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 */
40void 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}
46EXPORT_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 **/
58int 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}
100EXPORT_SYMBOL_GPL(ad_sd_write_reg);
101
102static 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 **/
146int 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
175out:
176	return ret;
177}
178EXPORT_SYMBOL_GPL(ad_sd_read_reg);
179
180static 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	reinit_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	}
207out:
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 **/
223int 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}
237EXPORT_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 */
247int 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	reinit_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
283out:
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}
305EXPORT_SYMBOL_GPL(ad_sigma_delta_single_conversion);
306
307static 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
335err_unlock:
336	spi_bus_unlock(sigma_delta->spi->master);
337err_predisable:
338
339	return ret;
340}
341
342static 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	reinit_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
360static 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	reg_size = indio_dev->channels[0].scan_type.realbits +
372			indio_dev->channels[0].scan_type.shift;
373	reg_size = DIV_ROUND_UP(reg_size, 8);
374
375	switch (reg_size) {
376	case 4:
377	case 2:
378	case 1:
379		ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
380			reg_size, &data[0]);
381		break;
382	case 3:
383		/* We store 24 bit samples in a 32 bit word. Keep the upper
384		 * byte set to zero. */
385		ret = ad_sd_read_reg_raw(sigma_delta, AD_SD_REG_DATA,
386			reg_size, &data[1]);
387		break;
388	}
389
390	iio_push_to_buffers_with_timestamp(indio_dev, data, pf->timestamp);
391
392	iio_trigger_notify_done(indio_dev->trig);
393	sigma_delta->irq_dis = false;
394	enable_irq(sigma_delta->spi->irq);
395
396	return IRQ_HANDLED;
397}
398
399static const struct iio_buffer_setup_ops ad_sd_buffer_setup_ops = {
400	.postenable = &ad_sd_buffer_postenable,
401	.predisable = &iio_triggered_buffer_predisable,
402	.postdisable = &ad_sd_buffer_postdisable,
403	.validate_scan_mask = &iio_validate_scan_mask_onehot,
404};
405
406static irqreturn_t ad_sd_data_rdy_trig_poll(int irq, void *private)
407{
408	struct ad_sigma_delta *sigma_delta = private;
409
410	complete(&sigma_delta->completion);
411	disable_irq_nosync(irq);
412	sigma_delta->irq_dis = true;
413	iio_trigger_poll(sigma_delta->trig);
414
415	return IRQ_HANDLED;
416}
417
418/**
419 * ad_sd_validate_trigger() - validate_trigger callback for ad_sigma_delta devices
420 * @indio_dev: The IIO device
421 * @trig: The new trigger
422 *
423 * Returns: 0 if the 'trig' matches the trigger registered by the ad_sigma_delta
424 * device, -EINVAL otherwise.
425 */
426int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig)
427{
428	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
429
430	if (sigma_delta->trig != trig)
431		return -EINVAL;
432
433	return 0;
434}
435EXPORT_SYMBOL_GPL(ad_sd_validate_trigger);
436
437static const struct iio_trigger_ops ad_sd_trigger_ops = {
438	.owner = THIS_MODULE,
439};
440
441static int ad_sd_probe_trigger(struct iio_dev *indio_dev)
442{
443	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
444	int ret;
445
446	sigma_delta->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
447						indio_dev->id);
448	if (sigma_delta->trig == NULL) {
449		ret = -ENOMEM;
450		goto error_ret;
451	}
452	sigma_delta->trig->ops = &ad_sd_trigger_ops;
453	init_completion(&sigma_delta->completion);
454
455	ret = request_irq(sigma_delta->spi->irq,
456			  ad_sd_data_rdy_trig_poll,
457			  IRQF_TRIGGER_LOW,
458			  indio_dev->name,
459			  sigma_delta);
460	if (ret)
461		goto error_free_trig;
462
463	if (!sigma_delta->irq_dis) {
464		sigma_delta->irq_dis = true;
465		disable_irq_nosync(sigma_delta->spi->irq);
466	}
467	sigma_delta->trig->dev.parent = &sigma_delta->spi->dev;
468	iio_trigger_set_drvdata(sigma_delta->trig, sigma_delta);
469
470	ret = iio_trigger_register(sigma_delta->trig);
471	if (ret)
472		goto error_free_irq;
473
474	/* select default trigger */
475	indio_dev->trig = iio_trigger_get(sigma_delta->trig);
476
477	return 0;
478
479error_free_irq:
480	free_irq(sigma_delta->spi->irq, sigma_delta);
481error_free_trig:
482	iio_trigger_free(sigma_delta->trig);
483error_ret:
484	return ret;
485}
486
487static void ad_sd_remove_trigger(struct iio_dev *indio_dev)
488{
489	struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
490
491	iio_trigger_unregister(sigma_delta->trig);
492	free_irq(sigma_delta->spi->irq, sigma_delta);
493	iio_trigger_free(sigma_delta->trig);
494}
495
496/**
497 * ad_sd_setup_buffer_and_trigger() -
498 * @indio_dev: The IIO device
499 */
500int ad_sd_setup_buffer_and_trigger(struct iio_dev *indio_dev)
501{
502	int ret;
503
504	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
505			&ad_sd_trigger_handler, &ad_sd_buffer_setup_ops);
506	if (ret)
507		return ret;
508
509	ret = ad_sd_probe_trigger(indio_dev);
510	if (ret) {
511		iio_triggered_buffer_cleanup(indio_dev);
512		return ret;
513	}
514
515	return 0;
516}
517EXPORT_SYMBOL_GPL(ad_sd_setup_buffer_and_trigger);
518
519/**
520 * ad_sd_cleanup_buffer_and_trigger() -
521 * @indio_dev: The IIO device
522 */
523void ad_sd_cleanup_buffer_and_trigger(struct iio_dev *indio_dev)
524{
525	ad_sd_remove_trigger(indio_dev);
526	iio_triggered_buffer_cleanup(indio_dev);
527}
528EXPORT_SYMBOL_GPL(ad_sd_cleanup_buffer_and_trigger);
529
530/**
531 * ad_sd_init() - Initializes a ad_sigma_delta struct
532 * @sigma_delta: The ad_sigma_delta device
533 * @indio_dev: The IIO device which the Sigma Delta device is used for
534 * @spi: The SPI device for the ad_sigma_delta device
535 * @info: Device specific callbacks and options
536 *
537 * This function needs to be called before any other operations are performed on
538 * the ad_sigma_delta struct.
539 */
540int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
541	struct spi_device *spi, const struct ad_sigma_delta_info *info)
542{
543	sigma_delta->spi = spi;
544	sigma_delta->info = info;
545	iio_device_set_drvdata(indio_dev, sigma_delta);
546
547	return 0;
548}
549EXPORT_SYMBOL_GPL(ad_sd_init);
550
551MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
552MODULE_DESCRIPTION("Analog Devices Sigma-Delta ADCs");
553MODULE_LICENSE("GPL v2");
554