drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_buffer.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * STMicroelectronics st_lsm6dsx FIFO buffer library driver
   4  *
   5  * Pattern FIFO:
   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  * Supported devices:
  18  * - ISM330DLC
  19  * - LSM6DS3
  20  * - LSM6DS3H
  21  * - LSM6DS3TR-C
  22  * - LSM6DSL
  23  * - LSM6DSM
  24  *
  25  * Tagged FIFO:
  26  * The FIFO buffer can be configured to store data from gyroscope and
  27  * accelerometer. Each sample is queued with a tag (1B) indicating data
  28  * source (gyroscope, accelerometer, hw timer).
  29  *
  30  * Supported devices:
  31  * - ASM330LHB
  32  * - ASM330LHH
  33  * - ASM330LHHX
  34  * - ASM330LHHXG1
  35  * - ISM330DHCX
  36  * - LSM6DSO
  37  * - LSM6DSOP
  38  * - LSM6DSOX
  39  * - LSM6DSR
  40  * - LSM6DSRX
  41  * - LSM6DST
  42  * - LSM6DSTX
  43  * - LSM6DSV
  44  *
  45  * FIFO supported modes:
  46  *  - BYPASS: FIFO disabled
  47  *  - CONTINUOUS: FIFO enabled. When the buffer is full, the FIFO index
  48  *    restarts from the beginning and the oldest sample is overwritten
  49  *
  50  * Copyright 2016 STMicroelectronics Inc.
  51  *
  52  * Lorenzo Bianconi <[email protected]>
  53  * Denis Ciocca <[email protected]>
  54  */
  55 #include <linux/module.h>
  56 #include <linux/iio/kfifo_buf.h>
  57 #include <linux/iio/iio.h>
  58 #include <linux/iio/buffer.h>
  59 #include <linux/regmap.h>
  60 #include <linux/bitfield.h>
  61
  62 #include <linux/platform_data/st_sensors_pdata.h>
  63
  64 #include "st_lsm6dsx.h"
  65
  66 #define ST_LSM6DSX_REG_FIFO_MODE_ADDR           0x0a
  67 #define ST_LSM6DSX_FIFO_MODE_MASK               GENMASK(2, 0)
  68 #define ST_LSM6DSX_FIFO_ODR_MASK                GENMASK(6, 3)
  69 #define ST_LSM6DSX_FIFO_EMPTY_MASK              BIT(12)
  70 #define ST_LSM6DSX_REG_FIFO_OUTL_ADDR           0x3e
  71 #define ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR        0x78
  72 #define ST_LSM6DSX_REG_TS_RESET_ADDR            0x42
  73
  74 #define ST_LSM6DSX_MAX_FIFO_ODR_VAL             0x08
  75
  76 #define ST_LSM6DSX_TS_RESET_VAL                 0xaa
  77
  78 struct st_lsm6dsx_decimator_entry {
  79         u8 decimator;
  80         u8 val;
  81 };
  82
  83 enum st_lsm6dsx_fifo_tag {
  84         ST_LSM6DSX_GYRO_TAG = 0x01,
  85         ST_LSM6DSX_ACC_TAG = 0x02,
  86         ST_LSM6DSX_TS_TAG = 0x04,
  87         ST_LSM6DSX_EXT0_TAG = 0x0f,
  88         ST_LSM6DSX_EXT1_TAG = 0x10,
  89         ST_LSM6DSX_EXT2_TAG = 0x11,
  90 };
  91
  92 static const
  93 struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = {
  94         {  0, 0x0 },
  95         {  1, 0x1 },
  96         {  2, 0x2 },
  97         {  3, 0x3 },
  98         {  4, 0x4 },
  99         {  8, 0x5 },
 100         { 16, 0x6 },
 101         { 32, 0x7 },
 102 };
 103
 104 static int
 105 st_lsm6dsx_get_decimator_val(struct st_lsm6dsx_sensor *sensor, u32 max_odr)
 106 {
 107         const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table);
 108         u32 decimator =  max_odr / sensor->odr;
 109         int i;
 110
 111         if (decimator > 1)
 112                 decimator = round_down(decimator, 2);
 113
 114         for (i = 0; i < max_size; i++) {
 115                 if (st_lsm6dsx_decimator_table[i].decimator == decimator)
 116                         break;
 117         }
 118
 119         sensor->decimator = decimator;
 120         return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val;
 121 }
 122
 123 static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw,
 124                                        u32 *max_odr, u32 *min_odr)
 125 {
 126         struct st_lsm6dsx_sensor *sensor;
 127         int i;
 128
 129         *max_odr = 0, *min_odr = ~0;
 130         for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
 131                 if (!hw->iio_devs[i])
 132                         continue;
 133
 134                 sensor = iio_priv(hw->iio_devs[i]);
 135
 136                 if (!(hw->enable_mask & BIT(sensor->id)))
 137                         continue;
 138
 139                 *max_odr = max_t(u32, *max_odr, sensor->odr);
 140                 *min_odr = min_t(u32, *min_odr, sensor->odr);
 141         }
 142 }
 143
 144 static u8 st_lsm6dsx_get_sip(struct st_lsm6dsx_sensor *sensor, u32 min_odr)
 145 {
 146         u8 sip = sensor->odr / min_odr;
 147
