summaryrefslogtreecommitdiffstats
path: root/drivers/iio/chemical/ccs811.c
blob: 80ef1aa9aae3b0482c76f549ff6cf993cc91e640 (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * ccs811.c - Support for AMS CCS811 VOC Sensor
 *
 * Copyright (C) 2017 Narcisa Vasile <narcisaanamaria12@gmail.com>
 *
 * Datasheet: ams.com/content/download/951091/2269479/CCS811_DS000459_3-00.pdf
 *
 * IIO driver for AMS CCS811 (I2C address 0x5A/0x5B set by ADDR Low/High)
 *
 * TODO:
 * 1. Make the drive mode selectable form userspace
 * 2. Add support for interrupts
 * 3. Adjust time to wait for data to be ready based on selected operation mode
 * 4. Read error register and put the information in logs
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/module.h>

#define CCS811_STATUS		0x00
#define CCS811_MEAS_MODE	0x01
#define CCS811_ALG_RESULT_DATA	0x02
#define CCS811_RAW_DATA		0x03
#define CCS811_HW_ID		0x20
#define CCS811_HW_ID_VALUE	0x81
#define CCS811_HW_VERSION	0x21
#define CCS811_HW_VERSION_VALUE	0x10
#define CCS811_HW_VERSION_MASK	0xF0
#define CCS811_ERR		0xE0
/* Used to transition from boot to application mode */
#define CCS811_APP_START	0xF4
#define CCS811_SW_RESET		0xFF

/* Status register flags */
#define CCS811_STATUS_ERROR		BIT(0)
#define CCS811_STATUS_DATA_READY	BIT(3)
#define CCS811_STATUS_APP_VALID_MASK	BIT(4)
#define CCS811_STATUS_APP_VALID_LOADED	BIT(4)
/*
 * Value of FW_MODE bit of STATUS register describes the sensor's state:
 * 0: Firmware is in boot mode, this allows new firmware to be loaded
 * 1: Firmware is in application mode. CCS811 is ready to take ADC measurements
 */
#define CCS811_STATUS_FW_MODE_MASK	BIT(7)
#define CCS811_STATUS_FW_MODE_APPLICATION	BIT(7)

/* Measurement modes */
#define CCS811_MODE_IDLE	0x00
#define CCS811_MODE_IAQ_1SEC	0x10
#define CCS811_MODE_IAQ_10SEC	0x20
#define CCS811_MODE_IAQ_60SEC	0x30
#define CCS811_MODE_RAW_DATA	0x40

#define CCS811_MEAS_MODE_INTERRUPT	BIT(3)

#define CCS811_VOLTAGE_MASK	0x3FF

struct ccs811_reading {
	__be16 co2;
	__be16 voc;
	u8 status;
	u8 error;
	__be16 raw_data;
} __attribute__((__packed__));

struct ccs811_data {
	struct i2c_client *client;
	struct mutex lock; /* Protect readings */
	struct ccs811_reading buffer;
	struct iio_trigger *drdy_trig;
	struct gpio_desc *wakeup_gpio;
	bool drdy_trig_on;
	/* Ensures correct alignment of timestamp if present */
	struct {
		s16 channels[2];
		s64 ts __aligned(8);
	} scan;
};

static const struct iio_chan_spec ccs811_channels[] = {
	{
		.type = IIO_CURRENT,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				      BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = -1,
	}, {
		.type = IIO_VOLTAGE,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				      BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = -1,
	}, {
		.type = IIO_CONCENTRATION,
		.channel2 = IIO_MOD_CO2,
		.modified = 1,
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
				      BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 0,
		.scan_type = {
			.sign = 'u',
			.realbits = 16,
			.storagebits = 16,
			.endianness = IIO_BE,
		},
	}, {
		.type = IIO_CONCENTRATION,
		.channel2 = IIO_MOD_VOC,
		.modified = 1,
		.info_mask_separate =  BIT(IIO_CHAN_INFO_RAW) |
				       BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 1,
		.scan_type = {
			.sign = 'u',
			.realbits = 16,
			.storagebits = 16,
			.endianness = IIO_BE,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(2),
};

