summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/ad7266.c
blob: 4a5f639bc68492e6d912db45b5460d050b60cad3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
/*
 * AD7266/65 SPI ADC driver
 *
 * Copyright 2012 Analog Devices Inc.
 *
 * Licensed under the GPL-2.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/module.h>

#include <linux/interrupt.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include <linux/platform_data/ad7266.h>

struct ad7266_state {
	struct spi_device	*spi;
	struct regulator	*reg;
	unsigned long		vref_uv;

	struct spi_transfer	single_xfer[3];
	struct spi_message	single_msg;

	enum ad7266_range	range;
	enum ad7266_mode	mode;
	bool			fixed_addr;
	struct gpio		gpios[3];

	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 * The buffer needs to be large enough to hold two samples (4 bytes) and
	 * the naturally aligned timestamp (8 bytes).
	 */
	uint8_t data[ALIGN(4, sizeof(s64)) + sizeof(s64)] ____cacheline_aligned;
};

static int ad7266_wakeup(struct ad7266_state *st)
{
	/* Any read with >= 2 bytes will wake the device */
	return spi_read(st->spi, st->data, 2);
}

static int ad7266_powerdown(struct ad7266_state *st)
{
	/* Any read with < 2 bytes will powerdown the device */
	return spi_read(st->spi, st->data, 1);
}

static int ad7266_preenable(struct iio_dev *indio_dev)
{
	struct ad7266_state *st = iio_priv(indio_dev);
	int ret;

	ret = ad7266_wakeup(st);
	if (ret)
		return ret;

	ret = iio_sw_buffer_preenable(indio_dev);
	if (ret)
		ad7266_powerdown(st);

	return ret;
}

static int ad7266_postdisable(struct iio_dev *indio_dev)
{
	struct ad7266_state *st = iio_priv(indio_dev);
	return ad7266_powerdown(st);
}

static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
	.preenable = &ad7266_preenable,
	.postenable = &iio_triggered_buffer_postenable,
	.predisable = &iio_triggered_buffer_predisable,
	.postdisable = &ad7266_postdisable,
};

static irqreturn_t ad7266_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad7266_state *st = iio_priv(indio_dev);
	int ret;

	ret = spi_read(st->spi, st->data, 4);
	if (ret == 0) {
		if (indio_dev->scan_timestamp)
			((s64 *)st->data)[1] = pf->timestamp;
		iio_push_to_buffers(indio_dev, (u8 *)st->data);
	}

	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static void ad7266_select_input(struct ad7266_state *st, unsigned int nr)
{
	unsigned int i;

	if (st->fixed_addr)
		return;

	switch (st->mode) {
	case AD7266_MODE_SINGLE_ENDED:
		nr >>= 1;
		break;
	case AD7266_MODE_PSEUDO_DIFF:
		nr |= 1;
		break;
	case AD7266_MODE_DIFF:
		nr &= ~1;
		break;
	}

	for (i = 0; i < 3; ++i)
		gpio_set_value(st->gpios[i].gpio, (bool)(nr & BIT(i)));
}

static int ad7266_update_scan_mode(struct iio_dev *indio_dev,
	const unsigned long *scan_mask)
{
	struct ad7266_state *st = iio_priv(indio_dev);
	unsigned int nr = find_first_bit(scan_mask, indio_dev->masklength);

	ad7266_select_input(st, nr);

	return 0;
}

static int ad7266_read_single(struct ad7266_state *st, int *val,
	unsigned int address)
{
	int ret;

	ad7266_select_input(st, address);

	ret = spi_sync(st->spi, &st->single_msg);
	*val = be16_to_cpu(st->data[address % 2]);

	return ret;
}

static int ad7266_read_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan, int *val, int *val2, long m)
{
	struct ad7266_state *st = iio_priv(indio_dev);
	unsigned long scale_uv;
	int ret;

	switch (m) {
	case IIO_CHAN_INFO_RAW:
		if (iio_buffer_enabled(indio_dev))
			return -EBUSY;

		ret = ad7266_read_single(st, val, chan->address);
		if (ret)
			return ret;

		*val = (*val >> 2) & 0xfff;
		if (chan->scan_type.sign == 's')
			*val = sign_extend32(*val, 11);

