1 /* 2 * STMicroelectronics st_lsm6dsx FIFO buffer library driver 3 * 4 * LSM6DS3/LSM6DS3H/LSM6DSL/LSM6DSM/ISM330DLC: The FIFO buffer can be 5 * configured to store data from gyroscope and accelerometer. Samples are 6 * queued without any tag according to a specific pattern based on 7 * 'FIFO data sets' (6 bytes each): 8 * - 1st data set is reserved for gyroscope data 9 * - 2nd data set is reserved for accelerometer data 10 * The FIFO pattern changes depending on the ODRs and decimation factors 11 * assigned to the FIFO data sets. The first sequence of data stored in FIFO 12 * buffer contains the data of all the enabled FIFO data sets 13 * (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated depending on the 14 * value of the decimation factor and ODR set for each FIFO data set. 15 * FIFO supported modes: 16 * - BYPASS: FIFO disabled 17 * - CONTINUOUS: FIFO enabled. When the buffer is full, the FIFO index 18 * restarts from the beginning and the oldest sample is overwritten 19 * 20 * Copyright 2016 STMicroelectronics Inc. 21 * 22 * Lorenzo Bianconi <lorenzo.bianconi@st.com> 23 * Denis Ciocca <denis.ciocca@st.com> 24 * 25 * Licensed under the GPL-2. 26 */ 27 #include <linux/module.h> 28 #include <linux/interrupt.h> 29 #include <linux/irq.h> 30 #include <linux/iio/kfifo_buf.h> 31 #include <linux/iio/iio.h> 32 #include <linux/iio/buffer.h> 33 #include <linux/regmap.h> 34 #include <linux/bitfield.h> 35 36 #include <linux/platform_data/st_sensors_pdata.h> 37 38 #include "st_lsm6dsx.h" 39 40 #define ST_LSM6DSX_REG_HLACTIVE_ADDR 0x12 41 #define ST_LSM6DSX_REG_HLACTIVE_MASK BIT(5) 42 #define ST_LSM6DSX_REG_PP_OD_ADDR 0x12 43 #define ST_LSM6DSX_REG_PP_OD_MASK BIT(4) 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_TS_RESET_ADDR 0x42 50 51 #define ST_LSM6DSX_MAX_FIFO_ODR_VAL 0x08 52 53 #define ST_LSM6DSX_TS_SENSITIVITY 25000UL /* 25us */ 54 #define ST_LSM6DSX_TS_RESET_VAL 0xaa 55 56 struct st_lsm6dsx_decimator_entry { 57 u8 decimator; 58 u8 val; 59 }; 60 61 static const 62 struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = { 63 { 0, 0x0 }, 64 { 1, 0x1 }, 65 { 2, 0x2 }, 66 { 3, 0x3 }, 67 { 4, 0x4 }, 68 { 8, 0x5 }, 69 { 16, 0x6 }, 70 { 32, 0x7 }, 71 }; 72 73 static int st_lsm6dsx_get_decimator_val(u8 val) 74 { 75 const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table); 76 int i; 77 78 for (i = 0; i < max_size; i++) 79 if (st_lsm6dsx_decimator_table[i].decimator == val) 80 break; 81 82 return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val; 83 } 84 85 static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw, 86 u16 *max_odr, u16 *min_odr) 87 { 88 struct st_lsm6dsx_sensor *sensor; 89 int i; 90 91 *max_odr = 0, *min_odr = ~0; 92 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 93 sensor = iio_priv(hw->iio_devs[i]); 94 95 if (!