1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * STMicroelectronics st_lsm6dsx FIFO buffer library driver
4  *
5  * LSM6DS3/LSM6DS3H/LSM6DSL/LSM6DSM/ISM330DLC/LSM6DS3TR-C:
6  * The FIFO buffer can be configured to store data from gyroscope and
7  * accelerometer. Samples are queued without any tag according to a
8  * specific pattern based on 'FIFO data sets' (6 bytes each):
9  *  - 1st data set is reserved for gyroscope data
10  *  - 2nd data set is reserved for accelerometer data
11  * The FIFO pattern changes depending on the ODRs and decimation factors
12  * assigned to the FIFO data sets. The first sequence of data stored in FIFO
13  * buffer contains the data of all the enabled FIFO data sets
14  * (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated depending on the
15  * value of the decimation factor and ODR set for each FIFO data set.
16  *
17  * LSM6DSO/LSM6DSOX/ASM330LHH/LSM6DSR/LSM6DSRX/ISM330DHCX/LSM6DST/LSM6DSOP:
18  * The FIFO buffer can be configured to store data from gyroscope and
19  * accelerometer. Each sample is queued with a tag (1B) indicating data
20  * source (gyroscope, accelerometer, hw timer).
21  *
22  * FIFO supported modes:
23  *  - BYPASS: FIFO disabled
24  *  - CONTINUOUS: FIFO enabled. When the buffer is full, the FIFO index
25  *    restarts from the beginning and the oldest sample is overwritten
26  *
27  * Copyright 2016 STMicroelectronics Inc.
28  *
29  * Lorenzo Bianconi <lorenzo.bianconi@st.com>
30  * Denis Ciocca <denis.ciocca@st.com>
31  */
32 #include <linux/module.h>
33 #include <linux/iio/kfifo_buf.h>
34 #include <linux/iio/iio.h>
35 #include <linux/iio/buffer.h>
36 #include <linux/regmap.h>
37 #include <linux/bitfield.h>
38 
39 #include <linux/platform_data/st_sensors_pdata.h>
40 
41 #include "st_lsm6dsx.h"
42 
43 #define ST_LSM6DSX_REG_FIFO_MODE_ADDR		0x0a
44 #define ST_LSM6DSX_FIFO_MODE_MASK		GENMASK(2, 0)
45 #define ST_LSM6DSX_FIFO_ODR_MASK		GENMASK(6, 3)
46 #define ST_LSM6DSX_FIFO_EMPTY_MASK		BIT(12)
47 #define ST_LSM6DSX_REG_FIFO_OUTL_ADDR		0x3e
48 #define ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR	0x78
49 #define ST_LSM6DSX_REG_TS_RESET_ADDR		0x42
50 
51 #define ST_LSM6DSX_MAX_FIFO_ODR_VAL		0x08
52 
53 #define ST_LSM6DSX_TS_RESET_VAL			0xaa
54 
55 struct st_lsm6dsx_decimator_entry {
56 	u8 decimator;
57 	u8 val;
58 };
59 
60 enum st_lsm6dsx_fifo_tag {
61 	ST_LSM6DSX_GYRO_TAG = 0x01,
62 	ST_LSM6DSX_ACC_TAG = 0x02,
63 	ST_LSM6DSX_TS_TAG = 0x04,
64 	ST_LSM6DSX_EXT0_TAG = 0x0f,
65 	ST_LSM6DSX_EXT1_TAG = 0x10,
66 	ST_LSM6DSX_EXT2_TAG = 0x11,
67 };
68 
69 static const
70 struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = {
71 	{  0, 0x0 },
72 	{  1, 0x1 },
73 	{  2, 0x2 },
74 	{  3, 0x3 },
75 	{  4, 0x4 },
76 	{  8, 0x5 },
77 	{ 16, 0x6 },
78 	{ 32, 0x7 },
79 };
80 
81 static int
82 st_lsm6dsx_get_decimator_val(struct st_lsm6dsx_sensor *sensor, u32 max_odr)
83 {
84 	const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table);
85 	u32 decimator =  max_odr / sensor->odr;
86 	int i;
87 
88 	if (decimator > 1)
89 		decimator = round_down(decimator, 2);
90 
91 	for (i = 0; i < max_size; i++) {
92 		if (st_lsm6dsx_decimator_table[i].decimator == decimator)
93 			break;
94 	}
95 
