1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Sensortek STK8BA50 3-Axis Accelerometer
4 *
5 * Copyright (c) 2015, Intel Corporation.
6 *
7 * STK8BA50 7-bit I2C address: 0x18.
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/mod_devicetable.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 STK8BA50_REG_XOUT 0x02
23 #define STK8BA50_REG_YOUT 0x04
24 #define STK8BA50_REG_ZOUT 0x06
25 #define STK8BA50_REG_RANGE 0x0F
26 #define STK8BA50_REG_BWSEL 0x10
27 #define STK8BA50_REG_POWMODE 0x11
28 #define STK8BA50_REG_SWRST 0x14
29 #define STK8BA50_REG_INTEN2 0x17
30 #define STK8BA50_REG_INTMAP2 0x1A
31
32 #define STK8BA50_MODE_NORMAL 0
33 #define STK8BA50_MODE_SUSPEND 1
34 #define STK8BA50_MODE_POWERBIT BIT(7)
35 #define STK8BA50_DATA_SHIFT 6
36 #define STK8BA50_RESET_CMD 0xB6
37 #define STK8BA50_SR_1792HZ_IDX 7
38 #define STK8BA50_DREADY_INT_MASK 0x10
39 #define STK8BA50_DREADY_INT_MAP 0x81
40 #define STK8BA50_ALL_CHANNEL_MASK 7
41 #define STK8BA50_ALL_CHANNEL_SIZE 6
42
43 #define STK8BA50_DRIVER_NAME "stk8ba50"
44 #define STK8BA50_IRQ_NAME "stk8ba50_event"
45
46 #define STK8BA50_SCALE_AVAIL "0.0384 0.0767 0.1534 0.3069"
47
48 /*
49 * The accelerometer has four measurement ranges:
50 * +/-2g; +/-4g; +/-8g; +/-16g
51 *
52 * Acceleration values are 10-bit, 2's complement.
53 * Scales are calculated as following:
54 *
55 * scale1 = (2 + 2) * 9.81 / (2^10 - 1) = 0.0384
56 * scale2 = (4 + 4) * 9.81 / (2^10 - 1) = 0.0767
57 * etc.
58 *
59 * Scales are stored in this format:
60 * { <register value>, <scale value> }
61 *
62 * Locally, the range is stored as a table index.
63 */
64 static const struct {
65 u8 reg_val;
66 u32 scale_val;
67 } stk8ba50_scale_table[] = {
68 {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
69 };
70
71 /* Sample rates are stored as { <register value>, <Hz value> } */
72 static const struct {
73 u8 reg_val;
74 u16 samp_freq;
75 } stk8ba50_samp_freq_table[] = {
76 {0x08, 14}, {0x09, 25}, {0x0A, 56}, {0x0B, 112},
77 {0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
78 };
79
80 /* Used to map scan mask bits to their corresponding channel register. */
81 static const int stk8ba50_channel_table[] = {
82 STK8BA50_REG_XOUT,
83 STK8BA50_REG_YOUT,
84 STK8BA50_REG_ZOUT
85 };
86
87 struct stk8ba50_data {
88 struct i2c_client *client;
89 struct mutex lock;
90 int range;
91 u8 sample_rate_idx;
92 struct iio_trigger *dready_trig;
93 bool dready_trigger_on;
94 /* Ensure timestamp is naturally aligned */
95 struct {
96 s16 chans[3];
97 s64 timetamp __aligned(8);
98 } scan;
99 };
100
101 #define STK8BA50_ACCEL_CHANNEL(index, reg, axis) { \
102 .type = IIO_ACCEL, \
103 .address = reg, \
104 .modified = 1, \
105 .channel2 = IIO_MOD_##axis, \
106 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
107 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
108 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
109 .scan_index = index, \
110 .scan_type = { \
111 .sign = 's', \
112 .realbits = 10, \
113 .storagebits = 16, \
114 .shift = STK8BA50_DATA_SHIFT, \
115 .endianness = IIO_CPU, \
116 }, \
117 }
118
119 static const struct iio_chan_spec stk8ba50_channels[] = {
120 STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
121 STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
122 STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
123 IIO_CHAN_SOFT_TIMESTAMP(3),
124 };
125
126 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
127
128 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");
129
130 static struct attribute *stk8ba50_attributes[] = {
131 &iio_const_attr_in_accel_scale_available.dev_attr.attr,
132 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
133 NULL,
134 };
135
136 static const struct attribute_group stk8ba50_attribute_group = {
137 .attrs = stk8ba50_attributes
138 };
139
stk8ba50_read_accel(struct stk8ba50_data * data,u8 reg)140 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
