1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * srf08.c - Support for Devantech SRFxx ultrasonic ranger
4 * with i2c interface
5 * actually supported are srf02, srf08, srf10
6 *
7 * Copyright (c) 2016, 2017 Andreas Klinger <ak@it-klinger.de>
8 *
9 * For details about the device see:
10 * https://www.robot-electronics.co.uk/htm/srf08tech.html
11 * https://www.robot-electronics.co.uk/htm/srf10tech.htm
12 * https://www.robot-electronics.co.uk/htm/srf02tech.htm
13 */
14
15 #include <linux/err.h>
16 #include <linux/i2c.h>
17 #include <linux/delay.h>
18 #include <linux/module.h>
19 #include <linux/bitops.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/buffer.h>
23 #include <linux/iio/trigger_consumer.h>
24 #include <linux/iio/triggered_buffer.h>
25
26 /* registers of SRF08 device */
27 #define SRF08_WRITE_COMMAND 0x00 /* Command Register */
28 #define SRF08_WRITE_MAX_GAIN 0x01 /* Max Gain Register: 0 .. 31 */
29 #define SRF08_WRITE_RANGE 0x02 /* Range Register: 0 .. 255 */
30 #define SRF08_READ_SW_REVISION 0x00 /* Software Revision */
31 #define SRF08_READ_LIGHT 0x01 /* Light Sensor during last echo */
32 #define SRF08_READ_ECHO_1_HIGH 0x02 /* Range of first echo received */
33 #define SRF08_READ_ECHO_1_LOW 0x03 /* Range of first echo received */
34
35 #define SRF08_CMD_RANGING_CM 0x51 /* Ranging Mode - Result in cm */
36
37 enum srf08_sensor_type {
38 SRF02,
39 SRF08,
40 SRF10,
41 SRF_MAX_TYPE
42 };
43
44 struct srf08_chip_info {
45 const int *sensitivity_avail;
46 int num_sensitivity_avail;
47 int sensitivity_default;
48
49 /* default value of Range in mm */
50 int range_default;
51 };
52
53 struct srf08_data {
54 struct i2c_client *client;
55
56 /*
57 * Gain in the datasheet is called sensitivity here to distinct it
58 * from the gain used with amplifiers of adc's
59 */
60 int sensitivity;
61
62 /* max. Range in mm */
63 int range_mm;
64 struct mutex lock;
65
66 /* Ensure timestamp is naturally aligned */
67 struct {
68 s16 chan;
69 s64 timestamp __aligned(8);
70 } scan;
71
72 /* Sensor-Type */
73 enum srf08_sensor_type sensor_type;
74
75 /* Chip-specific information */
76 const struct srf08_chip_info *chip_info;
77 };
78
79 /*
80 * in the documentation one can read about the "Gain" of the device
81 * which is used here for amplifying the signal and filtering out unwanted
82 * ones.
83 * But with ADC's this term is already used differently and that's why it
84 * is called "Sensitivity" here.
85 */
86 static const struct srf08_chip_info srf02_chip_info = {
87 .sensitivity_avail = NULL,
88 .num_sensitivity_avail = 0,
89 .sensitivity_default = 0,
90
91 .range_default = 0,
92 };
93
94 static const int srf08_sensitivity_avail[] = {
95 94, 97, 100, 103, 107, 110, 114, 118,
96 123, 128, 133, 139, 145, 152, 159, 168,
97 177, 187, 199, 212, 227, 245, 265, 288,
98 317, 352, 395, 450, 524, 626, 777, 1025
99 };
100
101 static const struct srf08_chip_info srf08_chip_info = {
102 .sensitivity_avail = srf08_sensitivity_avail,
103 .num_sensitivity_avail = ARRAY_SIZE(srf08_sensitivity_avail),
104 .sensitivity_default = 1025,
105
106 .range_default = 6020,
107 };
108
109 static const int srf10_sensitivity_avail[] = {
110 40, 40, 50, 60, 70, 80, 100, 120,
111 140, 200, 250, 300, 350, 400, 500, 600,
112 700,
113 };
114
115 static const struct srf08_chip_info srf10_chip_info = {
116 .sensitivity_avail = srf10_sensitivity_avail,
117 .num_sensitivity_avail = ARRAY_SIZE(srf10_sensitivity_avail),
118 .sensitivity_default = 700,
119
120 .range_default = 6020,
121 };
122
srf08_read_ranging(struct srf08_data * data)123 static int srf08_read_ranging(struct srf08_data *data)
124 {
125 struct i2c_client *client = data->client;
126 int ret, i;
127 int waittime;
