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         struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor, *ext_sensor = NULL;
 340         int err, acc_sip, gyro_sip, ts_sip, ext_sip, read_len, offset;
 341         u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE;
 342         u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
 343         u8 gyro_buff[ST_LSM6DSX_IIO_BUFF_SIZE];
 344         u8 acc_buff[ST_LSM6DSX_IIO_BUFF_SIZE];
 345         u8 ext_buff[ST_LSM6DSX_IIO_BUFF_SIZE];
 346         bool reset_ts = false;
 347         __le16 fifo_status;
 348         s64 ts = 0;
 349
 350         err = st_lsm6dsx_read_locked(hw,
 351                                      hw->settings->fifo_ops.fifo_diff.addr,
 352                                      &fifo_status, sizeof(fifo_status));
 353         if (err < 0) {
 354                 dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
 355                         err);
 356                 return err;
 357         }
 358
 359         if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK))
 360                 return 0;
 361
 362         fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
 363                    ST_LSM6DSX_CHAN_SIZE;
 364         fifo_len = (fifo_len / pattern_len) * pattern_len;
 365
 366         acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]);
 367         gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]);
 368         if (hw->iio_devs[ST_LSM6DSX_ID_EXT0])
 369                 ext_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_EXT0]);
 370
 371         for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
 372                 err = st_lsm6dsx_read_block(hw, ST_LSM6DSX_REG_FIFO_OUTL_ADDR,
 373                                             hw->buff, pattern_len,
 374                                             ST_LSM6DSX_MAX_WORD_LEN);
 375                 if (err < 0) {
 376                         dev_err(hw->dev,
 377                                 "failed to read pattern from fifo (err=%d)\n",
 378                                 err);
 379                         return err;
 380                 }
 381
 382                 /*
 383                  * Data are written to the FIFO with a specific pattern
 384                  * depending on the configured ODRs. The first sequence of data
 385                  * stored in FIFO contains the data of all enabled sensors
 386                  * (e.g. Gx, Gy, Gz, Ax, Ay, Az, Ts), then data are repeated
 387                  * depending on the value of the decimation factor set for each
 388                  * sensor.
 389                  *
 390                  * Supposing the FIFO is storing data from gyroscope and
 391                  * accelerometer at different ODRs:
 392                  *   - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz
 393                  * Since the gyroscope ODR is twice the accelerometer one, the
 394                  * following pattern is repeated every 9 samples:
 395                  *   - Gx, Gy, Gz, Ax, Ay, Az, Ts, Gx, Gy, Gz, Ts, Gx, ..
 396                  */
 397                 ext_sip = ext_sensor ? ext_sensor->sip : 0;
 398                 gyro_sip = gyro_sensor->sip;
 399                 acc_sip = acc_sensor->sip;
 400                 ts_sip = hw->ts_sip;
 401                 offset = 0;
 402
 403                 while (acc_sip > 0 || gyro_sip > 0 || ext_sip > 0) {
 404                         if (gyro_sip > 0) {
 405                                 memcpy(gyro_buff, &hw->buff[offset],
 406                                        ST_LSM6DSX_SAMPLE_SIZE);
 407                                 offset += ST_LSM6DSX_SAMPLE_SIZE;
 408                         }
 409                         if (acc_sip > 0) {
 410                                 memcpy(acc_buff, &hw->buff[offset],
 411                                        ST_LSM6DSX_SAMPLE_SIZE);
 412                                 offset += ST_LSM6DSX_SAMPLE_SIZE;
 413                         }
 414                         if (ext_sip > 0) {
 415                                 memcpy(ext_buff, &hw->buff[offset],
 416                                        ST_LSM6DSX_SAMPLE_SIZE);
 417                                 offset += ST_LSM6DSX_SAMPLE_SIZE;
 418                         }
 419
 420                         if (ts_sip-- > 0) {
 421                                 u8 data[ST_LSM6DSX_SAMPLE_SIZE];
 422
 423                                 memcpy(data, &hw->buff[offset], sizeof(data));
 424                                 /*
 425                                  * hw timestamp is 3B long and it is stored
 426                                  * in FIFO using 6B as 4th FIFO data set
