summaryrefslogtreecommitdiff
path: root/drivers/iio/adc/ti-ads1015.c
blob: 73cbf0b54e54f6c13fe1d5892f2859915be18ef8 (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
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
/*
 * ADS1015 - Texas Instruments Analog-to-Digital Converter
 *
 * Copyright (c) 2016, Intel Corporation.
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * IIO driver for ADS1015 ADC 7-bit I2C slave address:
 *	* 0x48 - ADDR connected to Ground
 *	* 0x49 - ADDR connected to Vdd
 *	* 0x4A - ADDR connected to SDA
 *	* 0x4B - ADDR connected to SCL
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/pm_runtime.h>
#include <linux/mutex.h>
#include <linux/delay.h>

#include <linux/i2c/ads1015.h>

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

#define ADS1015_DRV_NAME "ads1015"

#define ADS1015_CONV_REG	0x00
#define ADS1015_CFG_REG		0x01

#define ADS1015_CFG_DR_SHIFT	5
#define ADS1015_CFG_MOD_SHIFT	8
#define ADS1015_CFG_PGA_SHIFT	9
#define ADS1015_CFG_MUX_SHIFT	12

#define ADS1015_CFG_DR_MASK	GENMASK(7, 5)
#define ADS1015_CFG_MOD_MASK	BIT(8)
#define ADS1015_CFG_PGA_MASK	GENMASK(11, 9)
#define ADS1015_CFG_MUX_MASK	GENMASK(14, 12)

/* device operating modes */
#define ADS1015_CONTINUOUS	0
#define ADS1015_SINGLESHOT	1

#define ADS1015_SLEEP_DELAY_MS		2000
#define ADS1015_DEFAULT_PGA		2
#define ADS1015_DEFAULT_DATA_RATE	4
#define ADS1015_DEFAULT_CHAN		0

enum ads1015_channels {
	ADS1015_AIN0_AIN1 = 0,
	ADS1015_AIN0_AIN3,
	ADS1015_AIN1_AIN3,
	ADS1015_AIN2_AIN3,
	ADS1015_AIN0,
	ADS1015_AIN1,
	ADS1015_AIN2,
	ADS1015_AIN3,
	ADS1015_TIMESTAMP,
};

static const unsigned int ads1015_data_rate[] = {
	128, 250, 490, 920, 1600, 2400, 3300, 3300
};

static const struct {
	int scale;
	int uscale;
} ads1015_scale[] = {
	{3, 0},
	{2, 0},
	{1, 0},
	{0, 500000},
	{0, 250000},
	{0, 125000},
	{0, 125000},
	{0, 125000},
};

#define ADS1015_V_CHAN(_chan, _addr) {				\
	.type = IIO_VOLTAGE,					\
	.indexed = 1,						\
	.address = _addr,					\
	.channel = _chan,					\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
				BIT(IIO_CHAN_INFO_SCALE) |	\
				BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
	.scan_index = _addr,					\
	.scan_type = {						\
		.sign = 's',					\
		.realbits = 12,					\
		.storagebits = 16,				\
		.shift = 4,					\
		.endianness = IIO_CPU,				\
	},							\
}

#define ADS1015_V_DIFF_CHAN(_chan, _chan2, _addr) {		\
	.type = IIO_VOLTAGE,					\
	.differential = 1,					\
	.indexed = 1,						\
	.address = _addr,					\
	.channel = _chan,					\
	.channel2 = _chan2,					\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
				BIT(IIO_CHAN_INFO_SCALE) |	\
				BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
	.scan_index = _addr,					\
	.scan_type = {						\
		.sign = 's',					\
		.realbits = 12,					\
		.storagebits = 16,				\
		.shift = 4,					\
		.endianness = IIO_CPU,				\
	},							\
}

struct ads1015_data {
	struct regmap *regmap;
	/*
	 * Protects ADC ops, e.g: concurrent sysfs/buffered
	 * data reads, configuration updates
	 */
	struct mutex lock;
	struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
};

static bool ads1015_is_writeable_reg(struct device *dev, unsigned int reg)
{
	return (reg == ADS1015_CFG_REG);
}

static const struct regmap_config ads1015_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.max_register = ADS1015_CFG_REG,
	.writeable_reg = ads1015_is_writeable_reg,
};

