ad_sigma_delta.c

  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/bitmap.h>
 11#include <linux/bitops.h>
 12#include <linux/cleanup.h>
 13#include <linux/completion.h>
 14#include <linux/device.h>
 15#include <linux/err.h>
 16#include <linux/export.h>
 17#include <linux/find.h>
 18#include <linux/gpio/consumer.h>
 19#include <linux/interrupt.h>
 20#include <linux/module.h>
 21#include <linux/property.h>
 22#include <linux/slab.h>
 23#include <linux/spi/offload/consumer.h>
 24#include <linux/spi/spi.h>
 25#include <linux/spinlock.h>
 26#include <linux/string.h>
 27#include <linux/types.h>
 28#include <linux/unaligned.h>
 29
 30#include <linux/iio/adc/ad_sigma_delta.h>
 31#include <linux/iio/buffer-dmaengine.h>
 32#include <linux/iio/buffer.h>
 33#include <linux/iio/iio.h>
 34#include <linux/iio/trigger_consumer.h>
 35#include <linux/iio/trigger.h>
 36#include <linux/iio/triggered_buffer.h>
 37
 38#define AD_SD_COMM_CHAN_MASK	0x3
 39
 40#define AD_SD_REG_COMM		0x00
 41#define AD_SD_REG_STATUS	0x00
 42#define AD_SD_REG_DATA		0x03
 43
 44#define AD_SD_REG_STATUS_RDY	0x80
 45
 46/**
 47 * ad_sd_set_comm() - Set communications register
 48 *
 49 * @sigma_delta: The sigma delta device
 50 * @comm: New value for the communications register
 51 */
 52void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, u8 comm)
 53{
 54	/* Some variants use the lower two bits of the communications register
 55	 * to select the channel */
 56	sigma_delta->comm = comm & AD_SD_COMM_CHAN_MASK;
 57}
 58EXPORT_SYMBOL_NS_GPL(ad_sd_set_comm, "IIO_AD_SIGMA_DELTA");
 59
 60/**
 61 * ad_sd_write_reg() - Write a register
 62 *
 63 * @sigma_delta: The sigma delta device
 64 * @reg: Address of the register
 65 * @size: Size of the register (0-3)
 66 * @val: Value to write to the register
 67 *
 68 * Returns 0 on success, an error code otherwise.
 69 **/
 70int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
 71	unsigned int size, unsigned int val)
 72{
 73	u8 *data = sigma_delta->tx_buf;
 74	struct spi_transfer t = {
 75		.tx_buf		= data,
 76		.len		= size + 1,
 77		.cs_change	= sigma_delta->keep_cs_asserted,
 78	};
 79	struct spi_message m;
 80	int ret;
 81
 82	data[0] = (reg << sigma_delta->info->addr_shift) | sigma_delta->comm;
 83
 84	switch (size) {
 85	case 3:
 86		put_unaligned_be24(val, &data[1]);
 87		break;
 88	case 2:
 89		put_unaligned_be16(val, &data[1]);
 90		break;
 91	case 1:
 92		data[1] = val;
 93		break;
 94	case 0:
 95		break;
 96	default:
 97		return -EINVAL;
 98	}
 99
100	spi_message_init(&m);
101	spi_message_add_tail(&t, &m);
102
103	if (sigma_delta->bus_locked)
104		ret = spi_sync_locked(sigma_delta->spi, &m);
105	else
106		ret = spi_sync(sigma_delta->spi, &m);
107
108	return ret;
109}
110EXPORT_SYMBOL_NS_GPL(ad_sd_write_reg, "IIO_AD_SIGMA_DELTA");
111
112static void ad_sd_set_read_reg_addr(struct ad_sigma_delta *sigma_delta, u8 reg,
113				    u8 *data)
114{
115	data[0] = reg << sigma_delta->info->addr_shift;
116	data[0] |= sigma_delta->info->read_mask;
117	data[0] |= sigma_delta->comm;
118}
119
120static int ad_sd_read_reg_raw(struct ad_sigma_delta *sigma_delta,
121			      unsigned int reg, unsigned int size, u8 *val)
122{
123	u8 *data = sigma_delta->tx_buf;
124	int ret;
125	struct spi_transfer t[] = {
126		{
127			.tx_buf = data,
128			.len = 1,
129		}, {
130			.rx_buf = val,
131			.len = size,
132			.cs_change = sigma_delta->keep_cs_asserted,
133		},
134	};
135	struct spi_message m;
136
137	spi_message_init(&m);
138
139	if (sigma_delta->info->has_registers) {
140		ad_sd_set_read_reg_addr(sigma_delta, reg, data);
141		spi_message_add_tail(&t[0], &m);
142	}
143	spi_message_add_tail(&t[1], &m);
144
145	if (sigma_delta->bus_locked)
146		ret = spi_sync_locked(sigma_delta->spi, &m);
147	else
148		ret = spi_sync(sigma_delta->spi, &m);
149
150	return ret;
151}
152
153/**
154 * ad_sd_read_reg() - Read a register
155 *
156 * @sigma_delta: The sigma delta device
157 * @reg: Address of the register
158 * @size: Size of the register (1-4)
159 * @val: Read value
160 *
161 * Returns 0 on success, an error code otherwise.
