stk8312.c

  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/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 STK8312_REG_XOUT		0x00
 24#define STK8312_REG_YOUT		0x01
 25#define STK8312_REG_ZOUT		0x02
 26#define STK8312_REG_INTSU		0x06
 27#define STK8312_REG_MODE		0x07
 28#define STK8312_REG_SR			0x08
 29#define STK8312_REG_STH			0x13
 30#define STK8312_REG_RESET		0x20
 31#define STK8312_REG_AFECTRL		0x24
 32#define STK8312_REG_OTPADDR		0x3D
 33#define STK8312_REG_OTPDATA		0x3E
 34#define STK8312_REG_OTPCTRL		0x3F
 35
 36#define STK8312_MODE_ACTIVE		BIT(0)
 37#define STK8312_MODE_STANDBY		0x00
 38#define STK8312_MODE_INT_AH_PP		0xC0	/* active-high, push-pull */
 39#define STK8312_DREADY_BIT		BIT(4)
 40#define STK8312_RNG_6G			1
 41#define STK8312_RNG_SHIFT		6
 42#define STK8312_RNG_MASK		GENMASK(7, 6)
 43#define STK8312_SR_MASK			GENMASK(2, 0)
 44#define STK8312_SR_400HZ_IDX		0
 45#define STK8312_ALL_CHANNEL_MASK	GENMASK(2, 0)
 46#define STK8312_ALL_CHANNEL_SIZE	3
 47
 48#define STK8312_DRIVER_NAME		"stk8312"
 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
 61static const int stk8312_scale_table[][2] = {
 62	{0, 461600}, {1, 231100}
 63};
 64
 65static 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
 90static 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
 97struct 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		aligned_s64 timestamp;
109	} scan;
110};
111
112static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
113
114static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("3.125 6.25 12.5 25 50 100 200 400");
115
116static 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
122static const struct attribute_group stk8312_attribute_group = {
123	.attrs = stk8312_attributes
124};
125
126static 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
165exit_err:
166	dev_err(&client->dev, "failed to initialize sensor\n");
167	return ret;
168}
169
170static 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
194static 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
216static 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
238static const struct iio_trigger_ops stk8312_trigger_ops = {
239	.set_trigger_state = stk8312_data_rdy_trigger_set_state,
240};
241
242static 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
272err_activate:
273	dev_err(&client->dev, "failed to set sampling rate\n");
274	stk8312_set_mode(data, mode);
275
276	return ret;
277}
278
279static 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
312err_activate:
313	dev_err(&client->dev, "failed to change sensor range\n");
314	stk8312_set_mode(data, mode);
315
316	return ret;
317}
318
319static 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
334static 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
378static 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
422static 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
428static 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_ts(indio_dev, &data->scan, sizeof(data->scan),
463				    pf->timestamp);
464err:
465	iio_trigger_notify_done(indio_dev->trig);
466
467	return IRQ_HANDLED;
468}
469
470static 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
481static 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
488static 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
495static const struct iio_buffer_setup_ops stk8312_buffer_setup_ops = {
496	.preenable   = stk8312_buffer_preenable,
497	.postdisable = stk8312_buffer_postdisable,
498};
499
500static 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		return -ENOMEM;
509
510	data = iio_priv(indio_dev);
511	data->client = client;
512	i2c_set_clientdata(client, indio_dev);
513	mutex_init(&data->lock);
514
515	indio_dev->info = &stk8312_info;
516	indio_dev->name = STK8312_DRIVER_NAME;
517	indio_dev->modes = INDIO_DIRECT_MODE;