static const struct iio_chan_spec ads1015_channels[] = {
	ADS1015_V_DIFF_CHAN(0, 1, ADS1015_AIN0_AIN1),
	ADS1015_V_DIFF_CHAN(0, 3, ADS1015_AIN0_AIN3),
	ADS1015_V_DIFF_CHAN(1, 3, ADS1015_AIN1_AIN3),
	ADS1015_V_DIFF_CHAN(2, 3, ADS1015_AIN2_AIN3),
	ADS1015_V_CHAN(0, ADS1015_AIN0),
	ADS1015_V_CHAN(1, ADS1015_AIN1),
	ADS1015_V_CHAN(2, ADS1015_AIN2),
	ADS1015_V_CHAN(3, ADS1015_AIN3),
	IIO_CHAN_SOFT_TIMESTAMP(ADS1015_TIMESTAMP),
};

static int ads1015_set_power_state(struct ads1015_data *data, bool on)
{
	int ret;
	struct device *dev = regmap_get_device(data->regmap);

	if (on) {
		ret = pm_runtime_get_sync(dev);
		if (ret < 0)
			pm_runtime_put_noidle(dev);
	} else {
		pm_runtime_mark_last_busy(dev);
		ret = pm_runtime_put_autosuspend(dev);
	}

	return ret;
}

static
int ads1015_get_adc_result(struct ads1015_data *data, int chan, int *val)
{
	int ret, pga, dr, conv_time;
	bool change;

	if (chan < 0 || chan >= ADS1015_CHANNELS)
		return -EINVAL;

	pga = data->channel_data[chan].pga;
	dr = data->channel_data[chan].data_rate;

	ret = regmap_update_bits_check(data->regmap, ADS1015_CFG_REG,
				       ADS1015_CFG_MUX_MASK |
				       ADS1015_CFG_PGA_MASK,
				       chan << ADS1015_CFG_MUX_SHIFT |
				       pga << ADS1015_CFG_PGA_SHIFT,
				       &change);
	if (ret < 0)
		return ret;

	if (change) {
		conv_time = DIV_ROUND_UP(USEC_PER_SEC, ads1015_data_rate[dr]);
		usleep_range(conv_time, conv_time + 1);
	}

	return regmap_read(data->regmap, ADS1015_CONV_REG, val);
}

static irqreturn_t ads1015_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ads1015_data *data = iio_priv(indio_dev);
	s16 buf[8]; /* 1x s16 ADC val + 3x s16 padding +  4x s16 timestamp */
	int chan, ret, res;

	memset(buf, 0, sizeof(buf));

	mutex_lock(&data->lock);
	chan = find_first_bit(indio_dev->active_scan_mask,
			      indio_dev->masklength);
	ret = ads1015_get_adc_result(data, chan, &res);
	if (ret < 0) {
		mutex_unlock(&data->lock);
		goto err;
	}

	buf[0] = res;
	mutex_unlock(&data->lock);

	iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());

err:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static int ads1015_set_scale(struct ads1015_data *data, int chan,
			     int scale, int uscale)
{
	int i, ret, rindex = -1;

	for (i = 0; i < ARRAY_SIZE(ads1015_scale); i++)
		if (ads1015_scale[i].scale == scale &&
		    ads1015_scale[i].uscale == uscale) {
			rindex = i;
			break;
		}
	if (rindex < 0)
		return -EINVAL;

	ret = regmap_update_bits(data->regmap, ADS1015_CFG_REG,
				 ADS1015_CFG_PGA_MASK,
				 rindex << ADS1015_CFG_PGA_SHIFT);
	if (ret < 0)
		return ret;

	data->channel_data[chan].pga = rindex;

	return 0;
}

static int ads1015_set_data_rate(struct ads1015_data *data, int chan, int rate)
{
	int i, ret, rindex = -1;

	for (i = 0; i < ARRAY_SIZE(ads1015_data_rate); i++)
		if (ads1015_data_rate[i] == rate) {
			rindex = i;
			break;
		}
	if (rindex < 0)
		return -EINVAL;

	ret = regmap_update_bits(data->regmap, ADS1015_CFG_REG,
				 ADS1015_CFG_DR_MASK,
				 rindex << ADS1015_CFG_DR_SHIFT);
	if (ret < 0)
		return ret;

	data->channel_data[chan].data_rate = rindex;

	return 0;
}

static int ads1015_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan, int *val,
			    int *val2, long mask)
{
	int ret, idx;
	struct ads1015_data *data = iio_priv(indio_dev);

	mutex_lock(&indio_dev->mlock);
	mutex_lock(&data->lock);
	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (iio_buffer_enabled(indio_dev)) {
			ret = -EBUSY;
			break;
		}

		ret = ads1015_set_power_state(data, true);
		if (ret < 0)
			break;

		ret = ads1015_get_adc_result(data, chan->address, val);
		if (ret < 0) {
			ads1015_set_power_state(data, false);
			break;
		}

