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/types.h>
16 #include <linux/iio/buffer.h>
17 #include <linux/iio/iio.h>
18 #include <linux/iio/sysfs.h>
19 #include <linux/iio/trigger.h>
20 #include <linux/iio/triggered_buffer.h>
21 #include <linux/iio/trigger_consumer.h>
22
23 #define STK8BA50_REG_XOUT 0x02
24 #define STK8BA50_REG_YOUT 0x04
25 #define STK8BA50_REG_ZOUT 0x06
26 #define STK8BA50_REG_RANGE 0x0F
27 #define STK8BA50_REG_BWSEL 0x10
28 #define STK8BA50_REG_POWMODE 0x11
29 #define STK8BA50_REG_SWRST 0x14
30 #define STK8BA50_REG_INTEN2 0x17
31 #define STK8BA50_REG_INTMAP2 0x1A
32
33 #define STK8BA50_MODE_NORMAL 0
34 #define STK8BA50_MODE_SUSPEND 1
35 #define STK8BA50_MODE_POWERBIT BIT(7)
36 #define STK8BA50_DATA_SHIFT 6
37 #define STK8BA50_RESET_CMD 0xB6
38 #define STK8BA50_SR_1792HZ_IDX 7
39 #define STK8BA50_DREADY_INT_MASK 0x10
40 #define STK8BA50_DREADY_INT_MAP 0x81
41 #define STK8BA50_ALL_CHANNEL_MASK 7
42 #define STK8BA50_ALL_CHANNEL_SIZE 6
43
44 #define STK8BA50_DRIVER_NAME "stk8ba50"
45 #define STK8BA50_IRQ_NAME "stk8ba50_event"
46
47 #define STK8BA50_SCALE_AVAIL "0.0384 0.0767 0.1534 0.3069"
48
49 /*
50 * The accelerometer has four measurement ranges:
51 * +/-2g; +/-4g; +/-8g; +/-16g
52 *
53 * Acceleration values are 10-bit, 2's complement.
54 * Scales are calculated as following:
55 *
56 * scale1 = (2 + 2) * 9.81 / (2^10 - 1) = 0.0384
57 * scale2 = (4 + 4) * 9.81 / (2^10 - 1) = 0.0767
58 * etc.
59 *
60 * Scales are stored in this format:
61 * { <register value>, <scale value> }
62 *
63 * Locally, the range is stored as a table index.
64 */
65 static const struct {
66 u8 reg_val;
67 u32 scale_val;
68 } stk8ba50_scale_table[] = {
69 {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
70 };
71
72 /* Sample rates are stored as { <register value>, <Hz value> } */
73 static const struct {
74 u8 reg_val;
75 u16 samp_freq;
76 } stk8ba50_samp_freq_table[] = {
77 {0x08, 14}, {0x09, 25}, {0x0A, 56}, {0x0B, 112},
78 {0x0C, 224}, {0x0D, 448}, {0x0E, 896}, {0x0F, 1792}
79 };
80
81 /* Used to map scan mask bits to their corresponding channel register. */
82 static const int stk8ba50_channel_table[] = {
83 STK8BA50_REG_XOUT,
84 STK8BA50_REG_YOUT,
85 STK8BA50_REG_ZOUT
86 };
87
88 struct stk8ba50_data {
89 struct i2c_client *client;
90 struct mutex lock;
91 int range;
92 u8 sample_rate_idx;
93 struct iio_trigger *dready_trig;
94 bool dready_trigger_on;
95 /* Ensure timestamp is naturally aligned */
96 struct {
97 s16 chans[3];
98 aligned_s64 timetamp;
99 } scan;
100 };
101
102 #define STK8BA50_ACCEL_CHANNEL(index, reg, axis) { \
103 .type = IIO_ACCEL, \
104 .address = reg, \
105 .modified = 1, \
106 .channel2 = IIO_MOD_##axis, \
107 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
108 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
109 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
110 .scan_index = index, \
111 .scan_type = { \
112 .sign = 's', \
113 .realbits = 10, \
114 .storagebits = 16, \
115 .shift = STK8BA50_DATA_SHIFT, \
116 .endianness = IIO_CPU, \
117 }, \
118 }
119
120 static const struct iio_chan_spec stk8ba50_channels[] = {
121 STK8BA50_ACCEL_CHANNEL(0, STK8BA50_REG_XOUT, X),
122 STK8BA50_ACCEL_CHANNEL(1, STK8BA50_REG_YOUT, Y),
123 STK8BA50_ACCEL_CHANNEL(2, STK8BA50_REG_ZOUT, Z),
124 IIO_CHAN_SOFT_TIMESTAMP(3),
125 };
126
127 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
128
129 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");
130
131 static struct attribute *stk8ba50_attributes[] = {
132 &iio_const_attr_in_accel_scale_available.dev_attr.attr,
133 &iio_const_attr_sampling_frequency_available.dev_attr.attr,
134 NULL,
135 };
136
137 static const struct attribute_group stk8ba50_attribute_group = {
138 .attrs = stk8ba50_attributes
139 };
140
stk8ba50_read_accel(struct stk8ba50_data * data,u8 reg)141 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
142 {
143 int ret;