96 	sensor->decimator = decimator;
97 	return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val;
98 }
99 
100 static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw,
101 				       u32 *max_odr, u32 *min_odr)
102 {
103 	struct st_lsm6dsx_sensor *sensor;
104 	int i;
105 
106 	*max_odr = 0, *min_odr = ~0;
107 	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
108 		if (!hw->iio_devs[i])
109 			continue;
110 
111 		sensor = iio_priv(hw->iio_devs[i]);
112 
113 		if (!(hw->enable_mask & BIT(sensor->id)))
114 			continue;
115 
116 		*max_odr = max_t(u32, *max_odr, sensor->odr);
117 		*min_odr = min_t(u32, *min_odr, sensor->odr);
118 	}
119 }
120 
121 static u8 st_lsm6dsx_get_sip(struct st_lsm6dsx_sensor *sensor, u32 min_odr)
122 {
123 	u8 sip = sensor->odr / min_odr;
124 
125 	return sip > 1 ? round_down(sip, 2) : sip;
126 }
127 
128 static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw)
129 {
130 	const struct st_lsm6dsx_reg *ts_dec_reg;
131 	struct st_lsm6dsx_sensor *sensor;
132 	u16 sip = 0, ts_sip = 0;
133 	u32 max_odr, min_odr;
134 	int err = 0, i;
135 	u8 data;
136 
137 	st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr);
138 
139 	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
140 		const struct st_lsm6dsx_reg *dec_reg;
141 
142 		if (!hw->iio_devs[i])
143 			continue;
144 
145 		sensor = iio_priv(hw->iio_devs[i]);
146 		/* update fifo decimators and sample in pattern */
147 		if (hw->enable_mask & BIT(sensor->id)) {
148 			sensor->sip = st_lsm6dsx_get_sip(sensor, min_odr);
149 			data = st_lsm6dsx_get_decimator_val(sensor, max_odr);
150 		} else {
151 			sensor->sip = 0;
152 			data = 0;
153 		}
154 		ts_sip = max_t(u16, ts_sip, sensor->sip);
155 
156 		dec_reg = &hw->settings->decimator[sensor->id];
157 		if (dec_reg->addr) {
158 			int val = ST_LSM6DSX_SHIFT_VAL(data, dec_reg->mask);
159 
160 			err = st_lsm6dsx_update_bits_locked(hw, dec_reg->addr,
161 							    dec_reg->mask,
162 							    val);
163 			if (err < 0)
164 				return err;
165 		}
166 		sip += sensor->sip;
167 	}
168 	hw->sip = sip + ts_sip;
169 	hw->ts_sip = ts_sip;
170 
171 	/*
172 	 * update hw ts decimator if necessary. Decimator for hw timestamp
173 	 * is always 1 or 0 in order to have a ts sample for each data
174 	 * sample in FIFO
175 	 */
176 	ts_dec_reg = &hw->settings->ts_settings.decimator;
177 	if (ts_dec_reg->addr) {
178 		int val, ts_dec = !!hw->ts_sip;
179 
180 		val = ST_LSM6DSX_SHIFT_VAL(ts_dec, ts_dec_reg->mask);
181 		err = st_lsm6dsx_update_bits_locked(hw, ts_dec_reg->addr,
182 						    ts_dec_reg->mask, val);
183 	}
184 	return err;
185 }
186 
187 static int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
188 				    enum st_lsm6dsx_fifo_mode fifo_mode)
189 {
190 	unsigned int data;
191 
192 	data = FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, fifo_mode);
193 	return st_lsm6dsx_update_bits_locked(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
194 					     ST_LSM6DSX_FIFO_MODE_MASK, data);
195 }
196 
197 static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor,
198 				   bool enable)
199 {
200 	struct st_lsm6dsx_hw *hw = sensor->hw;
201 	const struct st_lsm6dsx_reg *batch_reg;
202 	u8 data;
203 
