1 /*
2 * mag3110.c - Support for Freescale MAG3110 magnetometer sensor
3 *
4 * Copyright (c) 2013 Peter Meerwald <pmeerw@pmeerw.net>
5 *
6 * This file is subject to the terms and conditions of version 2 of
7 * the GNU General Public License. See the file COPYING in the main
8 * directory of this archive for more details.
9 *
10 * (7-bit I2C slave address 0x0e)
11 *
12 * TODO: irq, user offset, oversampling, continuous mode
13 */
14
15 #include <linux/module.h>
16 #include <linux/i2c.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/iio/trigger_consumer.h>
20 #include <linux/iio/buffer.h>
21 #include <linux/iio/triggered_buffer.h>
22 #include <linux/delay.h>
23
24 #define MAG3110_STATUS 0x00
25 #define MAG3110_OUT_X 0x01 /* MSB first */
26 #define MAG3110_OUT_Y 0x03
27 #define MAG3110_OUT_Z 0x05
28 #define MAG3110_WHO_AM_I 0x07
29 #define MAG3110_SYSMOD 0x08
30 #define MAG3110_OFF_X 0x09 /* MSB first */
31 #define MAG3110_OFF_Y 0x0b
32 #define MAG3110_OFF_Z 0x0d
33 #define MAG3110_DIE_TEMP 0x0f
34 #define MAG3110_CTRL_REG1 0x10
35 #define MAG3110_CTRL_REG2 0x11
36
37 #define MAG3110_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
38
39 #define MAG3110_CTRL_DR_MASK (BIT(7) | BIT(6) | BIT(5))
40 #define MAG3110_CTRL_DR_SHIFT 5
41 #define MAG3110_CTRL_DR_DEFAULT 0
42
43 #define MAG3110_SYSMOD_MODE_MASK GENMASK(1, 0)
44
45 #define MAG3110_CTRL_TM BIT(1) /* trigger single measurement */
46 #define MAG3110_CTRL_AC BIT(0) /* continuous measurements */
47
48 #define MAG3110_CTRL_AUTO_MRST_EN BIT(7) /* magnetic auto-reset */
49 #define MAG3110_CTRL_RAW BIT(5) /* measurements not user-offset corrected */
50
51 #define MAG3110_DEVICE_ID 0xc4
52
53 /* Each client has this additional data */
54 struct mag3110_data {
55 struct i2c_client *client;
56 struct mutex lock;
57 u8 ctrl_reg1;
58 int sleep_val;
59 };
60
mag3110_request(struct mag3110_data * data)61 static int mag3110_request(struct mag3110_data *data)
62 {
63 int ret, tries = 150;
64
65 if ((data->ctrl_reg1 & MAG3110_CTRL_AC) == 0) {
66 /* trigger measurement */
67 ret = i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
68 data->ctrl_reg1 | MAG3110_CTRL_TM);
69 if (ret < 0)
70 return ret;
71 }
72
73 while (tries-- > 0) {
74 ret = i2c_smbus_read_byte_data(data->client, MAG3110_STATUS);
75 if (ret < 0)
76 return ret;
77 /* wait for data ready */
78 if ((ret & MAG3110_STATUS_DRDY) == MAG3110_STATUS_DRDY)
79 break;
80
81 if (data->sleep_val <= 20)
82 usleep_range(data->sleep_val * 250, data->sleep_val * 500);
83 else
84 msleep(20);
85 }
86
87 if (tries < 0) {
88 dev_err(&data->client->dev, "data not ready\n");
89 return -EIO;
90 }
91
92 return 0;
93 }
94
mag3110_read(struct mag3110_data * data,__be16 buf[3])95 static int mag3110_read(struct mag3110_data *data, __be16 buf[3])
96 {
97 int ret;
98
99 mutex_lock(&data->lock);
100 ret = mag3110_request(data);
101 if (ret < 0) {
102 mutex_unlock(&data->lock);
103 return ret;
104 }
105 ret = i2c_smbus_read_i2c_block_data(data->client,
106 MAG3110_OUT_X, 3 * sizeof(__be16), (u8 *) buf);
107 mutex_unlock(&data->lock);
108
109 return ret;
110 }
111
mag3110_show_int_plus_micros(char * buf,const int (* vals)[2],int n)112 static ssize_t mag3110_show_int_plus_micros(char *buf,
113 const int (*vals)[2], int n)
