ad_sigma_delta_single_conversion(struct iio_dev * indio_dev,const struct iio_chan_spec * chan,int * val)382 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
383 const struct iio_chan_spec *chan, int *val)
384 {
385 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
386 unsigned int sample, raw_sample;
387 unsigned int data_reg;
388 int ret = 0;
389
390 if (!iio_device_claim_direct(indio_dev))
391 return -EBUSY;
392
393 ret = ad_sigma_delta_set_channel(sigma_delta, chan->address);
394 if (ret)
395 goto out_release;
396
397 spi_bus_lock(sigma_delta->spi->controller);
398 sigma_delta->bus_locked = true;
399 sigma_delta->keep_cs_asserted = true;
400 reinit_completion(&sigma_delta->completion);
401
402 ret = ad_sigma_delta_clear_pending_event(sigma_delta);
403 if (ret)
404 goto out_unlock;
405
406 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
407
408 ad_sd_enable_irq(sigma_delta);
409 ret = wait_for_completion_interruptible_timeout(
410 &sigma_delta->completion, HZ);
411
412 if (ret == 0)
413 ret = -EIO;
414 if (ret < 0)
415 goto out;
416
417 if (sigma_delta->info->data_reg != 0)
418 data_reg = sigma_delta->info->data_reg;
419 else
420 data_reg = AD_SD_REG_DATA;
421
422 ret = ad_sd_read_reg(sigma_delta, data_reg,
423 DIV_ROUND_UP(chan->scan_type.realbits + chan->scan_type.shift, 8),
424 &raw_sample);
425
426 out:
427 ad_sd_disable_irq(sigma_delta);
428
429 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
430 ad_sigma_delta_disable_one(sigma_delta, chan->address);
431
432 out_unlock:
433 sigma_delta->keep_cs_asserted = false;
434 sigma_delta->bus_locked = false;
435 spi_bus_unlock(sigma_delta->spi->controller);
436 out_release:
437 iio_device_release_direct(indio_dev);
438
439 if (ret)
440 return ret;
441
442 sample = raw_sample >> chan->scan_type.shift;
443 sample &= (1 << chan->scan_type.realbits) - 1;
444 *val = sample;
445
446 ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
447 if (ret)
448 return ret;
449
450 return IIO_VAL_INT;
451 }
452 EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, "IIO_AD_SIGMA_DELTA");
453
ad_sd_buffer_postenable(struct iio_dev * indio_dev)454 static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
455 {
456 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
457 unsigned int i, slot, samples_buf_size;
458 unsigned int channel;
459 uint8_t *samples_buf;
460 int ret;
461
462 if (sigma_delta->num_slots == 1) {
463 channel = find_first_bit(indio_dev->active_scan_mask,
464 iio_get_masklength(indio_dev));
465 ret = ad_sigma_delta_set_channel(sigma_delta,
466 indio_dev->channels[channel].address);
467 if (ret)
468 return ret;
469 slot = 1;
470 } else {
471 /*
472 * At this point update_scan_mode already enabled the required channels.
473 * For sigma-delta sequencer drivers with multiple slots, an update_scan_mode
474 * implementation is mandatory.
