Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  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
/*
 * srf08.c - Support for Devantech SRFxx ultrasonic ranger
 *           with i2c interface
 * actually supported are srf02, srf08, srf10
 *
 * Copyright (c) 2016, 2017 Andreas Klinger <ak@it-klinger.de>
 *
 * 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.
 *
 * For details about the device see:
 * http://www.robot-electronics.co.uk/htm/srf08tech.html
 * http://www.robot-electronics.co.uk/htm/srf10tech.htm
 * http://www.robot-electronics.co.uk/htm/srf02tech.htm
 */

#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/bitops.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

/* registers of SRF08 device */
#define SRF08_WRITE_COMMAND	0x00	/* Command Register */
#define SRF08_WRITE_MAX_GAIN	0x01	/* Max Gain Register: 0 .. 31 */
#define SRF08_WRITE_RANGE	0x02	/* Range Register: 0 .. 255 */
#define SRF08_READ_SW_REVISION	0x00	/* Software Revision */
#define SRF08_READ_LIGHT	0x01	/* Light Sensor during last echo */
#define SRF08_READ_ECHO_1_HIGH	0x02	/* Range of first echo received */
#define SRF08_READ_ECHO_1_LOW	0x03	/* Range of first echo received */

#define SRF08_CMD_RANGING_CM	0x51	/* Ranging Mode - Result in cm */

enum srf08_sensor_type {
	SRF02,
	SRF08,
	SRF10,
	SRF_MAX_TYPE
};

struct srf08_chip_info {
	const int		*sensitivity_avail;
	int			num_sensitivity_avail;
	int			sensitivity_default;

	/* default value of Range in mm */
	int			range_default;
};

struct srf08_data {
	struct i2c_client	*client;

	/*
	 * Gain in the datasheet is called sensitivity here to distinct it
	 * from the gain used with amplifiers of adc's
	 */
	int			sensitivity;

	/* max. Range in mm */
	int			range_mm;
	struct mutex		lock;

	/*
	 * triggered buffer
	 * 1x16-bit channel + 3x16 padding + 4x16 timestamp
	 */
	s16			buffer[8];

	/* Sensor-Type */
	enum srf08_sensor_type	sensor_type;

	/* Chip-specific information */
	const struct srf08_chip_info	*chip_info;
};

/*
 * in the documentation one can read about the "Gain" of the device
 * which is used here for amplifying the signal and filtering out unwanted
 * ones.
 * But with ADC's this term is already used differently and that's why it
 * is called "Sensitivity" here.
 */
static const struct srf08_chip_info srf02_chip_info = {
	.sensitivity_avail	= NULL,
	.num_sensitivity_avail	= 0,
	.sensitivity_default	= 0,

	.range_default		= 0,
};

static const int srf08_sensitivity_avail[] = {
	 94,  97, 100, 103, 107, 110, 114, 118,
	123, 128, 133, 139, 145, 152, 159, 168,
	177, 187, 199, 212, 227, 245, 265, 288,
	317, 352, 395, 450, 524, 626, 777, 1025
	};

static const struct srf08_chip_info srf08_chip_info = {
	.sensitivity_avail	= srf08_sensitivity_avail,
	.num_sensitivity_avail	= ARRAY_SIZE(srf08_sensitivity_avail),
	.sensitivity_default	= 1025,

	.range_default		= 6020,
};

static const int srf10_sensitivity_avail[] = {
	 40,  40,  50,  60,  70,  80, 100, 120,
	140, 200, 250, 300, 350, 400, 500, 600,
	700,
	};

static const struct srf08_chip_info srf10_chip_info = {
	.sensitivity_avail	= srf10_sensitivity_avail,
	.num_sensitivity_avail	= ARRAY_SIZE(srf10_sensitivity_avail),
	.sensitivity_default	= 700,

	.range_default		= 6020,
};

static int srf08_read_ranging(struct srf08_data *data)
{
	struct i2c_client *client = data->client;
	int ret, i;
	int waittime;

	mutex_lock(&data->lock);

	ret = i2c_smbus_write_byte_data(data->client,
			SRF08_WRITE_COMMAND, SRF08_CMD_RANGING_CM);
	if (ret < 0) {
		dev_err(&client->dev, "write command - err: %d\n", ret);
		mutex_unlock(&data->lock);
		return ret;
	}

	/*
	 * we read here until a correct version number shows up as
	 * suggested by the documentation
	 *
	 * with an ultrasonic speed of 343 m/s and a roundtrip of it
	 * sleep the expected duration and try to read from the device
	 * if nothing useful is read try it in a shorter grid
	 *
	 * polling for not more than 20 ms should be enough
	 */
	waittime = 1 + data->range_mm / 172;
	msleep(waittime);
	for (i = 0; i < 4; i++) {
		ret = i2c_smbus_read_byte_data(data->client,
						SRF08_READ_SW_REVISION);