144 struct i2c_client *client = data->client;
145
146 ret = i2c_smbus_read_word_data(client, reg);
147 if (ret < 0) {
148 dev_err(&client->dev, "register read failed\n");
149 return ret;
150 }
151
152 return ret;
153 }
154
stk8ba50_data_rdy_trigger_set_state(struct iio_trigger * trig,bool state)155 static int stk8ba50_data_rdy_trigger_set_state(struct iio_trigger *trig,
156 bool state)
157 {
158 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
159 struct stk8ba50_data *data = iio_priv(indio_dev);
160 int ret;
161
162 if (state)
163 ret = i2c_smbus_write_byte_data(data->client,
164 STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
165 else
166 ret = i2c_smbus_write_byte_data(data->client,
167 STK8BA50_REG_INTEN2, 0x00);
168
169 if (ret < 0)
170 dev_err(&data->client->dev, "failed to set trigger state\n");
171 else
172 data->dready_trigger_on = state;
173
174 return ret;
175 }
176
177 static const struct iio_trigger_ops stk8ba50_trigger_ops = {
178 .set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
179 };
180
stk8ba50_set_power(struct stk8ba50_data * data,bool mode)181 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
182 {
183 int ret;
184 u8 masked_reg;
185 struct i2c_client *client = data->client;
186
187 ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
188 if (ret < 0)
189 goto exit_err;
190
191 if (mode)
192 masked_reg = ret | STK8BA50_MODE_POWERBIT;
193 else
194 masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
195
196 ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
197 masked_reg);
198 if (ret < 0)
199 goto exit_err;
200
201 return ret;
202
203 exit_err:
204 dev_err(&client->dev, "failed to change sensor mode\n");
205 return ret;
206 }
207
stk8ba50_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)208 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
209 struct iio_chan_spec const *chan,
210 int *val, int *val2, long mask)
211 {
212 struct stk8ba50_data *data = iio_priv(indio_dev);
213 int ret;
214
215 switch (mask) {
216 case IIO_CHAN_INFO_RAW:
217 if (iio_buffer_enabled(indio_dev))
218 return -EBUSY;
219 mutex_lock(&data->lock);
220 ret = stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
221 if (ret < 0) {
222 mutex_unlock(&data->lock);
223 return -EINVAL;
224 }
225 ret = stk8ba50_read_accel(data, chan->address);
226 if (ret < 0) {
227 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
228 mutex_unlock(&data->lock);
229 return -EINVAL;
230 }
231 *val = sign_extend32(ret >> chan->scan_type.shift,
232 chan->scan_type.realbits - 1);
233 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
234 mutex_unlock(&data->lock);
235 return IIO_VAL_INT;
236 case IIO_CHAN_INFO_SCALE:
237 *val = 0;
238 *val2 = stk8ba50_scale_table[data->range].scale_val;
239 return IIO_VAL_INT_PLUS_MICRO;
240 case IIO_CHAN_INFO_SAMP_FREQ:
241 *val = stk8ba50_samp_freq_table
242 [data->sample_rate_idx].samp_freq;
243 *val2 = 0;
244 return IIO_VAL_INT;
245 }
246
247 return -EINVAL;
248 }
249
stk8ba50_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)250 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
251 struct iio_chan_spec const *chan,
252 int val, int val2, long mask)
253 {
254 int ret;
255 int i;
256 int index = -1;
257 struct stk8ba50_data *data = iio_priv(indio_dev);
258
259 switch (mask) {
260 case IIO_CHAN_INFO_SCALE:
261 if (val != 0)
262 return -EINVAL;
263
264 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
265 if (val2 == stk8ba50_scale_table[i].scale_val) {
266 index = i;
267 break;
268 }
269 if (index < 0)
270 return -EINVAL;
271
272 ret = i2c_smbus_write_byte_data(data->client,
273 STK8BA50_REG_RANGE,
274 stk8ba50_scale_table[index].reg_val);
275 if (ret < 0)
276 dev_err(&data->client->dev,
277 "failed to set measurement range\n");
278 else
279 data->range = index;
280
281 return ret;
282 case IIO_CHAN_INFO_SAMP_FREQ:
283 for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