/*
 * The CCS811 powers-up in boot mode. A setup write to CCS811_APP_START will
 * transition the sensor to application mode.
 */
static int ccs811_start_sensor_application(struct i2c_client *client)
{
	int ret;

	ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
	if (ret < 0)
		return ret;

	if ((ret & CCS811_STATUS_FW_MODE_APPLICATION))
		return 0;

	if ((ret & CCS811_STATUS_APP_VALID_MASK) !=
	    CCS811_STATUS_APP_VALID_LOADED)
		return -EIO;

	ret = i2c_smbus_write_byte(client, CCS811_APP_START);
	if (ret < 0)
		return ret;

	ret = i2c_smbus_read_byte_data(client, CCS811_STATUS);
	if (ret < 0)
		return ret;

	if ((ret & CCS811_STATUS_FW_MODE_MASK) !=
	    CCS811_STATUS_FW_MODE_APPLICATION) {
		dev_err(&client->dev, "Application failed to start. Sensor is still in boot mode.\n");
		return -EIO;
	}

	return 0;
}

static int ccs811_setup(struct i2c_client *client)
{
	int ret;

	ret = ccs811_start_sensor_application(client);
	if (ret < 0)
		return ret;

	return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
					 CCS811_MODE_IAQ_1SEC);
}

static void ccs811_set_wakeup(struct ccs811_data *data, bool enable)
{
	if (!data->wakeup_gpio)
		return;

	gpiod_set_value(data->wakeup_gpio, enable);

	if (enable)
		usleep_range(50, 60);
	else
		usleep_range(20, 30);
}

static int ccs811_get_measurement(struct ccs811_data *data)
{
	int ret, tries = 11;

	ccs811_set_wakeup(data, true);

	/* Maximum waiting time: 1s, as measurements are made every second */
	while (tries-- > 0) {
		ret = i2c_smbus_read_byte_data(data->client, CCS811_STATUS);
		if (ret < 0)
			return ret;

		if ((ret & CCS811_STATUS_DATA_READY) || tries == 0)
			break;
		msleep(100);
	}
	if (!(ret & CCS811_STATUS_DATA_READY))
		return -EIO;

	ret = i2c_smbus_read_i2c_block_data(data->client,
					    CCS811_ALG_RESULT_DATA, 8,
					    (char *)&data->buffer);
	ccs811_set_wakeup(data, false);

	return ret;
}

static int ccs811_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct ccs811_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = iio_device_claim_direct_mode(indio_dev);
		if (ret)
			return ret;
		mutex_lock(&data->lock);
		ret = ccs811_get_measurement(data);
		if (ret < 0) {
			mutex_unlock(&data->lock);
			iio_device_release_direct_mode(indio_dev);
			return ret;
		}

		switch (chan->type) {
		case IIO_VOLTAGE:
			*val = be16_to_cpu(data->buffer.raw_data) &
					   CCS811_VOLTAGE_MASK;
			ret = IIO_VAL_INT;
			break;
		case IIO_CURRENT:
			*val = be16_to_cpu(data->buffer.raw_data) >> 10;
			ret = IIO_VAL_INT;
			break;
		case IIO_CONCENTRATION:
			switch (chan->channel2) {
			case IIO_MOD_CO2:
				*val = be16_to_cpu(data->buffer.co2);
				ret =  IIO_VAL_INT;
				break;
			case IIO_MOD_VOC:
				*val = be16_to_cpu(data->buffer.voc);
				ret = IIO_VAL_INT;
				break;
			default:
				ret = -EINVAL;
			}
			break;
		default:
			ret = -EINVAL;
		}
		mutex_unlock(&data->lock);
		iio_device_release_direct_mode(indio_dev);

		return ret;

	case IIO_CHAN_INFO_SCALE:
		switch (chan->type) {
		case IIO_VOLTAGE:
			*val = 1;
			*val2 = 612903;
			return IIO_VAL_INT_PLUS_MICRO;
		case IIO_CURRENT:
			*val = 0;
			*val2 = 1000;
			return IIO_VAL_INT_PLUS_MICRO;
		case IIO_CONCENTRATION:
			switch (chan->channel2) {
			case IIO_MOD_CO2:
				*val = 0;
				*val2 = 100;
				return IIO_VAL_INT_PLUS_MICRO;
			case IIO_MOD_VOC:
				*val = 0;
				*val2 = 100;
				return IIO_VAL_INT_PLUS_NANO;
			default:
				return -EINVAL;
			}
		default:
			return -EINVAL;
		}
	default:
		return -EINVAL;
	}
}

