1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Sensortek STK8312 3-Axis Accelerometer
4 *
5 * Copyright (c) 2015, Intel Corporation.
6 *
7 * IIO driver for STK8312; 7-bit I2C address: 0x3D.
8 */
9
10 #include <linux/i2c.h>
11 #include <linux/interrupt.h>
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/delay.h>
15 #include <linux/iio/buffer.h>
16 #include <linux/iio/iio.h>
17 #include <linux/iio/sysfs.h>
18 #include <linux/iio/trigger.h>
19 #include <linux/iio/triggered_buffer.h>
20 #include <linux/iio/trigger_consumer.h>
21
22 #define STK8312_REG_XOUT 0x00
23 #define STK8312_REG_YOUT 0x01
24 #define STK8312_REG_ZOUT 0x02
25 #define STK8312_REG_INTSU 0x06
26 #define STK8312_REG_MODE 0x07
27 #define STK8312_REG_SR 0x08
28 #define STK8312_REG_STH 0x13
29 #define STK8312_REG_RESET 0x20
30 #define STK8312_REG_AFECTRL 0x24
31 #define STK8312_REG_OTPADDR 0x3D
32 #define STK8312_REG_OTPDATA 0x3E
33 #define STK8312_REG_OTPCTRL 0x3F
34
35 #define STK8312_MODE_ACTIVE BIT(0)
36 #define STK8312_MODE_STANDBY 0x00
37 #define STK8312_MODE_INT_AH_PP 0xC0 /* active-high, push-pull */
38 #define STK8312_DREADY_BIT BIT(4)
39 #define STK8312_RNG_6G 1
40 #define STK8312_RNG_SHIFT 6
41 #define STK8312_RNG_MASK GENMASK(7, 6)
42 #define STK8312_SR_MASK GENMASK(2, 0)
43 #define STK8312_SR_400HZ_IDX 0
44 #define STK8312_ALL_CHANNEL_MASK GENMASK(2, 0)
45 #define STK8312_ALL_CHANNEL_SIZE 3
46
47 #define STK8312_DRIVER_NAME "stk8312"
48 #define STK8312_IRQ_NAME "stk8312_event"
49
50 /*
51 * The accelerometer has two measurement ranges:
52 *
53 * -6g - +6g (8-bit, signed)
54 * -16g - +16g (8-bit, signed)
55 *
56 * scale1 = (6 + 6) * 9.81 / (2^8 - 1) = 0.4616
57 * scale2 = (16 + 16) * 9.81 / (2^8 - 1) = 1.2311
58 */
59 #define STK8312_SCALE_AVAIL "0.4616 1.2311"
60
61 static const int stk8312_scale_table[][2] = {
62 {0, 461600}, {1, 231100}
63 };
64
65 static const struct {
66 int val;
67 int val2;
68 } stk8312_samp_freq_table[] = {
69 {400, 0}, {200, 0}, {100, 0}, {50, 0}, {25, 0},
70 {12, 500000}, {6, 250000}, {3, 125000}
71 };
72
73 #define STK8312_ACCEL_CHANNEL(index, reg, axis) { \
74 .type = IIO_ACCEL, \
75 .address = reg, \
76 .modified = 1, \
77 .channel2 = IIO_MOD_##axis, \
78 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
79 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
80 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
81 .scan_index = index, \
82 .scan_type = { \
83 .sign = 's', \
84 .realbits = 8, \
85 .storagebits = 8, \
86 .endianness = IIO_CPU, \
87 }, \
88 }
89
90 static const struct iio_chan_spec stk8312_channels[] = {
91 STK8312_ACCEL_CHANNEL(0, STK8312_REG_XOUT, X),
92 STK8312_ACCEL_CHANNEL(1, STK8312_REG_YOUT, Y),
93 STK8312_ACCEL_CHANNEL(2, STK8312_REG_ZOUT, Z),
94 IIO_CHAN_SOFT_TIMESTAMP(3),
95 };
96
97 struct stk8312_data {
98 struct i2c_client *client;
99 struct mutex lock;
100 u8 range;
101 u8 sample_rate_idx;
102 u8 mode;
103 struct iio_trigger *dready_trig;
104 bool dready_trigger_on;
105 /* Ensure timestamp is naturally aligned */
106 struct {
107 s8 chans[3];
108 s64 timestamp __aligned(8);
109 } scan;
110 };
111
112 static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
113
114 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("3.125 6.25 12.5 25 50 100 200 400");
115
116 static struct attribute *stk8312_attributes[] = {
117 &iio_const_attr_in_accel_scale_available.dev_attr.attr,
118 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
119 NULL,
120 };
121
122 static const struct attribute_group stk8312_attribute_group = {
123 .attrs = stk8312_attributes
124 };
125
stk8312_otp_init(struct stk8312_data * data)126 static int stk8312_otp_init(struct stk8312_data *data)
127 {