162 **/
163int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta,
164	unsigned int reg, unsigned int size, unsigned int *val)
165{
166	int ret;
167
168	ret = ad_sd_read_reg_raw(sigma_delta, reg, size, sigma_delta->rx_buf);
169	if (ret < 0)
170		goto out;
171
172	switch (size) {
173	case 4:
174		*val = get_unaligned_be32(sigma_delta->rx_buf);
175		break;
176	case 3:
177		*val = get_unaligned_be24(sigma_delta->rx_buf);
178		break;
179	case 2:
180		*val = get_unaligned_be16(sigma_delta->rx_buf);
181		break;
182	case 1:
183		*val = sigma_delta->rx_buf[0];
184		break;
185	default:
186		ret = -EINVAL;
187		break;
188	}
189
190out:
191	return ret;
192}
193EXPORT_SYMBOL_NS_GPL(ad_sd_read_reg, "IIO_AD_SIGMA_DELTA");
194
195/**
196 * ad_sd_reset() - Reset the serial interface
197 *
198 * @sigma_delta: The sigma delta device
199 *
200 * Returns 0 on success, an error code otherwise.
201 **/
202int ad_sd_reset(struct ad_sigma_delta *sigma_delta)
203{
204	unsigned int reset_length = sigma_delta->info->num_resetclks;
205	unsigned int size;
206	u8 *buf;
207	int ret;
208
209	size = BITS_TO_BYTES(reset_length);
210	buf = kcalloc(size, sizeof(*buf), GFP_KERNEL);
211	if (!buf)
212		return -ENOMEM;
213
214	memset(buf, 0xff, size);
215	ret = spi_write(sigma_delta->spi, buf, size);
216	kfree(buf);
217
218	return ret;
219}
220EXPORT_SYMBOL_NS_GPL(ad_sd_reset, "IIO_AD_SIGMA_DELTA");
221
222static bool ad_sd_disable_irq(struct ad_sigma_delta *sigma_delta)
223{
224	guard(spinlock_irqsave)(&sigma_delta->irq_lock);
225
226	/* It's already off, return false to indicate nothing was changed */
227	if (sigma_delta->irq_dis)
228		return false;
229
230	sigma_delta->irq_dis = true;
231	disable_irq_nosync(sigma_delta->irq_line);
232	return true;
233}
234
235static void ad_sd_enable_irq(struct ad_sigma_delta *sigma_delta)
236{
237	guard(spinlock_irqsave)(&sigma_delta->irq_lock);
238
239	sigma_delta->irq_dis = false;
240	enable_irq(sigma_delta->irq_line);
241}
242
243#define AD_SD_CLEAR_DATA_BUFLEN 9
244
245/* Called with `sigma_delta->bus_locked == true` only. */
246static int ad_sigma_delta_clear_pending_event(struct ad_sigma_delta *sigma_delta)
247{
248	bool pending_event;
249	unsigned int data_read_len = BITS_TO_BYTES(sigma_delta->info->num_resetclks);
250	u8 *data;
251	struct spi_transfer t[] = {
252		{
253			.len = 1,
254		}, {
255			.len = data_read_len,
256		}
257	};
258	struct spi_message m;
259	int ret;
260
261	/*
262	 * Read R̅D̅Y̅ pin (if possible) or status register to check if there is an
263	 * old event.