204 	batch_reg = &hw->settings->batch[sensor->id];
205 	if (batch_reg->addr) {
206 		int val;
207 
208 		if (enable) {
209 			int err;
210 
211 			err = st_lsm6dsx_check_odr(sensor, sensor->odr,
212 						   &data);
213 			if (err < 0)
214 				return err;
215 		} else {
216 			data = 0;
217 		}
218 		val = ST_LSM6DSX_SHIFT_VAL(data, batch_reg->mask);
219 		return st_lsm6dsx_update_bits_locked(hw, batch_reg->addr,
220 						     batch_reg->mask, val);
221 	} else {
222 		data = hw->enable_mask ? ST_LSM6DSX_MAX_FIFO_ODR_VAL : 0;
223 		return st_lsm6dsx_update_bits_locked(hw,
224 					ST_LSM6DSX_REG_FIFO_MODE_ADDR,
225 					ST_LSM6DSX_FIFO_ODR_MASK,
226 					FIELD_PREP(ST_LSM6DSX_FIFO_ODR_MASK,
227 						   data));
228 	}
229 }
230 
231 int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark)
232 {
233 	u16 fifo_watermark = ~0, cur_watermark, fifo_th_mask;
234 	struct st_lsm6dsx_hw *hw = sensor->hw;
235 	struct st_lsm6dsx_sensor *cur_sensor;
236 	int i, err, data;
237 	__le16 wdata;
238 
239 	if (!hw->sip)
240 		return 0;
241 
242 	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
243 		if (!hw->iio_devs[i])
244 			continue;
245 
246 		cur_sensor = iio_priv(hw->iio_devs[i]);
247 
248 		if (!(hw->enable_mask & BIT(cur_sensor->id)))
249 			continue;
250 
251 		cur_watermark = (cur_sensor == sensor) ? watermark
252 						       : cur_sensor->watermark;
253 
254 		fifo_watermark = min_t(u16, fifo_watermark, cur_watermark);
255 	}
256 
257 	fifo_watermark = max_t(u16, fifo_watermark, hw->sip);
258 	fifo_watermark = (fifo_watermark / hw->sip) * hw->sip;
259 	fifo_watermark = fifo_watermark * hw->settings->fifo_ops.th_wl;
260 
261 	mutex_lock(&hw->page_lock);
262 	err = regmap_read(hw->regmap, hw->settings->fifo_ops.fifo_th.addr + 1,
263 			  &data);
264 	if (err < 0)
265 		goto out;
266 
267 	fifo_th_mask = hw->settings->fifo_ops.fifo_th.mask;
268 	fifo_watermark = ((data << 8) & ~fifo_th_mask) |
269 			 (fifo_watermark & fifo_th_mask);
270 
271 	wdata = cpu_to_le16(fifo_watermark);
272 	err = regmap_bulk_write(hw->regmap,
273 				hw->settings->fifo_ops.fifo_th.addr,
274 				&wdata, sizeof(wdata));
275 out:
276 	mutex_unlock(&hw->page_lock);
277 	return err;
278 }
279 
280 static int st_lsm6dsx_reset_hw_ts(struct st_lsm6dsx_hw *hw)
281 {
282 	struct st_lsm6dsx_sensor *sensor;
283 	int i, err;
284 
285 	/* reset hw ts counter */
286 	err = st_lsm6dsx_write_locked(hw, ST_LSM6DSX_REG_TS_RESET_ADDR,
287 				      ST_LSM6DSX_TS_RESET_VAL);
288 	if (err < 0)
289 		return err;
290 
291 	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
292 		if (!hw->iio_devs[i])
293 			continue;
294 
295 		sensor = iio_priv(hw->iio_devs[i]);
296 		/*
297 		 * store enable buffer timestamp as reference for
298 		 * hw timestamp
299 		 */
300 		sensor->ts_ref = iio_get_time_ns(hw->iio_devs[i]);
301 	}
302 	return 0;
303 }
304 
305 int st_lsm6dsx_resume_fifo(struct st_lsm6dsx_hw *hw)
306 {
307 	int err;
308 
309 	/* reset hw ts counter */
310 	err = st_lsm6dsx_reset_hw_ts(hw);
311 	if (err < 0)
312 		return err;
313 
314 	return st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
315 }
316 
317 /*
318  * Set max bulk read to ST_LSM6DSX_MAX_WORD_LEN/ST_LSM6DSX_MAX_TAGGED_WORD_LEN