475 */
476 slot = 0;
477 iio_for_each_active_channel(indio_dev, i) {
478 sigma_delta->slots[slot] = indio_dev->channels[i].address;
479 slot++;
480 }
481 }
482
483 sigma_delta->active_slots = slot;
484 sigma_delta->current_slot = 0;
485
486 if (sigma_delta->active_slots > 1) {
487 ret = ad_sigma_delta_append_status(sigma_delta, true);
488 if (ret)
489 return ret;
490 }
491
492 samples_buf_size = ALIGN(slot * indio_dev->channels[0].scan_type.storagebits, 8);
493 samples_buf_size += sizeof(int64_t);
494 samples_buf = devm_krealloc(&sigma_delta->spi->dev, sigma_delta->samples_buf,
495 samples_buf_size, GFP_KERNEL);
496 if (!samples_buf)
497 return -ENOMEM;
498
499 sigma_delta->samples_buf = samples_buf;
500
501 spi_bus_lock(sigma_delta->spi->controller);
502 sigma_delta->bus_locked = true;
503 sigma_delta->keep_cs_asserted = true;
504
505 ret = ad_sigma_delta_clear_pending_event(sigma_delta);
506 if (ret)
507 goto err_unlock;
508
509 ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
510 if (ret)
511 goto err_unlock;
512
513 ad_sd_enable_irq(sigma_delta);
514
515 return 0;
516
517 err_unlock:
518 spi_bus_unlock(sigma_delta->spi->controller);
519
520 return ret;
521 }
522
ad_sd_buffer_postdisable(struct iio_dev * indio_dev)523 static int ad_sd_buffer_postdisable(struct iio_dev *indio_dev)
524 {
525 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
526
527 reinit_completion(&sigma_delta->completion);
528 wait_for_completion_timeout(&sigma_delta->completion, HZ);
529
530 ad_sd_disable_irq(sigma_delta);
531
532 sigma_delta->keep_cs_asserted = false;
533 ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
534
535 if (sigma_delta->status_appended)
536 ad_sigma_delta_append_status(sigma_delta, false);
537
538 ad_sigma_delta_disable_all(sigma_delta);
539 sigma_delta->bus_locked = false;
540 return spi_bus_unlock(sigma_delta->spi->controller);
541 }
542
ad_sd_trigger_handler(int irq,void * p)543 static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
544 {
545 struct iio_poll_func *pf = p;
546 struct iio_dev *indio_dev = pf->indio_dev;
547 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
548 uint8_t *data = sigma_delta->rx_buf;
549 unsigned int transfer_size;
550 unsigned int sample_size;
551 unsigned int sample_pos;
552 unsigned int status_pos;
553 unsigned int reg_size;
554 unsigned int data_reg;
555
556 reg_size = indio_dev->channels[0].scan_type.realbits +
557 indio_dev->channels[0].scan_type.shift;
558 reg_size = DIV_ROUND_UP(reg_size, 8);
559
560 if (sigma_delta->info->data_reg != 0)
561 data_reg = sigma_delta->info->data_reg;
562 else
563 data_reg = AD_SD_REG_DATA;
564
565 /* Status word will be appended to the sample during transfer */
566 if (sigma_delta->status_appended)
567 transfer_size = reg_size + 1;
568 else
569 transfer_size = reg_size;
570
571 switch (reg_size) {
572 case 4:
573 case 2:
574 case 1:
575 status_pos = reg_size;
576 ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[0]);
577 break;
578 case 3:
579 /*
580 * Data array after transfer will look like (if status is appended):
581 * data[] = { [0][sample][sample][sample][status] }
582 * Keeping the first byte 0 shifts the status position by 1 byte to the right.
583 */
584 status_pos = reg_size + 1;
585
586 /* We store 24 bit samples in a 32 bit word. Keep the upper
587 * byte set to zero. */
588 ad_sd_read_reg_raw(sigma_delta, data_reg, transfer_size, &data[1]);
589 break;
590
591 default:
592 dev_err_ratelimited(&indio_dev->dev, "Unsupported reg_size: %u\n", reg_size);
593 goto irq_handled;
594 }
595
596 /*
597 * For devices sampling only one channel at
598 * once, there is no need for sample number tracking.
599 */
600 if (sigma_delta->active_slots == 1) {
601 iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
602 goto irq_handled;
603 }
604
605 if (sigma_delta->status_appended) {
606 u8 converted_channel;
607
608 converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask;
609 if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) {
610 /*
611 * Desync occurred during continuous sampling of multiple channels.
612 * Drop this incomplete sample and start from first channel again.