264	 */
265	if (sigma_delta->rdy_gpiod) {
266		pending_event = gpiod_get_value(sigma_delta->rdy_gpiod);
267	} else {
268		unsigned int status_reg;
269
270		ret = ad_sd_read_reg(sigma_delta, AD_SD_REG_STATUS, 1, &status_reg);
271		if (ret)
272			return ret;
273
274		pending_event = !(status_reg & AD_SD_REG_STATUS_RDY);
275	}
276
277	if (!pending_event)
278		return 0;
279
280	/*
281	 * In general the size of the data register is unknown. It varies from
282	 * device to device, might be one byte longer if CONTROL.DATA_STATUS is
283	 * set and even varies on some devices depending on which input is
284	 * selected. So send one byte to start reading the data register and
285	 * then just clock for some bytes with DIN (aka MOSI) high to not
286	 * confuse the register access state machine after the data register was
287	 * completely read. Note however that the sequence length must be
288	 * shorter than the reset procedure.
289	 */
290
291	data = kzalloc(data_read_len + 1, GFP_KERNEL);
292	if (!data)
293		return -ENOMEM;
294
295	spi_message_init(&m);
296	if (sigma_delta->info->has_registers) {
297		unsigned int data_reg = sigma_delta->info->data_reg ?: AD_SD_REG_DATA;
298
299		ad_sd_set_read_reg_addr(sigma_delta, data_reg, data);
300		t[0].tx_buf = data;
301		spi_message_add_tail(&t[0], &m);
302	}
303
304	/*
305	 * The first transferred byte is part of the real data register,
306	 * so this doesn't need to be 0xff. In the remaining
307	 * `data_read_len - 1` bytes are less than $num_resetclks ones.
308	 */
309	t[1].tx_buf = data + 1;
310	data[1] = 0x00;
311	memset(data + 2, 0xff, data_read_len - 1);
312	spi_message_add_tail(&t[1], &m);
313
314	ret = spi_sync_locked(sigma_delta->spi, &m);
315
316	kfree(data);
317
318	return ret;
319}
320
321int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
322	unsigned int mode, unsigned int channel)
323{
324	int ret;
325	unsigned long time_left;
326
327	ret = ad_sigma_delta_set_channel(sigma_delta, channel);
328	if (ret)
329		return ret;
330
331	spi_bus_lock(sigma_delta->spi->controller);
332	sigma_delta->bus_locked = true;
333	sigma_delta->keep_cs_asserted = true;
334	reinit_completion(&sigma_delta->completion);
335
336	ret = ad_sigma_delta_clear_pending_event(sigma_delta);
337	if (ret)
338		goto out;
339
340	ret = ad_sigma_delta_set_mode(sigma_delta, mode);
341	if (ret < 0)
342		goto out;
343
344	ad_sd_enable_irq(sigma_delta);
345	time_left = wait_for_completion_timeout(&sigma_delta->completion, 2 * HZ);
346	if (time_left == 0) {
347		ad_sd_disable_irq(sigma_delta);
348		ret = -EIO;
349	} else {
350		ret = 0;
351	}
352out:
353	sigma_delta->keep_cs_asserted = false;
354	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
355	ad_sigma_delta_disable_one(sigma_delta, channel);
356	sigma_delta->bus_locked = false;
357	spi_bus_unlock(sigma_delta->spi->controller);
358
359	return ret;
360}
361EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate, "IIO_AD_SIGMA_DELTA");
362
363/**
364 * ad_sd_calibrate_all() - Performs channel calibration
365 * @sigma_delta: The sigma delta device
366 * @cb: Array of channels and calibration type to perform
367 * @n: Number of items in cb
368 *
369 * Returns 0 on success, an error code otherwise.