static const struct iio_info ccs811_info = {
	.read_raw = ccs811_read_raw,
};

static int ccs811_set_trigger_state(struct iio_trigger *trig,
				    bool state)
{
	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
	struct ccs811_data *data = iio_priv(indio_dev);
	int ret;

	ret = i2c_smbus_read_byte_data(data->client, CCS811_MEAS_MODE);
	if (ret < 0)
		return ret;

	if (state)
		ret |= CCS811_MEAS_MODE_INTERRUPT;
	else
		ret &= ~CCS811_MEAS_MODE_INTERRUPT;

	data->drdy_trig_on = state;

	return i2c_smbus_write_byte_data(data->client, CCS811_MEAS_MODE, ret);
}

static const struct iio_trigger_ops ccs811_trigger_ops = {
	.set_trigger_state = ccs811_set_trigger_state,
};

static irqreturn_t ccs811_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ccs811_data *data = iio_priv(indio_dev);
	struct i2c_client *client = data->client;
	int ret;

	ret = i2c_smbus_read_i2c_block_data(client, CCS811_ALG_RESULT_DATA,
					    sizeof(data->scan.channels),
					    (u8 *)data->scan.channels);
	if (ret != 4) {
		dev_err(&client->dev, "cannot read sensor data\n");
		goto err;
	}

	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
					   iio_get_time_ns(indio_dev));

err:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static irqreturn_t ccs811_data_rdy_trigger_poll(int irq, void *private)
{
	struct iio_dev *indio_dev = private;
	struct ccs811_data *data = iio_priv(indio_dev);

	if (data->drdy_trig_on)
		iio_trigger_poll(data->drdy_trig);

	return IRQ_HANDLED;
}

static int ccs811_reset(struct i2c_client *client)
{
	struct gpio_desc *reset_gpio;
	int ret;

	reset_gpio = devm_gpiod_get_optional(&client->dev, "reset",
					     GPIOD_OUT_LOW);
	if (IS_ERR(reset_gpio))
		return PTR_ERR(reset_gpio);

	/* Try to reset using nRESET pin if available else do SW reset */
	if (reset_gpio) {
		gpiod_set_value(reset_gpio, 1);
		usleep_range(20, 30);
		gpiod_set_value(reset_gpio, 0);
	} else {
		/*
		 * As per the datasheet, this sequence of values needs to be
		 * written to the SW_RESET register for triggering the soft
		 * reset in the device and placing it in boot mode.
		 */
		static const u8 reset_seq[] = {
			0x11, 0xE5, 0x72, 0x8A,
		};

		ret = i2c_smbus_write_i2c_block_data(client, CCS811_SW_RESET,
					     sizeof(reset_seq), reset_seq);
		if (ret < 0) {
			dev_err(&client->dev, "Failed to reset sensor\n");
			return ret;
		}
	}

	/* tSTART delay required after reset */
	usleep_range(1000, 2000);

	return 0;
}

static int ccs811_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct iio_dev *indio_dev;
	struct ccs811_data *data;
	int ret;

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WRITE_BYTE
				     | I2C_FUNC_SMBUS_BYTE_DATA
				     | I2C_FUNC_SMBUS_READ_I2C_BLOCK))
		return -EOPNOTSUPP;

	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);
	data->client = client;

	data->wakeup_gpio = devm_gpiod_get_optional(&client->dev, "wakeup",
						    GPIOD_OUT_HIGH);
	if (IS_ERR(data->wakeup_gpio))
		return PTR_ERR(data->wakeup_gpio);

	ccs811_set_wakeup(data, true);

	ret = ccs811_reset(client);
	if (ret) {
		ccs811_set_wakeup(data, false);
		return ret;
	}