128
129 mutex_lock(&data->lock);
130
131 ret = i2c_smbus_write_byte_data(data->client,
132 SRF08_WRITE_COMMAND, SRF08_CMD_RANGING_CM);
133 if (ret < 0) {
134 dev_err(&client->dev, "write command - err: %d\n", ret);
135 mutex_unlock(&data->lock);
136 return ret;
137 }
138
139 /*
140 * we read here until a correct version number shows up as
141 * suggested by the documentation
142 *
143 * with an ultrasonic speed of 343 m/s and a roundtrip of it
144 * sleep the expected duration and try to read from the device
145 * if nothing useful is read try it in a shorter grid
146 *
147 * polling for not more than 20 ms should be enough
148 */
149 waittime = 1 + data->range_mm / 172;
150 msleep(waittime);
151 for (i = 0; i < 4; i++) {
152 ret = i2c_smbus_read_byte_data(data->client,
153 SRF08_READ_SW_REVISION);
154
155 /* check if a valid version number is read */
156 if (ret < 255 && ret > 0)
157 break;
158 msleep(5);
159 }
160
161 if (ret >= 255 || ret <= 0) {
162 dev_err(&client->dev, "device not ready\n");
163 mutex_unlock(&data->lock);
164 return -EIO;
165 }
166
167 ret = i2c_smbus_read_word_swapped(data->client,
168 SRF08_READ_ECHO_1_HIGH);
169 if (ret < 0) {
170 dev_err(&client->dev, "cannot read distance: ret=%d\n", ret);
171 mutex_unlock(&data->lock);
172 return ret;
173 }
174
175 mutex_unlock(&data->lock);
176
177 return ret;
178 }
179
srf08_trigger_handler(int irq,void * p)180 static irqreturn_t srf08_trigger_handler(int irq, void *p)
181 {
182 struct iio_poll_func *pf = p;
183 struct iio_dev *indio_dev = pf->indio_dev;
184 struct srf08_data *data = iio_priv(indio_dev);
185 s16 sensor_data;
186
187 sensor_data = srf08_read_ranging(data);
188 if (sensor_data < 0)
189 goto err;
190
191 mutex_lock(&data->lock);
192
193 data->scan.chan = sensor_data;
194 iio_push_to_buffers_with_timestamp(indio_dev,
195 &data->scan, pf->timestamp);
196
197 mutex_unlock(&data->lock);
198 err:
199 iio_trigger_notify_done(indio_dev->trig);
200 return IRQ_HANDLED;
201 }
202
srf08_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * channel,int * val,int * val2,long mask)203 static int srf08_read_raw(struct iio_dev *indio_dev,
204 struct iio_chan_spec const *channel, int *val,
205 int *val2, long mask)
206 {
207 struct srf08_data *data = iio_priv(indio_dev);
208 int ret;
209
210 if (channel->type != IIO_DISTANCE)
211 return -EINVAL;
212
213 switch (mask) {
214 case IIO_CHAN_INFO_RAW:
215 ret = srf08_read_ranging(data);
216 if (ret < 0)
217 return ret;
218 *val = ret;
219 return IIO_VAL_INT;
220 case IIO_CHAN_INFO_SCALE:
221 /* 1 LSB is 1 cm */
222 *val = 0;
223 *val2 = 10000;
224 return IIO_VAL_INT_PLUS_MICRO;
225 default:
226 return -EINVAL;
227 }
228 }
229
srf08_show_range_mm_available(struct device * dev,struct device_attribute * attr,char * buf)230 static ssize_t srf08_show_range_mm_available(struct device *dev,
231 struct device_attribute *attr, char *buf)
232 {
233 return sprintf(buf, "[0.043 0.043 11.008]\n");
234 }
235
236 static IIO_DEVICE_ATTR(sensor_max_range_available, S_IRUGO,
237 srf08_show_range_mm_available, NULL, 0);
238
srf08_show_range_mm(struct device * dev,struct device_attribute * attr,char * buf)239 static ssize_t srf08_show_range_mm(struct device *dev,
240 struct device_attribute *attr, char *buf)
241 {
242 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
243 struct srf08_data *data = iio_priv(indio_dev);
244
245 return sprintf(buf, "%d.%03d\n", data->range_mm / 1000,
246 data->range_mm % 1000);
247 }
248
249 /*
250 * set the range of the sensor to an even multiple of 43 mm
251 * which corresponds to 1 LSB in the register
252 *
253 * register value corresponding range
254 * 0x00 43 mm
255 * 0x01 86 mm
256 * 0x02 129 mm
257 * ...
