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