	/* Check hardware id (should be 0x81 for this family of devices) */
	ret = i2c_smbus_read_byte_data(client, CCS811_HW_ID);
	if (ret < 0) {
		ccs811_set_wakeup(data, false);
		return ret;
	}

	if (ret != CCS811_HW_ID_VALUE) {
		dev_err(&client->dev, "hardware id doesn't match CCS81x\n");
		ccs811_set_wakeup(data, false);
		return -ENODEV;
	}

	ret = i2c_smbus_read_byte_data(client, CCS811_HW_VERSION);
	if (ret < 0) {
		ccs811_set_wakeup(data, false);
		return ret;
	}

	if ((ret & CCS811_HW_VERSION_MASK) != CCS811_HW_VERSION_VALUE) {
		dev_err(&client->dev, "no CCS811 sensor\n");
		ccs811_set_wakeup(data, false);
		return -ENODEV;
	}

	ret = ccs811_setup(client);
	if (ret < 0) {
		ccs811_set_wakeup(data, false);
		return ret;
	}

	ccs811_set_wakeup(data, false);

	mutex_init(&data->lock);

	indio_dev->name = id->name;
	indio_dev->info = &ccs811_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	indio_dev->channels = ccs811_channels;
	indio_dev->num_channels = ARRAY_SIZE(ccs811_channels);

	if (client->irq > 0) {
		ret = devm_request_threaded_irq(&client->dev, client->irq,
						ccs811_data_rdy_trigger_poll,
						NULL,
						IRQF_TRIGGER_FALLING |
						IRQF_ONESHOT,
						"ccs811_irq", indio_dev);
		if (ret) {
			dev_err(&client->dev, "irq request error %d\n", -ret);
			goto err_poweroff;
		}

		data->drdy_trig = devm_iio_trigger_alloc(&client->dev,
							 "%s-dev%d",
							 indio_dev->name,
							 iio_device_id(indio_dev));
		if (!data->drdy_trig) {
			ret = -ENOMEM;
			goto err_poweroff;
		}

		data->drdy_trig->ops = &ccs811_trigger_ops;
		iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
		ret = iio_trigger_register(data->drdy_trig);
		if (ret)
			goto err_poweroff;

		indio_dev->trig = iio_trigger_get(data->drdy_trig);
	}

	ret = iio_triggered_buffer_setup(indio_dev, NULL,
					 ccs811_trigger_handler, NULL);

	if (ret < 0) {
		dev_err(&client->dev, "triggered buffer setup failed\n");
		goto err_trigger_unregister;
	}

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

err_buffer_cleanup:
	iio_triggered_buffer_cleanup(indio_dev);
err_trigger_unregister:
	if (data->drdy_trig)
		iio_trigger_unregister(data->drdy_trig);
err_poweroff:
	i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE, CCS811_MODE_IDLE);

	return ret;
}

static int ccs811_remove(struct i2c_client *client)
{
	struct iio_dev *indio_dev = i2c_get_clientdata(client);
	struct ccs811_data *data = iio_priv(indio_dev);

	iio_device_unregister(indio_dev);
	iio_triggered_buffer_cleanup(indio_dev);
	if (data->drdy_trig)
		iio_trigger_unregister(data->drdy_trig);

	return i2c_smbus_write_byte_data(client, CCS811_MEAS_MODE,
					 CCS811_MODE_IDLE);
}

static const struct i2c_device_id ccs811_id[] = {
	{"ccs811", 0},
	{	}
};
MODULE_DEVICE_TABLE(i2c, ccs811_id);

static const struct of_device_id ccs811_dt_ids[] = {
	{ .compatible = "ams,ccs811" },
	{ }
};
MODULE_DEVICE_TABLE(of, ccs811_dt_ids);

static struct i2c_driver ccs811_driver = {
	.driver = {
		.name = "ccs811",
		.of_match_table = ccs811_dt_ids,
	},
	.probe = ccs811_probe,
	.remove = ccs811_remove,
	.id_table = ccs811_id,
};
module_i2c_driver(ccs811_driver);

MODULE_AUTHOR("Narcisa Vasile <narcisaanamaria12@gmail.com>");
MODULE_DESCRIPTION("CCS811 volatile organic compounds sensor");
MODULE_LICENSE("GPL v2");