370 **/
371int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
372	const struct ad_sd_calib_data *cb, unsigned int n)
373{
374	unsigned int i;
375	int ret;
376
377	for (i = 0; i < n; i++) {
378		ret = ad_sd_calibrate(sigma_delta, cb[i].mode, cb[i].channel);
379		if (ret)
380			return ret;
381	}
382
383	return 0;
384}
385EXPORT_SYMBOL_NS_GPL(ad_sd_calibrate_all, "IIO_AD_SIGMA_DELTA");
386
387/**
388 * ad_sigma_delta_single_conversion() - Performs a single data conversion
389 * @indio_dev: The IIO device
390 * @chan: The conversion is done for this channel
391 * @val: Pointer to the location where to store the read value
392 *
393 * Returns: 0 on success, an error value otherwise.
394 */
395int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
396	const struct iio_chan_spec *chan, int *val)
397{
398	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
399	unsigned int sample, raw_sample;
400	unsigned int data_reg;
401	int ret = 0;
402
403	if (!iio_device_claim_direct(indio_dev))
404		return -EBUSY;
405
406	ret = ad_sigma_delta_set_channel(sigma_delta, chan->address);
407	if (ret)
408		goto out_release;
409
410	spi_bus_lock(sigma_delta->spi->controller);
411	sigma_delta->bus_locked = true;
412	sigma_delta->keep_cs_asserted = true;
413	reinit_completion(&sigma_delta->completion);
414
415	ret = ad_sigma_delta_clear_pending_event(sigma_delta);
416	if (ret)
417		goto out_unlock;
418
419	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_SINGLE);
420
421	ad_sd_enable_irq(sigma_delta);
422	ret = wait_for_completion_interruptible_timeout(
423			&sigma_delta->completion, HZ);
424
425	if (ret == 0)
426		ret = -EIO;
427	if (ret < 0)
428		goto out;
429
430	if (sigma_delta->info->data_reg != 0)
431		data_reg = sigma_delta->info->data_reg;
432	else
433		data_reg = AD_SD_REG_DATA;
434
435	ret = ad_sd_read_reg(sigma_delta, data_reg,
436		BITS_TO_BYTES(chan->scan_type.realbits + chan->scan_type.shift),
437		&raw_sample);
438
439out:
440	ad_sd_disable_irq(sigma_delta);
441
442	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
443	ad_sigma_delta_disable_one(sigma_delta, chan->address);
444
445out_unlock:
446	sigma_delta->keep_cs_asserted = false;
447	sigma_delta->bus_locked = false;
448	spi_bus_unlock(sigma_delta->spi->controller);
449out_release:
450	iio_device_release_direct(indio_dev);
451
452	if (ret)
453		return ret;
454
455	sample = raw_sample >> chan->scan_type.shift;
456	sample &= (1 << chan->scan_type.realbits) - 1;
457	*val = sample;
458
459	ret = ad_sigma_delta_postprocess_sample(sigma_delta, raw_sample);
460	if (ret)
461		return ret;
462
463	return IIO_VAL_INT;
464}
465EXPORT_SYMBOL_NS_GPL(ad_sigma_delta_single_conversion, "IIO_AD_SIGMA_DELTA");
466
467static int ad_sd_buffer_postenable(struct iio_dev *indio_dev)
468{
469	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
470	const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type;
471	struct spi_transfer *xfer = sigma_delta->sample_xfer;
472	unsigned int i, slot, channel;
473	u8 *samples_buf;
474	int ret;
475
476	if (sigma_delta->num_slots == 1) {
477		channel = find_first_bit(indio_dev->active_scan_mask,
478					 iio_get_masklength(indio_dev));
479		ret = ad_sigma_delta_set_channel(sigma_delta,
480						 indio_dev->channels[channel].address);
481		if (ret)
482			return ret;
483		slot = 1;
484	} else {
485		/*
486		 * At this point update_scan_mode already enabled the required channels.
487		 * For sigma-delta sequencer drivers with multiple slots, an update_scan_mode
488		 * implementation is mandatory.
