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/acpi.h>
11#include <linux/i2c.h>
12#include <linux/interrupt.h>
13#include <linux/kernel.h>
14#include <linux/module.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 */
64static 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> } */
72static 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. */
81static const int stk8ba50_channel_table[] = {
82	STK8BA50_REG_XOUT,
83	STK8BA50_REG_YOUT,
84	STK8BA50_REG_ZOUT
85};
86
87struct 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
119static 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
126static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
127
128static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("14 25 56 112 224 448 896 1792");
129
130static 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
136static const struct attribute_group stk8ba50_attribute_group = {
137	.attrs = stk8ba50_attributes
138};
139
140static 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
154static 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
176static const struct iio_trigger_ops stk8ba50_trigger_ops = {
177	.set_trigger_state = stk8ba50_data_rdy_trigger_set_state,
178};
179
180static 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
202exit_err:
203	dev_err(&client->dev, "failed to change sensor mode\n");
204	return ret;
205}
206
207static 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 >> STK8BA50_DATA_SHIFT, 9);
231		stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
232		mutex_unlock(&data->lock);
233		return IIO_VAL_INT;
234	case IIO_CHAN_INFO_SCALE:
235		*val = 0;
236		*val2 = stk8ba50_scale_table[data->range].scale_val;
237		return IIO_VAL_INT_PLUS_MICRO;
238	case IIO_CHAN_INFO_SAMP_FREQ:
239		*val = stk8ba50_samp_freq_table
240				[data->sample_rate_idx].samp_freq;
241		*val2 = 0;
242		return IIO_VAL_INT;
243	}
244
245	return -EINVAL;
246}
247
248static int stk8ba50_write_raw(struct iio_dev *indio_dev,
249			      struct iio_chan_spec const *chan,
250			      int val, int val2, long mask)
251{
252	int ret;
253	int i;
254	int index = -1;
255	struct stk8ba50_data *data = iio_priv(indio_dev);
256
257	switch (mask) {
258	case IIO_CHAN_INFO_SCALE:
259		if (val != 0)
260			return -EINVAL;
261
262		for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
263			if (val2 == stk8ba50_scale_table[i].scale_val) {
264				index = i;
265				break;
266			}
267		if (index < 0)
268			return -EINVAL;
269
270		ret = i2c_smbus_write_byte_data(data->client,
271				STK8BA50_REG_RANGE,
272				stk8ba50_scale_table[index].reg_val);
273		if (ret < 0)
274			dev_err(&data->client->dev,
275					"failed to set measurement range\n");
276		else
277			data->range = index;
278
279		return ret;
280	case IIO_CHAN_INFO_SAMP_FREQ:
281		for (i = 0; i < ARRAY_SIZE(stk8ba50_samp_freq_table); i++)
282			if (val == stk8ba50_samp_freq_table[i].samp_freq) {
283				index = i;
284				break;
285			}
286		if (index < 0)
287			return -EINVAL;
288
289		ret = i2c_smbus_write_byte_data(data->client,
290				STK8BA50_REG_BWSEL,
291				stk8ba50_samp_freq_table[index].reg_val);
292		if (ret < 0)
293			dev_err(&data->client->dev,
294					"failed to set sampling rate\n");
295		else
296			data->sample_rate_idx = index;
297
298		return ret;
299	}
300
301	return -EINVAL;
302}
303
304static const struct iio_info stk8ba50_info = {
305	.read_raw		= stk8ba50_read_raw,
306	.write_raw		= stk8ba50_write_raw,
307	.attrs			= &stk8ba50_attribute_group,
308};
309
310static irqreturn_t stk8ba50_trigger_handler(int irq, void *p)
311{
312	struct iio_poll_func *pf = p;
313	struct iio_dev *indio_dev = pf->indio_dev;
314	struct stk8ba50_data *data = iio_priv(indio_dev);
315	int bit, ret, i = 0;
316
317	mutex_lock(&data->lock);
318	/*
319	 * Do a bulk read if all channels are requested,
320	 * from 0x02 (XOUT1) to 0x07 (ZOUT2)
321	 */
322	if (*(indio_dev->active_scan_mask) == STK8BA50_ALL_CHANNEL_MASK) {
323		ret = i2c_smbus_read_i2c_block_data(data->client,
324						    STK8BA50_REG_XOUT,
325						    STK8BA50_ALL_CHANNEL_SIZE,
