xref: /openbmc/linux/drivers/iio/accel/adxl372.c (revision 2169e6da)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * ADXL372 3-Axis Digital Accelerometer core driver
4  *
5  * Copyright 2018 Analog Devices Inc.
6  */
7 
8 #include <linux/bitops.h>
9 #include <linux/interrupt.h>
10 #include <linux/irq.h>
11 #include <linux/module.h>
12 #include <linux/regmap.h>
13 #include <linux/spi/spi.h>
14 
15 #include <linux/iio/iio.h>
16 #include <linux/iio/sysfs.h>
17 #include <linux/iio/buffer.h>
18 #include <linux/iio/events.h>
19 #include <linux/iio/trigger.h>
20 #include <linux/iio/trigger_consumer.h>
21 #include <linux/iio/triggered_buffer.h>
22 
23 #include "adxl372.h"
24 
25 /* ADXL372 registers definition */
26 #define ADXL372_DEVID			0x00
27 #define ADXL372_DEVID_MST		0x01
28 #define ADXL372_PARTID			0x02
29 #define ADXL372_STATUS_1		0x04
30 #define ADXL372_STATUS_2		0x05
31 #define ADXL372_FIFO_ENTRIES_2		0x06
32 #define ADXL372_FIFO_ENTRIES_1		0x07
33 #define ADXL372_X_DATA_H		0x08
34 #define ADXL372_X_DATA_L		0x09
35 #define ADXL372_Y_DATA_H		0x0A
36 #define ADXL372_Y_DATA_L		0x0B
37 #define ADXL372_Z_DATA_H		0x0C
38 #define ADXL372_Z_DATA_L		0x0D
39 #define ADXL372_X_MAXPEAK_H		0x15
40 #define ADXL372_X_MAXPEAK_L		0x16
41 #define ADXL372_Y_MAXPEAK_H		0x17
42 #define ADXL372_Y_MAXPEAK_L		0x18
43 #define ADXL372_Z_MAXPEAK_H		0x19
44 #define ADXL372_Z_MAXPEAK_L		0x1A
45 #define ADXL372_OFFSET_X		0x20
46 #define ADXL372_OFFSET_Y		0x21
47 #define ADXL372_OFFSET_Z		0x22
48 #define ADXL372_X_THRESH_ACT_H		0x23
49 #define ADXL372_X_THRESH_ACT_L		0x24
50 #define ADXL372_Y_THRESH_ACT_H		0x25
51 #define ADXL372_Y_THRESH_ACT_L		0x26
52 #define ADXL372_Z_THRESH_ACT_H		0x27
53 #define ADXL372_Z_THRESH_ACT_L		0x28
54 #define ADXL372_TIME_ACT		0x29
55 #define ADXL372_X_THRESH_INACT_H	0x2A
56 #define ADXL372_X_THRESH_INACT_L	0x2B
57 #define ADXL372_Y_THRESH_INACT_H	0x2C
58 #define ADXL372_Y_THRESH_INACT_L	0x2D
59 #define ADXL372_Z_THRESH_INACT_H	0x2E
60 #define ADXL372_Z_THRESH_INACT_L	0x2F
61 #define ADXL372_TIME_INACT_H		0x30
62 #define ADXL372_TIME_INACT_L		0x31
63 #define ADXL372_X_THRESH_ACT2_H		0x32
64 #define ADXL372_X_THRESH_ACT2_L		0x33
65 #define ADXL372_Y_THRESH_ACT2_H		0x34
66 #define ADXL372_Y_THRESH_ACT2_L		0x35
67 #define ADXL372_Z_THRESH_ACT2_H		0x36
68 #define ADXL372_Z_THRESH_ACT2_L		0x37
69 #define ADXL372_HPF			0x38
70 #define ADXL372_FIFO_SAMPLES		0x39
71 #define ADXL372_FIFO_CTL		0x3A
72 #define ADXL372_INT1_MAP		0x3B
73 #define ADXL372_INT2_MAP		0x3C
74 #define ADXL372_TIMING			0x3D
75 #define ADXL372_MEASURE			0x3E
76 #define ADXL372_POWER_CTL		0x3F
77 #define ADXL372_SELF_TEST		0x40
78 #define ADXL372_RESET			0x41
79 #define ADXL372_FIFO_DATA		0x42
80 
81 #define ADXL372_DEVID_VAL		0xAD
82 #define ADXL372_PARTID_VAL		0xFA
83 #define ADXL372_RESET_CODE		0x52
84 
85 /* ADXL372_POWER_CTL */
86 #define ADXL372_POWER_CTL_MODE_MSK		GENMASK_ULL(1, 0)
87 #define ADXL372_POWER_CTL_MODE(x)		(((x) & 0x3) << 0)
88 
89 /* ADXL372_MEASURE */
90 #define ADXL372_MEASURE_LINKLOOP_MSK		GENMASK_ULL(5, 4)
91 #define ADXL372_MEASURE_LINKLOOP_MODE(x)	(((x) & 0x3) << 4)
92 #define ADXL372_MEASURE_BANDWIDTH_MSK		GENMASK_ULL(2, 0)
93 #define ADXL372_MEASURE_BANDWIDTH_MODE(x)	(((x) & 0x7) << 0)