284 if (val == stk8ba50_samp_freq_table[i].samp_freq) {
285 index = i;
286 break;
287 }
288 if (index < 0)
289 return -EINVAL;
290
291 ret = i2c_smbus_write_byte_data(data->client,
292 STK8BA50_REG_BWSEL,
293 stk8ba50_samp_freq_table[index].reg_val);
294 if (ret < 0)
295 dev_err(&data->client->dev,
296 "failed to set sampling rate\n");
297 else
298 data->sample_rate_idx = index;
299
300 return ret;
301 }
302
303 return -EINVAL;
304 }
305
306 static const struct iio_info stk8ba50_info = {
307 .read_raw = stk8ba50_read_raw,
308 .write_raw = stk8ba50_write_raw,
309 .attrs = &stk8ba50_attribute_group,
310 };
311
stk8ba50_trigger_handler(int irq,void * p)312 static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
313 {
314 struct iio_poll_func *pf = p;
315 struct iio_dev *indio_dev = pf->indio_dev;
316 struct stk8ba50_data *data = iio_priv(indio_dev);
317 int bit, ret, i = 0;
318
319 mutex_lock(&data->lock);
320 /*
321 * Do a bulk read if all channels are requested,
322 * from 0x02 (XOUT1) to 0x07 (ZOUT2)
323 */
324 if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
325 ret = i2c_smbus_read_i2c_block_data(data->client,
326 STK8BA50_REG_XOUT,
327 STK8BA50_ALL_CHANNEL_SIZE,
328 (u8 *)data->scan.chans);
329 if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
330 dev_err(&data->client->dev, "register read failed\n");
331 goto err;
332 }
333 } else {
334 iio_for_each_active_channel(indio_dev, bit) {
335 ret = stk8ba50_read_accel(data,
336 stk8ba50_channel_table[bit]);
337 if (ret < 0)
338 goto err;
339
340 data->scan.chans[i++] = ret;
341 }
342 }
343 iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
344 pf->timestamp);
345 err:
346 mutex_unlock(&data->lock);
347 iio_trigger_notify_done(indio_dev->trig);
348
349 return IRQ_HANDLED;
350 }
351
stk8ba50_data_rdy_trig_poll(int irq,void * private)352 static irqreturn_t stk8ba50_data_rdy_trig_poll(int irq, void *private)
353 {
354 struct iio_dev *indio_dev = private;
355 struct stk8ba50_data *data = iio_priv(indio_dev);
356
357 if (data->dready_trigger_on)
358 iio_trigger_poll(data->dready_trig);
359
360 return IRQ_HANDLED;
361 }
362
stk8ba50_buffer_preenable(struct iio_dev * indio_dev)363 static int stk8ba50_buffer_preenable(struct iio_dev *indio_dev)
364 {
365 struct stk8ba50_data *data = iio_priv(indio_dev);
366
367 return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
368 }
369
stk8ba50_buffer_postdisable(struct iio_dev * indio_dev)370 static int stk8ba50_buffer_postdisable(struct iio_dev *indio_dev)
371 {
372 struct stk8ba50_data *data = iio_priv(indio_dev);
373
374 return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
375 }
376
377 static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
378 .preenable = stk8ba50_buffer_preenable,
379 .postdisable = stk8ba50_buffer_postdisable,
380 };
381
stk8ba50_probe(struct i2c_client * client)382 static int stk8ba50_probe(struct i2c_client *client)
383 {
384 int ret;
385 struct iio_dev *indio_dev;
386 struct stk8ba50_data *data;
387
388 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
389 if (!indio_dev) {
390 dev_err(&client->dev, "iio allocation failed!\n");
391 return -ENOMEM;
392 }
393
394 data = iio_priv(indio_dev);
395 data->client = client;
396 i2c_set_clientdata(client, indio_dev);
397 mutex_init(&data->lock);
398
399 indio_dev->info = &stk8ba50_info;
400 indio_dev->name = STK8BA50_DRIVER_NAME;
401 indio_dev->modes = INDIO_DIRECT_MODE;
402 indio_dev->channels = stk8ba50_channels;
403 indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
404
405 /* Reset all registers on startup */
406 ret = i2c_smbus_write_byte_data(client,
407 STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
408 if (ret < 0) {
409 dev_err(&client->dev, "failed to reset sensor\n");
410 goto err_power_off;
411 }
412
413 /* The default range is +/-2g */
414 data->range = 0;
415
416 /* The default sampling rate is 1792 Hz (maximum) */
