2 * Sensortek STK8312 3-Axis Accelerometer
4 * Copyright (c) 2015, Intel Corporation.
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.
10 * IIO driver for STK8312; 7-bit I2C address: 0x3D.
13 #include <linux/acpi.h>
14 #include <linux/i2c.h>
15 #include <linux/interrupt.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/delay.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/iio.h>
21 #include <linux/iio/sysfs.h>
22 #include <linux/iio/trigger.h>
23 #include <linux/iio/triggered_buffer.h>
24 #include <linux/iio/trigger_consumer.h>
26 #define STK8312_REG_XOUT 0x00
27 #define STK8312_REG_YOUT 0x01
28 #define STK8312_REG_ZOUT 0x02
29 #define STK8312_REG_INTSU 0x06
30 #define STK8312_REG_MODE 0x07
31 #define STK8312_REG_SR 0x08
32 #define STK8312_REG_STH 0x13
33 #define STK8312_REG_RESET 0x20
34 #define STK8312_REG_AFECTRL 0x24
35 #define STK8312_REG_OTPADDR 0x3D
36 #define STK8312_REG_OTPDATA 0x3E
37 #define STK8312_REG_OTPCTRL 0x3F
39 #define STK8312_MODE_ACTIVE BIT(0)
40 #define STK8312_MODE_STANDBY 0x00
41 #define STK8312_MODE_INT_AH_PP 0xC0 /* active-high, push-pull */
42 #define STK8312_DREADY_BIT BIT(4)
43 #define STK8312_RNG_6G 1
44 #define STK8312_RNG_SHIFT 6
45 #define STK8312_RNG_MASK GENMASK(7, 6)
46 #define STK8312_SR_MASK GENMASK(2, 0)
47 #define STK8312_SR_400HZ_IDX 0
48 #define STK8312_ALL_CHANNEL_MASK GENMASK(2, 0)
49 #define STK8312_ALL_CHANNEL_SIZE 3
51 #define STK8312_DRIVER_NAME "stk8312"
52 #define STK8312_IRQ_NAME "stk8312_event"
55 * The accelerometer has two measurement ranges:
57 * -6g - +6g (8-bit, signed)
58 * -16g - +16g (8-bit, signed)
60 * scale1 = (6 + 6) * 9.81 / (2^8 - 1) = 0.4616
61 * scale2 = (16 + 16) * 9.81 / (2^8 - 1) = 1.2311
63 #define STK8312_SCALE_AVAIL "0.4616 1.2311"
65 static const int stk8312_scale_table[][2] = {
66 {0, 461600}, {1, 231100}
72 } stk8312_samp_freq_table[] = {
73 {400, 0}, {200, 0}, {100, 0}, {50, 0}, {25, 0},
74 {12, 500000}, {6, 250000}, {3, 125000}
77 #define STK8312_ACCEL_CHANNEL(index, reg, axis) { \
81 .channel2 = IIO_MOD_##axis, \
82 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
83 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
84 BIT(IIO_CHAN_INFO_SAMP_FREQ), \
85 .scan_index = index, \
90 .endianness = IIO_CPU, \
94 static const struct iio_chan_spec stk8312_channels[] = {
95 STK8312_ACCEL_CHANNEL(0, STK8312_REG_XOUT, X),
96 STK8312_ACCEL_CHANNEL(1, STK8312_REG_YOUT, Y),
97 STK8312_ACCEL_CHANNEL(2, STK8312_REG_ZOUT, Z),
98 IIO_CHAN_SOFT_TIMESTAMP(3),
101 struct stk8312_data {
102 struct i2c_client *client;
107 struct iio_trigger *dready_trig;
108 bool dready_trigger_on;
109 s8 buffer[16]; /* 3x8-bit channels + 5x8 padding + 64-bit timestamp */
112 static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
114 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("3.125 6.25 12.5 25 50 100 200 400");
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,
122 static const struct attribute_group stk8312_attribute_group = {
123 .attrs = stk8312_attributes
126 static int stk8312_otp_init(struct stk8312_data *data)
130 struct i2c_client *client = data->client;
132 ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPADDR, 0x70);
135 ret = i2c_smbus_write_byte_data(client, STK8312_REG_OTPCTRL, 0x02);
140 usleep_range(1000, 5000);
141 ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPCTRL);
145 } while (!(ret & BIT(7)) && count > 0);
152 ret = i2c_smbus_read_byte_data(client, STK8312_REG_OTPDATA);
158 ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_AFECTRL, ret);
166 dev_err(&client->dev, "failed to initialize sensor\n");
170 static int stk8312_set_mode(struct stk8312_data *data, u8 mode)
173 struct i2c_client *client = data->client;
175 if (mode == data->mode)
178 ret = i2c_smbus_write_byte_data(client, STK8312_REG_MODE, mode);
180 dev_err(&client->dev, "failed to change sensor mode\n");
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);
194 static int stk8312_set_interrupts(struct stk8312_data *data, u8 int_mask)
198 struct i2c_client *client = data->client;
201 /* We need to go in standby mode to modify registers */
202 ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
206 ret = i2c_smbus_write_byte_data(client, STK8312_REG_INTSU, int_mask);
208 dev_err(&client->dev, "failed to set interrupts\n");
209 stk8312_set_mode(data, mode);
213 return stk8312_set_mode(data, mode);