94 
95 /* ADXL372_TIMING */
96 #define ADXL372_TIMING_ODR_MSK			GENMASK_ULL(7, 5)
97 #define ADXL372_TIMING_ODR_MODE(x)		(((x) & 0x7) << 5)
98 
99 /* ADXL372_FIFO_CTL */
100 #define ADXL372_FIFO_CTL_FORMAT_MSK		GENMASK(5, 3)
101 #define ADXL372_FIFO_CTL_FORMAT_MODE(x)		(((x) & 0x7) << 3)
102 #define ADXL372_FIFO_CTL_MODE_MSK		GENMASK(2, 1)
103 #define ADXL372_FIFO_CTL_MODE_MODE(x)		(((x) & 0x3) << 1)
104 #define ADXL372_FIFO_CTL_SAMPLES_MSK		BIT(1)
105 #define ADXL372_FIFO_CTL_SAMPLES_MODE(x)	(((x) > 0xFF) ? 1 : 0)
106 
107 /* ADXL372_STATUS_1 */
108 #define ADXL372_STATUS_1_DATA_RDY(x)		(((x) >> 0) & 0x1)
109 #define ADXL372_STATUS_1_FIFO_RDY(x)		(((x) >> 1) & 0x1)
110 #define ADXL372_STATUS_1_FIFO_FULL(x)		(((x) >> 2) & 0x1)
111 #define ADXL372_STATUS_1_FIFO_OVR(x)		(((x) >> 3) & 0x1)
112 #define ADXL372_STATUS_1_USR_NVM_BUSY(x)	(((x) >> 5) & 0x1)
113 #define ADXL372_STATUS_1_AWAKE(x)		(((x) >> 6) & 0x1)
114 #define ADXL372_STATUS_1_ERR_USR_REGS(x)	(((x) >> 7) & 0x1)
115 
116 /* ADXL372_INT1_MAP */
117 #define ADXL372_INT1_MAP_DATA_RDY_MSK		BIT(0)
118 #define ADXL372_INT1_MAP_DATA_RDY_MODE(x)	(((x) & 0x1) << 0)
119 #define ADXL372_INT1_MAP_FIFO_RDY_MSK		BIT(1)
120 #define ADXL372_INT1_MAP_FIFO_RDY_MODE(x)	(((x) & 0x1) << 1)
121 #define ADXL372_INT1_MAP_FIFO_FULL_MSK		BIT(2)
122 #define ADXL372_INT1_MAP_FIFO_FULL_MODE(x)	(((x) & 0x1) << 2)
123 #define ADXL372_INT1_MAP_FIFO_OVR_MSK		BIT(3)
124 #define ADXL372_INT1_MAP_FIFO_OVR_MODE(x)	(((x) & 0x1) << 3)
125 #define ADXL372_INT1_MAP_INACT_MSK		BIT(4)
126 #define ADXL372_INT1_MAP_INACT_MODE(x)		(((x) & 0x1) << 4)
127 #define ADXL372_INT1_MAP_ACT_MSK		BIT(5)
128 #define ADXL372_INT1_MAP_ACT_MODE(x)		(((x) & 0x1) << 5)
129 #define ADXL372_INT1_MAP_AWAKE_MSK		BIT(6)
130 #define ADXL372_INT1_MAP_AWAKE_MODE(x)		(((x) & 0x1) << 6)
131 #define ADXL372_INT1_MAP_LOW_MSK		BIT(7)
132 #define ADXL372_INT1_MAP_LOW_MODE(x)		(((x) & 0x1) << 7)
133 
134 /* The ADXL372 includes a deep, 512 sample FIFO buffer */
135 #define ADXL372_FIFO_SIZE			512
136 
137 /*
138  * At +/- 200g with 12-bit resolution, scale is computed as:
139  * (200 + 200) * 9.81 / (2^12 - 1) = 0.958241
140  */
141 #define ADXL372_USCALE	958241
142 
143 enum adxl372_op_mode {
144 	ADXL372_STANDBY,
145 	ADXL372_WAKE_UP,
146 	ADXL372_INSTANT_ON,
147 	ADXL372_FULL_BW_MEASUREMENT,
148 };
149 
150 enum adxl372_act_proc_mode {
151 	ADXL372_DEFAULT,
152 	ADXL372_LINKED,
153 	ADXL372_LOOPED,
154 };
155 
156 enum adxl372_th_activity {
157 	ADXL372_ACTIVITY,
158 	ADXL372_ACTIVITY2,
159 	ADXL372_INACTIVITY,
160 };
161 
162 enum adxl372_odr {
163 	ADXL372_ODR_400HZ,
164 	ADXL372_ODR_800HZ,
165 	ADXL372_ODR_1600HZ,
166 	ADXL372_ODR_3200HZ,
167 	ADXL372_ODR_6400HZ,
168 };
169 
170 enum adxl372_bandwidth {
171 	ADXL372_BW_200HZ,
172 	ADXL372_BW_400HZ,
173 	ADXL372_BW_800HZ,
174 	ADXL372_BW_1600HZ,
175 	ADXL372_BW_3200HZ,
176 };
177 
178 static const unsigned int adxl372_th_reg_high_addr[3] = {
179 	[ADXL372_ACTIVITY] = ADXL372_X_THRESH_ACT_H,
180 	[ADXL372_ACTIVITY2] = ADXL372_X_THRESH_ACT2_H,
181 	[ADXL372_INACTIVITY] = ADXL372_X_THRESH_INACT_H,
182 };
183 
184 enum adxl372_fifo_format {
185 	ADXL372_XYZ_FIFO,
186 	ADXL372_X_FIFO,
187 	ADXL372_Y_FIFO,
188 	ADXL372_XY_FIFO,