		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		scale_uv = (st->vref_uv * 100);
		if (st->mode == AD7266_MODE_DIFF)
			scale_uv *= 2;
		if (st->range == AD7266_RANGE_2VREF)
			scale_uv *= 2;

		scale_uv >>= chan->scan_type.realbits;
		*val =  scale_uv / 100000;
		*val2 = (scale_uv % 100000) * 10;
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_OFFSET:
		if (st->range == AD7266_RANGE_2VREF &&
			st->mode != AD7266_MODE_DIFF)
			*val = 2048;
		else
			*val = 0;
		return IIO_VAL_INT;
	}
	return -EINVAL;
}

#define AD7266_CHAN(_chan, _sign) {			\
	.type = IIO_VOLTAGE,				\
	.indexed = 1,					\
	.channel = (_chan),				\
	.address = (_chan),				\
	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT	\
		| IIO_CHAN_INFO_SCALE_SHARED_BIT	\
		| IIO_CHAN_INFO_OFFSET_SHARED_BIT,	\
	.scan_index = (_chan),				\
	.scan_type = {					\
		.sign = (_sign),			\
		.realbits = 12,				\
		.storagebits = 16,			\
		.shift = 2,				\
		.endianness = IIO_BE,			\
	},						\
}

#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS(_name, _sign) \
const struct iio_chan_spec ad7266_channels_##_name[] = { \
	AD7266_CHAN(0, (_sign)), \
	AD7266_CHAN(1, (_sign)), \
	AD7266_CHAN(2, (_sign)), \
	AD7266_CHAN(3, (_sign)), \
	AD7266_CHAN(4, (_sign)), \
	AD7266_CHAN(5, (_sign)), \
	AD7266_CHAN(6, (_sign)), \
	AD7266_CHAN(7, (_sign)), \
	AD7266_CHAN(8, (_sign)), \
	AD7266_CHAN(9, (_sign)), \
	AD7266_CHAN(10, (_sign)), \
	AD7266_CHAN(11, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(13), \
}

#define AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(_name, _sign) \
const struct iio_chan_spec ad7266_channels_##_name##_fixed[] = { \
	AD7266_CHAN(0, (_sign)), \
	AD7266_CHAN(1, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(2), \
}

static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(u, 'u');
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS(s, 's');
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(u, 'u');
static AD7266_DECLARE_SINGLE_ENDED_CHANNELS_FIXED(s, 's');

#define AD7266_CHAN_DIFF(_chan, _sign) {			\
	.type = IIO_VOLTAGE,				\
	.indexed = 1,					\
	.channel = (_chan) * 2,				\
	.channel2 = (_chan) * 2 + 1,			\
	.address = (_chan),				\
	.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT	\
		| IIO_CHAN_INFO_SCALE_SHARED_BIT	\
		| IIO_CHAN_INFO_OFFSET_SHARED_BIT,	\
	.scan_index = (_chan),				\
	.scan_type = {					\
		.sign = _sign,			\
		.realbits = 12,				\
		.storagebits = 16,			\
		.shift = 2,				\
		.endianness = IIO_BE,			\
	},						\
	.differential = 1,				\
}

#define AD7266_DECLARE_DIFF_CHANNELS(_name, _sign) \
const struct iio_chan_spec ad7266_channels_diff_##_name[] = { \
	AD7266_CHAN_DIFF(0, (_sign)), \
	AD7266_CHAN_DIFF(1, (_sign)), \
	AD7266_CHAN_DIFF(2, (_sign)), \
	AD7266_CHAN_DIFF(3, (_sign)), \
	AD7266_CHAN_DIFF(4, (_sign)), \
	AD7266_CHAN_DIFF(5, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(6), \
}

static AD7266_DECLARE_DIFF_CHANNELS(s, 's');
static AD7266_DECLARE_DIFF_CHANNELS(u, 'u');