(hw->enable_mask & BIT(sensor->id))) 96 continue; 97 98 *max_odr = max_t(u16, *max_odr, sensor->odr); 99 *min_odr = min_t(u16, *min_odr, sensor->odr); 100 } 101 } 102 103 static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw) 104 { 105 u16 max_odr, min_odr, sip = 0, ts_sip = 0; 106 const struct st_lsm6dsx_reg *ts_dec_reg; 107 struct st_lsm6dsx_sensor *sensor; 108 int err = 0, i; 109 u8 data; 110 111 st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr); 112 113 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 114 const struct st_lsm6dsx_reg *dec_reg; 115 116 sensor = iio_priv(hw->iio_devs[i]); 117 /* update fifo decimators and sample in pattern */ 118 if (hw->enable_mask & BIT(sensor->id)) { 119 sensor->sip = sensor->odr / min_odr; 120 sensor->decimator = max_odr / sensor->odr; 121 data = st_lsm6dsx_get_decimator_val(sensor->decimator); 122 } else { 123 sensor->sip = 0; 124 sensor->decimator = 0; 125 data = 0; 126 } 127 ts_sip = max_t(u16, ts_sip, sensor->sip); 128 129 dec_reg = &hw->settings->decimator[sensor->id]; 130 if (dec_reg->addr) { 131 int val = ST_LSM6DSX_SHIFT_VAL(data, dec_reg->mask); 132 133 err = regmap_update_bits(hw->regmap, dec_reg->addr, 134 dec_reg->mask, val); 135 if (err < 0) 136 return err; 137 } 138 sip += sensor->sip; 139 } 140 hw->sip = sip + ts_sip; 141 hw->ts_sip = ts_sip; 142 143 /* 144 * update hw ts decimator if necessary. Decimator for hw timestamp 145 * is always 1 or 0 in order to have a ts sample for each data 146 * sample in FIFO 147 */ 148 ts_dec_reg = &hw->settings->ts_settings.decimator; 149 if (ts_dec_reg->addr) { 150 int val, ts_dec = !!hw->ts_sip; 151 152 val = ST_LSM6DSX_SHIFT_VAL(ts_dec, ts_dec_reg->mask); 153 err = regmap_update_bits(hw->regmap, ts_dec_reg->addr, 154 ts_dec_reg->mask, val); 155 } 156 return err; 157 } 158 159 int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw, 160 enum st_lsm6dsx_fifo_mode fifo_mode) 161 { 162 int err; 163 164 err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_FIFO_MODE_ADDR, 165 ST_LSM6DSX_FIFO_MODE_MASK, 166 FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, 167 fifo_mode)); 168 if (err < 0) 169 return err; 170 171 hw->fifo_mode = fifo_mode; 172 173 return 0; 174 } 175 176 static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor, 177 bool enable) 178 { 179 struct st_lsm6dsx_hw *hw = sensor->hw; 180 u8 data; 181 182 data = hw->enable_mask ? ST_LSM6DSX_MAX_FIFO_ODR_VAL : 0; 183 return regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_FIFO_MODE_ADDR, 184 ST_LSM6DSX_FIFO_ODR_MASK, 185 FIELD_PREP(ST_LSM6DSX_FIFO_ODR_MASK, data)); 186 } 187 188 int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark) 189 { 190 u16 fifo_watermark = ~0, cur_watermark, sip = 0, fifo_th_mask; 191 struct st_lsm6dsx_hw *hw = sensor->hw; 192 struct st_lsm6dsx_sensor *cur_sensor; 193 int i, err, data; 194 __le16 wdata; 195 196 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 197 cur_sensor = iio_priv(hw->iio_devs[i]); 198 199 if (!(hw->enable_mask & BIT(cur_sensor->id))) 200 continue; 201 202 cur_watermark = (cur_sensor == sensor) ? watermark 203 : cur_sensor->watermark; 204 205 fifo_watermark = min_t(u16, fifo_watermark, cur_watermark); 206 sip += cur_sensor->sip; 207 } 208 209 if (!sip) 210 return 0; 211 212 fifo_watermark = max_t(u16, fifo_watermark, sip); 213 fifo_watermark = (fifo_watermark / sip) * sip; 214 fifo_watermark = fifo_watermark * hw->settings->fifo_ops.th_wl; 215 216 err = regmap_read(hw->regmap, hw->settings->fifo_ops.fifo_th.addr + 1, 217 &data); 218 if (err < 0) 219 return err; 220 221 fifo_th_mask = hw->settings->fifo_ops.fifo_th.mask; 