189 	ADXL372_Z_FIFO,
190 	ADXL372_XZ_FIFO,
191 	ADXL372_YZ_FIFO,
192 	ADXL372_XYZ_PEAK_FIFO,
193 };
194 
195 enum adxl372_fifo_mode {
196 	ADXL372_FIFO_BYPASSED,
197 	ADXL372_FIFO_STREAMED,
198 	ADXL372_FIFO_TRIGGERED,
199 	ADXL372_FIFO_OLD_SAVED
200 };
201 
202 static const int adxl372_samp_freq_tbl[5] = {
203 	400, 800, 1600, 3200, 6400,
204 };
205 
206 static const int adxl372_bw_freq_tbl[5] = {
207 	200, 400, 800, 1600, 3200,
208 };
209 
210 struct adxl372_axis_lookup {
211 	unsigned int bits;
212 	enum adxl372_fifo_format fifo_format;
213 };
214 
215 static const struct adxl372_axis_lookup adxl372_axis_lookup_table[] = {
216 	{ BIT(0), ADXL372_X_FIFO },
217 	{ BIT(1), ADXL372_Y_FIFO },
218 	{ BIT(2), ADXL372_Z_FIFO },
219 	{ BIT(0) | BIT(1), ADXL372_XY_FIFO },
220 	{ BIT(0) | BIT(2), ADXL372_XZ_FIFO },
221 	{ BIT(1) | BIT(2), ADXL372_YZ_FIFO },
222 	{ BIT(0) | BIT(1) | BIT(2), ADXL372_XYZ_FIFO },
223 };
224 
225 #define ADXL372_ACCEL_CHANNEL(index, reg, axis) {			\
226 	.type = IIO_ACCEL,						\
227 	.address = reg,							\
228 	.modified = 1,							\
229 	.channel2 = IIO_MOD_##axis,					\
230 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
231 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
232 				    BIT(IIO_CHAN_INFO_SAMP_FREQ) |	\
233 		BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),	\
234 	.scan_index = index,						\
235 	.scan_type = {							\
236 		.sign = 's',						\
237 		.realbits = 12,						\
238 		.storagebits = 16,					\
239 		.shift = 4,						\
240 	},								\
241 }
242 
243 static const struct iio_chan_spec adxl372_channels[] = {
244 	ADXL372_ACCEL_CHANNEL(0, ADXL372_X_DATA_H, X),
245 	ADXL372_ACCEL_CHANNEL(1, ADXL372_Y_DATA_H, Y),
246 	ADXL372_ACCEL_CHANNEL(2, ADXL372_Z_DATA_H, Z),
247 };
248 
249 struct adxl372_state {
250 	int				irq;
251 	struct device			*dev;
252 	struct regmap			*regmap;
253 	struct iio_trigger		*dready_trig;
254 	enum adxl372_fifo_mode		fifo_mode;
255 	enum adxl372_fifo_format	fifo_format;
256 	enum adxl372_op_mode		op_mode;
257 	enum adxl372_act_proc_mode	act_proc_mode;
258 	enum adxl372_odr		odr;
259 	enum adxl372_bandwidth		bw;
260 	u32				act_time_ms;
261 	u32				inact_time_ms;
262 	u8				fifo_set_size;
263 	u8				int1_bitmask;
264 	u8				int2_bitmask;
265 	u16				watermark;
266 	__be16				fifo_buf[ADXL372_FIFO_SIZE];
267 };
268 
269 static const unsigned long adxl372_channel_masks[] = {
270 	BIT(0), BIT(1), BIT(2),
271 	BIT(0) | BIT(1),
272 	BIT(0) | BIT(2),
273 	BIT(1) | BIT(2),
274 	BIT(0) | BIT(1) | BIT(2),
275 	0
276 };
277 
278 static int adxl372_read_axis(struct adxl372_state *st, u8 addr)
279 {
280 	__be16 regval;
281 	int ret;
282 
283 	ret = regmap_bulk_read(st->regmap, addr, &regval, sizeof(regval));
284 	if (ret < 0)
285 		return ret;
286 
287 	return be16_to_cpu(regval);
288 }
289 
290 static int adxl372_set_op_mode(struct adxl372_state *st,
291 			       enum adxl372_op_mode op_mode)
292 {
293 	int ret;
294 
295 	ret = regmap_update_bits(st->regmap, ADXL372_POWER_CTL,
296 				 ADXL372_POWER_CTL_MODE_MSK,
297 				 ADXL372_POWER_CTL_MODE(op_mode));
298 	if (ret < 0)
299 		return ret;
300 
301 	st->op_mode = op_mode;
302 
303 	return ret;
304 }
305 
306 static int adxl372_set_odr(struct adxl372_state *st,