 427                                  * according to this schema:
 428                                  * B0 = ts[15:8], B1 = ts[23:16], B3 = ts[7:0]
 429                                  */
 430                                 ts = data[1] << 16 | data[0] << 8 | data[3];
 431                                 /*
 432                                  * check if hw timestamp engine is going to
 433                                  * reset (the sensor generates an interrupt
 434                                  * to signal the hw timestamp will reset in
 435                                  * 1.638s)
 436                                  */
 437                                 if (!reset_ts && ts >= 0xff0000)
 438                                         reset_ts = true;
 439                                 ts *= hw->ts_gain;
 440
 441                                 offset += ST_LSM6DSX_SAMPLE_SIZE;
 442                         }
 443
 444                         if (gyro_sip-- > 0)
 445                                 iio_push_to_buffers_with_timestamp(
 446                                         hw->iio_devs[ST_LSM6DSX_ID_GYRO],
 447                                         gyro_buff, gyro_sensor->ts_ref + ts);
 448                         if (acc_sip-- > 0)
 449                                 iio_push_to_buffers_with_timestamp(
 450                                         hw->iio_devs[ST_LSM6DSX_ID_ACC],
 451                                         acc_buff, acc_sensor->ts_ref + ts);
 452                         if (ext_sip-- > 0)
 453                                 iio_push_to_buffers_with_timestamp(
 454                                         hw->iio_devs[ST_LSM6DSX_ID_EXT0],
 455                                         ext_buff, ext_sensor->ts_ref + ts);
 456                 }
 457         }
 458
 459         if (unlikely(reset_ts)) {
 460                 err = st_lsm6dsx_reset_hw_ts(hw);
 461                 if (err < 0) {
 462                         dev_err(hw->dev, "failed to reset hw ts (err=%d)\n",
 463                                 err);
 464                         return err;
 465                 }
 466         }
 467         return read_len;
 468 }
 469
 470 #define ST_LSM6DSX_INVALID_SAMPLE       0x7ffd
 471 static int
 472 st_lsm6dsx_push_tagged_data(struct st_lsm6dsx_hw *hw, u8 tag,
 473                             u8 *data, s64 ts)
 474 {
 475         s16 val = le16_to_cpu(*(__le16 *)data);
 476         struct st_lsm6dsx_sensor *sensor;
 477         struct iio_dev *iio_dev;
 478
 479         /* invalid sample during bootstrap phase */
 480         if (val >= ST_LSM6DSX_INVALID_SAMPLE)
 481                 return -EINVAL;
 482
 483         /*
 484          * EXT_TAG are managed in FIFO fashion so ST_LSM6DSX_EXT0_TAG
 485          * corresponds to the first enabled channel, ST_LSM6DSX_EXT1_TAG
 486          * to the second one and ST_LSM6DSX_EXT2_TAG to the last enabled
 487          * channel
 488          */
 489         switch (tag) {
 490         case ST_LSM6DSX_GYRO_TAG:
 491                 iio_dev = hw->iio_devs[ST_LSM6DSX_ID_GYRO];
 492                 break;
 493         case ST_LSM6DSX_ACC_TAG:
 494                 iio_dev = hw->iio_devs[ST_LSM6DSX_ID_ACC];
 495                 break;
 496         case ST_LSM6DSX_EXT0_TAG:
 497                 if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0))
 498                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT0];
 499                 else if (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1))
 500                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
 501                 else
 502                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
 503                 break;
 504         case ST_LSM6DSX_EXT1_TAG:
 505                 if ((hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT0)) &&
 506                     (hw->enable_mask & BIT(ST_LSM6DSX_ID_EXT1)))
 507                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT1];
 508                 else
 509                         iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
 510                 break;
 511         case ST_LSM6DSX_EXT2_TAG:
 512                 iio_dev = hw->iio_devs[ST_LSM6DSX_ID_EXT2];
 513                 break;
 514         default:
 515                 return -EINVAL;
 516         }
 517
 518         sensor = iio_priv(iio_dev);
 519         iio_push_to_buffers_with_timestamp(iio_dev, data,
 520                                            ts + sensor->ts_ref);
 521
 522         return 0;
 523 }
 524
 525 /**
 526  * st_lsm6dsx_read_tagged_fifo() - tagged hw FIFO read routine
 527  * @hw: Pointer to instance of struct st_lsm6dsx_hw.