128 int ret;
129 int count = 10;
130 struct i2c_client *client = data->client;
131
132 ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPADDR, 0x70);
133 if (ret < 0)
134 goto exit_err;
135 ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPCTRL, 0x02);
136 if (ret < 0)
137 goto exit_err;
138
139 do {
140 usleep_range(1000, 5000);
141 ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPCTRL);
142 if (ret < 0)
143 goto exit_err;
144 count--;
145 } while (!(ret & BIT(7)) && count > 0);
146
147 if (count == 0) {
148 ret = -ETIMEDOUT;
149 goto exit_err;
150 }
151
152 ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPDATA);
153 if (ret == 0)
154 ret = -EINVAL;
155 if (ret < 0)
156 goto exit_err;
157
158 ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_AFECTRL, ret);
159 if (ret < 0)
160 goto exit_err;
161 msleep(150);
162
163 return 0;
164
165 exit_err:
166 dev_err(&client->dev, "failed to initialize sensor\n");
167 return ret;
168 }
169
stk8312_set_mode(struct stk8312_data * data,u8 mode)170 static int stk8312_set_mode(struct stk8312_data *data, u8 mode)
171 {
172 int ret;
173 struct i2c_client *client = data->client;
174
175 if (mode == data->mode)
176 return 0;
177
178 ret = i2c_smbus_write_byte_data(client, STK8312_REG_MODE, mode);
179 if (ret < 0) {
180 dev_err(&client->dev, "failed to change sensor mode\n");
181 return ret;
182 }
183
184 data->mode = mode;
185 if (mode & STK8312_MODE_ACTIVE) {
186 /* Need to run OTP sequence before entering active mode */
187 usleep_range(1000, 5000);
188 ret = stk8312_otp_init(data);
189 }
190
191 return ret;
192 }
193
stk8312_set_interrupts(struct stk8312_data * data,u8 int_mask)194 static int stk8312_set_interrupts(struct stk8312_data *data, u8 int_mask)
195 {
196 int ret;
197 u8 mode;
198 struct i2c_client *client = data->client;
199
200 mode = data->mode;
201 /* We need to go in standby mode to modify registers */
202 ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
203 if (ret < 0)
204 return ret;
205
206 ret = i2c_smbus_write_byte_data(client, STK8312_REG_INTSU, int_mask);
207 if (ret < 0) {
208 dev_err(&client->dev, "failed to set interrupts\n");
209 stk8312_set_mode(data, mode);
210 return ret;
211 }
212
213 return stk8312_set_mode(data, mode);
214 }
215
stk8312_data_rdy_trigger_set_state(struct iio_trigger * trig,bool state)216 static int stk8312_data_rdy_trigger_set_state(struct iio_trigger *trig,
217 bool state)
218 {
219 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
220 struct stk8312_data *data = iio_priv(indio_dev);
221 int ret;
222
223 if (state)
224 ret = stk8312_set_interrupts(data, STK8312_DREADY_BIT);
225 else
226 ret = stk8312_set_interrupts(data, 0x00);
227
228 if (ret < 0) {
229 dev_err(&data->client->dev, "failed to set trigger state\n");
230 return ret;
231 }
232
233 data->dready_trigger_on = state;
234
235 return 0;
236 }
237
238 static const struct iio_trigger_ops stk8312_trigger_ops = {
239 .set_trigger_state = stk8312_data_rdy_trigger_set_state,
240 };
241
stk8312_set_sample_rate(struct stk8312_data * data,u8 rate)242 static int stk8312_set_sample_rate(struct stk8312_data *data, u8 rate)
243 {
244 int ret;
245 u8 masked_reg;
246 u8 mode;
247 struct i2c_client *client = data->client;
248
249 if (rate == data->sample_rate_idx)
250 return 0;
251
252 mode = data->mode;
253 /* We need to go in standby mode to modify registers */
254 ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
255 if (ret < 0)
256 return ret;
257
258 ret = i2c_smbus_read_byte_data(client, STK8312_REG_SR);
259 if (ret < 0)
260 goto err_activate;
261
262 masked_reg = (ret & (~STK8312_SR_MASK)) | rate;
263
264 ret = i2c_smbus_write_byte_data(client, STK8312_REG_SR, masked_reg);