417 data->sample_rate_idx = STK8BA50_SR_1792HZ_IDX;
418
419 /* Set up interrupts */
420 ret = i2c_smbus_write_byte_data(client,
421 STK8BA50_REG_INTEN2, STK8BA50_DREADY_INT_MASK);
422 if (ret < 0) {
423 dev_err(&client->dev, "failed to set up interrupts\n");
424 goto err_power_off;
425 }
426 ret = i2c_smbus_write_byte_data(client,
427 STK8BA50_REG_INTMAP2, STK8BA50_DREADY_INT_MAP);
428 if (ret < 0) {
429 dev_err(&client->dev, "failed to set up interrupts\n");
430 goto err_power_off;
431 }
432
433 if (client->irq > 0) {
434 ret = devm_request_threaded_irq(&client->dev, client->irq,
435 stk8ba50_data_rdy_trig_poll,
436 NULL,
437 IRQF_TRIGGER_RISING |
438 IRQF_ONESHOT,
439 STK8BA50_IRQ_NAME,
440 indio_dev);
441 if (ret < 0) {
442 dev_err(&client->dev, "request irq %d failed\n",
443 client->irq);
444 goto err_power_off;
445 }
446
447 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
448 "%s-dev%d",
449 indio_dev->name,
450 iio_device_id(indio_dev));
451 if (!data->dready_trig) {
452 ret = -ENOMEM;
453 goto err_power_off;
454 }
455
456 data->dready_trig->ops = &stk8ba50_trigger_ops;
457 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
458 ret = iio_trigger_register(data->dready_trig);
459 if (ret) {
460 dev_err(&client->dev, "iio trigger register failed\n");
461 goto err_power_off;
462 }
463 }
464
465 ret = iio_triggered_buffer_setup(indio_dev,
466 iio_pollfunc_store_time,
467 stk8ba50_trigger_handler,
468 &stk8ba50_buffer_setup_ops);
469 if (ret < 0) {
470 dev_err(&client->dev, "iio triggered buffer setup failed\n");
471 goto err_trigger_unregister;
472 }
473
474 ret = iio_device_register(indio_dev);
475 if (ret < 0) {
476 dev_err(&client->dev, "device_register failed\n");
477 goto err_buffer_cleanup;
478 }
479
480 return ret;
481
482 err_buffer_cleanup:
483 iio_triggered_buffer_cleanup(indio_dev);
484 err_trigger_unregister:
485 if (data->dready_trig)
486 iio_trigger_unregister(data->dready_trig);
487 err_power_off:
488 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
489 return ret;
490 }
491
stk8ba50_remove(struct i2c_client * client)492 static void stk8ba50_remove(struct i2c_client *client)
493 {
494 struct iio_dev *indio_dev = i2c_get_clientdata(client);
495 struct stk8ba50_data *data = iio_priv(indio_dev);
496
497 iio_device_unregister(indio_dev);
498 iio_triggered_buffer_cleanup(indio_dev);
499
500 if (data->dready_trig)
501 iio_trigger_unregister(data->dready_trig);
502
503 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
504 }
505
stk8ba50_suspend(struct device * dev)506 static int stk8ba50_suspend(struct device *dev)
507 {
508 struct stk8ba50_data *data;
509
510 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
511
512 return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
513 }
514
stk8ba50_resume(struct device * dev)515 static int stk8ba50_resume(struct device *dev)
516 {
517 struct stk8ba50_data *data;
518
519 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
520
521 return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
522 }
523
524 static DEFINE_SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend,
525 stk8ba50_resume);
526
527 static const struct i2c_device_id stk8ba50_i2c_id[] = {
528 { "stk8ba50" },
529 {}
530 };
531 MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);
532
533 static const struct acpi_device_id stk8ba50_acpi_id[] = {
534 {"STK8BA50", 0},
535 {}
536 };
537
538 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
539
540 static struct i2c_driver stk8ba50_driver = {
541 .driver = {
542 .name = "stk8ba50",
543 .pm = pm_sleep_ptr(&stk8ba50_pm_ops),
544 .acpi_match_table = stk8ba50_acpi_id,
545 },
546 .probe = stk8ba50_probe,
547 .remove = stk8ba50_remove,
548 .id_table = stk8ba50_i2c_id,
549 };
550
551 module_i2c_driver(stk8ba50_driver);
552
553 MODULE_AUTHOR("Tiberiu Breana <[email protected]>");
554 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
555 MODULE_LICENSE("GPL v2");
556