141 {
142 int ret;
143 struct i2c_client *client = data->client;
144
145 ret = i2c_smbus_read_word_data(client, reg);
146 if (ret < 0) {
147 dev_err(&client->dev, "register read failed\n");
148 return ret;
149 }
150
151 return ret;
152 }
153
stk8ba50_data_rdy_trigger_set_state(struct iio_trigger * trig,bool state)154 static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
155 bool state)
156 {
157 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
158 struct stk8ba50_data *data = iio_priv(indio_dev);
159 int ret;
160
161 if (state)
162 ret = i2c_smbus_write_byte_data(data->client,
163 STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
164 else
165 ret = i2c_smbus_write_byte_data(data->client,
166 STK8BA50_REG_INTEN2, 0x00);
167
168 if (ret < 0)
169 dev_err(&data->client->dev, "failed to set trigger state\n");
170 else
171 data->dready_trigger_on = state;
172
173 return ret;
174 }
175
176 static const struct iio_trigger_ops stk8ba50_trigger_ops = {
177 .set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
178 };
179
stk8ba50_set_power(struct stk8ba50_data * data,bool mode)180 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
181 {
182 int ret;
183 u8 masked_reg;
184 struct i2c_client *client = data->client;
185
186 ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
187 if (ret < 0)
188 goto exit_err;
189
190 if (mode)
191 masked_reg = ret | STK8BA50_MODE_POWERBIT;
192 else
193 masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
194
195 ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
196 masked_reg);
197 if (ret < 0)
198 goto exit_err;
199
200 return ret;
201
202 exit_err:
203 dev_err(&client->dev, "failed to change sensor mode\n");
204 return ret;
205 }
206
stk8ba50_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)207 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
208 struct iio_chan_spec const *chan,
209 int *val, int *val2, long mask)
210 {
211 struct stk8ba50_data *data = iio_priv(indio_dev);
212 int ret;
213
214 switch (mask) {
215 case IIO_CHAN_INFO_RAW:
216 if (iio_buffer_enabled(indio_dev))
217 return -EBUSY;
218 mutex_lock(&data->lock);
219 ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
220 if (ret < 0) {
221 mutex_unlock(&data->lock);
222 return -EINVAL;
223 }
224 ret = stk8ba50_read_accel(data, chan->address);
225 if (ret < 0) {
226 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
227 mutex_unlock(&data->lock);
228 return -EINVAL;
229 }
230 *val = sign_extend32(ret >> chan->scan_type.shift,
231 chan->scan_type.realbits - 1);
232 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
233 mutex_unlock(&data->lock);
234 return IIO_VAL_INT;
235 case IIO_CHAN_INFO_SCALE:
236 *val = 0;
237 *val2 = stk8ba50_scale_table[data->range].scale_val;
238 return IIO_VAL_INT_PLUS_MICRO;
239 case IIO_CHAN_INFO_SAMP_FREQ:
240 *val = stk8ba50_samp_freq_table
241 [data->sample_rate_idx].samp_freq;
242 *val2 = 0;
243 return IIO_VAL_INT;
244 }
245
246 return -EINVAL;
247 }
248
stk8ba50_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)249 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
250 struct iio_chan_spec const *chan,
251 int val, int val2, long mask)
252 {
253 int ret;
254 int i;
255 int index = -1;
256 struct stk8ba50_data *data = iio_priv(indio_dev);
257
258 switch (mask) {
259 case IIO_CHAN_INFO_SCALE:
260 if (val != 0)
261 return -EINVAL;
262
263 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
264 if (val2 == stk8ba50_scale_table[i].scale_val) {
265 index = i;
266 break;
267 }
268 if (index < 0)
269 return -EINVAL;
270
271 ret = i2c_smbus_write_byte_data(data->client,
272 STK8BA50_REG_RANGE,
273 stk8ba50_scale_table[index].reg_val);
274 if (ret < 0)
275 dev_err(&data->client->dev,
276 "failed to set measurement range\n");
277 else
278 data->range = index;
279
280 return ret;
281 case IIO_CHAN_INFO_SAMP_FREQ:
282 for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
