summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/ad7791.c
blob: 54025ea10239adbb6e858e90489da8fe10fbf4a7 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * AD7787/AD7788/AD7789/AD7790/AD7791 SPI ADC driver
 *
 * Copyright 2012 Analog Devices Inc.
 *  Author: Lars-Peter Clausen <lars@metafoo.de>
 */

#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/spi/spi.h>
#include <linux/regulator/consumer.h>
#include <linux/err.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/adc/ad_sigma_delta.h>

#include <linux/platform_data/ad7791.h>

#define AD7791_REG_COMM			0x0 /* For writes */
#define AD7791_REG_STATUS		0x0 /* For reads */
#define AD7791_REG_MODE			0x1
#define AD7791_REG_FILTER		0x2
#define AD7791_REG_DATA			0x3

#define AD7791_MODE_CONTINUOUS		0x00
#define AD7791_MODE_SINGLE		0x02
#define AD7791_MODE_POWERDOWN		0x03

#define AD7791_CH_AIN1P_AIN1N		0x00
#define AD7791_CH_AIN2			0x01
#define AD7791_CH_AIN1N_AIN1N		0x02
#define AD7791_CH_AVDD_MONITOR		0x03

#define AD7791_FILTER_CLK_DIV_1		(0x0 << 4)
#define AD7791_FILTER_CLK_DIV_2		(0x1 << 4)
#define AD7791_FILTER_CLK_DIV_4		(0x2 << 4)
#define AD7791_FILTER_CLK_DIV_8		(0x3 << 4)
#define AD7791_FILTER_CLK_MASK		(0x3 << 4)
#define AD7791_FILTER_RATE_120		0x0
#define AD7791_FILTER_RATE_100		0x1
#define AD7791_FILTER_RATE_33_3		0x2
#define AD7791_FILTER_RATE_20		0x3
#define AD7791_FILTER_RATE_16_6		0x4
#define AD7791_FILTER_RATE_16_7		0x5
#define AD7791_FILTER_RATE_13_3		0x6
#define AD7791_FILTER_RATE_9_5		0x7
#define AD7791_FILTER_RATE_MASK		0x7

#define AD7791_MODE_BUFFER		BIT(1)
#define AD7791_MODE_UNIPOLAR		BIT(2)
#define AD7791_MODE_BURNOUT		BIT(3)
#define AD7791_MODE_SEL_MASK		(0x3 << 6)
#define AD7791_MODE_SEL(x)		((x) << 6)

#define DECLARE_AD7787_CHANNELS(name, bits, storagebits) \
const struct iio_chan_spec name[] = { \
	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
		(bits), (storagebits), 0), \
	AD_SD_CHANNEL(1, 1, AD7791_CH_AIN2, (bits), (storagebits), 0), \
	AD_SD_SHORTED_CHANNEL(2, 0, AD7791_CH_AIN1N_AIN1N, \
		(bits), (storagebits), 0), \
	AD_SD_SUPPLY_CHANNEL(3, 2, AD7791_CH_AVDD_MONITOR,  \
		(bits), (storagebits), 0), \
	IIO_CHAN_SOFT_TIMESTAMP(4), \
}

#define DECLARE_AD7791_CHANNELS(name, bits, storagebits) \
const struct iio_chan_spec name[] = { \
	AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \
		(bits), (storagebits), 0), \
	AD_SD_SHORTED_CHANNEL(1, 0, AD7791_CH_AIN1N_AIN1N, \
		(bits), (storagebits), 0), \
	AD_SD_SUPPLY_CHANNEL(2, 1, AD7791_CH_AVDD_MONITOR, \
		(bits), (storagebits), 0), \
	IIO_CHAN_SOFT_TIMESTAMP(3), \
}

static DECLARE_AD7787_CHANNELS(ad7787_channels, 24, 32);
static DECLARE_AD7791_CHANNELS(ad7790_channels, 16, 16);
static DECLARE_AD7791_CHANNELS(ad7791_channels, 24, 32);

enum {
	AD7787,
	AD7788,
	AD7789,
	AD7790,
	AD7791,
};

enum ad7791_chip_info_flags {
	AD7791_FLAG_HAS_FILTER		= (1 << 0),
	AD7791_FLAG_HAS_BUFFER		= (1 << 1),
	AD7791_FLAG_HAS_UNIPOLAR	= (1 << 2),
	AD7791_FLAG_HAS_BURNOUT		= (1 << 3),
};

struct ad7791_chip_info {
	const struct iio_chan_spec *channels;
	unsigned int num_channels;
	enum ad7791_chip_info_flags flags;
};