222 fifo_watermark = ((data << 8) & ~fifo_th_mask) | 223 (fifo_watermark & fifo_th_mask); 224 225 wdata = cpu_to_le16(fifo_watermark); 226 return regmap_bulk_write(hw->regmap, 227 hw->settings->fifo_ops.fifo_th.addr, 228 &wdata, sizeof(wdata)); 229 } 230 231 static int st_lsm6dsx_reset_hw_ts(struct st_lsm6dsx_hw *hw) 232 { 233 struct st_lsm6dsx_sensor *sensor; 234 int i, err; 235 236 /* reset hw ts counter */ 237 err = regmap_write(hw->regmap, ST_LSM6DSX_REG_TS_RESET_ADDR, 238 ST_LSM6DSX_TS_RESET_VAL); 239 if (err < 0) 240 return err; 241 242 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 243 sensor = iio_priv(hw->iio_devs[i]); 244 /* 245 * store enable buffer timestamp as reference for 246 * hw timestamp 247 */ 248 sensor->ts_ref = iio_get_time_ns(hw->iio_devs[i]); 249 } 250 return 0; 251 } 252 253 /* 254 * Set max bulk read to ST_LSM6DSX_MAX_WORD_LEN in order to avoid 255 * a kmalloc for each bus access 256 */ 257 static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 *data, 258 unsigned int data_len) 259 { 260 unsigned int word_len, read_len = 0; 261 int err; 262 263 while (read_len < data_len) { 264 word_len = min_t(unsigned int, data_len - read_len, 265 ST_LSM6DSX_MAX_WORD_LEN); 266 err = regmap_bulk_read(hw->regmap, 267 ST_LSM6DSX_REG_FIFO_OUTL_ADDR, 268 data + read_len, word_len); 269 if (err < 0) 270 return err; 271 read_len += word_len; 272 } 273 return 0; 274 } 275 276 #define ST_LSM6DSX_IIO_BUFF_SIZE (ALIGN(ST_LSM6DSX_SAMPLE_SIZE, \ 277 sizeof(s64)) + sizeof(s64)) 278 /** 279 * st_lsm6dsx_read_fifo() - hw FIFO read routine 280 * @hw: Pointer to instance of struct st_lsm6dsx_hw. 281 * 282 * Read samples from the hw FIFO and push them to IIO buffers. 283 * 284 * Return: Number of bytes read from the FIFO 285 */ 286 static int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw) 287 { 288 u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE; 289 u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask; 290 int err, acc_sip, gyro_sip, ts_sip, read_len, offset; 291 struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor; 292 u8 gyro_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; 293 u8 acc_buff[ST_LSM6DSX_IIO_BUFF_SIZE]; 294 bool reset_ts = false; 295 __le16 fifo_status; 296 s64 ts = 0; 297 298 err = regmap_bulk_read(hw->regmap, 299 hw->settings->fifo_ops.fifo_diff.addr, 300 &fifo_status, sizeof(fifo_status)); 301 if (err < 0) { 302 dev_err(hw->dev, "failed to read fifo status (err=%d)\n", 303 err); 304 return err; 305 } 306 307 if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK)) 308 return 0; 309 310 fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) * 311 ST_LSM6DSX_CHAN_SIZE; 312 fifo_len = (fifo_len / pattern_len) * pattern_len; 313 314 acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]); 315 gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]); 316 317 for (read_len = 0; read_len < fifo_len; read_len += pattern_len) { 318 err = st_lsm6dsx_read_block(hw, hw->buff, pattern_len); 319 if (err < 0) { 320 dev_err(hw->dev, 321 "failed to read pattern from fifo (err=%d)\n", 322 err); 323 return err; 324 } 325 326 /* 327 * Data are written to the FIFO with a specific pattern 328 * depending on the configured ODRs. The first sequence of data 329 * stored in FIFO contains the data of all enabled sensors 330 * (e.g. Gx, Gy, Gz, Ax, Ay, Az, Ts), then data are repeated 331 * depending on the value of the decimation factor set for each 332 * sensor. 