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