 148         return sip > 1 ? round_down(sip, 2) : sip;
 149 }
 150
 151 static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw)
 152 {
 153         const struct st_lsm6dsx_reg *ts_dec_reg;
 154         struct st_lsm6dsx_sensor *sensor;
 155         u16 sip = 0, ts_sip = 0;
 156         u32 max_odr, min_odr;
 157         int err = 0, i;
 158         u8 data;
 159
 160         st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr);
 161
 162         for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
 163                 const struct st_lsm6dsx_reg *dec_reg;
 164
 165                 if (!hw->iio_devs[i])
 166                         continue;
 167
 168                 sensor = iio_priv(hw->iio_devs[i]);
 169                 /* update fifo decimators and sample in pattern */
 170                 if (hw->enable_mask & BIT(sensor->id)) {
 171                         sensor->sip = st_lsm6dsx_get_sip(sensor, min_odr);
 172                         data = st_lsm6dsx_get_decimator_val(sensor, max_odr);
 173                 } else {
 174                         sensor->sip = 0;
 175                         data = 0;
 176                 }
 177                 ts_sip = max_t(u16, ts_sip, sensor->sip);
 178
 179                 dec_reg = &hw->settings->decimator[sensor->id];
 180                 if (dec_reg->addr) {
 181                         int val = ST_LSM6DSX_SHIFT_VAL(data, dec_reg->mask);
 182
 183                         err = st_lsm6dsx_update_bits_locked(hw, dec_reg->addr,
 184                                                             dec_reg->mask,
 185                                                             val);
 186                         if (err < 0)
 187                                 return err;
 188                 }
 189                 sip += sensor->sip;
 190         }
 191         hw->sip = sip + ts_sip;
 192         hw->ts_sip = ts_sip;
 193
 194         /*
 195          * update hw ts decimator if necessary. Decimator for hw timestamp
 196          * is always 1 or 0 in order to have a ts sample for each data
 197          * sample in FIFO
 198          */
 199         ts_dec_reg = &hw->settings->ts_settings.decimator;
 200         if (ts_dec_reg->addr) {
 201                 int val, ts_dec = !!hw->ts_sip;
 202
 203                 val = ST_LSM6DSX_SHIFT_VAL(ts_dec, ts_dec_reg->mask);
 204                 err = st_lsm6dsx_update_bits_locked(hw, ts_dec_reg->addr,
 205                                                     ts_dec_reg->mask, val);
 206         }
 207         return err;
 208 }
 209
 210 static int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw,
 211                                     enum st_lsm6dsx_fifo_mode fifo_mode)
 212 {
 213         unsigned int data;
 214
 215         data = FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, fifo_mode);
 216         return st_lsm6dsx_update_bits_locked(hw, ST_LSM6DSX_REG_FIFO_MODE_ADDR,
 217                                              ST_LSM6DSX_FIFO_MODE_MASK, data);
 218 }
 219
 220 static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor,
 221                                    bool enable)
 222 {
 223         struct st_lsm6dsx_hw *hw = sensor->hw;
 224         const struct st_lsm6dsx_reg *batch_reg;
 225         u8 data;
 226
 227         batch_reg = &hw->settings->batch[sensor->id];
 228         if (batch_reg->addr) {
 229                 int val;
 230
 231                 if (enable) {
 232                         int err;
 233
 234                         err = st_lsm6dsx_check_odr(sensor, sensor->odr,
 235                                                    &data);
 236                         if (err < 0)
 237                                 return err;
 238                 } else {
 239                         data = 0;
 240                 }
 241                 val = ST_LSM6DSX_SHIFT_VAL(data, batch_reg->mask);
 242                 return st_lsm6dsx_update_bits_locked(hw, batch_reg->addr,
 243                                                      batch_reg->mask, val);
 244         } else {
 245                 data = hw->enable_mask ? ST_LSM6DSX_MAX_FIFO_ODR_VAL : 0;
 246                 return st_lsm6dsx_update_bits_locked(hw,
 247                                         ST_LSM6DSX_REG_FIFO_MODE_ADDR,
 248                                         ST_LSM6DSX_FIFO_ODR_MASK,
 249                                         FIELD_PREP(ST_LSM6DSX_FIFO_ODR_MASK,