307 			   enum adxl372_odr odr)
308 {
309 	int ret;
310 
311 	ret = regmap_update_bits(st->regmap, ADXL372_TIMING,
312 				 ADXL372_TIMING_ODR_MSK,
313 				 ADXL372_TIMING_ODR_MODE(odr));
314 	if (ret < 0)
315 		return ret;
316 
317 	st->odr = odr;
318 
319 	return ret;
320 }
321 
322 static int adxl372_find_closest_match(const int *array,
323 				      unsigned int size, int val)
324 {
325 	int i;
326 
327 	for (i = 0; i < size; i++) {
328 		if (val <= array[i])
329 			return i;
330 	}
331 
332 	return size - 1;
333 }
334 
335 static int adxl372_set_bandwidth(struct adxl372_state *st,
336 				 enum adxl372_bandwidth bw)
337 {
338 	int ret;
339 
340 	ret = regmap_update_bits(st->regmap, ADXL372_MEASURE,
341 				 ADXL372_MEASURE_BANDWIDTH_MSK,
342 				 ADXL372_MEASURE_BANDWIDTH_MODE(bw));
343 	if (ret < 0)
344 		return ret;
345 
346 	st->bw = bw;
347 
348 	return ret;
349 }
350 
351 static int adxl372_set_act_proc_mode(struct adxl372_state *st,
352 				     enum adxl372_act_proc_mode mode)
353 {
354 	int ret;
355 
356 	ret = regmap_update_bits(st->regmap,
357 				 ADXL372_MEASURE,
358 				 ADXL372_MEASURE_LINKLOOP_MSK,
359 				 ADXL372_MEASURE_LINKLOOP_MODE(mode));
360 	if (ret < 0)
361 		return ret;
362 
363 	st->act_proc_mode = mode;
364 
365 	return ret;
366 }
367 
368 static int adxl372_set_activity_threshold(struct adxl372_state *st,
369 					  enum adxl372_th_activity act,
370 					  bool ref_en, bool enable,
371 					  unsigned int threshold)
372 {
373 	unsigned char buf[6];
374 	unsigned char th_reg_high_val, th_reg_low_val, th_reg_high_addr;
375 
376 	/* scale factor is 100 mg/code */
377 	th_reg_high_val = (threshold / 100) >> 3;
378 	th_reg_low_val = ((threshold / 100) << 5) | (ref_en << 1) | enable;
379 	th_reg_high_addr = adxl372_th_reg_high_addr[act];
380 
381 	buf[0] = th_reg_high_val;
382 	buf[1] = th_reg_low_val;
383 	buf[2] = th_reg_high_val;
384 	buf[3] = th_reg_low_val;
385 	buf[4] = th_reg_high_val;
386 	buf[5] = th_reg_low_val;
387 
388 	return regmap_bulk_write(st->regmap, th_reg_high_addr,
389 				 buf, ARRAY_SIZE(buf));
390 }
391 
392 static int adxl372_set_activity_time_ms(struct adxl372_state *st,
393 					unsigned int act_time_ms)
394 {
395 	unsigned int reg_val, scale_factor;
396 	int ret;
397 
398 	/*
399 	 * 3.3 ms per code is the scale factor of the TIME_ACT register for
400 	 * ODR = 6400 Hz. It is 6.6 ms per code for ODR = 3200 Hz and below.
401 	 */
402 	if (st->odr == ADXL372_ODR_6400HZ)
403 		scale_factor = 3300;
404 	else
405 		scale_factor = 6600;
406 
407 	reg_val = DIV_ROUND_CLOSEST(act_time_ms * 1000, scale_factor);
408 
409 	/* TIME_ACT register is 8 bits wide */
410 	if (reg_val > 0xFF)
411 		reg_val = 0xFF;
412 
413 	ret = regmap_write(st->regmap, ADXL372_TIME_ACT, reg_val);
414 	if (ret < 0)
415 		return ret;
416 
417 	st->act_time_ms = act_time_ms;
418 
419 	return ret;
420 }
421 
422 static int adxl372_set_inactivity_time_ms(struct adxl372_state *st,
423 					  unsigned int inact_time_ms)
424 {
425 	unsigned int reg_val_h, reg_val_l, res, scale_factor;
426 	int ret;
427 
428 	/*
429 	 * 13 ms per code is the scale factor of the TIME_INACT register for
430 	 * ODR = 6400 Hz. It is 26 ms per code for ODR = 3200 Hz and below.