#define AD7266_DECLARE_DIFF_CHANNELS_FIXED(_name, _sign) \
const struct iio_chan_spec ad7266_channels_diff_fixed_##_name[] = { \
	AD7266_CHAN_DIFF(0, (_sign)), \
	AD7266_CHAN_DIFF(1, (_sign)), \
	IIO_CHAN_SOFT_TIMESTAMP(2), \
}

static AD7266_DECLARE_DIFF_CHANNELS_FIXED(s, 's');
static AD7266_DECLARE_DIFF_CHANNELS_FIXED(u, 'u');

static const struct iio_info ad7266_info = {
	.read_raw = &ad7266_read_raw,
	.update_scan_mode = &ad7266_update_scan_mode,
	.driver_module = THIS_MODULE,
};

static unsigned long ad7266_available_scan_masks[] = {
	0x003,
	0x00c,
	0x030,
	0x0c0,
	0x300,
	0xc00,
	0x000,
};

static unsigned long ad7266_available_scan_masks_diff[] = {
	0x003,
	0x00c,
	0x030,
	0x000,
};

static unsigned long ad7266_available_scan_masks_fixed[] = {
	0x003,
	0x000,
};

struct ad7266_chan_info {
	const struct iio_chan_spec *channels;
	unsigned int num_channels;
	unsigned long *scan_masks;
};

#define AD7266_CHAN_INFO_INDEX(_differential, _signed, _fixed) \
	(((_differential) << 2) | ((_signed) << 1) | ((_fixed) << 0))

static const struct ad7266_chan_info ad7266_chan_infos[] = {
	[AD7266_CHAN_INFO_INDEX(0, 0, 0)] = {
		.channels = ad7266_channels_u,
		.num_channels = ARRAY_SIZE(ad7266_channels_u),
		.scan_masks = ad7266_available_scan_masks,
	},
	[AD7266_CHAN_INFO_INDEX(0, 0, 1)] = {
		.channels = ad7266_channels_u_fixed,
		.num_channels = ARRAY_SIZE(ad7266_channels_u_fixed),
		.scan_masks = ad7266_available_scan_masks_fixed,
	},
	[AD7266_CHAN_INFO_INDEX(0, 1, 0)] = {
		.channels = ad7266_channels_s,
		.num_channels = ARRAY_SIZE(ad7266_channels_s),
		.scan_masks = ad7266_available_scan_masks,
	},
	[AD7266_CHAN_INFO_INDEX(0, 1, 1)] = {
		.channels = ad7266_channels_s_fixed,
		.num_channels = ARRAY_SIZE(ad7266_channels_s_fixed),
		.scan_masks = ad7266_available_scan_masks_fixed,
	},
	[AD7266_CHAN_INFO_INDEX(1, 0, 0)] = {
		.channels = ad7266_channels_diff_u,
		.num_channels = ARRAY_SIZE(ad7266_channels_diff_u),
		.scan_masks = ad7266_available_scan_masks_diff,
	},
	[AD7266_CHAN_INFO_INDEX(1, 0, 1)] = {
		.channels = ad7266_channels_diff_fixed_u,
		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_u),
		.scan_masks = ad7266_available_scan_masks_fixed,
	},
	[AD7266_CHAN_INFO_INDEX(1, 1, 0)] = {
		.channels = ad7266_channels_diff_s,
		.num_channels = ARRAY_SIZE(ad7266_channels_diff_s),
		.scan_masks = ad7266_available_scan_masks_diff,
	},
	[AD7266_CHAN_INFO_INDEX(1, 1, 1)] = {
		.channels = ad7266_channels_diff_fixed_s,
		.num_channels = ARRAY_SIZE(ad7266_channels_diff_fixed_s),
		.scan_masks = ad7266_available_scan_masks_fixed,
	},
};

static void ad7266_init_channels(struct iio_dev *indio_dev)
{
	struct ad7266_state *st = iio_priv(indio_dev);
	bool is_differential, is_signed;
	const struct ad7266_chan_info *chan_info;
	int i;

	is_differential = st->mode != AD7266_MODE_SINGLE_ENDED;
	is_signed = (st->range == AD7266_RANGE_2VREF) |
		    (st->mode == AD7266_MODE_DIFF);

	i = AD7266_CHAN_INFO_INDEX(is_differential, is_signed, st->fixed_addr);
	chan_info = &ad7266_chan_infos[i];

	indio_dev->channels = chan_info->channels;
	indio_dev->num_channels = chan_info->num_channels;
	indio_dev->available_scan_masks = chan_info->scan_masks;
	indio_dev->masklength = chan_info->num_channels - 1;
}