 250                                                    data));
 251         }
 252 }
 253
 254 int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark)
 255 {
 256         u16 fifo_watermark = ~0, cur_watermark, fifo_th_mask;
 257         struct st_lsm6dsx_hw *hw = sensor->hw;
 258         struct st_lsm6dsx_sensor *cur_sensor;
 259         int i, err, data;
 260         __le16 wdata;
 261
 262         if (!hw->sip)
 263                 return 0;
 264
 265         for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
 266                 if (!hw->iio_devs[i])
 267                         continue;
 268
 269                 cur_sensor = iio_priv(hw->iio_devs[i]);
 270
 271                 if (!(hw->enable_mask & BIT(cur_sensor->id)))
 272                         continue;
 273
 274                 cur_watermark = (cur_sensor == sensor) ? watermark
 275                                                        : cur_sensor->watermark;
 276
 277                 fifo_watermark = min_t(u16, fifo_watermark, cur_watermark);
 278         }
 279
 280         fifo_watermark = max_t(u16, fifo_watermark, hw->sip);
 281         fifo_watermark = (fifo_watermark / hw->sip) * hw->sip;
 282         fifo_watermark = fifo_watermark * hw->settings->fifo_ops.th_wl;
 283
 284         mutex_lock(&hw->page_lock);
 285         err = regmap_read(hw->regmap, hw->settings->fifo_ops.fifo_th.addr + 1,
 286                           &data);
 287         if (err < 0)
 288                 goto out;
 289
 290         fifo_th_mask = hw->settings->fifo_ops.fifo_th.mask;
 291         fifo_watermark = ((data << 8) & ~fifo_th_mask) |
 292                          (fifo_watermark & fifo_th_mask);
 293
 294         wdata = cpu_to_le16(fifo_watermark);
 295         err = regmap_bulk_write(hw->regmap,
 296                                 hw->settings->fifo_ops.fifo_th.addr,
 297                                 &wdata, sizeof(wdata));
 298 out:
 299         mutex_unlock(&hw->page_lock);
 300         return err;
 301 }
 302
 303 static int st_lsm6dsx_reset_hw_ts(struct st_lsm6dsx_hw *hw)
 304 {
 305         struct st_lsm6dsx_sensor *sensor;
 306         int i, err;
 307
 308         /* reset hw ts counter */
 309         err = st_lsm6dsx_write_locked(hw, ST_LSM6DSX_REG_TS_RESET_ADDR,
 310                                       ST_LSM6DSX_TS_RESET_VAL);
 311         if (err < 0)
 312                 return err;
 313
 314         for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
 315                 if (!hw->iio_devs[i])
 316                         continue;
 317
 318                 sensor = iio_priv(hw->iio_devs[i]);
 319                 /*
 320                  * store enable buffer timestamp as reference for
 321                  * hw timestamp
 322                  */
 323                 sensor->ts_ref = iio_get_time_ns(hw->iio_devs[i]);
 324         }
 325         return 0;
 326 }
 327
 328 int st_lsm6dsx_resume_fifo(struct st_lsm6dsx_hw *hw)
 329 {
 330         int err;
 331
 332         /* reset hw ts counter */
 333         err = st_lsm6dsx_reset_hw_ts(hw);
 334         if (err < 0)
 335                 return err;
 336
 337         return st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
 338 }
 339
 340 /*
 341  * Set max bulk read to ST_LSM6DSX_MAX_WORD_LEN/ST_LSM6DSX_MAX_TAGGED_WORD_LEN
 342  * in order to avoid a kmalloc for each bus access
 343  */
 344 static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 addr,
 345                                         u8 *data, unsigned int data_len,
 346                                         unsigned int max_word_len)
 347 {
 348         unsigned int word_len, read_len = 0;
 349         int err;
 350
 351         while (read_len < data_len) {
 352                 word_len = min_t(unsigned int, data_len - read_len,
 353                                  max_word_len);
 354                 err = st_lsm6dsx_read_locked(hw, addr, data + read_len,
 355                                              word_len);
 356                 if (err < 0)
 357                         return err;
 358                 read_len += word_len;
 359         }
 360         return 0;
 361 }
 362
 363 #define ST_LSM6DSX_IIO_BUFF_SIZE        (ALIGN(ST_LSM6DSX_SAMPLE_SIZE, \
 364                                                sizeof(s64)) + sizeof(s64))
 365 /**
 366  * st_lsm6dsx_read_fifo() - hw FIFO read routine
 367  * @hw: Pointer to instance of struct st_lsm6dsx_hw.