114 {
115 size_t len = 0;
116
117 while (n-- > 0)
118 len += scnprintf(buf + len, PAGE_SIZE - len,
119 "%d.%06d ", vals[n][0], vals[n][1]);
120
121 /* replace trailing space by newline */
122 buf[len - 1] = '\n';
123
124 return len;
125 }
126
mag3110_get_int_plus_micros_index(const int (* vals)[2],int n,int val,int val2)127 static int mag3110_get_int_plus_micros_index(const int (*vals)[2], int n,
128 int val, int val2)
129 {
130 while (n-- > 0)
131 if (val == vals[n][0] && val2 == vals[n][1])
132 return n;
133
134 return -EINVAL;
135 }
136
137 static const int mag3110_samp_freq[8][2] = {
138 {80, 0}, {40, 0}, {20, 0}, {10, 0}, {5, 0}, {2, 500000},
139 {1, 250000}, {0, 625000}
140 };
141
mag3110_show_samp_freq_avail(struct device * dev,struct device_attribute * attr,char * buf)142 static ssize_t mag3110_show_samp_freq_avail(struct device *dev,
143 struct device_attribute *attr, char *buf)
144 {
145 return mag3110_show_int_plus_micros(buf, mag3110_samp_freq, 8);
146 }
147
148 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mag3110_show_samp_freq_avail);
149
mag3110_get_samp_freq_index(struct mag3110_data * data,int val,int val2)150 static int mag3110_get_samp_freq_index(struct mag3110_data *data,
151 int val, int val2)
152 {
153 return mag3110_get_int_plus_micros_index(mag3110_samp_freq, 8, val,
154 val2);
155 }
156
mag3110_calculate_sleep(struct mag3110_data * data)157 static int mag3110_calculate_sleep(struct mag3110_data *data)
158 {
159 int ret, i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
160
161 if (mag3110_samp_freq[i][0] > 0)
162 ret = 1000 / mag3110_samp_freq[i][0];
163 else
164 ret = 1000;
165
166 return ret == 0 ? 1 : ret;
167 }
168
mag3110_standby(struct mag3110_data * data)169 static int mag3110_standby(struct mag3110_data *data)
170 {
171 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
172 data->ctrl_reg1 & ~MAG3110_CTRL_AC);
173 }
174
mag3110_wait_standby(struct mag3110_data * data)175 static int mag3110_wait_standby(struct mag3110_data *data)
176 {
177 int ret, tries = 30;
178
179 /*
180 * Takes up to 1/ODR to come out of active mode into stby
181 * Longest expected period is 12.5seconds.
182 * We'll sleep for 500ms between checks
183 */
184 while (tries-- > 0) {
185 ret = i2c_smbus_read_byte_data(data->client, MAG3110_SYSMOD);
186 if (ret < 0) {
187 dev_err(&data->client->dev, "i2c error\n");
188 return ret;
189 }
190 /* wait for standby */
191 if ((ret & MAG3110_SYSMOD_MODE_MASK) == 0)
192 break;
193
194 msleep_interruptible(500);
195 }
196
197 if (tries < 0) {
198 dev_err(&data->client->dev, "device not entering standby mode\n");
199 return -EIO;
200 }
201
202 return 0;
203 }
204
mag3110_active(struct mag3110_data * data)205 static int mag3110_active(struct mag3110_data *data)
206 {
207 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
208 data->ctrl_reg1);
209 }
210
211 /* returns >0 if active, 0 if in standby and <0 on error */
mag3110_is_active(struct mag3110_data * data)212 static int mag3110_is_active(struct mag3110_data *data)
213 {
214 int reg;
215
216 reg = i2c_smbus_read_byte_data(data->client, MAG3110_CTRL_REG1);
217 if (reg < 0)
218 return reg;
219
220 return reg & MAG3110_CTRL_AC;
221 }
222