258 * 0xFF 11008 mm
259 */
srf08_write_range_mm(struct srf08_data * data,unsigned int val)260 static ssize_t srf08_write_range_mm(struct srf08_data *data, unsigned int val)
261 {
262 int ret;
263 struct i2c_client *client = data->client;
264 unsigned int mod;
265 u8 regval;
266
267 ret = val / 43 - 1;
268 mod = val % 43;
269
270 if (mod || (ret < 0) || (ret > 255))
271 return -EINVAL;
272
273 regval = ret;
274
275 mutex_lock(&data->lock);
276
277 ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_RANGE, regval);
278 if (ret < 0) {
279 dev_err(&client->dev, "write_range - err: %d\n", ret);
280 mutex_unlock(&data->lock);
281 return ret;
282 }
283
284 data->range_mm = val;
285
286 mutex_unlock(&data->lock);
287
288 return 0;
289 }
290
srf08_store_range_mm(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)291 static ssize_t srf08_store_range_mm(struct device *dev,
292 struct device_attribute *attr,
293 const char *buf, size_t len)
294 {
295 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
296 struct srf08_data *data = iio_priv(indio_dev);
297 int ret;
298 int integer, fract;
299
300 ret = iio_str_to_fixpoint(buf, 100, &integer, &fract);
301 if (ret)
302 return ret;
303
304 ret = srf08_write_range_mm(data, integer * 1000 + fract);
305 if (ret < 0)
306 return ret;
307
308 return len;
309 }
310
311 static IIO_DEVICE_ATTR(sensor_max_range, S_IRUGO | S_IWUSR,
312 srf08_show_range_mm, srf08_store_range_mm, 0);
313
srf08_show_sensitivity_available(struct device * dev,struct device_attribute * attr,char * buf)314 static ssize_t srf08_show_sensitivity_available(struct device *dev,
315 struct device_attribute *attr, char *buf)
316 {
317 int i, len = 0;
318 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
319 struct srf08_data *data = iio_priv(indio_dev);
320
321 for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
322 if (data->chip_info->sensitivity_avail[i])
323 len += sprintf(buf + len, "%d ",
324 data->chip_info->sensitivity_avail[i]);
325
326 len += sprintf(buf + len, "\n");
327
328 return len;
329 }
330
331 static IIO_DEVICE_ATTR(sensor_sensitivity_available, S_IRUGO,
332 srf08_show_sensitivity_available, NULL, 0);
333
srf08_show_sensitivity(struct device * dev,struct device_attribute * attr,char * buf)334 static ssize_t srf08_show_sensitivity(struct device *dev,
335 struct device_attribute *attr, char *buf)
336 {
337 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
338 struct srf08_data *data = iio_priv(indio_dev);
339 int len;
340
341 len = sprintf(buf, "%d\n", data->sensitivity);
342
343 return len;
344 }
345
srf08_write_sensitivity(struct srf08_data * data,unsigned int val)346 static ssize_t srf08_write_sensitivity(struct srf08_data *data,
347 unsigned int val)
348 {
349 struct i2c_client *client = data->client;
350 int ret, i;
351 u8 regval;
352
353 if (!val)
354 return -EINVAL;
355
356 for (i = 0; i < data->chip_info->num_sensitivity_avail; i++)
357 if (val == data->chip_info->sensitivity_avail[i]) {
358 regval = i;
359 break;
360 }
361
362 if (i >= data->chip_info->num_sensitivity_avail)
363 return -EINVAL;
364
365 mutex_lock(&data->lock);
366
367 ret = i2c_smbus_write_byte_data(client, SRF08_WRITE_MAX_GAIN, regval);
368 if (ret < 0) {
369 dev_err(&client->dev, "write_sensitivity - err: %d\n", ret);
370 mutex_unlock(&data->lock);
371 return ret;
372 }
373
374 data->sensitivity = val;
375
376 mutex_unlock(&data->lock);
377
378 return 0;
379 }
380
srf08_store_sensitivity(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)381 static ssize_t srf08_store_sensitivity(struct device *dev,
382 struct device_attribute *attr,
383 const char *buf, size_t len)
384 {
385 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
386 struct srf08_data *data = iio_priv(indio_dev);
387 int ret;
388 unsigned int val;
389
390 ret = kstrtouint(buf, 10, &val);
391 if (ret)
392 return ret;
393
394 ret = srf08_write_sensitivity(data, val);
395 if (ret < 0)
396 return ret;
397
398 return len;
399 }
400
401 static IIO_DEVICE_ATTR(sensor_sensitivity, S_IRUGO | S_IWUSR,
402 srf08_show_sensitivity, srf08_store_sensitivity, 0);
403
404 static struct attribute *srf08_attributes[] = {
405 &iio_dev_attr_sensor_max_range.dev_attr.attr,
406 &iio_dev_attr_sensor_max_range_available.dev_attr.attr,