 368  *
 369  * Read samples from the hw FIFO and push them to IIO buffers.
 370  *
 371  * Return: Number of bytes read from the FIFO
 372  */
 373 int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw)
 374 {
 375         struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor, *ext_sensor = NULL;
 376         int err, sip, acc_sip, gyro_sip, ts_sip, ext_sip, read_len, offset;
 377         u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE;
 378         u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
 379         bool reset_ts = false;
 380         __le16 fifo_status;
 381         s64 ts = 0;
 382
 383         err = st_lsm6dsx_read_locked(hw,
 384                                      hw->settings->fifo_ops.fifo_diff.addr,
 385                                      &fifo_status, sizeof(fifo_status));
 386         if (err < 0) {
 387                 dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
 388                         err);
 389                 return err;
 390         }
 391
 392         if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
 393                 return 0;
 394
 395         fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
 396                    ST_LSM6DSX_CHAN_SIZE;
 397         fifo_len = (fifo_len / pattern_len) * pattern_len;
 398
 399         acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
 400         gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
 401         if (hw->iio_devs[ST_LSM6DSX_ID_EXT0])
 402                 ext_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_EXT0]);
 403
 404         for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
 405                 err = st_lsm6dsx_read_block(hw, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
 406                                             hw->buff, pattern_len,
 407                                             ST_LSM6DSX_MAX_WORD_LEN);
 408                 if (err < 0) {
 409                         dev_err(hw->dev,
 410                                 "failed to read pattern from fifo (err=%d)\n",
 411                                 err);
 412                         return err;
 413                 }
 414
 415                 /*
 416                  * Data are written to the FIFO with a specific pattern
 417                  * depending on the configured ODRs. The first sequence of data
 418                  * stored in FIFO contains the data of all enabled sensors
 419                  * (e.g. Gx, Gy, Gz, Ax, Ay, Az, Ts), then data are repeated
 420                  * depending on the value of the decimation factor set for each
 421                  * sensor.
 422                  *
 423                  * Supposing the FIFO is storing data from gyroscope and
 424                  * accelerometer at different ODRs:
 425                  *   - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz
 426                  * Since the gyroscope ODR is twice the accelerometer one, the
 427                  * following pattern is repeated every 9 samples:
 428                  *   - Gx, Gy, Gz, Ax, Ay, Az, Ts, Gx, Gy, Gz, Ts, Gx, ..