mag3110_change_config(struct mag3110_data * data,u8 reg,u8 val)223 static int mag3110_change_config(struct mag3110_data *data, u8 reg, u8 val)
224 {
225 int ret;
226 int is_active;
227
228 mutex_lock(&data->lock);
229
230 is_active = mag3110_is_active(data);
231 if (is_active < 0) {
232 ret = is_active;
233 goto fail;
234 }
235
236 /* config can only be changed when in standby */
237 if (is_active > 0) {
238 ret = mag3110_standby(data);
239 if (ret < 0)
240 goto fail;
241 }
242
243 /*
244 * After coming out of active we must wait for the part
245 * to transition to STBY. This can take up to 1 /ODR to occur
246 */
247 ret = mag3110_wait_standby(data);
248 if (ret < 0)
249 goto fail;
250
251 ret = i2c_smbus_write_byte_data(data->client, reg, val);
252 if (ret < 0)
253 goto fail;
254
255 if (is_active > 0) {
256 ret = mag3110_active(data);
257 if (ret < 0)
258 goto fail;
259 }
260
261 ret = 0;
262 fail:
263 mutex_unlock(&data->lock);
264
265 return ret;
266 }
267
mag3110_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)268 static int mag3110_read_raw(struct iio_dev *indio_dev,
269 struct iio_chan_spec const *chan,
270 int *val, int *val2, long mask)
271 {
272 struct mag3110_data *data = iio_priv(indio_dev);
273 __be16 buffer[3];
274 int i, ret;
275
276 switch (mask) {
277 case IIO_CHAN_INFO_RAW:
278 ret = iio_device_claim_direct_mode(indio_dev);
279 if (ret)
280 return ret;
281
282 switch (chan->type) {
283 case IIO_MAGN: /* in 0.1 uT / LSB */
284 ret = mag3110_read(data, buffer);
285 if (ret < 0)
286 goto release;
287 *val = sign_extend32(
288 be16_to_cpu(buffer[chan->scan_index]), 15);
289 ret = IIO_VAL_INT;
290 break;
291 case IIO_TEMP: /* in 1 C / LSB */
292 mutex_lock(&data->lock);
293 ret = mag3110_request(data);
294 if (ret < 0) {
295 mutex_unlock(&data->lock);
296 goto release;
297 }
298 ret = i2c_smbus_read_byte_data(data->client,
299 MAG3110_DIE_TEMP);
300 mutex_unlock(&data->lock);
301 if (ret < 0)
302 goto release;
303 *val = sign_extend32(ret, 7);
304 ret = IIO_VAL_INT;
305 break;
306 default:
307 ret = -EINVAL;
308 }
309 release:
310 iio_device_release_direct_mode(indio_dev);
311 return ret;
312
313 case IIO_CHAN_INFO_SCALE:
314 switch (chan->type) {
315 case IIO_MAGN:
316 *val = 0;
317 *val2 = 1000;
318 return IIO_VAL_INT_PLUS_MICRO;
319 case IIO_TEMP:
320 *val = 1000;
321 return IIO_VAL_INT;
322 default:
323 return -EINVAL;
324 }
325 case IIO_CHAN_INFO_SAMP_FREQ:
326 i = data->ctrl_reg1 >> MAG3110_CTRL_DR_SHIFT;
327 *val = mag3110_samp_freq[i][0];
328 *val2 = mag3110_samp_freq[i][1];
329 return IIO_VAL_INT_PLUS_MICRO;
330 case IIO_CHAN_INFO_CALIBBIAS:
331 ret = i2c_smbus_read_word_swapped(data->client,
332 MAG3110_OFF_X + 2 * chan->scan_index);
333 if (ret < 0)
334 return ret;
335 *val = sign_extend32(ret >> 1, 14);
336 return IIO_VAL_INT;
337 }
338 return -EINVAL;
339 }
340
mag3110_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)341 static int mag3110_write_raw(struct iio_dev *indio_dev,
342 struct iio_chan_spec const *chan,
343 int val, int val2, long mask)
344 {
345 struct mag3110_data *data = iio_priv(indio_dev);
346 int rate, ret;
347
348 ret = iio_device_claim_direct_mode(indio_dev);
349 if (ret)
350 return ret;
351
352 switch (mask) {
353 case IIO_CHAN_INFO_SAMP_FREQ:
354 rate = mag3110_get_samp_freq_index(data, val, val2);
355 if (rate < 0) {
356 ret = -EINVAL;
357 break;
358 }
359 data->ctrl_reg1 &= 0xff & ~MAG3110_CTRL_DR_MASK
360 & ~MAG3110_CTRL_AC;
361 data->ctrl_reg1 |= rate << MAG3110_CTRL_DR_SHIFT;
362 data->sleep_val = mag3110_calculate_sleep(data);
363 if (data->sleep_val < 40)
364 data->ctrl_reg1 |= MAG3110_CTRL_AC;
365
366 ret = mag3110_change_config(data, MAG3110_CTRL_REG1,
367 data->ctrl_reg1);
368 break;
369 case IIO_CHAN_INFO_CALIBBIAS:
370 if (val < -10000 || val > 10000) {
371 ret = -EINVAL;
372 break;
373 }
374 ret = i2c_smbus_write_word_swapped(data->client,
375 MAG3110_OFF_X + 2 * chan->scan_index, val << 1);
376 break;
377 default:
378 ret = -EINVAL;
379 break;
380 }
381 iio_device_release_direct_mode(indio_dev);
382 return ret;
383 }
384
mag3110_trigger_handler(int irq,void * p)385 static irqreturn_t mag3110_trigger_handler(int irq, void *p)
386 {
387 struct iio_poll_func *pf = p;
388 struct iio_dev *indio_dev = pf->indio_dev;
389 struct mag3110_data *data = iio_priv(indio_dev);
390 u8 buffer[16]; /* 3 16-bit channels + 1 byte temp + padding + ts */
391 int ret;
392
393 ret = mag3110_read(data, (__be16 *) buffer);
394 if (ret < 0)
395 goto done;
396
397 if (test_bit(3, indio_dev->active_scan_mask)) {
398 ret = i2c_smbus_read_byte_data(data->client,
399 MAG3110_DIE_TEMP);
400 if (ret < 0)
401 goto done;
402 buffer[6] = ret;
403 }
404
405 iio_push_to_buffers_with_timestamp(indio_dev, buffer,
406 iio_get_time_ns(indio_dev));
407
408 done:
409 iio_trigger_notify_done(indio_dev->trig);
410 return IRQ_HANDLED;
411 }
412
413 #define MAG3110_CHANNEL(axis, idx) { \
414 .type = IIO_MAGN, \
415 .modified = 1, \
416 .channel2 = IIO_MOD_##axis, \
417 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
418 BIT(IIO_CHAN_INFO_CALIBBIAS), \
419 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
420 BIT(IIO_CHAN_INFO_SCALE), \
421 .scan_index = idx, \
422 .scan_type = { \
423 .sign = 's', \
424 .realbits = 16, \
425 .storagebits = 16, \
426 .endianness = IIO_BE, \
427 }, \
428 }
429
430 static const struct iio_chan_spec mag3110_channels[] = {
431 MAG3110_CHANNEL(X, 0),
432 MAG3110_CHANNEL(Y, 1),
433 MAG3110_CHANNEL(Z, 2),
434 {
435 .type = IIO_TEMP,
436 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
437 BIT(IIO_CHAN_INFO_SCALE),
438 .scan_index = 3,
439 .scan_type = {
440 .sign = 's',
441 .realbits = 8,
442 .storagebits = 8,
443 },
444 },
445 IIO_CHAN_SOFT_TIMESTAMP(4),
446 };
447
448 static struct attribute *mag3110_attributes[] = {
449 &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
450 NULL
451 };
452
453 static const struct attribute_group mag3110_group = {
454 .attrs = mag3110_attributes,
455 };
456
457 static const struct iio_info mag3110_info = {
458 .attrs = &mag3110_group,
459 .read_raw = &mag3110_read_raw,
460 .write_raw = &mag3110_write_raw,
461 };
462
463 static const unsigned long mag3110_scan_masks[] = {0x7, 0xf, 0};
464
mag3110_probe(struct i2c_client * client,const struct i2c_device_id * id)465 static int mag3110_probe(struct i2c_client *client,
466 const struct i2c_device_id *id)
467 {
468 struct mag3110_data *data;
469 struct iio_dev *indio_dev;
470 int ret;
471
472 ret = i2c_smbus_read_byte_data(client, MAG3110_WHO_AM_I);