489		 */
490		slot = 0;
491		iio_for_each_active_channel(indio_dev, i) {
492			sigma_delta->slots[slot] = indio_dev->channels[i].address;
493			slot++;
494		}
495	}
496
497	sigma_delta->active_slots = slot;
498	sigma_delta->current_slot = 0;
499
500	if (ad_sigma_delta_has_spi_offload(sigma_delta)) {
501		xfer[1].offload_flags = SPI_OFFLOAD_XFER_RX_STREAM;
502		xfer[1].bits_per_word = scan_type->realbits;
503		xfer[1].len = spi_bpw_to_bytes(scan_type->realbits);
504	} else {
505		unsigned int samples_buf_size, scan_size;
506
507		if (sigma_delta->active_slots > 1) {
508			ret = ad_sigma_delta_append_status(sigma_delta, true);
509			if (ret)
510				return ret;
511		}
512
513		samples_buf_size =
514			ALIGN(slot * BITS_TO_BYTES(scan_type->storagebits),
515			      sizeof(s64));
516		samples_buf_size += sizeof(s64);
517		samples_buf = devm_krealloc(&sigma_delta->spi->dev,
518					    sigma_delta->samples_buf,
519					    samples_buf_size, GFP_KERNEL);
520		if (!samples_buf)
521			return -ENOMEM;
522
523		sigma_delta->samples_buf = samples_buf;
524		scan_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift);
525		/* For 24-bit data, there is an extra byte of padding. */
526		xfer[1].rx_buf = &sigma_delta->rx_buf[scan_size == 3 ? 1 : 0];
527		xfer[1].len = scan_size + (sigma_delta->status_appended ? 1 : 0);
528	}
529	xfer[1].cs_change = 1;
530
531	if (sigma_delta->info->has_registers) {
532		xfer[0].tx_buf = &sigma_delta->sample_addr;
533		xfer[0].len = 1;
534
535		ad_sd_set_read_reg_addr(sigma_delta,
536					sigma_delta->info->data_reg ?: AD_SD_REG_DATA,
537					&sigma_delta->sample_addr);
538		spi_message_init_with_transfers(&sigma_delta->sample_msg, xfer, 2);
539	} else {
540		spi_message_init_with_transfers(&sigma_delta->sample_msg,
541						&xfer[1], 1);
542	}
543
544	sigma_delta->sample_msg.offload = sigma_delta->offload;
545
546	ret = spi_optimize_message(sigma_delta->spi, &sigma_delta->sample_msg);
547	if (ret)
548		return ret;
549
550	spi_bus_lock(sigma_delta->spi->controller);
551	sigma_delta->bus_locked = true;
552	sigma_delta->keep_cs_asserted = true;
553
554	ret = ad_sigma_delta_clear_pending_event(sigma_delta);
555	if (ret)
556		goto err_unlock;
557
558	ret = ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_CONTINUOUS);
559	if (ret)
560		goto err_unlock;
561
562	if (ad_sigma_delta_has_spi_offload(sigma_delta)) {
563		struct spi_offload_trigger_config config = {
564			.type = SPI_OFFLOAD_TRIGGER_DATA_READY,
565		};
566
567		ret = spi_offload_trigger_enable(sigma_delta->offload,
568						 sigma_delta->offload_trigger,
569						 &config);
570		if (ret)
571			goto err_unlock;
572	} else {
573		ad_sd_enable_irq(sigma_delta);
574	}
575
576	return 0;
577
578err_unlock:
579	spi_bus_unlock(sigma_delta->spi->controller);
580	spi_unoptimize_message(&sigma_delta->sample_msg);
581
582	return ret;
583}
584
585static int ad_sd_buffer_predisable(struct iio_dev *indio_dev)
586{
587	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
588
589	if (ad_sigma_delta_has_spi_offload(sigma_delta)) {
590		spi_offload_trigger_disable(sigma_delta->offload,
591					    sigma_delta->offload_trigger);
592	} else {
593		reinit_completion(&sigma_delta->completion);
594		wait_for_completion_timeout(&sigma_delta->completion, HZ);
595
596		ad_sd_disable_irq(sigma_delta);
597	}
598
599	sigma_delta->keep_cs_asserted = false;
600	ad_sigma_delta_set_mode(sigma_delta, AD_SD_MODE_IDLE);
601
602	if (sigma_delta->status_appended)
603		ad_sigma_delta_append_status(sigma_delta, false);
604
605	ad_sigma_delta_disable_all(sigma_delta);