518	indio_dev->channels = stk8312_channels;
519	indio_dev->num_channels = ARRAY_SIZE(stk8312_channels);
520
521	/* A software reset is recommended at power-on */
522	ret = i2c_smbus_write_byte_data(data->client, STK8312_REG_RESET, 0x00);
523	if (ret < 0) {
524		dev_err(&client->dev, "failed to reset sensor\n");
525		return ret;
526	}
527	data->sample_rate_idx = STK8312_SR_400HZ_IDX;
528	ret = stk8312_set_range(data, STK8312_RNG_6G);
529	if (ret < 0)
530		return ret;
531
532	ret = stk8312_set_mode(data,
533			       STK8312_MODE_INT_AH_PP | STK8312_MODE_ACTIVE);
534	if (ret < 0)
535		return ret;
536
537	if (client->irq > 0) {
538		ret = devm_request_threaded_irq(&client->dev, client->irq,
539						stk8312_data_rdy_trig_poll,
540						NULL,
541						IRQF_TRIGGER_RISING |
542						IRQF_ONESHOT,
543						"stk8312_event",
544						indio_dev);
545		if (ret < 0) {
546			dev_err(&client->dev, "request irq %d failed\n",
547				client->irq);
548			goto err_power_off;
549		}
550
551		data->dready_trig = devm_iio_trigger_alloc(&client->dev,
552							   "%s-dev%d",
553							   indio_dev->name,
554							   iio_device_id(indio_dev));
555		if (!data->dready_trig) {
556			ret = -ENOMEM;
557			goto err_power_off;
558		}
559
560		data->dready_trig->ops = &stk8312_trigger_ops;
561		iio_trigger_set_drvdata(data->dready_trig, indio_dev);
562		ret = iio_trigger_register(data->dready_trig);
563		if (ret) {
564			dev_err(&client->dev, "iio trigger register failed\n");
565			goto err_power_off;
566		}
567	}
568
569	ret = iio_triggered_buffer_setup(indio_dev,
570					 iio_pollfunc_store_time,
571					 stk8312_trigger_handler,
572					 &stk8312_buffer_setup_ops);
573	if (ret < 0) {
574		dev_err(&client->dev, "iio triggered buffer setup failed\n");
575		goto err_trigger_unregister;
576	}
577
578	ret = iio_device_register(indio_dev);
579	if (ret < 0) {
580		dev_err(&client->dev, "device_register failed\n");
581		goto err_buffer_cleanup;
582	}
583
584	return 0;
585
586err_buffer_cleanup:
587	iio_triggered_buffer_cleanup(indio_dev);
588err_trigger_unregister:
589	if (data->dready_trig)
590		iio_trigger_unregister(data->dready_trig);
591err_power_off:
592	stk8312_set_mode(data, STK8312_MODE_STANDBY);
593	return ret;
594}
595
596static void stk8312_remove(struct i2c_client *client)
597{
598	struct iio_dev *indio_dev = i2c_get_clientdata(client);
599	struct stk8312_data *data = iio_priv(indio_dev);
600
601	iio_device_unregister(indio_dev);
602	iio_triggered_buffer_cleanup(indio_dev);
603
604	if (data->dready_trig)
605		iio_trigger_unregister(data->dready_trig);
606
607	stk8312_set_mode(data, STK8312_MODE_STANDBY);
608}
609
610static int stk8312_suspend(struct device *dev)
611{
612	struct stk8312_data *data;
613
614	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
615
616	return stk8312_set_mode(data, data->mode & (~STK8312_MODE_ACTIVE));
617}
618
619static int stk8312_resume(struct device *dev)
620{
621	struct stk8312_data *data;
622
623	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
624
625	return stk8312_set_mode(data, data->mode | STK8312_MODE_ACTIVE);
626}
627
628static DEFINE_SIMPLE_DEV_PM_OPS(stk8312_pm_ops, stk8312_suspend,
629				stk8312_resume);
630
631static const struct i2c_device_id stk8312_i2c_id[] = {
632	/* Deprecated in favour of lowercase form */
633	{ "STK8312" },
634	{ "stk8312" },
635	{ }
636};
637MODULE_DEVICE_TABLE(i2c, stk8312_i2c_id);
638
639static struct i2c_driver stk8312_driver = {
640	.driver = {
641		.name = STK8312_DRIVER_NAME,
642		.pm = pm_sleep_ptr(&stk8312_pm_ops),
643	},
644	.probe =        stk8312_probe,
645	.remove =           stk8312_remove,
646	.id_table =         stk8312_i2c_id,
647};
648
649module_i2c_driver(stk8312_driver);
650
651MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
652MODULE_DESCRIPTION("STK8312 3-Axis Accelerometer driver");
653MODULE_LICENSE("GPL v2");