216 static int stk8312_data_rdy_trigger_set_state(struct iio_trigger *trig,
219 struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
220 struct stk8312_data *data = iio_priv(indio_dev);
224 ret = stk8312_set_interrupts(data, STK8312_DREADY_BIT);
226 ret = stk8312_set_interrupts(data, 0x00);
229 dev_err(&data->client->dev, "failed to set trigger state\n");
233 data->dready_trigger_on = state;
238 static const struct iio_trigger_ops stk8312_trigger_ops = {
239 .set_trigger_state = stk8312_data_rdy_trigger_set_state,
242 static int stk8312_set_sample_rate(struct stk8312_data *data, u8 rate)
247 struct i2c_client *client = data->client;
249 if (rate == data->sample_rate_idx)
253 /* We need to go in standby mode to modify registers */
254 ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
258 ret = i2c_smbus_read_byte_data(client, STK8312_REG_SR);
262 masked_reg = (ret & (~STK8312_SR_MASK)) | rate;
264 ret = i2c_smbus_write_byte_data(client, STK8312_REG_SR, masked_reg);
268 data->sample_rate_idx = rate;
270 return stk8312_set_mode(data, mode);
273 dev_err(&client->dev, "failed to set sampling rate\n");
274 stk8312_set_mode(data, mode);
279 static int stk8312_set_range(struct stk8312_data *data, u8 range)
284 struct i2c_client *client = data->client;
286 if (range != 1 && range != 2)
288 else if (range == data->range)
292 /* We need to go in standby mode to modify registers */
293 ret = stk8312_set_mode(data, STK8312_MODE_STANDBY);
297 ret = i2c_smbus_read_byte_data(client, STK8312_REG_STH);
301 masked_reg = ret & (~STK8312_RNG_MASK);
302 masked_reg |= range << STK8312_RNG_SHIFT;
304 ret = i2c_smbus_write_byte_data(client, STK8312_REG_STH, masked_reg);
310 return stk8312_set_mode(data, mode);
313 dev_err(&client->dev, "failed to change sensor range\n");
314 stk8312_set_mode(data, mode);
319 static int stk8312_read_accel(struct stk8312_data *data, u8 address)
322 struct i2c_client *client = data->client;
327 ret = i2c_smbus_read_byte_data(client, address);
329 dev_err(&client->dev, "register read failed\n");
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)
338 struct stk8312_data *data = iio_priv(indio_dev);
342 case IIO_CHAN_INFO_RAW:
343 if (iio_buffer_enabled(indio_dev))
345 mutex_lock(&data->lock);
346 ret = stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
348 mutex_unlock(&data->lock);
351 ret = stk8312_read_accel(data, chan->address);
353 stk8312_set_mode(data,
354 data->mode & (~STK8312_MODE_ACTIVE));
355 mutex_unlock(&data->lock);
358 *val = sign_extend32(ret, 7);
359 ret = stk8312_set_mode(data,
360 data->mode & (~STK8312_MODE_ACTIVE));
361 mutex_unlock(&data->lock);
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;
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)
385 struct stk8312_data *data = iio_priv(indio_dev);
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]) {
398 mutex_lock(&data->lock);
399 ret = stk8312_set_range(data, index);
400 mutex_unlock(&data->lock);
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) {
412 mutex_lock(&data->lock);
413 ret = stk8312_set_sample_rate(data, index);
414 mutex_unlock(&data->lock);
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,
428 static irqreturn_t stk8312_trigger_handler(int irq, void *p)
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);
435 mutex_lock(&data->lock);
437 * Do a bulk read if all channels are requested,
438 * from 0x00 (XOUT) to 0x02 (ZOUT)
440 if (*(indio_dev->active_scan_mask) == STK8312_ALL_CHANNEL_MASK) {
441 ret = i2c_smbus_read_i2c_block_data(data->client,
443 STK8312_ALL_CHANNEL_SIZE,
445 if (ret < STK8312_ALL_CHANNEL_SIZE) {
446 dev_err(&data->client->dev, "register read failed\n");
447 mutex_unlock(&data->lock);
451 for_each_set_bit(bit, indio_dev->active_scan_mask,
452 indio_dev->masklength) {
453 ret = stk8312_read_accel(data, bit);
455 mutex_unlock(&data->lock);
458 data->buffer[i++] = ret;
461 mutex_unlock(&data->lock);
463 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
466 iio_trigger_notify_done(indio_dev->trig);
471 static irqreturn_t stk8312_data_rdy_trig_poll(int irq, void *private)
473 struct iio_dev *indio_dev = private;
474 struct stk8312_data *data = iio_priv(indio_dev);
476 if (data->dready_trigger_on)
477 iio_trigger_poll(data->dready_trig);
482 static int stk8312_buffer_preenable(struct iio_dev *indio_dev)