606	sigma_delta->bus_locked = false;
607	spi_bus_unlock(sigma_delta->spi->controller);
608	spi_unoptimize_message(&sigma_delta->sample_msg);
609
610	return 0;
611}
612
613static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
614{
615	struct iio_poll_func *pf = p;
616	struct iio_dev *indio_dev = pf->indio_dev;
617	const struct iio_scan_type *scan_type = &indio_dev->channels[0].scan_type;
618	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
619	u8 *data = sigma_delta->rx_buf;
620	unsigned int sample_size;
621	unsigned int sample_pos;
622	unsigned int status_pos;
623	unsigned int reg_size;
624	int ret;
625
626	reg_size = BITS_TO_BYTES(scan_type->realbits + scan_type->shift);
627	/* For 24-bit data, there is an extra byte of padding. */
628	status_pos = reg_size + (reg_size == 3 ? 1 : 0);
629
630	ret = spi_sync_locked(sigma_delta->spi, &sigma_delta->sample_msg);
631	if (ret)
632		goto irq_handled;
633
634	/*
635	 * For devices sampling only one channel at
636	 * once, there is no need for sample number tracking.
637	 */
638	if (sigma_delta->active_slots == 1) {
639		iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
640		goto irq_handled;
641	}
642
643	if (sigma_delta->status_appended) {
644		u8 converted_channel;
645
646		converted_channel = data[status_pos] & sigma_delta->info->status_ch_mask;
647		if (converted_channel != sigma_delta->slots[sigma_delta->current_slot]) {
648			/*
649			 * Desync occurred during continuous sampling of multiple channels.
650			 * Drop this incomplete sample and start from first channel again.
651			 */
652
653			sigma_delta->current_slot = 0;
654			goto irq_handled;
655		}
656	}
657
658	sample_size = BITS_TO_BYTES(scan_type->storagebits);
659	sample_pos = sample_size * sigma_delta->current_slot;
660	memcpy(&sigma_delta->samples_buf[sample_pos], data, sample_size);
661	sigma_delta->current_slot++;
662
663	if (sigma_delta->current_slot == sigma_delta->active_slots) {
664		sigma_delta->current_slot = 0;
665		iio_push_to_buffers_with_timestamp(indio_dev, sigma_delta->samples_buf,
666						   pf->timestamp);
667	}
668
669irq_handled:
670	iio_trigger_notify_done(indio_dev->trig);
671	ad_sd_enable_irq(sigma_delta);
672
673	return IRQ_HANDLED;
674}
675
676static bool ad_sd_validate_scan_mask(struct iio_dev *indio_dev, const unsigned long *mask)
677{
678	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
679
680	return bitmap_weight(mask, iio_get_masklength(indio_dev)) <= sigma_delta->num_slots;
681}
682
683static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
684	.postenable = &ad_sd_buffer_postenable,
685	.predisable = &ad_sd_buffer_predisable,
686	.validate_scan_mask = &ad_sd_validate_scan_mask,
687};
688
689static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
690{
691	struct ad_sigma_delta *sigma_delta = private;
692
693	/*
694	 * AD7124 and a few others use the same physical line for interrupt
695	 * reporting (R̅D̅Y̅) and MISO.
696	 * As MISO toggles when reading a register, this likely results in a
697	 * pending interrupt. This has two consequences: a) The irq might
698	 * trigger immediately after it's enabled even though the conversion
699	 * isn't done yet; and b) checking the STATUS register's R̅D̅Y̅ flag is
700	 * off-limits as reading that would trigger another irq event.
701	 *
702	 * So read the MOSI line as GPIO (if available) and only trigger the irq
703	 * if the line is active. Without such a GPIO assume this is a valid
704	 * interrupt.
705	 *
706	 * Also as disable_irq_nosync() is used to disable the irq, only act if
707	 * the irq wasn't disabled before.