431 	 */
432 	if (st->odr == ADXL372_ODR_6400HZ)
433 		scale_factor = 13;
434 	else
435 		scale_factor = 26;
436 
437 	res = DIV_ROUND_CLOSEST(inact_time_ms, scale_factor);
438 	reg_val_h = (res >> 8) & 0xFF;
439 	reg_val_l = res & 0xFF;
440 
441 	ret = regmap_write(st->regmap, ADXL372_TIME_INACT_H, reg_val_h);
442 	if (ret < 0)
443 		return ret;
444 
445 	ret = regmap_write(st->regmap, ADXL372_TIME_INACT_L, reg_val_l);
446 	if (ret < 0)
447 		return ret;
448 
449 	st->inact_time_ms = inact_time_ms;
450 
451 	return ret;
452 }
453 
454 static int adxl372_set_interrupts(struct adxl372_state *st,
455 				  unsigned char int1_bitmask,
456 				  unsigned char int2_bitmask)
457 {
458 	int ret;
459 
460 	ret = regmap_write(st->regmap, ADXL372_INT1_MAP, int1_bitmask);
461 	if (ret < 0)
462 		return ret;
463 
464 	return regmap_write(st->regmap, ADXL372_INT2_MAP, int2_bitmask);
465 }
466 
467 static int adxl372_configure_fifo(struct adxl372_state *st)
468 {
469 	unsigned int fifo_samples, fifo_ctl;
470 	int ret;
471 
472 	/* FIFO must be configured while in standby mode */
473 	ret = adxl372_set_op_mode(st, ADXL372_STANDBY);
474 	if (ret < 0)
475 		return ret;
476 
477 	fifo_samples = st->watermark & 0xFF;
478 	fifo_ctl = ADXL372_FIFO_CTL_FORMAT_MODE(st->fifo_format) |
479 		   ADXL372_FIFO_CTL_MODE_MODE(st->fifo_mode) |
480 		   ADXL372_FIFO_CTL_SAMPLES_MODE(st->watermark);
481 
482 	ret = regmap_write(st->regmap, ADXL372_FIFO_SAMPLES, fifo_samples);
483 	if (ret < 0)
484 		return ret;
485 
486 	ret = regmap_write(st->regmap, ADXL372_FIFO_CTL, fifo_ctl);
487 	if (ret < 0)
488 		return ret;
489 
490 	return adxl372_set_op_mode(st, ADXL372_FULL_BW_MEASUREMENT);
491 }
492 
493 static int adxl372_get_status(struct adxl372_state *st,
494 			      u8 *status1, u8 *status2,
495 			      u16 *fifo_entries)
496 {
497 	__be32 buf;
498 	u32 val;
499 	int ret;
500 
501 	/* STATUS1, STATUS2, FIFO_ENTRIES2 and FIFO_ENTRIES are adjacent regs */
502 	ret = regmap_bulk_read(st->regmap, ADXL372_STATUS_1,
503 			       &buf, sizeof(buf));
504 	if (ret < 0)
505 		return ret;
506 
507 	val = be32_to_cpu(buf);
508 
509 	*status1 = (val >> 24) & 0x0F;
510 	*status2 = (val >> 16) & 0x0F;
511 	/*
512 	 * FIFO_ENTRIES contains the least significant byte, and FIFO_ENTRIES2
513 	 * contains the two most significant bits
514 	 */
515 	*fifo_entries = val & 0x3FF;
516 
517 	return ret;
518 }
519 
520 static irqreturn_t adxl372_trigger_handler(int irq, void  *p)
521 {
522 	struct iio_poll_func *pf = p;
523 	struct iio_dev *indio_dev = pf->indio_dev;
524 	struct adxl372_state *st = iio_priv(indio_dev);
525 	u8 status1, status2;
526 	u16 fifo_entries;
527 	int i, ret;
528 
529 	ret = adxl372_get_status(st, &status1, &status2, &fifo_entries);
530 	if (ret < 0)
531 		goto err;
532 
533 	if (st->fifo_mode != ADXL372_FIFO_BYPASSED &&
534 	    ADXL372_STATUS_1_FIFO_FULL(status1)) {
535 		/*
536 		 * When reading data from multiple axes from the FIFO,
537 		 * to ensure that data is not overwritten and stored out
538 		 * of order at least one sample set must be left in the
539 		 * FIFO after every read.