265 if (ret < 0)
266 goto err_activate;
267
268 data->sample_rate_idx = rate;
269
270 return stk8312_set_mode(data, mode);
271
272 err_activate:
273 dev_err(&client->dev, "failed to set sampling rate\n");
274 stk8312_set_mode(data, mode);
275
276 return ret;
277 }
278
stk8312_set_range(struct stk8312_data * data,u8 range)279 static int stk8312_set_range(struct stk8312_data *data, u8 range)
280 {
281 int ret;
282 u8 masked_reg;
283 u8 mode;
284 struct i2c_client *client = data->client;
285
286 if (range != 1 && range != 2)
287 return -EINVAL;
288 else if (range == data->range)
289 return 0;
290
291 mode = data->mode;
292 /* We need to go in standby mode to modify registers */
293 ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
294 if (ret < 0)
295 return ret;
296
297 ret = i2c_smbus_read_byte_data(client, STK8312_REG_STH);
298 if (ret < 0)
299 goto err_activate;
300
301 masked_reg = ret & (~STK8312_RNG_MASK);
302 masked_reg |= range << STK8312_RNG_SHIFT;
303
304 ret = i2c_smbus_write_byte_data(client, STK8312_REG_STH, masked_reg);
305 if (ret < 0)
306 goto err_activate;
307
308 data->range = range;
309
310 return stk8312_set_mode(data, mode);
311
312 err_activate:
313 dev_err(&client->dev, "failed to change sensor range\n");
314 stk8312_set_mode(data, mode);
315
316 return ret;
317 }
318
stk8312_read_accel(struct stk8312_data * data,u8 address)319 static int stk8312_read_accel(struct stk8312_data *data, u8 address)
320 {
321 int ret;
322 struct i2c_client *client = data->client;
323
324 if (address > 2)
325 return -EINVAL;
326
327 ret = i2c_smbus_read_byte_data(client, address);
328 if (ret < 0)
329 dev_err(&client->dev, "register read failed\n");
330
331 return ret;
332 }
333
stk8312_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)334 static int stk8312_read_raw(struct iio_dev *indio_dev,
335 struct iio_chan_spec const *chan,
336 int *val, int *val2, long mask)
337 {
338 struct stk8312_data *data = iio_priv(indio_dev);
339 int ret;
340
341 switch (mask) {
342 case IIO_CHAN_INFO_RAW:
343 if (iio_buffer_enabled(indio_dev))
344 return -EBUSY;
345 mutex_lock(&data->lock);
346 ret = stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
347 if (ret < 0) {
348 mutex_unlock(&data->lock);
349 return ret;
350 }
351 ret = stk8312_read_accel(data, chan->address);
352 if (ret < 0) {
353 stk8312_set_mode(data,
354 data->mode & (~STK8312_MODE_ACTIVE));
355 mutex_unlock(&data->lock);
356 return ret;
357 }
358 *val = sign_extend32(ret, chan->scan_type.realbits - 1);
359 ret = stk8312_set_mode(data,
360 data->mode & (~STK8312_MODE_ACTIVE));
361 mutex_unlock(&data->lock);
362 if (ret < 0)
363 return ret;
364 return IIO_VAL_INT;
365 case IIO_CHAN_INFO_SCALE:
366 *val = stk8312_scale_table[data->range - 1][0];
367 *val2 = stk8312_scale_table[data->range - 1][1];
368 return IIO_VAL_INT_PLUS_MICRO;
369 case IIO_CHAN_INFO_SAMP_FREQ:
370 *val = stk8312_samp_freq_table[data->sample_rate_idx].val;
371 *val2 = stk8312_samp_freq_table[data->sample_rate_idx].val2;
372 return IIO_VAL_INT_PLUS_MICRO;
373 }
374
375 return -EINVAL;
376 }
377
stk8312_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)378 static int stk8312_write_raw(struct iio_dev *indio_dev,
379 struct iio_chan_spec const *chan,
380 int val, int val2, long mask)
381 {
382 int i;
383 int index = -1;
384 int ret;
385 struct stk8312_data *data = iio_priv(indio_dev);
386
387 switch (mask) {
388 case IIO_CHAN_INFO_SCALE:
389 for (i = 0; i < ARRAY_SIZE(stk8312_scale_table); i++)
390 if (val == stk8312_scale_table[i][0] &&
391 val2 == stk8312_scale_table[i][1]) {
392 index = i + 1;
393 break;
394 }
395 if (index < 0)
396 return -EINVAL;
397
398 mutex_lock(&data->lock);