319  * in order to avoid a kmalloc for each bus access
320  */
321 static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 addr,
322 					u8 *data, unsigned int data_len,
323 					unsigned int max_word_len)
324 {
325 	unsigned int word_len, read_len = 0;
326 	int err;
327 
328 	while (read_len < data_len) {
329 		word_len = min_t(unsigned int, data_len - read_len,
330 				 max_word_len);
331 		err = st_lsm6dsx_read_locked(hw, addr, data + read_len,
332 					     word_len);
333 		if (err < 0)
334 			return err;
335 		read_len += word_len;
336 	}
337 	return 0;
338 }
339 
340 #define ST_LSM6DSX_IIO_BUFF_SIZE	(ALIGN(ST_LSM6DSX_SAMPLE_SIZE, \
341 					       sizeof(s64)) + sizeof(s64))
342 /**
343  * st_lsm6dsx_read_fifo() - hw FIFO read routine
344  * @hw: Pointer to instance of struct st_lsm6dsx_hw.
345  *
346  * Read samples from the hw FIFO and push them to IIO buffers.
347  *
348  * Return: Number of bytes read from the FIFO
349  */
350 int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
351 {
352 	struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor, *ext_sensor = NULL;
353 	int err, sip, acc_sip, gyro_sip, ts_sip, ext_sip, read_len, offset;
354 	u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE;
355 	u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
356 	bool reset_ts = false;
357 	__le16 fifo_status;
358 	s64 ts = 0;
359 
360 	err = st_lsm6dsx_read_locked(hw,
361 				     hw->settings->fifo_ops.fifo_diff.addr,
362 				     &fifo_status, sizeof(fifo_status));
363 	if (err < 0) {
364 		dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
365 			err);
366 		return err;
367 	}
368 
369 	if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
370 		return 0;
371 
372 	fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
373 		   ST_LSM6DSX_CHAN_SIZE;
374 	fifo_len = (fifo_len / pattern_len) * pattern_len;
375 
376 	acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
377 	gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
378 	if (hw->iio_devs[ST_LSM6DSX_ID_EXT0])
379 		ext_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_EXT0]);
380 
381 	for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
382 		err = st_lsm6dsx_read_block(hw, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
383 					    hw->buff, pattern_len,
384 					    ST_LSM6DSX_MAX_WORD_LEN);
385 		if (err < 0) {
386 			dev_err(hw->dev,
387 				"failed to read pattern from fifo (err=%d)\n",
388 				err);
389 			return err;
390 		}
391 
392 		/*
393 		 * Data are written to the FIFO with a specific pattern
394 		 * depending on the configured ODRs. The first sequence of data
395 		 * stored in FIFO contains the data of all enabled sensors
396 		 * (e.g. Gx, Gy, Gz, Ax, Ay, Az, Ts), then data are repeated
397 		 * depending on the value of the decimation factor set for each
398 		 * sensor.
399 		 *
400 		 * Supposing the FIFO is storing data from gyroscope and
401 		 * accelerometer at different ODRs:
402 		 *   - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz
403 		 * Since the gyroscope ODR is twice the accelerometer one, the
404 		 * following pattern is repeated every 9 samples:
405 		 *   - Gx, Gy, Gz, Ax, Ay, Az, Ts, Gx, Gy, Gz, Ts, Gx, ..