484 struct stk8312_data *data = iio_priv(indio_dev);
486 return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
489 static int stk8312_buffer_postdisable(struct iio_dev *indio_dev)
491 struct stk8312_data *data = iio_priv(indio_dev);
493 return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
496 static const struct iio_buffer_setup_ops stk8312_buffer_setup_ops = {
497 .preenable = stk8312_buffer_preenable,
498 .postenable = iio_triggered_buffer_postenable,
499 .predisable = iio_triggered_buffer_predisable,
500 .postdisable = stk8312_buffer_postdisable,
503 static int stk8312_probe(struct i2c_client *client,
504 const struct i2c_device_id *id)
507 struct iio_dev *indio_dev;
508 struct stk8312_data *data;
510 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
512 dev_err(&client->dev, "iio allocation failed!\n");
516 data = iio_priv(indio_dev);
517 data->client = client;
518 i2c_set_clientdata(client, indio_dev);
519 mutex_init(&data->lock);
521 indio_dev->dev.parent = &client->dev;
522 indio_dev->info = &stk8312_info;
523 indio_dev->name = STK8312_DRIVER_NAME;
524 indio_dev->modes = INDIO_DIRECT_MODE;
525 indio_dev->channels = stk8312_channels;
526 indio_dev->num_channels = ARRAY_SIZE(stk8312_channels);
528 /* A software reset is recommended at power-on */
529 ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_RESET, 0x00);
531 dev_err(&client->dev, "failed to reset sensor\n");
534 data->sample_rate_idx = STK8312_SR_400HZ_IDX;
535 ret = stk8312_set_range(data, STK8312_RNG_6G);
539 ret = stk8312_set_mode(data,
540 STK8312_MODE_INT_AH_PP | STK8312_MODE_ACTIVE);
544 if (client->irq > 0) {
545 ret = devm_request_threaded_irq(&client->dev, client->irq,
546 stk8312_data_rdy_trig_poll,
548 IRQF_TRIGGER_RISING |
553 dev_err(&client->dev, "request irq %d failed\n",
558 data->dready_trig = devm_iio_trigger_alloc(&client->dev,
562 if (!data->dready_trig) {
567 data->dready_trig->dev.parent = &client->dev;
568 data->dready_trig->ops = &stk8312_trigger_ops;
569 iio_trigger_set_drvdata(data->dready_trig, indio_dev);
570 ret = iio_trigger_register(data->dready_trig);
572 dev_err(&client->dev, "iio trigger register failed\n");
577 ret = iio_triggered_buffer_setup(indio_dev,
578 iio_pollfunc_store_time,
579 stk8312_trigger_handler,
580 &stk8312_buffer_setup_ops);
582 dev_err(&client->dev, "iio triggered buffer setup failed\n");
583 goto err_trigger_unregister;
586 ret = iio_device_register(indio_dev);
588 dev_err(&client->dev, "device_register failed\n");
589 goto err_buffer_cleanup;
595 iio_triggered_buffer_cleanup(indio_dev);
596 err_trigger_unregister:
597 if (data->dready_trig)
598 iio_trigger_unregister(data->dready_trig);
600 stk8312_set_mode(data, STK8312_MODE_STANDBY);
604 static int stk8312_remove(struct i2c_client *client)
606 struct iio_dev *indio_dev = i2c_get_clientdata(client);
607 struct stk8312_data *data = iio_priv(indio_dev);
609 iio_device_unregister(indio_dev);
610 iio_triggered_buffer_cleanup(indio_dev);
612 if (data->dready_trig)
613 iio_trigger_unregister(data->dready_trig);
615 return stk8312_set_mode(data, STK8312_MODE_STANDBY);
618 #ifdef CONFIG_PM_SLEEP
619 static int stk8312_suspend(struct device *dev)
621 struct stk8312_data *data;
623 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
625 return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
628 static int stk8312_resume(struct device *dev)
630 struct stk8312_data *data;
632 data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
634 return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
637 static SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend, stk8312_resume);
639 #define STK8312_PM_OPS (&stk8312_pm_ops)
641 #define STK8312_PM_OPS NULL
644 static const struct i2c_device_id stk8312_i2c_id[] = {
648 MODULE_DEVICE_TABLE(i2c, stk8312_i2c_id);
650 static const struct acpi_device_id stk8312_acpi_id[] = {
655 MODULE_DEVICE_TABLE(acpi, stk8312_acpi_id);
657 static struct i2c_driver stk8312_driver = {
659 .name = STK8312_DRIVER_NAME,
660 .pm = STK8312_PM_OPS,
661 .acpi_match_table = ACPI_PTR(stk8312_acpi_id),
663 .probe = stk8312_probe,
664 .remove = stk8312_remove,
665 .id_table = stk8312_i2c_id,
668 module_i2c_driver(stk8312_driver);
670 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
671 MODULE_DESCRIPTION("STK8312 3-Axis Accelerometer driver");
672 MODULE_LICENSE("GPL v2");