399 ret = stk8312_set_range(data, index);
400 mutex_unlock(&data->lock);
401
402 return ret;
403 case IIO_CHAN_INFO_SAMP_FREQ:
404 for (i = 0; i < ARRAY_SIZE(stk8312_samp_freq_table); i++)
405 if (val == stk8312_samp_freq_table[i].val &&
406 val2 == stk8312_samp_freq_table[i].val2) {
407 index = i;
408 break;
409 }
410 if (index < 0)
411 return -EINVAL;
412 mutex_lock(&data->lock);
413 ret = stk8312_set_sample_rate(data, index);
414 mutex_unlock(&data->lock);
415
416 return ret;
417 }
418
419 return -EINVAL;
420 }
421
422 static const struct iio_info stk8312_info = {
423 .read_raw = stk8312_read_raw,
424 .write_raw = stk8312_write_raw,
425 .attrs = &stk8312_attribute_group,
426 };
427
stk8312_trigger_handler(int irq,void * p)428 static irqreturn_t stk8312_trigger_handler(int irq, void *p)
429 {
430 struct iio_poll_func *pf = p;
431 struct iio_dev *indio_dev = pf->indio_dev;
432 struct stk8312_data *data = iio_priv(indio_dev);
433 int bit, ret, i = 0;
434
435 mutex_lock(&data->lock);
436 /*
437 * Do a bulk read if all channels are requested,
438 * from 0x00 (XOUT) to 0x02 (ZOUT)
439 */
440 if (*(indio_dev->active_scan_mask) == STK8312_ALL_CHANNEL_MASK) {
441 ret = i2c_smbus_read_i2c_block_data(data->client,
442 STK8312_REG_XOUT,
443 STK8312_ALL_CHANNEL_SIZE,
444 data->scan.chans);
445 if (ret < STK8312_ALL_CHANNEL_SIZE) {
446 dev_err(&data->client->dev, "register read failed\n");
447 mutex_unlock(&data->lock);
448 goto err;
449 }
450 } else {
451 iio_for_each_active_channel(indio_dev, bit) {
452 ret = stk8312_read_accel(data, bit);
453 if (ret < 0) {
454 mutex_unlock(&data->lock);
455 goto err;
456 }
457 data->scan.chans[i++] = ret;
458 }
459 }
460 mutex_unlock(&data->lock);
461
462 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
463 pf->timestamp);
464 err:
465 iio_trigger_notify_done(indio_dev->trig);
466
467 return IRQ_HANDLED;
468 }
469
stk8312_data_rdy_trig_poll(int irq,void * private)470 static irqreturn_t stk8312_data_rdy_trig_poll(int irq, void *private)
471 {
472 struct iio_dev *indio_dev = private;
473 struct stk8312_data *data = iio_priv(indio_dev);
474
475 if (data->dready_trigger_on)
476 iio_trigger_poll(data->dready_trig);
477
478 return IRQ_HANDLED;
479 }
480
stk8312_buffer_preenable(struct iio_dev * indio_dev)481 static int stk8312_buffer_preenable(struct iio_dev *indio_dev)
482 {
483 struct stk8312_data *data = iio_priv(indio_dev);
484
485 return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
486 }
487
stk8312_buffer_postdisable(struct iio_dev * indio_dev)488 static int stk8312_buffer_postdisable(struct iio_dev *indio_dev)
489 {
490 struct stk8312_data *data = iio_priv(indio_dev);
491
492 return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
493 }
494
495 static const struct iio_buffer_setup_ops stk8312_buffer_setup_ops = {
496 .preenable = stk8312_buffer_preenable,
497 .postdisable = stk8312_buffer_postdisable,
498 };
499
stk8312_probe(struct i2c_client * client)500 static int stk8312_probe(struct i2c_client *client)
501 {
502 int ret;
503 struct iio_dev *indio_dev;
504 struct stk8312_data *data;
505
506 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
507 if (!indio_dev) {
508 dev_err(&client->dev, "iio allocation failed!\n");
509 return -ENOMEM;
510 }
511
512 data = iio_priv(indio_dev);
513 data->client = client;
514 i2c_set_clientdata(client, indio_dev);
515 mutex_init(&data->lock);
516
517 indio_dev->info = &stk8312_info;
518 indio_dev->name = STK8312_DRIVER_NAME;
519 indio_dev->modes = INDIO_DIRECT_MODE;
520 indio_dev->channels = stk8312_channels;
521 indio_dev->num_channels = ARRAY_SIZE(stk8312_channels);
522
523 /* A software reset is recommended at power-on */