static const char * const ad7266_gpio_labels[] = {
	"AD0", "AD1", "AD2",
};

static int ad7266_probe(struct spi_device *spi)
{
	struct ad7266_platform_data *pdata = spi->dev.platform_data;
	struct iio_dev *indio_dev;
	struct ad7266_state *st;
	unsigned int i;
	int ret;

	indio_dev = iio_device_alloc(sizeof(*st));
	if (indio_dev == NULL)
		return -ENOMEM;

	st = iio_priv(indio_dev);

	st->reg = regulator_get(&spi->dev, "vref");
	if (!IS_ERR_OR_NULL(st->reg)) {
		ret = regulator_enable(st->reg);
		if (ret)
			goto error_put_reg;

		st->vref_uv = regulator_get_voltage(st->reg);
	} else {
		/* Use internal reference */
		st->vref_uv = 2500000;
	}

	if (pdata) {
		st->fixed_addr = pdata->fixed_addr;
		st->mode = pdata->mode;
		st->range = pdata->range;

		if (!st->fixed_addr) {
			for (i = 0; i < ARRAY_SIZE(st->gpios); ++i) {
				st->gpios[i].gpio = pdata->addr_gpios[i];
				st->gpios[i].flags = GPIOF_OUT_INIT_LOW;
				st->gpios[i].label = ad7266_gpio_labels[i];
			}
			ret = gpio_request_array(st->gpios,
				ARRAY_SIZE(st->gpios));
			if (ret)
				goto error_disable_reg;
		}
	} else {
		st->fixed_addr = true;
		st->range = AD7266_RANGE_VREF;
		st->mode = AD7266_MODE_DIFF;
	}

	spi_set_drvdata(spi, indio_dev);
	st->spi = spi;

	indio_dev->dev.parent = &spi->dev;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &ad7266_info;

	ad7266_init_channels(indio_dev);

	/* wakeup */
	st->single_xfer[0].rx_buf = &st->data;
	st->single_xfer[0].len = 2;
	st->single_xfer[0].cs_change = 1;
	/* conversion */
	st->single_xfer[1].rx_buf = &st->data;
	st->single_xfer[1].len = 4;
	st->single_xfer[1].cs_change = 1;
	/* powerdown */
	st->single_xfer[2].tx_buf = &st->data;
	st->single_xfer[2].len = 1;

	spi_message_init(&st->single_msg);
	spi_message_add_tail(&st->single_xfer[0], &st->single_msg);
	spi_message_add_tail(&st->single_xfer[1], &st->single_msg);
	spi_message_add_tail(&st->single_xfer[2], &st->single_msg);

	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
		&ad7266_trigger_handler, &iio_triggered_buffer_setup_ops);
	if (ret)
		goto error_free_gpios;

	ret = iio_device_register(indio_dev);
	if (ret)
		goto error_buffer_cleanup;

	return 0;

error_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
error_free_gpios:
	if (!st->fixed_addr)
		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
error_disable_reg:
	if (!IS_ERR_OR_NULL(st->reg))
		regulator_disable(st->reg);
error_put_reg:
	if (!IS_ERR_OR_NULL(st->reg))
		regulator_put(st->reg);

	iio_device_free(indio_dev);

	return ret;
}

static int ad7266_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7266_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	if (!st->fixed_addr)
		gpio_free_array(st->gpios, ARRAY_SIZE(st->gpios));
	if (!IS_ERR_OR_NULL(st->reg)) {
		regulator_disable(st->reg);
		regulator_put(st->reg);
	}
	iio_device_free(indio_dev);

	return 0;
}

static const struct spi_device_id ad7266_id[] = {
	{"ad7265", 0},
	{"ad7266", 0},
	{ }
};
MODULE_DEVICE_TABLE(spi, ad7266_id);

static struct spi_driver ad7266_driver = {
	.driver = {
		.name	= "ad7266",
		.owner	= THIS_MODULE,
	},
	.probe		= ad7266_probe,
	.remove		= ad7266_remove,
	.id_table	= ad7266_id,
};
module_spi_driver(ad7266_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Devices AD7266/65 ADC");
MODULE_LICENSE("GPL v2");