333 * 334 * Supposing the FIFO is storing data from gyroscope and 335 * accelerometer at different ODRs: 336 * - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz 337 * Since the gyroscope ODR is twice the accelerometer one, the 338 * following pattern is repeated every 9 samples: 339 * - Gx, Gy, Gz, Ax, Ay, Az, Ts, Gx, Gy, Gz, Ts, Gx, .. 340 */ 341 gyro_sip = gyro_sensor->sip; 342 acc_sip = acc_sensor->sip; 343 ts_sip = hw->ts_sip; 344 offset = 0; 345 346 while (acc_sip > 0 || gyro_sip > 0) { 347 if (gyro_sip > 0) { 348 memcpy(gyro_buff, &hw->buff[offset], 349 ST_LSM6DSX_SAMPLE_SIZE); 350 offset += ST_LSM6DSX_SAMPLE_SIZE; 351 } 352 if (acc_sip > 0) { 353 memcpy(acc_buff, &hw->buff[offset], 354 ST_LSM6DSX_SAMPLE_SIZE); 355 offset += ST_LSM6DSX_SAMPLE_SIZE; 356 } 357 358 if (ts_sip-- > 0) { 359 u8 data[ST_LSM6DSX_SAMPLE_SIZE]; 360 361 memcpy(data, &hw->buff[offset], sizeof(data)); 362 /* 363 * hw timestamp is 3B long and it is stored 364 * in FIFO using 6B as 4th FIFO data set 365 * according to this schema: 366 * B0 = ts[15:8], B1 = ts[23:16], B3 = ts[7:0] 367 */ 368 ts = data[1] << 16 | data[0] << 8 | data[3]; 369 /* 370 * check if hw timestamp engine is going to 371 * reset (the sensor generates an interrupt 372 * to signal the hw timestamp will reset in 373 * 1.638s) 374 */ 375 if (!reset_ts && ts >= 0xff0000) 376 reset_ts = true; 377 ts *= ST_LSM6DSX_TS_SENSITIVITY; 378 379 offset += ST_LSM6DSX_SAMPLE_SIZE; 380 } 381 382 if (gyro_sip-- > 0) 383 iio_push_to_buffers_with_timestamp( 384 hw->iio_devs[ST_LSM6DSX_ID_GYRO], 385 gyro_buff, gyro_sensor->ts_ref + ts); 386 if (acc_sip-- > 0) 387 iio_push_to_buffers_with_timestamp( 388 hw->iio_devs[ST_LSM6DSX_ID_ACC], 389 acc_buff, acc_sensor->ts_ref + ts); 390 } 391 } 392 393 if (unlikely(reset_ts)) { 394 err = st_lsm6dsx_reset_hw_ts(hw); 395 if (err < 0) { 396 dev_err(hw->dev, "failed to reset hw ts (err=%d)\n", 397 err); 398 return err; 399 } 400 } 401 return read_len; 402 } 403 404 int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw) 405 { 406 int err; 407 408 mutex_lock(&hw->fifo_lock); 409 410 st_lsm6dsx_read_fifo(hw); 411 err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS); 412 413 mutex_unlock(&hw->fifo_lock); 414 415 return err; 416 } 417 418 static int st_lsm6dsx_update_fifo(struct iio_dev *iio_dev, bool enable) 419 { 420 struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev); 421 struct st_lsm6dsx_hw *hw = sensor->hw; 422 int err; 423 424 mutex_lock(&hw->conf_lock); 425 426 if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) { 427 err = st_lsm6dsx_flush_fifo(hw); 428 if (err < 0) 429 goto out; 430 } 431 432 if (enable) { 433 err = st_lsm6dsx_sensor_enable(sensor); 434 if (err < 0) 435 goto out; 436 } else { 437 err = st_lsm6dsx_sensor_disable(sensor); 438 if (err < 0) 439 goto out; 440 } 441 442 err = st_lsm6dsx_set_fifo_odr(sensor, enable); 443 if (err < 0) 444 goto out; 445 446 err = st_lsm6dsx_update_decimators(hw); 447 if (err < 0) 