406 		 */
407 		ext_sip = ext_sensor ? ext_sensor->sip : 0;
408 		gyro_sip = gyro_sensor->sip;
409 		acc_sip = acc_sensor->sip;
410 		ts_sip = hw->ts_sip;
411 		offset = 0;
412 		sip = 0;
413 
414 		while (acc_sip > 0 || gyro_sip > 0 || ext_sip > 0) {
415 			if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
416 				memcpy(hw->scan[ST_LSM6DSX_ID_GYRO].channels,
417 				       &hw->buff[offset],
418 				       sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels));
419 				offset += sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels);
420 			}
421 			if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
422 				memcpy(hw->scan[ST_LSM6DSX_ID_ACC].channels,
423 				       &hw->buff[offset],
424 				       sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels));
425 				offset += sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels);
426 			}
427 			if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
428 				memcpy(hw->scan[ST_LSM6DSX_ID_EXT0].channels,
429 				       &hw->buff[offset],
430 				       sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels));
431 				offset += sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels);
432 			}
433 
434 			if (ts_sip-- > 0) {
435 				u8 data[ST_LSM6DSX_SAMPLE_SIZE];
436 
437 				memcpy(data, &hw->buff[offset], sizeof(data));
438 				/*
439 				 * hw timestamp is 3B long and it is stored
440 				 * in FIFO using 6B as 4th FIFO data set
441 				 * according to this schema:
442 				 * B0 = ts[15:8], B1 = ts[23:16], B3 = ts[7:0]
443 				 */
444 				ts = data[1] << 16 | data[0] << 8 | data[3];
445 				/*
446 				 * check if hw timestamp engine is going to
447 				 * reset (the sensor generates an interrupt
448 				 * to signal the hw timestamp will reset in
449 				 * 1.638s)
450 				 */
451 				if (!reset_ts && ts >= 0xff0000)
452 					reset_ts = true;
453 				ts *= hw->ts_gain;
454 
455 				offset += ST_LSM6DSX_SAMPLE_SIZE;
456 			}
457 
458 			if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
459 				iio_push_to_buffers_with_timestamp(
460 					hw->iio_devs[ST_LSM6DSX_ID_GYRO],
461 					&hw->scan[ST_LSM6DSX_ID_GYRO],
462 					gyro_sensor->ts_ref + ts);
463 				gyro_sip--;
464 			}
465 			if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
466 				iio_push_to_buffers_with_timestamp(
467 					hw->iio_devs[ST_LSM6DSX_ID_ACC],
468 					&hw->scan[ST_LSM6DSX_ID_ACC],
469 					acc_sensor->ts_ref + ts);
470 				acc_sip--;
471 			}
472 			if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
473 				iio_push_to_buffers_with_timestamp(
474 					hw->iio_devs[ST_LSM6DSX_ID_EXT0],
475 					&hw->scan[ST_LSM6DSX_ID_EXT0],
476 					ext_sensor->ts_ref + ts);
477 				ext_sip--;
478 			}
479 			sip++;
480 		}
481 	}
482 
483 	if (unlikely(reset_ts)) {
484 		err = st_lsm6dsx_reset_hw_ts(hw);
485 		if (err < 0) {
486 			dev_err(hw->dev, "failed to reset hw ts (err=%d)\n",
487 				err);
488 			return err;
489 		}
490 	}
491 	return read_len;
492 }
493 
494 #define ST_LSM6DSX_INVALID_SAMPLE	0x7ffd
495 static int
496 st_lsm6dsx_push_tagged_data(struct st_lsm6dsx_hw *hw, u8 tag,
497 			    u8 *data, s64 ts)
498 {
499 	s16 val = le16_to_cpu(*(__le16 *)data);
500 	struct st_lsm6dsx_sensor *sensor;
501 	struct iio_dev *iio_dev;
502 
503 	/* invalid sample during bootstrap phase */
504 	if (val >= ST_LSM6DSX_INVALID_SAMPLE)
505 		return -EINVAL;
506 
507 	/*
508 	 * EXT_TAG are managed in FIFO fashion so ST_LSM6DSX_EXT0_TAG
509 	 * corresponds to the first enabled channel, ST_LSM6DSX_EXT1_TAG
510 	 * to the second one and ST_LSM6DSX_EXT2_TAG to the last enabled