static const struct ad7791_chip_info ad7791_chip_infos[] = {
	[AD7787] = {
		.channels = ad7787_channels,
		.num_channels = ARRAY_SIZE(ad7787_channels),
		.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
			AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
	},
	[AD7788] = {
		.channels = ad7790_channels,
		.num_channels = ARRAY_SIZE(ad7790_channels),
		.flags = AD7791_FLAG_HAS_UNIPOLAR,
	},
	[AD7789] = {
		.channels = ad7791_channels,
		.num_channels = ARRAY_SIZE(ad7791_channels),
		.flags = AD7791_FLAG_HAS_UNIPOLAR,
	},
	[AD7790] = {
		.channels = ad7790_channels,
		.num_channels = ARRAY_SIZE(ad7790_channels),
		.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
			AD7791_FLAG_HAS_BURNOUT,
	},
	[AD7791] = {
		.channels = ad7791_channels,
		.num_channels = ARRAY_SIZE(ad7791_channels),
		.flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER |
			AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT,
	},
};

struct ad7791_state {
	struct ad_sigma_delta sd;
	uint8_t mode;
	uint8_t filter;

	struct regulator *reg;
	const struct ad7791_chip_info *info;
};

static const int ad7791_sample_freq_avail[8][2] = {
	[AD7791_FILTER_RATE_120] =  { 120, 0 },
	[AD7791_FILTER_RATE_100] =  { 100, 0 },
	[AD7791_FILTER_RATE_33_3] = { 33,  300000 },
	[AD7791_FILTER_RATE_20] =   { 20,  0 },
	[AD7791_FILTER_RATE_16_6] = { 16,  600000 },
	[AD7791_FILTER_RATE_16_7] = { 16,  700000 },
	[AD7791_FILTER_RATE_13_3] = { 13,  300000 },
	[AD7791_FILTER_RATE_9_5] =  { 9,   500000 },
};

static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd)
{
	return container_of(sd, struct ad7791_state, sd);
}

static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel)
{
	ad_sd_set_comm(sd, channel);

	return 0;
}

static int ad7791_set_mode(struct ad_sigma_delta *sd,
	enum ad_sigma_delta_mode mode)
{
	struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd);

	switch (mode) {
	case AD_SD_MODE_CONTINUOUS:
		mode = AD7791_MODE_CONTINUOUS;
		break;
	case AD_SD_MODE_SINGLE:
		mode = AD7791_MODE_SINGLE;
		break;
	case AD_SD_MODE_IDLE:
	case AD_SD_MODE_POWERDOWN:
		mode = AD7791_MODE_POWERDOWN;
		break;
	}

	st->mode &= ~AD7791_MODE_SEL_MASK;
	st->mode |= AD7791_MODE_SEL(mode);

	return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode);
}

static const struct ad_sigma_delta_info ad7791_sigma_delta_info = {
	.set_channel = ad7791_set_channel,
	.set_mode = ad7791_set_mode,
	.has_registers = true,
	.addr_shift = 4,
	.read_mask = BIT(3),
};

static int ad7791_read_raw(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, int *val, int *val2, long info)
{
	struct ad7791_state *st = iio_priv(indio_dev);
	bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR);
	unsigned int rate;

	switch (info) {
	case IIO_CHAN_INFO_RAW:
		return ad_sigma_delta_single_conversion(indio_dev, chan, val);
	case IIO_CHAN_INFO_OFFSET:
		/**
		 * Unipolar: 0 to VREF
		 * Bipolar -VREF to VREF
		 **/
		if (unipolar)
			*val = 0;
		else
			*val = -(1 << (chan->scan_type.realbits - 1));
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		/* The monitor channel uses an internal reference. */
		if (chan->address == AD7791_CH_AVDD_MONITOR) {
			/*
			 * The signal is attenuated by a factor of 5 and
			 * compared against a 1.17V internal reference.
			 */
			*val = 1170 * 5;
		} else {
			int voltage_uv;

			voltage_uv = regulator_get_voltage(st->reg);
			if (voltage_uv < 0)
				return voltage_uv;

			*val = voltage_uv / 1000;
		}
		if (unipolar)
			*val2 = chan->scan_type.realbits;
		else
			*val2 = chan->scan_type.realbits - 1;

		return IIO_VAL_FRACTIONAL_LOG2;
	case IIO_CHAN_INFO_SAMP_FREQ:
		rate = st->filter & AD7791_FILTER_RATE_MASK;
		*val = ad7791_sample_freq_avail[rate][0];
		*val2 = ad7791_sample_freq_avail[rate][1];
		return IIO_VAL_INT_PLUS_MICRO;
	}

	return -EINVAL;
}

static int ad7791_write_raw(struct iio_dev *indio_dev,
	struct iio_chan_spec const *chan, int val, int val2, long mask)
{
	struct ad7791_state *st = iio_priv(indio_dev);
	int ret, i;