		/* 12 bit res, D0 is bit 4 in conversion register */
		*val = sign_extend32(*val >> 4, 11);

		ret = ads1015_set_power_state(data, false);
		if (ret < 0)
			break;

		ret = IIO_VAL_INT;
		break;
	case IIO_CHAN_INFO_SCALE:
		idx = data->channel_data[chan->address].pga;
		*val = ads1015_scale[idx].scale;
		*val2 = ads1015_scale[idx].uscale;
		ret = IIO_VAL_INT_PLUS_MICRO;
		break;
	case IIO_CHAN_INFO_SAMP_FREQ:
		idx = data->channel_data[chan->address].data_rate;
		*val = ads1015_data_rate[idx];
		ret = IIO_VAL_INT;
		break;
	default:
		ret = -EINVAL;
		break;
	}
	mutex_unlock(&data->lock);
	mutex_unlock(&indio_dev->mlock);

	return ret;
}

static int ads1015_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan, int val,
			     int val2, long mask)
{
	struct ads1015_data *data = iio_priv(indio_dev);
	int ret;

	mutex_lock(&data->lock);
	switch (mask) {
	case IIO_CHAN_INFO_SCALE:
		ret = ads1015_set_scale(data, chan->address, val, val2);
		break;
	case IIO_CHAN_INFO_SAMP_FREQ:
		ret = ads1015_set_data_rate(data, chan->address, val);
		break;
	default:
		ret = -EINVAL;
		break;
	}
	mutex_unlock(&data->lock);

	return ret;
}

static int ads1015_buffer_preenable(struct iio_dev *indio_dev)
{
	return ads1015_set_power_state(iio_priv(indio_dev), true);
}

static int ads1015_buffer_postdisable(struct iio_dev *indio_dev)
{
	return ads1015_set_power_state(iio_priv(indio_dev), false);
}

static const struct iio_buffer_setup_ops ads1015_buffer_setup_ops = {
	.preenable	= ads1015_buffer_preenable,
	.postenable	= iio_triggered_buffer_postenable,
	.predisable	= iio_triggered_buffer_predisable,
	.postdisable	= ads1015_buffer_postdisable,
	.validate_scan_mask = &iio_validate_scan_mask_onehot,
};

static IIO_CONST_ATTR(scale_available, "3 2 1 0.5 0.25 0.125");
static IIO_CONST_ATTR(sampling_frequency_available,
		      "128 250 490 920 1600 2400 3300");

static struct attribute *ads1015_attributes[] = {
	&iio_const_attr_scale_available.dev_attr.attr,
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	NULL,
};

static const struct attribute_group ads1015_attribute_group = {
	.attrs = ads1015_attributes,
};

static const struct iio_info ads1015_info = {
	.driver_module	= THIS_MODULE,
	.read_raw	= ads1015_read_raw,
	.write_raw	= ads1015_write_raw,
	.attrs		= &ads1015_attribute_group,
};

#ifdef CONFIG_OF
static int ads1015_get_channels_config_of(struct i2c_client *client)
{
	struct ads1015_data *data = i2c_get_clientdata(client);
	struct device_node *node;

	if (!client->dev.of_node ||
	    !of_get_next_child(client->dev.of_node, NULL))
		return -EINVAL;

	for_each_child_of_node(client->dev.of_node, node) {
		u32 pval;
		unsigned int channel;
		unsigned int pga = ADS1015_DEFAULT_PGA;
		unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;

		if (of_property_read_u32(node, "reg", &pval)) {
			dev_err(&client->dev, "invalid reg on %s\n",
				node->full_name);
			continue;
		}

		channel = pval;
		if (channel >= ADS1015_CHANNELS) {
			dev_err(&client->dev,
				"invalid channel index %d on %s\n",
				channel, node->full_name);
			continue;
		}

		if (!of_property_read_u32(node, "ti,gain", &pval)) {
			pga = pval;
			if (pga > 6) {
				dev_err(&client->dev, "invalid gain on %s\n",
					node->full_name);
				return -EINVAL;
			}
		}

		if (!of_property_read_u32(node, "ti,datarate", &pval)) {
			data_rate = pval;
			if (data_rate > 7) {
				dev_err(&client->dev,
					"invalid data_rate on %s\n",
					node->full_name);
				return -EINVAL;
			}
		}

		data->channel_data[channel].pga = pga;
		data->channel_data[channel].data_rate = data_rate;
	}

	return 0;
}
#endif

static void ads1015_get_channels_config(struct i2c_client *client)
{
	unsigned int k;