511 	 * channel
512 	 */
513 	switch (tag) {
514 	case ST_LSM6DSX_GYRO_TAG:
515 		iio_dev = hw->iio_devs[ST_LSM6DSX_ID_GYRO];
516 		break;
517 	case ST_LSM6DSX_ACC_TAG:
518 		iio_dev = hw->iio_devs[ST_LSM6DSX_ID_ACC];
519 		break;
520 	case ST_LSM6DSX_EXT0_TAG:
521 		if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0))
522 			iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT0];
523 		else if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1))
524 			iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
525 		else
526 			iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
527 		break;
528 	case ST_LSM6DSX_EXT1_TAG:
529 		if ((hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0)) &&
530 		    (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1)))
531 			iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
532 		else
533 			iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
534 		break;
535 	case ST_LSM6DSX_EXT2_TAG:
536 		iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
537 		break;
538 	default:
539 		return -EINVAL;
540 	}
541 
542 	sensor = iio_priv(iio_dev);
543 	iio_push_to_buffers_with_timestamp(iio_dev, data,
544 					   ts + sensor->ts_ref);
545 
546 	return 0;
547 }
548 
549 /**
550  * st_lsm6dsx_read_tagged_fifo() - tagged hw FIFO read routine
551  * @hw: Pointer to instance of struct st_lsm6dsx_hw.
552  *
553  * Read samples from the hw FIFO and push them to IIO buffers.
554  *
555  * Return: Number of bytes read from the FIFO
556  */
557 int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw)
558 {
559 	u16 pattern_len = hw->sip * ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
560 	u16 fifo_len, fifo_diff_mask;
561 	/*
562 	 * Alignment needed as this can ultimately be passed to a
563 	 * call to iio_push_to_buffers_with_timestamp() which
564 	 * must be passed a buffer that is aligned to 8 bytes so
565 	 * as to allow insertion of a naturally aligned timestamp.
566 	 */
567 	u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE] __aligned(8);
568 	u8 tag;
569 	bool reset_ts = false;
570 	int i, err, read_len;
571 	__le16 fifo_status;
572 	s64 ts = 0;
573 
574 	err = st_lsm6dsx_read_locked(hw,
575 				     hw->settings->fifo_ops.fifo_diff.addr,
576 				     &fifo_status, sizeof(fifo_status));
577 	if (err < 0) {
578 		dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
579 			err);
580 		return err;
581 	}
582 
583 	fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
584 	fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
585 		   ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
586 	if (!fifo_len)
587 		return 0;
588 
589 	for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
590 		err = st_lsm6dsx_read_block(hw,
591 					    ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR,
592 					    hw->buff, pattern_len,
593 					    ST_LSM6DSX_MAX_TAGGED_WORD_LEN);
594 		if (err < 0) {
595 			dev_err(hw->dev,
596 				"failed to read pattern from fifo (err=%d)\n",
597 				err);
598 			return err;
599 		}
600 
601 		for (i = 0; i < pattern_len;
602 		     i += ST_LSM6DSX_TAGGED_SAMPLE_SIZE) {
603 			memcpy(iio_buff, &hw->buff[i + ST_LSM6DSX_TAG_SIZE],
604 			       ST_LSM6DSX_SAMPLE_SIZE);
605 
606 			tag = hw->buff[i] >> 3;
607 			if (tag == ST_LSM6DSX_TS_TAG) {
608 				/*
609 				 * hw timestamp is 4B long and it is stored
610 				 * in FIFO according to this schema:
611 				 * B0 = ts[7:0], B1 = ts[15:8], B2 = ts[23:16],
612 				 * B3 = ts[31:24]
613 				 */
614 				ts = le32_to_cpu(*((__le32 *)iio_buff));
615 				/*