540 		 */
541 		fifo_entries -= st->fifo_set_size;
542 
543 		/* Read data from the FIFO */
544 		ret = regmap_noinc_read(st->regmap, ADXL372_FIFO_DATA,
545 					st->fifo_buf,
546 					fifo_entries * sizeof(u16));
547 		if (ret < 0)
548 			goto err;
549 
550 		/* Each sample is 2 bytes */
551 		for (i = 0; i < fifo_entries * sizeof(u16);
552 		     i += st->fifo_set_size * sizeof(u16))
553 			iio_push_to_buffers(indio_dev, &st->fifo_buf[i]);
554 	}
555 err:
556 	iio_trigger_notify_done(indio_dev->trig);
557 	return IRQ_HANDLED;
558 }
559 
560 static int adxl372_setup(struct adxl372_state *st)
561 {
562 	unsigned int regval;
563 	int ret;
564 
565 	ret = regmap_read(st->regmap, ADXL372_DEVID, &regval);
566 	if (ret < 0)
567 		return ret;
568 
569 	if (regval != ADXL372_DEVID_VAL) {
570 		dev_err(st->dev, "Invalid chip id %x\n", regval);
571 		return -ENODEV;
572 	}
573 
574 	ret = adxl372_set_op_mode(st, ADXL372_STANDBY);
575 	if (ret < 0)
576 		return ret;
577 
578 	/* Set threshold for activity detection to 1g */
579 	ret = adxl372_set_activity_threshold(st, ADXL372_ACTIVITY,
580 					     true, true, 1000);
581 	if (ret < 0)
582 		return ret;
583 
584 	/* Set threshold for inactivity detection to 100mg */
585 	ret = adxl372_set_activity_threshold(st, ADXL372_INACTIVITY,
586 					     true, true, 100);
587 	if (ret < 0)
588 		return ret;
589 
590 	/* Set activity processing in Looped mode */
591 	ret = adxl372_set_act_proc_mode(st, ADXL372_LOOPED);
592 	if (ret < 0)
593 		return ret;
594 
595 	ret = adxl372_set_odr(st, ADXL372_ODR_6400HZ);
596 	if (ret < 0)
597 		return ret;
598 
599 	ret = adxl372_set_bandwidth(st, ADXL372_BW_3200HZ);
600 	if (ret < 0)
601 		return ret;
602 
603 	/* Set activity timer to 1ms */
604 	ret = adxl372_set_activity_time_ms(st, 1);
605 	if (ret < 0)
606 		return ret;
607 
608 	/* Set inactivity timer to 10s */
609 	ret = adxl372_set_inactivity_time_ms(st, 10000);
610 	if (ret < 0)
611 		return ret;
612 
613 	/* Set the mode of operation to full bandwidth measurement mode */
614 	return adxl372_set_op_mode(st, ADXL372_FULL_BW_MEASUREMENT);
615 }
616 
617 static int adxl372_reg_access(struct iio_dev *indio_dev,
618 			      unsigned int reg,
619 			      unsigned int writeval,
620 			      unsigned int *readval)
621 {
622 	struct adxl372_state *st = iio_priv(indio_dev);
623 
624 	if (readval)
625 		return regmap_read(st->regmap, reg, readval);
626 	else
627 		return regmap_write(st->regmap, reg, writeval);
628 }
629 
630 static int adxl372_read_raw(struct iio_dev *indio_dev,
631 			    struct iio_chan_spec const *chan,
632 			    int *val, int *val2, long info)
633 {
634 	struct adxl372_state *st = iio_priv(indio_dev);
635 	int ret;
636 
637 	switch (info) {
638 	case IIO_CHAN_INFO_RAW:
639 		ret = iio_device_claim_direct_mode(indio_dev);
640 		if (ret)
641 			return ret;
642 
643 		ret = adxl372_read_axis(st, chan->address);
644 		iio_device_release_direct_mode(indio_dev);
645 		if (ret < 0)
646 			return ret;
647 
648 		*val = sign_extend32(ret >> chan->scan_type.shift,
649 				     chan->scan_type.realbits - 1);
650 		return IIO_VAL_INT;
651 	case IIO_CHAN_INFO_SCALE:
652 		*val = 0;
653 		*val2 = ADXL372_USCALE;
654 		return IIO_VAL_INT_PLUS_MICRO;
655 	case IIO_CHAN_INFO_SAMP_FREQ:
656 		*val = adxl372_samp_freq_tbl[st->odr];
657 		return IIO_VAL_INT;
658 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
659 		*val = adxl372_bw_freq_tbl[st->bw];
660 		return IIO_VAL_INT;
661 	}
662 
663 	return -EINVAL;
664 }
665 
666 static int adxl372_write_raw(struct iio_dev *indio_dev,
667 			     struct iio_chan_spec const *chan,
668 			     int val, int val2, long info)
669 {
670 	struct adxl372_state *st = iio_priv(indio_dev);
671 	int odr_index, bw_index, ret;
672 
673 	switch (info) {
674 	case IIO_CHAN_INFO_SAMP_FREQ:
675 		odr_index = adxl372_find_closest_match(adxl372_samp_freq_tbl,
676 					ARRAY_SIZE(adxl372_samp_freq_tbl),
677 					val);
678 		ret = adxl372_set_odr(st, odr_index);
679 		if (ret < 0)
680 			return ret;
681 		/*
682 		 * The timer period depends on the ODR selected.
683 		 * At 3200 Hz and below, it is 6.6 ms; at 6400 Hz, it is 3.3 ms
684 		 */
685 		ret = adxl372_set_activity_time_ms(st, st->act_time_ms);
686 		if (ret < 0)
687 			return ret;
688 		/*
689 		 * The timer period depends on the ODR selected.