407 &iio_dev_attr_sensor_sensitivity.dev_attr.attr,
408 &iio_dev_attr_sensor_sensitivity_available.dev_attr.attr,
409 NULL,
410 };
411
412 static const struct attribute_group srf08_attribute_group = {
413 .attrs = srf08_attributes,
414 };
415
416 static const struct iio_chan_spec srf08_channels[] = {
417 {
418 .type = IIO_DISTANCE,
419 .info_mask_separate =
420 BIT(IIO_CHAN_INFO_RAW) |
421 BIT(IIO_CHAN_INFO_SCALE),
422 .scan_index = 0,
423 .scan_type = {
424 .sign = 's',
425 .realbits = 16,
426 .storagebits = 16,
427 .endianness = IIO_CPU,
428 },
429 },
430 IIO_CHAN_SOFT_TIMESTAMP(1),
431 };
432
433 static const struct iio_info srf08_info = {
434 .read_raw = srf08_read_raw,
435 .attrs = &srf08_attribute_group,
436 };
437
438 /*
439 * srf02 don't have an adjustable range or sensitivity,
440 * so we don't need attributes at all
441 */
442 static const struct iio_info srf02_info = {
443 .read_raw = srf08_read_raw,
444 };
445
srf08_probe(struct i2c_client * client)446 static int srf08_probe(struct i2c_client *client)
447 {
448 const struct i2c_device_id *id = i2c_client_get_device_id(client);
449 struct iio_dev *indio_dev;
450 struct srf08_data *data;
451 int ret;
452
453 if (!i2c_check_functionality(client->adapter,
454 I2C_FUNC_SMBUS_READ_BYTE_DATA |
455 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
456 I2C_FUNC_SMBUS_READ_WORD_DATA))
457 return -ENODEV;
458
459 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
460 if (!indio_dev)
461 return -ENOMEM;
462
463 data = iio_priv(indio_dev);
464 i2c_set_clientdata(client, indio_dev);
465 data->client = client;
466 data->sensor_type = (enum srf08_sensor_type)id->driver_data;
467
468 switch (data->sensor_type) {
469 case SRF02:
470 data->chip_info = &srf02_chip_info;
471 indio_dev->info = &srf02_info;
472 break;
473 case SRF08:
474 data->chip_info = &srf08_chip_info;
475 indio_dev->info = &srf08_info;
476 break;
477 case SRF10:
478 data->chip_info = &srf10_chip_info;
479 indio_dev->info = &srf08_info;
480 break;
481 default:
482 return -EINVAL;
483 }
484
485 indio_dev->name = id->name;
486 indio_dev->modes = INDIO_DIRECT_MODE;
487 indio_dev->channels = srf08_channels;
488 indio_dev->num_channels = ARRAY_SIZE(srf08_channels);
489
490 mutex_init(&data->lock);
491
492 ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev,
493 iio_pollfunc_store_time, srf08_trigger_handler, NULL);
494 if (ret < 0) {
495 dev_err(&client->dev, "setup of iio triggered buffer failed\n");
496 return ret;
497 }
498
499 if (data->chip_info->range_default) {
500 /*
501 * set default range of device in mm here
502 * these register values cannot be read from the hardware
503 * therefore set driver specific default values
504 *
505 * srf02 don't have a default value so it'll be omitted
506 */
507 ret = srf08_write_range_mm(data,
508 data->chip_info->range_default);
509 if (ret < 0)
510 return ret;
511 }
512
513 if (data->chip_info->sensitivity_default) {
514 /*
515 * set default sensitivity of device here
516 * these register values cannot be read from the hardware
517 * therefore set driver specific default values
518 *
519 * srf02 don't have a default value so it'll be omitted
520 */
521 ret = srf08_write_sensitivity(data,
522 data->chip_info->sensitivity_default);
523 if (ret < 0)
524 return ret;
525 }
526
527 return devm_iio_device_register(&client->dev, indio_dev);
528 }
529
530 static const struct of_device_id of_srf08_match[] = {
531 { .compatible = "devantech,srf02", (void *)SRF02 },
532 { .compatible = "devantech,srf08", (void *)SRF08 },
533 { .compatible = "devantech,srf10", (void *)SRF10 },
534 {},
535 };
536
537 MODULE_DEVICE_TABLE(of, of_srf08_match);
538
539 static const struct i2c_device_id srf08_id[] = {
540 { "srf02", SRF02 },
541 { "srf08", SRF08 },
542 { "srf10", SRF10 },
543 { }
544 };
545 MODULE_DEVICE_TABLE(i2c, srf08_id);
546
547 static struct i2c_driver srf08_driver = {
548 .driver = {
549 .name = "srf08",
550 .of_match_table = of_srf08_match,
551 },
552 .probe = srf08_probe,
553 .id_table = srf08_id,
554 };
555 module_i2c_driver(srf08_driver);
556
557 MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
558 MODULE_DESCRIPTION("Devantech SRF02/SRF08/SRF10 i2c ultrasonic ranger driver");
559 MODULE_LICENSE("GPL");
560