283 if (val == stk8ba50_samp_freq_table[i].samp_freq) {
284 index = i;
285 break;
286 }
287 if (index < 0)
288 return -EINVAL;
289
290 ret = i2c_smbus_write_byte_data(data->client,
291 STK8BA50_REG_BWSEL,
292 stk8ba50_samp_freq_table[index].reg_val);
293 if (ret < 0)
294 dev_err(&data->client->dev,
295 "failed to set sampling rate\n");
296 else
297 data->sample_rate_idx = index;
298
299 return ret;
300 }
301
302 return -EINVAL;
303 }
304
305 static const struct iio_info stk8ba50_info = {
306 .read_raw = stk8ba50_read_raw,
307 .write_raw = stk8ba50_write_raw,
308 .attrs = &stk8ba50_attribute_group,
309 };
310
stk8ba50_trigger_handler(int irq,void * p)311 static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
312 {
313 struct iio_poll_func *pf = p;
314 struct iio_dev *indio_dev = pf->indio_dev;
315 struct stk8ba50_data *data = iio_priv(indio_dev);
316 int bit, ret, i = 0;
317
318 mutex_lock(&data->lock);
319 /*
320 * Do a bulk read if all channels are requested,
321 * from 0x02 (XOUT1) to 0x07 (ZOUT2)
322 */
323 if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
324 ret = i2c_smbus_read_i2c_block_data(data->client,
325 STK8BA50_REG_XOUT,
326 STK8BA50_ALL_CHANNEL_SIZE,
327 (u8 *)data->scan.chans);
328 if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
329 dev_err(&data->client->dev, "register read failed\n");
330 goto err;
331 }
332 } else {
333 iio_for_each_active_channel(indio_dev, bit) {
334 ret = stk8ba50_read_accel(data,
335 stk8ba50_channel_table[bit]);
336 if (ret < 0)
337 goto err;
338
339 data->scan.chans[i++] = ret;
340 }
341 }
342 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
343 pf->timestamp);
344 err:
345 mutex_unlock(&data->lock);
346 iio_trigger_notify_done(indio_dev->trig);
347
348 return IRQ_HANDLED;
349 }
350
stk8ba50_data_rdy_trig_poll(int irq,void * private)351 static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
352 {
353 struct iio_dev *indio_dev = private;
354 struct stk8ba50_data *data = iio_priv(indio_dev);
355
356 if (data->dready_trigger_on)
357 iio_trigger_poll(data->dready_trig);
358
359 return IRQ_HANDLED;
360 }
361
stk8ba50_buffer_preenable(struct iio_dev * indio_dev)362 static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
363 {
364 struct stk8ba50_data *data = iio_priv(indio_dev);
365
366 return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
367 }
368
stk8ba50_buffer_postdisable(struct iio_dev * indio_dev)369 static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
370 {
371 struct stk8ba50_data *data = iio_priv(indio_dev);
372
373 return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
374 }
375
376 static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
377 .preenable = stk8ba50_buffer_preenable,
378 .postdisable = stk8ba50_buffer_postdisable,
379 };
380
stk8ba50_probe(struct i2c_client * client)381 static int stk8ba50_probe(struct i2c_client *client)
382 {
383 int ret;
384 struct iio_dev *indio_dev;
385 struct stk8ba50_data *data;
386
387 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
388 if (!indio_dev) {
389 dev_err(&client->dev, "iio allocation failed!\n");
390 return -ENOMEM;
391 }
392
393 data = iio_priv(indio_dev);
394 data->client = client;
395 i2c_set_clientdata(client, indio_dev);
396 mutex_init(&data->lock);
397
398 indio_dev->info = &stk8ba50_info;
399 indio_dev->name = STK8BA50_DRIVER_NAME;
400 indio_dev->modes = INDIO_DIRECT_MODE;
401 indio_dev->channels = stk8ba50_channels;
402 indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
403
404 /* Reset all registers on startup */
405 ret = i2c_smbus_write_byte_data(client,
406 STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
407 if (ret < 0) {
408 dev_err(&client->dev, "failed to reset sensor\n");
409 goto err_power_off;
410 }
411
412 /* The default range is +/-2g */
413 data->range = 0;
414
415 /* The default sampling rate is 1792 Hz (maximum) */
416 data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;