	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret)
		return ret;

	switch (mask) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) {
			if (ad7791_sample_freq_avail[i][0] == val &&
			    ad7791_sample_freq_avail[i][1] == val2)
				break;
		}

		if (i == ARRAY_SIZE(ad7791_sample_freq_avail)) {
			ret = -EINVAL;
			break;
		}

		st->filter &= ~AD7791_FILTER_RATE_MASK;
		st->filter |= i;
		ad_sd_write_reg(&st->sd, AD7791_REG_FILTER,
				sizeof(st->filter),
				st->filter);
		break;
	default:
		ret = -EINVAL;
	}

	iio_device_release_direct_mode(indio_dev);
	return ret;
}

static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5");

static struct attribute *ad7791_attributes[] = {
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	NULL
};

static const struct attribute_group ad7791_attribute_group = {
	.attrs = ad7791_attributes,
};

static const struct iio_info ad7791_info = {
	.read_raw = &ad7791_read_raw,
	.write_raw = &ad7791_write_raw,
	.attrs = &ad7791_attribute_group,
	.validate_trigger = ad_sd_validate_trigger,
};

static const struct iio_info ad7791_no_filter_info = {
	.read_raw = &ad7791_read_raw,
	.write_raw = &ad7791_write_raw,
	.validate_trigger = ad_sd_validate_trigger,
};

static int ad7791_setup(struct ad7791_state *st,
			struct ad7791_platform_data *pdata)
{
	/* Set to poweron-reset default values */
	st->mode = AD7791_MODE_BUFFER;
	st->filter = AD7791_FILTER_RATE_16_6;

	if (!pdata)
		return 0;

	if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered)
		st->mode &= ~AD7791_MODE_BUFFER;

	if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) &&
		pdata->burnout_current)
		st->mode |= AD7791_MODE_BURNOUT;

	if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar)
		st->mode |= AD7791_MODE_UNIPOLAR;

	return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode),
		st->mode);
}

static int ad7791_probe(struct spi_device *spi)
{
	struct ad7791_platform_data *pdata = spi->dev.platform_data;
	struct iio_dev *indio_dev;
	struct ad7791_state *st;
	int ret;

	if (!spi->irq) {
		dev_err(&spi->dev, "Missing IRQ.\n");
		return -ENXIO;
	}

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (!indio_dev)
		return -ENOMEM;

	st = iio_priv(indio_dev);

	st->reg = devm_regulator_get(&spi->dev, "refin");
	if (IS_ERR(st->reg))
		return PTR_ERR(st->reg);

	ret = regulator_enable(st->reg);
	if (ret)
		return ret;

	st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data];
	ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info);

	spi_set_drvdata(spi, indio_dev);

	indio_dev->dev.parent = &spi->dev;
	indio_dev->dev.of_node = spi->dev.of_node;
	indio_dev->name = spi_get_device_id(spi)->name;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = st->info->channels;
	indio_dev->num_channels = st->info->num_channels;
	if (st->info->flags & AD7791_FLAG_HAS_FILTER)
		indio_dev->info = &ad7791_info;
	else
		indio_dev->info = &ad7791_no_filter_info;

	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
	if (ret)
		goto error_disable_reg;

	ret = ad7791_setup(st, pdata);
	if (ret)
		goto error_remove_trigger;

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

	return 0;

error_remove_trigger:
	ad_sd_cleanup_buffer_and_trigger(indio_dev);
error_disable_reg:
	regulator_disable(st->reg);

	return ret;
}

static int ad7791_remove(struct spi_device *spi)
{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);
	struct ad7791_state *st = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	ad_sd_cleanup_buffer_and_trigger(indio_dev);

	regulator_disable(st->reg);

	return 0;
}

static const struct spi_device_id ad7791_spi_ids[] = {
	{ "ad7787", AD7787 },
	{ "ad7788", AD7788 },
	{ "ad7789", AD7789 },
	{ "ad7790", AD7790 },
	{ "ad7791", AD7791 },
	{}
};
MODULE_DEVICE_TABLE(spi, ad7791_spi_ids);

static struct spi_driver ad7791_driver = {
	.driver = {
		.name	= "ad7791",
	},
	.probe		= ad7791_probe,
	.remove		= ad7791_remove,
	.id_table	= ad7791_spi_ids,
};
module_spi_driver(ad7791_driver);

MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver");
MODULE_LICENSE("GPL v2");