524 ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_RESET, 0x00);
525 if (ret < 0) {
526 dev_err(&client->dev, "failed to reset sensor\n");
527 return ret;
528 }
529 data->sample_rate_idx = STK8312_SR_400HZ_IDX;
530 ret = stk8312_set_range(data, STK8312_RNG_6G);
531 if (ret < 0)
532 return ret;
533
534 ret = stk8312_set_mode(data,
535 STK8312_MODE_INT_AH_PP | STK8312_MODE_ACTIVE);
536 if (ret < 0)
537 return ret;
538
539 if (client->irq > 0) {
540 ret = devm_request_threaded_irq(&client->dev, client->irq,
541 stk8312_data_rdy_trig_poll,
542 NULL,
543 IRQF_TRIGGER_RISING |
544 IRQF_ONESHOT,
545 STK8312_IRQ_NAME,
546 indio_dev);
547 if (ret < 0) {
548 dev_err(&client->dev, "request irq %d failed\n",
549 client->irq);
550 goto err_power_off;
551 }
552
553 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
554 "%s-dev%d",
555 indio_dev->name,
556 iio_device_id(indio_dev));
557 if (!data->dready_trig) {
558 ret = -ENOMEM;
559 goto err_power_off;
560 }
561
562 data->dready_trig->ops = &stk8312_trigger_ops;
563 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
564 ret = iio_trigger_register(data->dready_trig);
565 if (ret) {
566 dev_err(&client->dev, "iio trigger register failed\n");
567 goto err_power_off;
568 }
569 }
570
571 ret = iio_triggered_buffer_setup(indio_dev,
572 iio_pollfunc_store_time,
573 stk8312_trigger_handler,
574 &stk8312_buffer_setup_ops);
575 if (ret < 0) {
576 dev_err(&client->dev, "iio triggered buffer setup failed\n");
577 goto err_trigger_unregister;
578 }
579
580 ret = iio_device_register(indio_dev);
581 if (ret < 0) {
582 dev_err(&client->dev, "device_register failed\n");
583 goto err_buffer_cleanup;
584 }
585
586 return 0;
587
588 err_buffer_cleanup:
589 iio_triggered_buffer_cleanup(indio_dev);
590 err_trigger_unregister:
591 if (data->dready_trig)
592 iio_trigger_unregister(data->dready_trig);
593 err_power_off:
594 stk8312_set_mode(data, STK8312_MODE_STANDBY);
595 return ret;
596 }
597
stk8312_remove(struct i2c_client * client)598 static void stk8312_remove(struct i2c_client *client)
599 {
600 struct iio_dev *indio_dev = i2c_get_clientdata(client);
601 struct stk8312_data *data = iio_priv(indio_dev);
602
603 iio_device_unregister(indio_dev);
604 iio_triggered_buffer_cleanup(indio_dev);
605
606 if (data->dready_trig)
607 iio_trigger_unregister(data->dready_trig);
608
609 stk8312_set_mode(data, STK8312_MODE_STANDBY);
610 }
611
stk8312_suspend(struct device * dev)612 static int stk8312_suspend(struct device *dev)
613 {
614 struct stk8312_data *data;
615
616 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
617
618 return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
619 }
620
stk8312_resume(struct device * dev)621 static int stk8312_resume(struct device *dev)
622 {
623 struct stk8312_data *data;
624
625 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
626
627 return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
628 }
629
630 static DEFINE_SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend,
631 stk8312_resume);
632
633 static const struct i2c_device_id stk8312_i2c_id[] = {
634 /* Deprecated in favour of lowercase form */
635 { "STK8312" },
636 { "stk8312" },
637 {}
638 };
639 MODULE_DEVICE_TABLE(i2c, stk8312_i2c_id);
640
641 static struct i2c_driver stk8312_driver = {
642 .driver = {
643 .name = STK8312_DRIVER_NAME,
644 .pm = pm_sleep_ptr(&stk8312_pm_ops),
645 },
646 .probe = stk8312_probe,
647 .remove = stk8312_remove,
648 .id_table = stk8312_i2c_id,
649 };
650
651 module_i2c_driver(stk8312_driver);
652
653 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
654 MODULE_DESCRIPTION("STK8312 3-Axis Accelerometer driver");
655 MODULE_LICENSE("GPL v2");
656