		/* check if a valid version number is read */
		if (ret < 255 && ret > 0)
			break;
		msleep(5);
	}

	if (ret >= 255 || ret <= 0) {
		dev_err(&client->dev, "device not ready\n");
		mutex_unlock(&data->lock);
		return -EIO;
	}

	ret = i2c_smbus_read_word_swapped(data->client,
						SRF08_READ_ECHO_1_HIGH);
	if (ret < 0) {
		dev_err(&client->dev, "cannot read distance: ret=%d\n", ret);
		mutex_unlock(&data->lock);
		return ret;
	}

	mutex_unlock(&data->lock);

	return ret;
}

static irqreturn_t srf08_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct srf08_data *data = iio_priv(indio_dev);
	s16 sensor_data;

	sensor_data = srf08_read_ranging(data);
	if (sensor_data < 0)
		goto err;

	mutex_lock(&data->lock);

	data->buffer[0] = sensor_data;
	iio_push_to_buffers_with_timestamp(indio_dev,
						data->buffer, pf->timestamp);

	mutex_unlock(&data->lock);
err:
	iio_trigger_notify_done(indio_dev->trig);
	return IRQ_HANDLED;
}

static int srf08_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *channel, int *val,
			    int *val2, long mask)
{
	struct srf08_data *data = iio_priv(indio_dev);
	int ret;

	if (channel->type != IIO_DISTANCE)
		return -EINVAL;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = srf08_read_ranging(data);
		if (ret < 0)
			return ret;
		*val = ret;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		/* 1 LSB is 1 cm */
		*val = 0;
		*val2 = 10000;
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static ssize_t srf08_show_range_mm_available(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "[0.043 0.043 11.008]\n");
}

static IIO_DEVICE_ATTR(sensor_max_range_available, S_IRUGO,
				srf08_show_range_mm_available, NULL, 0);

static ssize_t srf08_show_range_mm(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct srf08_data *data = iio_priv(indio_dev);

	return sprintf(buf, "%d.%03d\n", data->range_mm / 1000,
						data->range_mm % 1000);
}

/*
 * set the range of the sensor to an even multiple of 43 mm
 * which corresponds to 1 LSB in the register
 *
 * register value    corresponding range
 *         0x00             43 mm
 *         0x01             86 mm
 *         0x02            129 mm
 *         ...
 *         0xFF          11008 mm
 */
static ssize_t srf08_write_range_mm(struct srf08_data *data, unsigned int val)
{
	int ret;
	struct i2c_client *client = data->client;
	unsigned int mod;
	u8 regval;

	ret = val / 43 - 1;
	mod = val % 43;

	if (mod || (ret < 0) || (ret > 255))
		return -EINVAL;

	regval = ret;

	mutex_lock(&data->lock);

	ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_RANGE, regval);
	if (ret < 0) {
		dev_err(&client->dev, "write_range - err: %d\n", ret);
		mutex_unlock(&data->lock);
		return ret;
	}

	data->range_mm = val;

	mutex_unlock(&data->lock);

	return 0;
}

static ssize_t srf08_store_range_mm(struct device *dev,
					struct device_attribute *attr,
					const char *buf, size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct srf08_data *data = iio_priv(indio_dev);
	int ret;
	int integer, fract;

	ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
	if (ret)
		return ret;

	ret = srf08_write_range_mm(data, integer * 1000 + fract);
	if (ret < 0)
		return ret;

	return len;
}

static IIO_DEVICE_ATTR(sensor_max_range, S_IRUGO | S_IWUSR,
			srf08_show_range_mm, srf08_store_range_mm, 0);

static ssize_t srf08_show_sensitivity_available(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	int i, len = 0;
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct srf08_data *data = iio_priv(indio_dev);

	for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
		if (data->chip_info->sensitivity_avail[i])
			len += sprintf(buf + len, "%d ",
				data->chip_info->sensitivity_avail[i]);

	len += sprintf(buf + len, "\n");

	return len;
}

static IIO_DEVICE_ATTR(sensor_sensitivity_available, S_IRUGO,
				srf08_show_sensitivity_available, NULL, 0);

static ssize_t srf08_show_sensitivity(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct srf08_data *data = iio_priv(indio_dev);
	int len;

	len = sprintf(buf, "%d\n", data->sensitivity);

	return len;
}

static ssize_t srf08_write_sensitivity(struct srf08_data *data,
							unsigned int val)
{
	struct i2c_client *client = data->client;
	int ret, i;
	u8 regval;

	if (!val)
		return -EINVAL;

	for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
		if (val && (val == data->chip_info->sensitivity_avail[i])) {
			regval = i;
			break;
		}

	if (i >= data->chip_info->num_sensitivity_avail)
		return -EINVAL;

	mutex_lock(&data->lock);

	ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_MAX_GAIN, regval);
	if (ret < 0) {
		dev_err(&client->dev, "write_sensitivity - err: %d\n", ret);
		mutex_unlock(&data->lock);
		return ret;
	}

	data->sensitivity = val;

	mutex_unlock(&data->lock);

	return 0;
}

static ssize_t srf08_store_sensitivity(struct device *dev,
						struct device_attribute *attr,
						const char *buf, size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct srf08_data *data = iio_priv(indio_dev);
	int ret;
	unsigned int val;

	ret = kstrtouint(buf, 10, &val);
	if (ret)
		return ret;

	ret = srf08_write_sensitivity(data, val);
	if (ret < 0)
		return ret;

	return len;
}

static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
			srf08_show_sensitivity, srf08_store_sensitivity, 0);

static struct attribute *srf08_attributes[] = {
	&iio_dev_attr_sensor_max_range.dev_attr.attr,
	&iio_dev_attr_sensor_max_range_available.dev_attr.attr,
	&iio_dev_attr_sensor_sensitivity.dev_attr.attr,
	&iio_dev_attr_sensor_sensitivity_available.dev_attr.attr,
	NULL,
};

static const struct attribute_group srf08_attribute_group = {
	.attrs = srf08_attributes,
};

static const struct iio_chan_spec srf08_channels[] = {
	{
		.type = IIO_DISTANCE,
		.info_mask_separate =
				BIT(IIO_CHAN_INFO_RAW) |
				BIT(IIO_CHAN_INFO_SCALE),
		.scan_index = 0,
		.scan_type = {
			.sign = 's',
			.realbits = 16,
			.storagebits = 16,
			.endianness = IIO_CPU,
		},
	},
	IIO_CHAN_SOFT_TIMESTAMP(1),
};

static const struct iio_info srf08_info = {
	.read_raw = srf08_read_raw,
	.attrs = &srf08_attribute_group,
	.driver_module = THIS_MODULE,
};

/*
 * srf02 don't have an adjustable range or sensitivity,
 * so we don't need attributes at all
 */
static const struct iio_info srf02_info = {
	.read_raw = srf08_read_raw,
	.driver_module = THIS_MODULE,
};

static int srf08_probe(struct i2c_client *client,
					 const struct i2c_device_id *id)
{
	struct iio_dev *indio_dev;
	struct srf08_data *data;
	int ret;

	if (!i2c_check_functionality(client->adapter,
					I2C_FUNC_SMBUS_READ_BYTE_DATA |
					I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
					I2C_FUNC_SMBUS_READ_WORD_DATA))
		return -ENODEV;

	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->sensor_type = (enum srf08_sensor_type)id->driver_data;

	switch (data->sensor_type) {
	case SRF02:
		data->chip_info = &srf02_chip_info;
		indio_dev->info = &srf02_info;
		break;
	case SRF08:
		data->chip_info = &srf08_chip_info;
		indio_dev->info = &srf08_info;
		break;
	case SRF10:
		data->chip_info = &srf10_chip_info;
		indio_dev->info = &srf08_info;
		break;
	default:
		return -EINVAL;
	}

	indio_dev->name = id->name;
	indio_dev->dev.parent = &client->dev;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = srf08_channels;
	indio_dev->num_channels = ARRAY_SIZE(srf08_channels);

	mutex_init(&data->lock);

	ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
			iio_pollfunc_store_time, srf08_trigger_handler, NULL);
	if (ret < 0) {
		dev_err(&client->dev, "setup of iio triggered buffer failed\n");
		return ret;
	}

	if (data->chip_info->range_default) {
		/*
		 * set default range of device in mm here
		 * these register values cannot be read from the hardware
		 * therefore set driver specific default values
		 *
		 * srf02 don't have a default value so it'll be omitted
		 */
		ret = srf08_write_range_mm(data,
					data->chip_info->range_default);
		if (ret < 0)
			return ret;
	}

	if (data->chip_info->sensitivity_default) {
		/*
		 * set default sensitivity of device here
		 * these register values cannot be read from the hardware
		 * therefore set driver specific default values
		 *
		 * srf02 don't have a default value so it'll be omitted
		 */
		ret = srf08_write_sensitivity(data,
				data->chip_info->sensitivity_default);
		if (ret < 0)
			return ret;
	}

	return devm_iio_device_register(&client->dev, indio_dev);
}

static const struct of_device_id of_srf08_match[] = {
	{ .compatible = "devantech,srf02", (void *)SRF02},
	{ .compatible = "devantech,srf08", (void *)SRF08},
	{ .compatible = "devantech,srf10", (void *)SRF10},
	{},
};

MODULE_DEVICE_TABLE(of, of_srf08_match);

static const struct i2c_device_id srf08_id[] = {
	{ "srf02", SRF02 },
	{ "srf08", SRF08 },
	{ "srf10", SRF10 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, srf08_id);

static struct i2c_driver srf08_driver = {
	.driver = {
		.name	= "srf08",
		.of_match_table	= of_srf08_match,
	},
	.probe = srf08_probe,
	.id_table = srf08_id,
};
module_i2c_driver(srf08_driver);

MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
MODULE_DESCRIPTION("Devantech SRF02/SRF08/SRF10 i2c ultrasonic ranger driver");
MODULE_LICENSE("GPL");