	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct ads1015_data *data = iio_priv(indio_dev);
	struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);

	/* prefer platform data */
	if (pdata) {
		memcpy(data->channel_data, pdata->channel_data,
		       sizeof(data->channel_data));
		return;
	}

#ifdef CONFIG_OF
	if (!ads1015_get_channels_config_of(client))
		return;
#endif
	/* fallback on default configuration */
	for (k = 0; k < ADS1015_CHANNELS; ++k) {
		data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
		data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
	}
}

static int ads1015_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct iio_dev *indio_dev;
	struct ads1015_data *data;
	int ret;

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

	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);

	mutex_init(&data->lock);

	indio_dev->dev.parent = &client->dev;
	indio_dev->info = &ads1015_info;
	indio_dev->name = ADS1015_DRV_NAME;
	indio_dev->channels = ads1015_channels;
	indio_dev->num_channels = ARRAY_SIZE(ads1015_channels);
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* we need to keep this ABI the same as used by hwmon ADS1015 driver */
	ads1015_get_channels_config(client);

	data->regmap = devm_regmap_init_i2c(client, &ads1015_regmap_config);
	if (IS_ERR(data->regmap)) {
		dev_err(&client->dev, "Failed to allocate register map\n");
		return PTR_ERR(data->regmap);
	}

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
					 ads1015_trigger_handler,
					 &ads1015_buffer_setup_ops);
	if (ret < 0) {
		dev_err(&client->dev, "iio triggered buffer setup failed\n");
		return ret;
	}
	ret = pm_runtime_set_active(&client->dev);
	if (ret)
		goto err_buffer_cleanup;
	pm_runtime_set_autosuspend_delay(&client->dev, ADS1015_SLEEP_DELAY_MS);
	pm_runtime_use_autosuspend(&client->dev);
	pm_runtime_enable(&client->dev);

	ret = iio_device_register(indio_dev);
	if (ret < 0) {
		dev_err(&client->dev, "Failed to register IIO device\n");
		goto err_buffer_cleanup;
	}

	return 0;

err_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);

	return ret;
}

static int ads1015_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct ads1015_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);

	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);
	pm_runtime_put_noidle(&client->dev);

	iio_triggered_buffer_cleanup(indio_dev);

	/* power down single shot mode */
	return regmap_update_bits(data->regmap, ADS1015_CFG_REG,
				  ADS1015_CFG_MOD_MASK,
				  ADS1015_SINGLESHOT << ADS1015_CFG_MOD_SHIFT);
}

#ifdef CONFIG_PM
static int ads1015_runtime_suspend(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct ads1015_data *data = iio_priv(indio_dev);

	return regmap_update_bits(data->regmap, ADS1015_CFG_REG,
				  ADS1015_CFG_MOD_MASK,
				  ADS1015_SINGLESHOT << ADS1015_CFG_MOD_SHIFT);
}

static int ads1015_runtime_resume(struct device *dev)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
	struct ads1015_data *data = iio_priv(indio_dev);

	return regmap_update_bits(data->regmap, ADS1015_CFG_REG,
				  ADS1015_CFG_MOD_MASK,
				  ADS1015_CONTINUOUS << ADS1015_CFG_MOD_SHIFT);
}
#endif

static const struct dev_pm_ops ads1015_pm_ops = {
	SET_RUNTIME_PM_OPS(ads1015_runtime_suspend,
			   ads1015_runtime_resume, NULL)
};

static const struct i2c_device_id ads1015_id[] = {
	{"ads1015", 0},
	{}
};
MODULE_DEVICE_TABLE(i2c, ads1015_id);

static struct i2c_driver ads1015_driver = {
	.driver = {
		.name = ADS1015_DRV_NAME,
		.pm = &ads1015_pm_ops,
	},
	.probe		= ads1015_probe,
	.remove		= ads1015_remove,
	.id_table	= ads1015_id,
};

module_i2c_driver(ads1015_driver);

MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("Texas Instruments ADS1015 ADC driver");
MODULE_LICENSE("GPL v2");