473 if (ret < 0)
474 return ret;
475 if (ret != MAG3110_DEVICE_ID)
476 return -ENODEV;
477
478 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
479 if (!indio_dev)
480 return -ENOMEM;
481
482 data = iio_priv(indio_dev);
483 data->client = client;
484 mutex_init(&data->lock);
485
486 i2c_set_clientdata(client, indio_dev);
487 indio_dev->info = &mag3110_info;
488 indio_dev->name = id->name;
489 indio_dev->dev.parent = &client->dev;
490 indio_dev->modes = INDIO_DIRECT_MODE;
491 indio_dev->channels = mag3110_channels;
492 indio_dev->num_channels = ARRAY_SIZE(mag3110_channels);
493 indio_dev->available_scan_masks = mag3110_scan_masks;
494
495 data->ctrl_reg1 = MAG3110_CTRL_DR_DEFAULT << MAG3110_CTRL_DR_SHIFT;
496 data->sleep_val = mag3110_calculate_sleep(data);
497 if (data->sleep_val < 40)
498 data->ctrl_reg1 |= MAG3110_CTRL_AC;
499
500 ret = mag3110_change_config(data, MAG3110_CTRL_REG1, data->ctrl_reg1);
501 if (ret < 0)
502 return ret;
503
504 ret = i2c_smbus_write_byte_data(client, MAG3110_CTRL_REG2,
505 MAG3110_CTRL_AUTO_MRST_EN);
506 if (ret < 0)
507 goto standby_on_error;
508
509 ret = iio_triggered_buffer_setup(indio_dev, NULL,
510 mag3110_trigger_handler, NULL);
511 if (ret < 0)
512 goto standby_on_error;
513
514 ret = iio_device_register(indio_dev);
515 if (ret < 0)
516 goto buffer_cleanup;
517 return 0;
518
519 buffer_cleanup:
520 iio_triggered_buffer_cleanup(indio_dev);
521 standby_on_error:
522 mag3110_standby(iio_priv(indio_dev));
523 return ret;
524 }
525
mag3110_remove(struct i2c_client * client)526 static int mag3110_remove(struct i2c_client *client)
527 {
528 struct iio_dev *indio_dev = i2c_get_clientdata(client);
529
530 iio_device_unregister(indio_dev);
531 iio_triggered_buffer_cleanup(indio_dev);
532 mag3110_standby(iio_priv(indio_dev));
533
534 return 0;
535 }
536
537 #ifdef CONFIG_PM_SLEEP
mag3110_suspend(struct device * dev)538 static int mag3110_suspend(struct device *dev)
539 {
540 return mag3110_standby(iio_priv(i2c_get_clientdata(
541 to_i2c_client(dev))));
542 }
543
mag3110_resume(struct device * dev)544 static int mag3110_resume(struct device *dev)
545 {
546 struct mag3110_data *data = iio_priv(i2c_get_clientdata(
547 to_i2c_client(dev)));
548
549 return i2c_smbus_write_byte_data(data->client, MAG3110_CTRL_REG1,
550 data->ctrl_reg1);
551 }
552
553 static SIMPLE_DEV_PM_OPS(mag3110_pm_ops, mag3110_suspend, mag3110_resume);
554 #define MAG3110_PM_OPS (&mag3110_pm_ops)
555 #else
556 #define MAG3110_PM_OPS NULL
557 #endif
558
559 static const struct i2c_device_id mag3110_id[] = {
560 { "mag3110", 0 },
561 { }
562 };
563 MODULE_DEVICE_TABLE(i2c, mag3110_id);
564
565 static const struct of_device_id mag3110_of_match[] = {
566 { .compatible = "fsl,mag3110" },
567 { }
568 };
569 MODULE_DEVICE_TABLE(of, mag3110_of_match);
570
571 static struct i2c_driver mag3110_driver = {
572 .driver = {
573 .name = "mag3110",
574 .of_match_table = mag3110_of_match,
575 .pm = MAG3110_PM_OPS,
576 },
577 .probe = mag3110_probe,
578 .remove = mag3110_remove,
579 .id_table = mag3110_id,
580 };
581 module_i2c_driver(mag3110_driver);
582
583 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
584 MODULE_DESCRIPTION("Freescale MAG3110 magnetometer driver");
585 MODULE_LICENSE("GPL");
586