 429                  */
 430                 ext_sip = ext_sensor ? ext_sensor->sip : 0;
 431                 gyro_sip = gyro_sensor->sip;
 432                 acc_sip = acc_sensor->sip;
 433                 ts_sip = hw->ts_sip;
 434                 offset = 0;
 435                 sip = 0;
 436
 437                 while (acc_sip > 0 || gyro_sip > 0 || ext_sip > 0) {
 438                         if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
 439                                 memcpy(hw->scan[ST_LSM6DSX_ID_GYRO].channels,
 440                                        &hw->buff[offset],
 441                                        sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels));
 442                                 offset += sizeof(hw->scan[ST_LSM6DSX_ID_GYRO].channels);
 443                         }
 444                         if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
 445                                 memcpy(hw->scan[ST_LSM6DSX_ID_ACC].channels,
 446                                        &hw->buff[offset],
 447                                        sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels));
 448                                 offset += sizeof(hw->scan[ST_LSM6DSX_ID_ACC].channels);
 449                         }
 450                         if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
 451                                 memcpy(hw->scan[ST_LSM6DSX_ID_EXT0].channels,
 452                                        &hw->buff[offset],
 453                                        sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels));
 454                                 offset += sizeof(hw->scan[ST_LSM6DSX_ID_EXT0].channels);
 455                         }
 456
 457                         if (ts_sip-- > 0) {
 458                                 u8 data[ST_LSM6DSX_SAMPLE_SIZE];
 459
 460                                 memcpy(data, &hw->buff[offset], sizeof(data));
 461                                 /*
 462                                  * hw timestamp is 3B long and it is stored
 463                                  * in FIFO using 6B as 4th FIFO data set
 464                                  * according to this schema:
 465                                  * B0 = ts[15:8], B1 = ts[23:16], B3 = ts[7:0]
 466                                  */
 467                                 ts = data[1] << 16 | data[0] << 8 | data[3];
 468                                 /*
 469                                  * check if hw timestamp engine is going to
 470                                  * reset (the sensor generates an interrupt
 471                                  * to signal the hw timestamp will reset in
 472                                  * 1.638s)
 473                                  */
 474                                 if (!reset_ts && ts >= 0xff0000)
 475                                         reset_ts = true;
 476                                 ts *= hw->ts_gain;
 477
 478                                 offset += ST_LSM6DSX_SAMPLE_SIZE;
 479                         }
 480
 481                         if (gyro_sip > 0 && !(sip % gyro_sensor->decimator)) {
 482                                 /*
 483                                  * We need to discards gyro samples during
 484                                  * filters settling time
 485                                  */
 486                                 if (gyro_sensor->samples_to_discard > 0)
 487                                         gyro_sensor->samples_to_discard--;
 488                                 else
 489                                         iio_push_to_buffers_with_timestamp(
 490                                                 hw->iio_devs[ST_LSM6DSX_ID_GYRO],
 491                                                 &hw->scan[ST_LSM6DSX_ID_GYRO],
 492                                                 gyro_sensor->ts_ref + ts);
 493                                 gyro_sip--;
 494                         }
 495                         if (acc_sip > 0 && !(sip % acc_sensor->decimator)) {
 496                                 /*
 497                                  * We need to discards accel samples during
 498                                  * filters settling time
 499                                  */
 500                                 if (acc_sensor->samples_to_discard > 0)
 501                                         acc_sensor->samples_to_discard--;
 502                                 else
 503                                         iio_push_to_buffers_with_timestamp(
 504                                                 hw->iio_devs[ST_LSM6DSX_ID_ACC],
 505                                                 &hw->scan[ST_LSM6DSX_ID_ACC],
 506                                                 acc_sensor->ts_ref + ts);
 507                                 acc_sip--;
 508                         }
 509                         if (ext_sip > 0 && !(sip % ext_sensor->decimator)) {
 510                                 iio_push_to_buffers_with_timestamp(
 511                                         hw->iio_devs[ST_LSM6DSX_ID_EXT0],
 512                                         &hw->scan[ST_LSM6DSX_ID_EXT0],
 513                                         ext_sensor->ts_ref + ts);
 514                                 ext_sip--;
 515                         }
 516                         sip++;
 517                 }
 518         }
 519
 520         if (unlikely(reset_ts)) {
 521                 err = st_lsm6dsx_reset_hw_ts(hw);
 522                 if (err < 0) {