690 		 * At 3200 Hz and below, it is 26 ms; at 6400 Hz, it is 13 ms
691 		 */
692 		ret = adxl372_set_inactivity_time_ms(st, st->inact_time_ms);
693 		if (ret < 0)
694 			return ret;
695 		/*
696 		 * The maximum bandwidth is constrained to at most half of
697 		 * the ODR to ensure that the Nyquist criteria is not violated
698 		 */
699 		if (st->bw > odr_index)
700 			ret = adxl372_set_bandwidth(st, odr_index);
701 
702 		return ret;
703 	case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
704 		bw_index = adxl372_find_closest_match(adxl372_bw_freq_tbl,
705 					ARRAY_SIZE(adxl372_bw_freq_tbl),
706 					val);
707 		return adxl372_set_bandwidth(st, bw_index);
708 	default:
709 		return -EINVAL;
710 	}
711 }
712 
713 static ssize_t adxl372_show_filter_freq_avail(struct device *dev,
714 					      struct device_attribute *attr,
715 					      char *buf)
716 {
717 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
718 	struct adxl372_state *st = iio_priv(indio_dev);
719 	int i;
720 	size_t len = 0;
721 
722 	for (i = 0; i <= st->odr; i++)
723 		len += scnprintf(buf + len, PAGE_SIZE - len,
724 				 "%d ", adxl372_bw_freq_tbl[i]);
725 
726 	buf[len - 1] = '\n';
727 
728 	return len;
729 }
730 
731 static ssize_t adxl372_get_fifo_enabled(struct device *dev,
732 					  struct device_attribute *attr,
733 					  char *buf)
734 {
735 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
736 	struct adxl372_state *st = iio_priv(indio_dev);
737 
738 	return sprintf(buf, "%d\n", st->fifo_mode);
739 }
740 
741 static ssize_t adxl372_get_fifo_watermark(struct device *dev,
742 					  struct device_attribute *attr,
743 					  char *buf)
744 {
745 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
746 	struct adxl372_state *st = iio_priv(indio_dev);
747 
748 	return sprintf(buf, "%d\n", st->watermark);
749 }
750 
751 static IIO_CONST_ATTR(hwfifo_watermark_min, "1");
752 static IIO_CONST_ATTR(hwfifo_watermark_max,
753 		      __stringify(ADXL372_FIFO_SIZE));
754 static IIO_DEVICE_ATTR(hwfifo_watermark, 0444,
755 		       adxl372_get_fifo_watermark, NULL, 0);
756 static IIO_DEVICE_ATTR(hwfifo_enabled, 0444,
757 		       adxl372_get_fifo_enabled, NULL, 0);
758 
759 static const struct attribute *adxl372_fifo_attributes[] = {
760 	&iio_const_attr_hwfifo_watermark_min.dev_attr.attr,
761 	&iio_const_attr_hwfifo_watermark_max.dev_attr.attr,
762 	&iio_dev_attr_hwfifo_watermark.dev_attr.attr,
763 	&iio_dev_attr_hwfifo_enabled.dev_attr.attr,
764 	NULL,
765 };
766 
767 static int adxl372_set_watermark(struct iio_dev *indio_dev, unsigned int val)
768 {
769 	struct adxl372_state *st  = iio_priv(indio_dev);
770 
771 	if (val > ADXL372_FIFO_SIZE)
772 		val = ADXL372_FIFO_SIZE;
773 
774 	st->watermark = val;
775 
776 	return 0;
777 }
778 
779 static int adxl372_buffer_postenable(struct iio_dev *indio_dev)
780 {
781 	struct adxl372_state *st = iio_priv(indio_dev);
782 	unsigned int mask;
783 	int i, ret;
784 
785 	ret = iio_triggered_buffer_postenable(indio_dev);
786 	if (ret < 0)
787 		return ret;
788 
789 	ret = adxl372_set_interrupts(st, ADXL372_INT1_MAP_FIFO_FULL_MSK, 0);
790 	if (ret < 0)
791 		goto err;
792 
793 	mask = *indio_dev->active_scan_mask;
794 
795 	for (i = 0; i < ARRAY_SIZE(adxl372_axis_lookup_table); i++) {
796 		if (mask == adxl372_axis_lookup_table[i].bits)
797 			break;
798 	}
799 
800 	if (i == ARRAY_SIZE(adxl372_axis_lookup_table)) {
801 		ret = -EINVAL;
802 		goto err;
803 	}
804 
805 	st->fifo_format = adxl372_axis_lookup_table[i].fifo_format;
806 	st->fifo_set_size = bitmap_weight(indio_dev->active_scan_mask,
807 					  indio_dev->masklength);
808 	/*
809 	 * The 512 FIFO samples can be allotted in several ways, such as:
810 	 * 170 sample sets of concurrent 3-axis data
811 	 * 256 sample sets of concurrent 2-axis data (user selectable)
812 	 * 512 sample sets of single-axis data
813 	 */
814 	if ((st->watermark * st->fifo_set_size) > ADXL372_FIFO_SIZE)
815 		st->watermark = (ADXL372_FIFO_SIZE  / st->fifo_set_size);
816 
817 	st->fifo_mode = ADXL372_FIFO_STREAMED;
818 
819 	ret = adxl372_configure_fifo(st);
820 	if (ret < 0) {
821 		st->fifo_mode = ADXL372_FIFO_BYPASSED;
822 		adxl372_set_interrupts(st, 0, 0);
823 		goto err;
824 	}
825 
826 	return 0;
827 
828 err:
829 	iio_triggered_buffer_predisable(indio_dev);
830 	return ret;
831 }
832 
833 static int adxl372_buffer_predisable(struct iio_dev *indio_dev)
834 {
835 	struct adxl372_state *st = iio_priv(indio_dev);
836 