708	 */
709	if ((!sigma_delta->rdy_gpiod || gpiod_get_value(sigma_delta->rdy_gpiod)) &&
710	    ad_sd_disable_irq(sigma_delta)) {
711		complete(&sigma_delta->completion);
712		if (sigma_delta->trig)
713			iio_trigger_poll(sigma_delta->trig);
714
715		return IRQ_HANDLED;
716	}
717
718	return IRQ_NONE;
719}
720
721/**
722 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
723 * @indio_dev: The IIO device
724 * @trig: The new trigger
725 *
726 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
727 * device, -EINVAL otherwise.
728 */
729int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
730{
731	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
732
733	if (sigma_delta->trig != trig)
734		return -EINVAL;
735
736	return 0;
737}
738EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, "IIO_AD_SIGMA_DELTA");
739
740static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev)
741{
742	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
743	unsigned long irq_flags = irq_get_trigger_type(sigma_delta->irq_line);
744	int ret;
745
746	init_completion(&sigma_delta->completion);
747
748	sigma_delta->irq_dis = true;
749
750	/* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
751	irq_set_status_flags(sigma_delta->irq_line, IRQ_DISABLE_UNLAZY);
752
753	/* Allow overwriting the flags from firmware */
754	if (!irq_flags)
755		irq_flags = sigma_delta->info->irq_flags;
756
757	ret = devm_request_irq(dev, sigma_delta->irq_line,
758			       ad_sd_data_rdy_trig_poll,
759			       irq_flags | IRQF_NO_AUTOEN,
760			       indio_dev->name,
761			       sigma_delta);
762	if (ret)
763		return ret;
764
765	if (ad_sigma_delta_has_spi_offload(sigma_delta)) {
766		sigma_delta->offload_trigger =
767			devm_spi_offload_trigger_get(dev, sigma_delta->offload,
768						     SPI_OFFLOAD_TRIGGER_DATA_READY);
769		if (IS_ERR(sigma_delta->offload_trigger))
770			return dev_err_probe(dev, PTR_ERR(sigma_delta->offload_trigger),
771					     "Failed to get SPI offload trigger\n");
772	} else {
773		if (dev != &sigma_delta->spi->dev)
774			return dev_err_probe(dev, -EFAULT,
775				"Trigger parent should be '%s', got '%s'\n",
776				dev_name(dev), dev_name(&sigma_delta->spi->dev));
777
778		sigma_delta->trig = devm_iio_trigger_alloc(dev, "%s-dev%d",
779			indio_dev->name, iio_device_id(indio_dev));
780		if (!sigma_delta->trig)
781			return -ENOMEM;
782
783		iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
784
785		ret = devm_iio_trigger_register(dev, sigma_delta->trig);
786		if (ret)
787			return ret;
788
789		/* select default trigger */
790		indio_dev->trig = iio_trigger_get(sigma_delta->trig);
791	}
792
793	return 0;
794}
795
796/**
797 * devm_ad_sd_setup_buffer_and_trigger() - Device-managed buffer & trigger setup
798 * @dev: Device object to which to bind the life-time of the resources attached
799 * @indio_dev: The IIO device
800 */
801int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev)
802{
803	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
804	int ret;
805
806	sigma_delta->slots = devm_kcalloc(dev, sigma_delta->num_slots,
807					  sizeof(*sigma_delta->slots), GFP_KERNEL);
808	if (!sigma_delta->slots)
809		return -ENOMEM;
810
811	if (ad_sigma_delta_has_spi_offload(sigma_delta)) {
812		struct dma_chan *rx_dma;
813
814		rx_dma = devm_spi_offload_rx_stream_request_dma_chan(dev,
815			sigma_delta->offload);
816		if (IS_ERR(rx_dma))
817			return dev_err_probe(dev, PTR_ERR(rx_dma),
818					     "Failed to get RX DMA channel\n");
819
820		ret = devm_iio_dmaengine_buffer_setup_with_handle(dev, indio_dev,
821			rx_dma, IIO_BUFFER_DIRECTION_IN);
822		if (ret)
823			return dev_err_probe(dev, ret, "Cannot setup DMA buffer\n");
824
825		indio_dev->setup_ops = &ad_sd_buffer_setup_ops;
826	} else {
827		ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
828						      &iio_pollfunc_store_time,
829						      &ad_sd_trigger_handler,
830						      &ad_sd_buffer_setup_ops);
831		if (ret)
832			return ret;
833	}
834
835	return devm_ad_sd_probe_trigger(dev, indio_dev);
836}
837EXPORT_SYMBOL_NS_GPL(devm_ad_sd_setup_buffer_and_trigger, "IIO_AD_SIGMA_DELTA");
838
839/**
840 * ad_sd_init() - Initializes a ad_sigma_delta struct
841 * @sigma_delta: The ad_sigma_delta device
842 * @indio_dev: The IIO device which the Sigma Delta device is used for
843 * @spi: The SPI device for the ad_sigma_delta device
844 * @info: Device specific callbacks and options
845 *
846 * This function needs to be called before any other operations are performed on
847 * the ad_sigma_delta struct.