 523                         dev_err(hw->dev, "failed to reset hw ts (err=%d)\n",
 524                                 err);
 525                         return err;
 526                 }
 527         }
 528         return read_len;
 529 }
 530
 531 #define ST_LSM6DSX_INVALID_SAMPLE       0x7ffd
 532 static int
 533 st_lsm6dsx_push_tagged_data(struct st_lsm6dsx_hw *hw, u8 tag,
 534                             u8 *data, s64 ts)
 535 {
 536         s16 val = le16_to_cpu(*(__le16 *)data);
 537         struct st_lsm6dsx_sensor *sensor;
 538         struct iio_dev *iio_dev;
 539
 540         /* invalid sample during bootstrap phase */
 541         if (val >= ST_LSM6DSX_INVALID_SAMPLE)
 542                 return -EINVAL;
 543
 544         /*
 545          * EXT_TAG are managed in FIFO fashion so ST_LSM6DSX_EXT0_TAG
 546          * corresponds to the first enabled channel, ST_LSM6DSX_EXT1_TAG
 547          * to the second one and ST_LSM6DSX_EXT2_TAG to the last enabled
 548          * channel
 549          */
 550         switch (tag) {
 551         case ST_LSM6DSX_GYRO_TAG:
 552                 iio_dev = hw->iio_devs[ST_LSM6DSX_ID_GYRO];
 553                 break;
 554         case ST_LSM6DSX_ACC_TAG:
 555                 iio_dev = hw->iio_devs[ST_LSM6DSX_ID_ACC];
 556                 break;
 557         case ST_LSM6DSX_EXT0_TAG:
 558                 if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0))
 559                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT0];
 560                 else if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1))
 561                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
 562                 else
 563                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
 564                 break;
 565         case ST_LSM6DSX_EXT1_TAG:
 566                 if ((hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0)) &&
 567                     (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1)))
 568                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
 569                 else
 570                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
 571                 break;
 572         case ST_LSM6DSX_EXT2_TAG:
 573                 iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
 574                 break;
 575         default:
 576                 return -EINVAL;
 577         }
 578
 579         sensor = iio_priv(iio_dev);
 580         iio_push_to_buffers_with_timestamp(iio_dev, data,
 581                                            ts + sensor->ts_ref);
 582
 583         return 0;
 584 }
 585
 586 /**
 587  * st_lsm6dsx_read_tagged_fifo() - tagged hw FIFO read routine
 588  * @hw: Pointer to instance of struct st_lsm6dsx_hw.
 589  *
 590  * Read samples from the hw FIFO and push them to IIO buffers.
 591  *
 592  * Return: Number of bytes read from the FIFO
 593  */
 594 int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw)
 595 {
 596         u16 pattern_len = hw->sip * ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
 597         u16 fifo_len, fifo_diff_mask;
 598         /*
 599          * Alignment needed as this can ultimately be passed to a
 600          * call to iio_push_to_buffers_with_timestamp() which
 601          * must be passed a buffer that is aligned to 8 bytes so
 602          * as to allow insertion of a naturally aligned timestamp.
 603          */
 604         u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE] __aligned(8);
 605         u8 tag;
 606         bool reset_ts = false;
 607         int i, err, read_len;
 608         __le16 fifo_status;
 609         s64 ts = 0;
 610
 611         err = st_lsm6dsx_read_locked(hw,
 612                                      hw->settings->fifo_ops.fifo_diff.addr,
 613                                      &fifo_status, sizeof(fifo_status));
 614         if (err < 0) {
 615                 dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
 616                         err);
 617                 return err;
 618         }
 619
 620         fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
 621         fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
 622                    ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
 623         if (!fifo_len)
 624                 return 0;
 625
 626         for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
 627                 err = st_lsm6dsx_read_block(hw,
 628                                             ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR,
 629                                             hw->buff, pattern_len,
 630                                             ST_LSM6DSX_MAX_TAGGED_WORD_LEN);
 631                 if (err < 0) {
 632                         dev_err(hw->dev,
 633                                 "failed to read pattern from fifo (err=%d)\n",
 634                                 err);
 635                         return err;
 636                 }
 637
 638                 for (i = 0; i < pattern_len;
 639                      i += ST_LSM6DSX_TAGGED_SAMPLE_SIZE) {
 640                         memcpy(iio_buff, &hw->buff[i + ST_LSM6DSX_TAG_SIZE],
 641                                ST_LSM6DSX_SAMPLE_SIZE);
 642
 643                         tag = hw->buff[i] >> 3;
 644                         if (tag == ST_LSM6DSX_TS_TAG) {
 645                                 /*
 646                                  * hw timestamp is 4B long and it is stored
 647                                  * in FIFO according to this schema:
 648                                  * B0 = ts[7:0], B1 = ts[15:8], B2 = ts[23:16],
 649                                  * B3 = ts[31:24]
 650                                  */
 651                                 ts = le32_to_cpu(*((__le32 *)iio_buff));
 652                                 /*
 653                                  * check if hw timestamp engine is going to
 654                                  * reset (the sensor generates an interrupt
 655                                  * to signal the hw timestamp will reset in
 656                                  * 1.638s)
 657                                  */
 658                                 if (!reset_ts && ts >= 0xffff0000)
 659                                         reset_ts = true;
 660                                 ts *= hw->ts_gain;
 661                         } else {
 662                                 st_lsm6dsx_push_tagged_data(hw, tag, iio_buff,
 663                                                             ts);
 664                         }
 665                 }
 666         }
 667
 668         if (unlikely(reset_ts)) {
 669                 err = st_lsm6dsx_reset_hw_ts(hw);
 670                 if (err < 0)
 671                         return err;
 672         }
 673         return read_len;
 674 }
 675
 676 int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
 677 {
 678         int err;
 679
 680         if (!hw->settings->fifo_ops.read_fifo)
 681                 return -ENOTSUPP;
 682
 683         mutex_lock(&hw->fifo_lock);
 684
 685         hw->settings->fifo_ops.read_fifo(hw);
 686         err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS);
 687
 688         mutex_unlock(&hw->fifo_lock);
 689
 690         return err;
 691 }
 692
 693 static void
 694 st_lsm6dsx_update_samples_to_discard(struct st_lsm6dsx_sensor *sensor)
 695 {
 696         const struct st_lsm6dsx_samples_to_discard *data;
 697         struct st_lsm6dsx_hw *hw = sensor->hw;
 698         int i;
 699
 700         if (sensor->id != ST_LSM6DSX_ID_GYRO &&
 701             sensor->id != ST_LSM6DSX_ID_ACC)
 702                 return;
 703
 704         /* check if drdy mask is supported in hw */
 705         if (hw->settings->drdy_mask.addr)
 706                 return;
 707
 708         data = &hw->settings->samples_to_discard[sensor->id];
 709         for (i = 0; i < ST_LSM6DSX_ODR_LIST_SIZE; i++) {
 710                 if (data->val[i].milli_hz == sensor->odr) {
 711                         sensor->samples_to_discard = data->val[i].samples;
 712                         return;
 713                 }
 714         }
 715 }
 716
 717 int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
 718 {
 719         struct st_lsm6dsx_hw *hw = sensor->hw;
 720         u8 fifo_mask;
 721         int err;
 722
 723         mutex_lock(&hw->conf_lock);
 724
 725         if (enable)
 726                 fifo_mask = hw->fifo_mask | BIT(sensor->id);
 727         else
 728                 fifo_mask = hw->fifo_mask & ~BIT(sensor->id);
 729
 730         if (hw->fifo_mask) {
 731                 err = st_lsm6dsx_flush_fifo(hw);
 732                 if (err < 0)
 733                         goto out;
 734         }
 735
 736         if (enable)
 737                 st_lsm6dsx_update_samples_to_discard(sensor);
 738
 739         err = st_lsm6dsx_device_set_enable(sensor, enable);
 740         if (err < 0)
 741                 goto out;
 742
 743         err = st_lsm6dsx_set_fifo_odr(sensor, enable);
 744         if (err < 0)
 745                 goto out;
 746
 747         err = st_lsm6dsx_update_decimators(hw);
 748         if (err < 0)
 749                 goto out;
 750
 751         err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
 752         if (err < 0)
 753                 goto out;
 754
 755         if (fifo_mask) {
 756                 err = st_lsm6dsx_resume_fifo(hw);
 757                 if (err < 0)
 758                         goto out;
 759         }
 760
 761         hw->fifo_mask = fifo_mask;
 762
 763 out:
 764         mutex_unlock(&hw->conf_lock);
 765
 766         return err;
 767 }
 768
 769 static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)
 770 {
 771         struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
 772         struct st_lsm6dsx_hw *hw = sensor->hw;
 773
 774         if (!hw->settings->fifo_ops.update_fifo)
 775                 return -ENOTSUPP;
 776
 777         return hw->settings->fifo_ops.update_fifo(sensor, true);
 778 }
 779
 780 static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev)
 781 {
 782         struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
 783         struct st_lsm6dsx_hw *hw = sensor->hw;
 784
 785         if (!hw->settings->fifo_ops.update_fifo)
 786                 return -ENOTSUPP;
 787
 788         return hw->settings->fifo_ops.update_fifo(sensor, false);
 789 }
 790
 791 static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = {
 792         .preenable = st_lsm6dsx_buffer_preenable,
 793         .postdisable = st_lsm6dsx_buffer_postdisable,
 794 };
 795
 796 int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
 797 {
 798         int i, ret;
 799
 800         for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
 801                 if (!hw->iio_devs[i])
 802                         continue;
 803
 804                 ret = devm_iio_kfifo_buffer_setup(hw->dev, hw->iio_devs[i],
 805                                                   &st_lsm6dsx_buffer_ops);
 806                 if (ret)
 807                         return ret;
 808         }
 809
 810         return 0;
 811 }