417
418 /* Set up interrupts */
419 ret = i2c_smbus_write_byte_data(client,
420 STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
421 if (ret < 0) {
422 dev_err(&client->dev, "failed to set up interrupts\n");
423 goto err_power_off;
424 }
425 ret = i2c_smbus_write_byte_data(client,
426 STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
427 if (ret < 0) {
428 dev_err(&client->dev, "failed to set up interrupts\n");
429 goto err_power_off;
430 }
431
432 if (client->irq > 0) {
433 ret = devm_request_threaded_irq(&client->dev, client->irq,
434 stk8ba50_data_rdy_trig_poll,
435 NULL,
436 IRQF_TRIGGER_RISING |
437 IRQF_ONESHOT,
438 STK8BA50_IRQ_NAME,
439 indio_dev);
440 if (ret < 0) {
441 dev_err(&client->dev, "request irq %d failed\n",
442 client->irq);
443 goto err_power_off;
444 }
445
446 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
447 "%s-dev%d",
448 indio_dev->name,
449 iio_device_id(indio_dev));
450 if (!data->dready_trig) {
451 ret = -ENOMEM;
452 goto err_power_off;
453 }
454
455 data->dready_trig->ops = &stk8ba50_trigger_ops;
456 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
457 ret = iio_trigger_register(data->dready_trig);
458 if (ret) {
459 dev_err(&client->dev, "iio trigger register failed\n");
460 goto err_power_off;
461 }
462 }
463
464 ret = iio_triggered_buffer_setup(indio_dev,
465 iio_pollfunc_store_time,
466 stk8ba50_trigger_handler,
467 &stk8ba50_buffer_setup_ops);
468 if (ret < 0) {
469 dev_err(&client->dev, "iio triggered buffer setup failed\n");
470 goto err_trigger_unregister;
471 }
472
473 ret = iio_device_register(indio_dev);
474 if (ret < 0) {
475 dev_err(&client->dev, "device_register failed\n");
476 goto err_buffer_cleanup;
477 }
478
479 return ret;
480
481 err_buffer_cleanup:
482 iio_triggered_buffer_cleanup(indio_dev);
483 err_trigger_unregister:
484 if (data->dready_trig)
485 iio_trigger_unregister(data->dready_trig);
486 err_power_off:
487 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
488 return ret;
489 }
490
stk8ba50_remove(struct i2c_client * client)491 static void stk8ba50_remove(struct i2c_client *client)
492 {
493 struct iio_dev *indio_dev = i2c_get_clientdata(client);
494 struct stk8ba50_data *data = iio_priv(indio_dev);
495
496 iio_device_unregister(indio_dev);
497 iio_triggered_buffer_cleanup(indio_dev);
498
499 if (data->dready_trig)
500 iio_trigger_unregister(data->dready_trig);
501
502 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
503 }
504
stk8ba50_suspend(struct device * dev)505 static int stk8ba50_suspend(struct device *dev)
506 {
507 struct stk8ba50_data *data;
508
509 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
510
511 return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
512 }
513
stk8ba50_resume(struct device * dev)514 static int stk8ba50_resume(struct device *dev)
515 {
516 struct stk8ba50_data *data;
517
518 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
519
520 return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
521 }
522
523 static DEFINE_SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend,
524 stk8ba50_resume);
525
526 static const struct i2c_device_id stk8ba50_i2c_id[] = {
527 { "stk8ba50" },
528 {}
529 };
530 MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);
531
532 static const struct acpi_device_id stk8ba50_acpi_id[] = {
533 {"STK8BA50", 0},
534 {}
535 };
536
537 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
538
539 static struct i2c_driver stk8ba50_driver = {
540 .driver = {
541 .name = "stk8ba50",
542 .pm = pm_sleep_ptr(&stk8ba50_pm_ops),
543 .acpi_match_table = stk8ba50_acpi_id,
544 },
545 .probe = stk8ba50_probe,
546 .remove = stk8ba50_remove,
547 .id_table = stk8ba50_i2c_id,
548 };
549
550 module_i2c_driver(stk8ba50_driver);
551
552 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
553 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
554 MODULE_LICENSE("GPL v2");
555