448 goto out; 449 450 err = st_lsm6dsx_update_watermark(sensor, sensor->watermark); 451 if (err < 0) 452 goto out; 453 454 if (hw->enable_mask) { 455 /* reset hw ts counter */ 456 err = st_lsm6dsx_reset_hw_ts(hw); 457 if (err < 0) 458 goto out; 459 460 err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT); 461 } 462 463 out: 464 mutex_unlock(&hw->conf_lock); 465 466 return err; 467 } 468 469 static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private) 470 { 471 struct st_lsm6dsx_hw *hw = private; 472 473 return hw->sip > 0 ? IRQ_WAKE_THREAD : IRQ_NONE; 474 } 475 476 static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private) 477 { 478 struct st_lsm6dsx_hw *hw = private; 479 int count; 480 481 mutex_lock(&hw->fifo_lock); 482 count = st_lsm6dsx_read_fifo(hw); 483 mutex_unlock(&hw->fifo_lock); 484 485 return !count ? IRQ_NONE : IRQ_HANDLED; 486 } 487 488 static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev) 489 { 490 return st_lsm6dsx_update_fifo(iio_dev, true); 491 } 492 493 static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev) 494 { 495 return st_lsm6dsx_update_fifo(iio_dev, false); 496 } 497 498 static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = { 499 .preenable = st_lsm6dsx_buffer_preenable, 500 .postdisable = st_lsm6dsx_buffer_postdisable, 501 }; 502 503 int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw) 504 { 505 struct device_node *np = hw->dev->of_node; 506 struct st_sensors_platform_data *pdata; 507 struct iio_buffer *buffer; 508 unsigned long irq_type; 509 bool irq_active_low; 510 int i, err; 511 512 irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq)); 513 514 switch (irq_type) { 515 case IRQF_TRIGGER_HIGH: 516 case IRQF_TRIGGER_RISING: 517 irq_active_low = false; 518 break; 519 case IRQF_TRIGGER_LOW: 520 case IRQF_TRIGGER_FALLING: 521 irq_active_low = true; 522 break; 523 default: 524 dev_info(hw->dev, "mode %lx unsupported\n", irq_type); 525 return -EINVAL; 526 } 527 528 err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_HLACTIVE_ADDR, 529 ST_LSM6DSX_REG_HLACTIVE_MASK, 530 FIELD_PREP(ST_LSM6DSX_REG_HLACTIVE_MASK, 531 irq_active_low)); 532 if (err < 0) 533 return err; 534 535 pdata = (struct st_sensors_platform_data *)hw->dev->platform_data; 536 if ((np && of_property_read_bool(np, "drive-open-drain")) || 537 (pdata && pdata->open_drain)) { 538 err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_PP_OD_ADDR, 539 ST_LSM6DSX_REG_PP_OD_MASK, 540 FIELD_PREP(ST_LSM6DSX_REG_PP_OD_MASK, 541 1)); 542 if (err < 0) 543 return err; 544 545 irq_type |= IRQF_SHARED; 546 } 547 548 err = devm_request_threaded_irq(hw->dev, hw->irq, 549 st_lsm6dsx_handler_irq, 550 st_lsm6dsx_handler_thread, 551 irq_type | IRQF_ONESHOT, 552 "lsm6dsx", hw); 553 if (err) { 554 dev_err(hw->dev, "failed to request trigger irq %d\n", 555 hw->irq); 556 return err; 557 } 558 559 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 560 buffer = devm_iio_kfifo_allocate(hw->dev); 561 if (!buffer) 562 return -ENOMEM; 563 564 iio_device_attach_buffer(hw->iio_devs[i], buffer); 565 hw->iio_devs[i]->modes |= INDIO_BUFFER_SOFTWARE; 566 hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops; 567 } 568 569 return 0; 570 } 571