 528  *
 529  * Read samples from the hw FIFO and push them to IIO buffers.
 530  *
 531  * Return: Number of bytes read from the FIFO
 532  */
 533 int st_lsm6dsx_read_tagged_fifo(struct st_lsm6dsx_hw *hw)
 534 {
 535         u16 pattern_len = hw->sip * ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
 536         u16 fifo_len, fifo_diff_mask;
 537         u8 iio_buff[ST_LSM6DSX_IIO_BUFF_SIZE], tag;
 538         bool reset_ts = false;
 539         int i, err, read_len;
 540         __le16 fifo_status;
 541         s64 ts = 0;
 542
 543         err = st_lsm6dsx_read_locked(hw,
 544                                      hw->settings->fifo_ops.fifo_diff.addr,
 545                                      &fifo_status, sizeof(fifo_status));
 546         if (err < 0) {
 547                 dev_err(hw->dev, "failed to read fifo status (err=%d)\n",
 548                         err);
 549                 return err;
 550         }
 551
 552         fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask;
 553         fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) *
 554                    ST_LSM6DSX_TAGGED_SAMPLE_SIZE;
 555         if (!fifo_len)
 556                 return 0;
 557
 558         for (read_len = 0; read_len < fifo_len; read_len += pattern_len) {
 559                 err = st_lsm6dsx_read_block(hw,
 560                                             ST_LSM6DSX_REG_FIFO_OUT_TAG_ADDR,
 561                                             hw->buff, pattern_len,
 562                                             ST_LSM6DSX_MAX_TAGGED_WORD_LEN);
 563                 if (err < 0) {
 564                         dev_err(hw->dev,
 565                                 "failed to read pattern from fifo (err=%d)\n",
 566                                 err);
 567                         return err;
 568                 }
 569
 570                 for (i = 0; i < pattern_len;
 571                      i += ST_LSM6DSX_TAGGED_SAMPLE_SIZE) {
 572                         memcpy(iio_buff, &hw->buff[i + ST_LSM6DSX_TAG_SIZE],
 573                                ST_LSM6DSX_SAMPLE_SIZE);
 574
 575                         tag = hw->buff[i] >> 3;
 576                         if (tag == ST_LSM6DSX_TS_TAG) {
 577                                 /*
 578                                  * hw timestamp is 4B long and it is stored
 579                                  * in FIFO according to this schema:
 580                                  * B0 = ts[7:0], B1 = ts[15:8], B2 = ts[23:16],
 581                                  * B3 = ts[31:24]
 582                                  */
 583                                 ts = le32_to_cpu(*((__le32 *)iio_buff));
 584                                 /*
 585                                  * check if hw timestamp engine is going to
 586                                  * reset (the sensor generates an interrupt
 587                                  * to signal the hw timestamp will reset in
 588                                  * 1.638s)
 589                                  */
 590                                 if (!reset_ts && ts >= 0xffff0000)
 591                                         reset_ts = true;
 592                                 ts *= hw->ts_gain;
 593                         } else {
 594                                 st_lsm6dsx_push_tagged_data(hw, tag, iio_buff,
 595                                                             ts);
 596                         }
 597                 }
 598         }
 599
 600         if (unlikely(reset_ts)) {
 601                 err = st_lsm6dsx_reset_hw_ts(hw);
 602                 if (err < 0)
 603                         return err;
 604         }
 605         return read_len;
 606 }
 607
 608 int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw)
 609 {
 610         int err;
 611
 612         if (!hw->settings->fifo_ops.read_fifo)
 613                 return -ENOTSUPP;
 614