837 	adxl372_set_interrupts(st, 0, 0);
838 	st->fifo_mode = ADXL372_FIFO_BYPASSED;
839 	adxl372_configure_fifo(st);
840 
841 	return iio_triggered_buffer_predisable(indio_dev);
842 }
843 
844 static const struct iio_buffer_setup_ops adxl372_buffer_ops = {
845 	.postenable = adxl372_buffer_postenable,
846 	.predisable = adxl372_buffer_predisable,
847 };
848 
849 static int adxl372_dready_trig_set_state(struct iio_trigger *trig,
850 					 bool state)
851 {
852 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
853 	struct adxl372_state *st = iio_priv(indio_dev);
854 	unsigned long int mask = 0;
855 
856 	if (state)
857 		mask = ADXL372_INT1_MAP_FIFO_FULL_MSK;
858 
859 	return adxl372_set_interrupts(st, mask, 0);
860 }
861 
862 static int adxl372_validate_trigger(struct iio_dev *indio_dev,
863 				    struct iio_trigger *trig)
864 {
865 	struct adxl372_state *st = iio_priv(indio_dev);
866 
867 	if (st->dready_trig != trig)
868 		return -EINVAL;
869 
870 	return 0;
871 }
872 
873 static const struct iio_trigger_ops adxl372_trigger_ops = {
874 	.validate_device = &iio_trigger_validate_own_device,
875 	.set_trigger_state = adxl372_dready_trig_set_state,
876 };
877 
878 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("400 800 1600 3200 6400");
879 static IIO_DEVICE_ATTR(in_accel_filter_low_pass_3db_frequency_available,
880 		       0444, adxl372_show_filter_freq_avail, NULL, 0);
881 
882 static struct attribute *adxl372_attributes[] = {
883 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
884 	&iio_dev_attr_in_accel_filter_low_pass_3db_frequency_available.dev_attr.attr,
885 	NULL,
886 };
887 
888 static const struct attribute_group adxl372_attrs_group = {
889 	.attrs = adxl372_attributes,
890 };
891 
892 static const struct iio_info adxl372_info = {
893 	.validate_trigger = &adxl372_validate_trigger,
894 	.attrs = &adxl372_attrs_group,
895 	.read_raw = adxl372_read_raw,
896 	.write_raw = adxl372_write_raw,
897 	.debugfs_reg_access = &adxl372_reg_access,
898 	.hwfifo_set_watermark = adxl372_set_watermark,
899 };
900 
901 bool adxl372_readable_noinc_reg(struct device *dev, unsigned int reg)
902 {
903 	return (reg == ADXL372_FIFO_DATA);
904 }
905 EXPORT_SYMBOL_GPL(adxl372_readable_noinc_reg);
906 
907 int adxl372_probe(struct device *dev, struct regmap *regmap,
908 		  int irq, const char *name)
909 {
910 	struct iio_dev *indio_dev;
911 	struct adxl372_state *st;
912 	int ret;
913 
914 	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
915 	if (!indio_dev)
916 		return -ENOMEM;
917 
918 	st = iio_priv(indio_dev);
919 	dev_set_drvdata(dev, indio_dev);
920 
921 	st->dev = dev;
922 	st->regmap = regmap;
923 	st->irq = irq;
924 
925 	indio_dev->channels = adxl372_channels;
926 	indio_dev->num_channels = ARRAY_SIZE(adxl372_channels);
927 	indio_dev->available_scan_masks = adxl372_channel_masks;
928 	indio_dev->dev.parent = dev;
929 	indio_dev->name = name;
930 	indio_dev->info = &adxl372_info;
931 	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
932 
933 	ret = adxl372_setup(st);
934 	if (ret < 0) {
935 		dev_err(dev, "ADXL372 setup failed\n");
936 		return ret;
937 	}
938 
939 	ret = devm_iio_triggered_buffer_setup(dev,
940 					      indio_dev, NULL,
941 					      adxl372_trigger_handler,
942 					      &adxl372_buffer_ops);
943 	if (ret < 0)
944 		return ret;
945 
946 	iio_buffer_set_attrs(indio_dev->buffer, adxl372_fifo_attributes);
947 
948 	if (st->irq) {
949 		st->dready_trig = devm_iio_trigger_alloc(dev,
950 							 "%s-dev%d",
951 							 indio_dev->name,
952 							 indio_dev->id);
953 		if (st->dready_trig == NULL)
954 			return -ENOMEM;
955 
956 		st->dready_trig->ops = &adxl372_trigger_ops;
957 		st->dready_trig->dev.parent = dev;
958 		iio_trigger_set_drvdata(st->dready_trig, indio_dev);
959 		ret = devm_iio_trigger_register(dev, st->dready_trig);
960 		if (ret < 0)
961 			return ret;
962 
963 		indio_dev->trig = iio_trigger_get(st->dready_trig);
964 
965 		ret = devm_request_threaded_irq(dev, st->irq,
966 					iio_trigger_generic_data_rdy_poll,
967 					NULL,
968 					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
969 					indio_dev->name, st->dready_trig);
970 		if (ret < 0)
971 			return ret;
972 	}
973 
974 	return devm_iio_device_register(dev, indio_dev);
975 }
976 EXPORT_SYMBOL_GPL(adxl372_probe);
977 
978 MODULE_AUTHOR("Stefan Popa <stefan.popa@analog.com>");
979 MODULE_DESCRIPTION("Analog Devices ADXL372 3-axis accelerometer driver");
980 MODULE_LICENSE("GPL");
981