326						    (u8 *)data->scan.chans);
327		if (ret < STK8BA50_ALL_CHANNEL_SIZE) {
328			dev_err(&data->client->dev, "register read failed\n");
329			goto err;
330		}
331	} else {
332		for_each_set_bit(bit, indio_dev->active_scan_mask,
333				 indio_dev->masklength) {
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);
344err:
345	mutex_unlock(&data->lock);
346	iio_trigger_notify_done(indio_dev->trig);
347
348	return IRQ_HANDLED;
349}
350
351static 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
362static 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
369static 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
376static const struct iio_buffer_setup_ops stk8ba50_buffer_setup_ops = {
377	.preenable   = stk8ba50_buffer_preenable,
378	.postdisable = stk8ba50_buffer_postdisable,
379};
380
381static int stk8ba50_probe(struct i2c_client *client,
382			  const struct i2c_device_id *id)
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							   indio_dev->id);
451		if (!data->dready_trig) {
452			ret = -ENOMEM;
453			goto err_power_off;
454		}
455
456		data->dready_trig->dev.parent = &client->dev;
457		data->dready_trig->ops = &stk8ba50_trigger_ops;
458		iio_trigger_set_drvdata(data->dready_trig, indio_dev);
459		ret = iio_trigger_register(data->dready_trig);
460		if (ret) {
461			dev_err(&client->dev, "iio trigger register failed\n");
462			goto err_power_off;
463		}
464	}
465
466	ret = iio_triggered_buffer_setup(indio_dev,
467					 iio_pollfunc_store_time,
468					 stk8ba50_trigger_handler,
469					 &stk8ba50_buffer_setup_ops);
470	if (ret < 0) {
471		dev_err(&client->dev, "iio triggered buffer setup failed\n");
472		goto err_trigger_unregister;
473	}
474
475	ret = iio_device_register(indio_dev);
476	if (ret < 0) {
477		dev_err(&client->dev, "device_register failed\n");
478		goto err_buffer_cleanup;
479	}
480
481	return ret;
482
483err_buffer_cleanup:
484	iio_triggered_buffer_cleanup(indio_dev);
485err_trigger_unregister:
486	if (data->dready_trig)
487		iio_trigger_unregister(data->dready_trig);
488err_power_off:
489	stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
490	return ret;
491}
492
493static int stk8ba50_remove(struct i2c_client *client)
494{
495	struct iio_dev *indio_dev = i2c_get_clientdata(client);
496	struct stk8ba50_data *data = iio_priv(indio_dev);
497
498	iio_device_unregister(indio_dev);
499	iio_triggered_buffer_cleanup(indio_dev);
500
501	if (data->dready_trig)
502		iio_trigger_unregister(data->dready_trig);
503
504	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
505}
506
507#ifdef CONFIG_PM_SLEEP
508static int stk8ba50_suspend(struct device *dev)
509{
510	struct stk8ba50_data *data;
511
512	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
513
514	return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
515}
516
517static int stk8ba50_resume(struct device *dev)
518{
519	struct stk8ba50_data *data;
520
521	data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
522
523	return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
524}
525
526static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
527
528#define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
529#else
530#define STK8BA50_PM_OPS NULL
531#endif
532
533static const struct i2c_device_id stk8ba50_i2c_id[] = {
534	{"stk8ba50", 0},
535	{}
536};
537MODULE_DEVICE_TABLE(i2c, stk8ba50_i2c_id);
538
539static const struct acpi_device_id stk8ba50_acpi_id[] = {
540	{"STK8BA50", 0},
541	{}
542};
543
544MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
545
546static struct i2c_driver stk8ba50_driver = {
547	.driver = {
548		.name = "stk8ba50",
549		.pm = STK8BA50_PM_OPS,
550		.acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
551	},
552	.probe =            stk8ba50_probe,
553	.remove =           stk8ba50_remove,
554	.id_table =         stk8ba50_i2c_id,
555};
556
557module_i2c_driver(stk8ba50_driver);
558
559MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
560MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
561MODULE_LICENSE("GPL v2");
562