613 */
614
615 sigma_delta->current_slot = 0;
616 goto irq_handled;
617 }
618 }
619
620 sample_size = indio_dev->channels[0].scan_type.storagebits / 8;
621 sample_pos = sample_size * sigma_delta->current_slot;
622 memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size);
623 sigma_delta->current_slot++;
624
625 if (sigma_delta->current_slot == sigma_delta->active_slots) {
626 sigma_delta->current_slot = 0;
627 iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf,
628 pf->timestamp);
629 }
630
631 irq_handled:
632 iio_trigger_notify_done(indio_dev->trig);
633 ad_sd_enable_irq(sigma_delta);
634
635 return IRQ_HANDLED;
636 }
637
ad_sd_validate_scan_mask(struct iio_dev * indio_dev,const unsigned long * mask)638 static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask)
639 {
640 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
641
642 return bitmap_weight(mask, iio_get_masklength(indio_dev)) <= sigma_delta->num_slots;
643 }
644
645 static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
646 .postenable = &ad_sd_buffer_postenable,
647 .postdisable = &ad_sd_buffer_postdisable,
648 .validate_scan_mask = &ad_sd_validate_scan_mask,
649 };
650
ad_sd_data_rdy_trig_poll(int irq,void * private)651 static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
652 {
653 struct ad_sigma_delta *sigma_delta = private;
654
655 /*
656 * AD7124 and a few others use the same physical line for interrupt
657 * reporting (R̅D̅Y̅) and MISO.
658 * As MISO toggles when reading a register, this likely results in a
659 * pending interrupt. This has two consequences: a) The irq might
660 * trigger immediately after it's enabled even though the conversion
661 * isn't done yet; and b) checking the STATUS register's R̅D̅Y̅ flag is
662 * off-limits as reading that would trigger another irq event.
663 *
664 * So read the MOSI line as GPIO (if available) and only trigger the irq
665 * if the line is active. Without such a GPIO assume this is a valid
666 * interrupt.
667 *
668 * Also as disable_irq_nosync() is used to disable the irq, only act if
669 * the irq wasn't disabled before.
670 */
671 if ((!sigma_delta->rdy_gpiod || gpiod_get_value(sigma_delta->rdy_gpiod)) &&
672 ad_sd_disable_irq(sigma_delta)) {
673 complete(&sigma_delta->completion);
674 iio_trigger_poll(sigma_delta->trig);
675
676 return IRQ_HANDLED;
677 }
678
679 return IRQ_NONE;
680 }
681
682 /**
683 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
684 * @indio_dev: The IIO device
685 * @trig: The new trigger
686 *
687 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
688 * device, -EINVAL otherwise.
689 */
ad_sd_validate_trigger(struct iio_dev * indio_dev,struct iio_trigger * trig)690 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
691 {
692 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
693
694 if (sigma_delta->trig != trig)
695 return -EINVAL;
696
697 return 0;
698 }
699 EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, "IIO_AD_SIGMA_DELTA");
700
devm_ad_sd_probe_trigger(struct device * dev,struct iio_dev * indio_dev)701 static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev)
702 {
703 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
704 unsigned long irq_flags = irq_get_trigger_type(sigma_delta->irq_line);
705 int ret;
706
707 if (dev != &sigma_delta->spi->dev) {
708 dev_err(dev, "Trigger parent should be '%s', got '%s'\n",
709 dev_name(dev), dev_name(&sigma_delta->spi->dev));
710 return -EFAULT;
711 }
712
713 sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
714 iio_device_id(indio_dev));
715 if (sigma_delta->trig == NULL)
716 return -ENOMEM;
717
718 init_completion(&sigma_delta->completion);
719
720 sigma_delta->irq_dis = true;
721
722 /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
723 irq_set_status_flags(sigma_delta->irq_line, IRQ_DISABLE_UNLAZY);