848 */
849int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
850	struct spi_device *spi, const struct ad_sigma_delta_info *info)
851{
852	sigma_delta->spi = spi;
853	sigma_delta->info = info;
854
855	/* If the field is unset in ad_sigma_delta_info, assume there can only be 1 slot. */
856	if (!info->num_slots)
857		sigma_delta->num_slots = 1;
858	else
859		sigma_delta->num_slots = info->num_slots;
860
861	if (sigma_delta->num_slots > 1) {
862		if (!indio_dev->info->update_scan_mode) {
863			dev_err(&spi->dev, "iio_dev lacks update_scan_mode().\n");
864			return -EINVAL;
865		}
866
867		if (!info->disable_all) {
868			dev_err(&spi->dev, "ad_sigma_delta_info lacks disable_all().\n");
869			return -EINVAL;
870		}
871	}
872
873	spin_lock_init(&sigma_delta->irq_lock);
874
875	if (info->has_named_irqs) {
876		sigma_delta->irq_line = fwnode_irq_get_byname(dev_fwnode(&spi->dev),
877							      "rdy");
878		if (sigma_delta->irq_line < 0)
879			return dev_err_probe(&spi->dev, sigma_delta->irq_line,
880					     "Interrupt 'rdy' is required\n");
881	} else {
882		sigma_delta->irq_line = spi->irq;
883	}
884
885	sigma_delta->rdy_gpiod = devm_gpiod_get_optional(&spi->dev, "rdy", GPIOD_IN);
886	if (IS_ERR(sigma_delta->rdy_gpiod))
887		return dev_err_probe(&spi->dev, PTR_ERR(sigma_delta->rdy_gpiod),
888				     "Failed to find rdy gpio\n");
889
890	if (sigma_delta->rdy_gpiod && !sigma_delta->irq_line) {
891		sigma_delta->irq_line = gpiod_to_irq(sigma_delta->rdy_gpiod);
892		if (sigma_delta->irq_line < 0)
893			return sigma_delta->irq_line;
894	}
895
896	if (info->supports_spi_offload) {
897		struct spi_offload_config offload_config = {
898			.capability_flags = SPI_OFFLOAD_CAP_TRIGGER |
899					    SPI_OFFLOAD_CAP_RX_STREAM_DMA,
900		};
901		int ret;
902
903		sigma_delta->offload = devm_spi_offload_get(&spi->dev, spi,
904							    &offload_config);
905		ret = PTR_ERR_OR_ZERO(sigma_delta->offload);
906		if (ret && ret != -ENODEV)
907			return dev_err_probe(&spi->dev, ret, "Failed to get SPI offload\n");
908	}
909
910	iio_device_set_drvdata(indio_dev, sigma_delta);
911
912	return 0;
913}
914EXPORT_SYMBOL_NS_GPL(ad_sd_init, "IIO_AD_SIGMA_DELTA");
915
916MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
917MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
918MODULE_LICENSE("GPL v2");
919MODULE_IMPORT_NS("IIO_DMAENGINE_BUFFER");