 615         mutex_lock(&hw->fifo_lock);
 616
 617         hw->settings->fifo_ops.read_fifo(hw);
 618         err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS);
 619
 620         mutex_unlock(&hw->fifo_lock);
 621
 622         return err;
 623 }
 624
 625 int st_lsm6dsx_update_fifo(struct st_lsm6dsx_sensor *sensor, bool enable)
 626 {
 627         struct st_lsm6dsx_hw *hw = sensor->hw;
 628         u8 fifo_mask;
 629         int err;
 630
 631         mutex_lock(&hw->conf_lock);
 632
 633         if (enable)
 634                 fifo_mask = hw->fifo_mask | BIT(sensor->id);
 635         else
 636                 fifo_mask = hw->fifo_mask & ~BIT(sensor->id);
 637
 638         if (hw->fifo_mask) {
 639                 err = st_lsm6dsx_flush_fifo(hw);
 640                 if (err < 0)
 641                         goto out;
 642         }
 643
 644         if (sensor->id == ST_LSM6DSX_ID_EXT0 ||
 645             sensor->id == ST_LSM6DSX_ID_EXT1 ||
 646             sensor->id == ST_LSM6DSX_ID_EXT2) {
 647                 err = st_lsm6dsx_shub_set_enable(sensor, enable);
 648                 if (err < 0)
 649                         goto out;
 650         } else {
 651                 err = st_lsm6dsx_sensor_set_enable(sensor, enable);
 652                 if (err < 0)
 653                         goto out;
 654         }
 655
 656         err = st_lsm6dsx_set_fifo_odr(sensor, enable);
 657         if (err < 0)
 658                 goto out;
 659
 660         err = st_lsm6dsx_update_decimators(hw);
 661         if (err < 0)
 662                 goto out;
 663
 664         err = st_lsm6dsx_update_watermark(sensor, sensor->watermark);
 665         if (err < 0)
 666                 goto out;
 667
 668         if (fifo_mask) {
 669                 /* reset hw ts counter */
 670                 err = st_lsm6dsx_reset_hw_ts(hw);
 671                 if (err < 0)
 672                         goto out;
 673
 674                 err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT);
 675                 if (err < 0)
 676                         goto out;
 677         }
 678
 679         hw->fifo_mask = fifo_mask;
 680
 681 out:
 682         mutex_unlock(&hw->conf_lock);
 683
 684         return err;
 685 }
 686
 687 static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev)
 688 {
 689         struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
 690         struct st_lsm6dsx_hw *hw = sensor->hw;
 691
 692         if (!hw->settings->fifo_ops.update_fifo)
 693                 return -ENOTSUPP;
 694
 695         return hw->settings->fifo_ops.update_fifo(sensor, true);
 696 }
 697
 698 static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev)
 699 {
 700         struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev);
 701         struct st_lsm6dsx_hw *hw = sensor->hw;
 702
 703         if (!hw->settings->fifo_ops.update_fifo)
 704                 return -ENOTSUPP;
 705
 706         return hw->settings->fifo_ops.update_fifo(sensor, false);
 707 }
 708
 709 static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = {
 710         .preenable = st_lsm6dsx_buffer_preenable,
 711         .postdisable = st_lsm6dsx_buffer_postdisable,
 712 };
 713
 714 int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw)
 715 {
 716         struct iio_buffer *buffer;
 717         int i;
 718
 719         for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) {
 720                 if (!hw->iio_devs[i])
 721                         continue;
 722
 723                 buffer = devm_iio_kfifo_allocate(hw->dev);
 724                 if (!buffer)
 725                         return -ENOMEM;
 726
 727                 iio_device_attach_buffer(hw->iio_devs[i], buffer);
 728                 hw->iio_devs[i]->modes |= INDIO_BUFFER_SOFTWARE;
 729                 hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops;
 730         }
 731
 732         return 0;
 733 }