724
725 /* Allow overwriting the flags from firmware */
726 if (!irq_flags)
727 irq_flags = sigma_delta->info->irq_flags;
728
729 ret = devm_request_irq(dev, sigma_delta->irq_line,
730 ad_sd_data_rdy_trig_poll,
731 irq_flags | IRQF_NO_AUTOEN,
732 indio_dev->name,
733 sigma_delta);
734 if (ret)
735 return ret;
736
737 iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
738
739 ret = devm_iio_trigger_register(dev, sigma_delta->trig);
740 if (ret)
741 return ret;
742
743 /* select default trigger */
744 indio_dev->trig = iio_trigger_get(sigma_delta->trig);
745
746 return 0;
747 }
748
749 /**
750 * devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup
751 * @dev: Device object to which to bind the life-time of the resources attached
752 * @indio_dev: The IIO device
753 */
devm_ad_sd_setup_buffer_and_trigger(struct device * dev,struct iio_dev * indio_dev)754 int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev)
755 {
756 struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
757 int ret;
758
759 sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots,
760 sizeof(*sigma_delta->slots), GFP_KERNEL);
761 if (!sigma_delta->slots)
762 return -ENOMEM;
763
764 ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
765 &iio_pollfunc_store_time,
766 &ad_sd_trigger_handler,
767 &ad_sd_buffer_setup_ops);
768 if (ret)
769 return ret;
770
771 return devm_ad_sd_probe_trigger(dev, indio_dev);
772 }
773 EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, "IIO_AD_SIGMA_DELTA");
774
775 /**
776 * ad_sd_init() - Initializes a ad_sigma_delta struct
777 * @sigma_delta: The ad_sigma_delta device
778 * @indio_dev: The IIO device which the Sigma Delta device is used for
779 * @spi: The SPI device for the ad_sigma_delta device
780 * @info: Device specific callbacks and options
781 *
782 * This function needs to be called before any other operations are performed on
783 * the ad_sigma_delta struct.
784 */
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)785 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
786 struct spi_device *spi, const struct ad_sigma_delta_info *info)
787 {
788 sigma_delta->spi = spi;
789 sigma_delta->info = info;
790
791 /* If the field is unset in ad_sigma_delta_info, assume there can only be 1 slot. */
792 if (!info->num_slots)
793 sigma_delta->num_slots = 1;
794 else
795 sigma_delta->num_slots = info->num_slots;
796
797 if (sigma_delta->num_slots > 1) {
798 if (!indio_dev->info->update_scan_mode) {
799 dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n");
800 return -EINVAL;
801 }
802
803 if (!info->disable_all) {
804 dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n");
805 return -EINVAL;
806 }
807 }
808
809 spin_lock_init(&sigma_delta->irq_lock);
810
811 if (info->has_named_irqs) {
812 sigma_delta->irq_line = fwnode_irq_get_byname(dev_fwnode(&spi->dev),
813 "rdy");
814 if (sigma_delta->irq_line < 0)
815 return dev_err_probe(&spi->dev, sigma_delta->irq_line,
816 "Interrupt 'rdy' is required\n");
817 } else {
818 sigma_delta->irq_line = spi->irq;
819 }
820
821 sigma_delta->rdy_gpiod = devm_gpiod_get_optional(&spi->dev, "rdy", GPIOD_IN);
822 if (IS_ERR(sigma_delta->rdy_gpiod))
823 return dev_err_probe(&spi->dev, PTR_ERR(sigma_delta->rdy_gpiod),
824 "Failed to find rdy gpio\n");
825
826 if (sigma_delta->rdy_gpiod && !sigma_delta->irq_line) {
827 sigma_delta->irq_line = gpiod_to_irq(sigma_delta->rdy_gpiod);
828 if (sigma_delta->irq_line < 0)
829 return sigma_delta->irq_line;
830 }
831
832 iio_device_set_drvdata(indio_dev, sigma_delta);
833
834 return 0;
835 }
836 EXPORT_SYMBOL_NS_GPL(ad_sd_init, "IIO_AD_SIGMA_DELTA");
837
838 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
839 MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
840 MODULE_LICENSE("GPL v2");
841