616 				 * check if hw timestamp engine is going to
617 				 * reset (the sensor generates an interrupt
618 				 * to signal the hw timestamp will reset in
619 				 * 1.638s)
620 				 */
621 				if (!reset_ts && ts >= 0xffff0000)
622 					reset_ts = true;
623 				ts *= hw->ts_gain;
624 			} else {
625 				st_lsm6dsx_push_tagged_data(hw, tag, iio_buff,
626 							    ts);
627 			}
628 		}
629 	}
630 
631 	if (unlikely(reset_ts)) {
632 		err = st_lsm6dsx_reset_hw_ts(hw);
633 		if (err < 0)
634 			return err;
635 	}
636 	return read_len;
637 }
638 
639 int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
640 {
641 	int err;
642 
643 	if (!hw->settings->fifo_ops.read_fifo)
644 		return -ENOTSUPP;
645 
646 	mutex_lock(&hw->fifo_lock);
647 
648 	hw->settings->fifo_ops.read_fifo(hw);
649 	err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS);
650 
651 	mutex_unlock(&hw->fifo_lock);
652 
653 	return err;
654 }
655 
656 int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
657 {
658 	struct st_lsm6dsx_hw *hw = sensor->hw;
659 	u8 fifo_mask;
660 	int err;
661 
662 	mutex_lock(&hw->conf_lock);
663 
664 	if (enable)
665 		fifo_mask = hw->fifo_mask | BIT(sensor->id);
666 	else
667 		fifo_mask = hw->fifo_mask & ~BIT(sensor->id);
668 
669 	if (hw->fifo_mask) {
670 		err = st_lsm6dsx_flush_fifo(hw);
671 		if (err < 0)
672 			goto out;
673 	}
674 
675 	if (sensor->id == ST_LSM6DSX_ID_EXT0 ||
676 	    sensor->id == ST_LSM6DSX_ID_EXT1 ||
677 	    sensor->id == ST_LSM6DSX_ID_EXT2) {
678 		err = st_lsm6dsx_shub_set_enable(sensor, enable);
679 		if (err < 0)
680 			goto out;
681 	} else {
682 		err = st_lsm6dsx_sensor_set_enable(sensor, enable);
683 		if (err < 0)
684 			goto out;
685 	}
686 
687 	err = st_lsm6dsx_set_fifo_odr(sensor, enable);
688 	if (err < 0)
689 		goto out;
690 
691 	err = st_lsm6dsx_update_decimators(hw);
692 	if (err < 0)
693 		goto out;
694 
695 	err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
696 	if (err < 0)
697 		goto out;
698 
699 	if (fifo_mask) {
700 		err = st_lsm6dsx_resume_fifo(hw);
701 		if (err < 0)
702 			goto out;
703 	}
704 
705 	hw->fifo_mask = fifo_mask;
706 
707 out:
708 	mutex_unlock(&hw->conf_lock);
709 
710 	return err;
711 }
712 
713 static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)
714 {
715 	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
716 	struct st_lsm6dsx_hw *hw = sensor->hw;
717 
718 	if (!hw->settings->fifo_ops.update_fifo)
719 		return -ENOTSUPP;
720 
721 	return hw->settings->fifo_ops.update_fifo(sensor, true);
722 }
723 
724 static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev)
725 {
726 	struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
727 	struct st_lsm6dsx_hw *hw = sensor->hw;
728 
729 	if (!hw->settings->fifo_ops.update_fifo)
730 		return -ENOTSUPP;
731 
732 	return hw->settings->fifo_ops.update_fifo(sensor, false);
733 }
734 
735 static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = {
736 	.preenable = st_lsm6dsx_buffer_preenable,
737 	.postdisable = st_lsm6dsx_buffer_postdisable,
738 };
739 
740 int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
741 {
742 	struct iio_buffer *buffer;
743 	int i;
744 
745 	for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
746 		if (!hw->iio_devs[i])
747 			continue;
748 
749 		buffer = devm_iio_kfifo_allocate(hw->dev);
750 		if (!buffer)
751 			return -ENOMEM;
752 
753 		iio_device_attach_buffer(hw->iio_devs[i], buffer);
754 		hw->iio_devs[i]->modes |= INDIO_BUFFER_SOFTWARE;
755 		hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops;
756 	}
757 
758 	return 0;
759 }
760