1 /* 2 * STMicroelectronics st_lsm6dsx FIFO buffer library driver 3 * 4 * LSM6DS3/LSM6DS3H/LSM6DSL/LSM6DSM: The FIFO buffer can be configured 5 * to store data from gyroscope and accelerometer. Samples are queued 6 * without any tag according to a specific pattern based on 'FIFO data sets' 7 * (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 50 #define ST_LSM6DSX_MAX_FIFO_ODR_VAL 0x08 51 52 struct st_lsm6dsx_decimator_entry { 53 u8 decimator; 54 u8 val; 55 }; 56 57 static const 58 struct st_lsm6dsx_decimator_entry st_lsm6dsx_decimator_table[] = { 59 { 0, 0x0 }, 60 { 1, 0x1 }, 61 { 2, 0x2 }, 62 { 3, 0x3 }, 63 { 4, 0x4 }, 64 { 8, 0x5 }, 65 { 16, 0x6 }, 66 { 32, 0x7 }, 67 }; 68 69 static int st_lsm6dsx_get_decimator_val(u8 val) 70 { 71 const int max_size = ARRAY_SIZE(st_lsm6dsx_decimator_table); 72 int i; 73 74 for (i = 0; i < max_size; i++) 75 if (st_lsm6dsx_decimator_table[i].decimator == val) 76 break; 77 78 return i == max_size ? 0 : st_lsm6dsx_decimator_table[i].val; 79 } 80 81 static void st_lsm6dsx_get_max_min_odr(struct st_lsm6dsx_hw *hw, 82 u16 *max_odr, u16 *min_odr) 83 { 84 struct st_lsm6dsx_sensor *sensor; 85 int i; 86 87 *max_odr = 0, *min_odr = ~0; 88 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 89 sensor = iio_priv(hw->iio_devs[i]); 90 91 if (!(hw->enable_mask & BIT(sensor->id))) 92 continue; 93 94 *max_odr = max_t(u16, *max_odr, sensor->odr); 95 *min_odr = min_t(u16, *min_odr, sensor->odr); 96 } 97 } 98 99 static int st_lsm6dsx_update_decimators(struct st_lsm6dsx_hw *hw) 100 { 101 struct st_lsm6dsx_sensor *sensor; 102 u16 max_odr, min_odr, sip = 0; 103 int err, i; 104 u8 data; 105 106 st_lsm6dsx_get_max_min_odr(hw, &max_odr, &min_odr); 107 108 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 109 const struct st_lsm6dsx_reg *dec_reg; 110 111 sensor = iio_priv(hw->iio_devs[i]); 112 /* update fifo decimators and sample in pattern */ 113 if (hw->enable_mask & BIT(sensor->id)) { 114 sensor->sip = sensor->odr / min_odr; 115 sensor->decimator = max_odr / sensor->odr; 116 data = st_lsm6dsx_get_decimator_val(sensor->decimator); 117 } else { 118 sensor->sip = 0; 119 sensor->decimator = 0; 120 data = 0; 121 } 122 123 dec_reg = &hw->settings->decimator[sensor->id]; 124 if (dec_reg->addr) { 125 int val = ST_LSM6DSX_SHIFT_VAL(data, dec_reg->mask); 126 127 err = regmap_update_bits(hw->regmap, dec_reg->addr, 128 dec_reg->mask, val); 129 if (err < 0) 130 return err; 131 } 132 sip += sensor->sip; 133 } 134 hw->sip = sip; 135 136 return 0; 137 } 138 139 int st_lsm6dsx_set_fifo_mode(struct st_lsm6dsx_hw *hw, 140 enum st_lsm6dsx_fifo_mode fifo_mode) 141 { 142 int err; 143 144 err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_FIFO_MODE_ADDR, 145 ST_LSM6DSX_FIFO_MODE_MASK, 146 FIELD_PREP(ST_LSM6DSX_FIFO_MODE_MASK, 147 fifo_mode)); 148 if (err < 0) 149 return err; 150 151 hw->fifo_mode = fifo_mode; 152 153 return 0; 154 } 155 156 static int st_lsm6dsx_set_fifo_odr(struct st_lsm6dsx_sensor *sensor, 157 bool enable) 158 { 159 struct st_lsm6dsx_hw *hw = sensor->hw; 160 u8 data; 161 162 data = hw->enable_mask ? ST_LSM6DSX_MAX_FIFO_ODR_VAL : 0; 163 return regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_FIFO_MODE_ADDR, 164 ST_LSM6DSX_FIFO_ODR_MASK, 165 FIELD_PREP(ST_LSM6DSX_FIFO_ODR_MASK, data)); 166 } 167 168 int st_lsm6dsx_update_watermark(struct st_lsm6dsx_sensor *sensor, u16 watermark) 169 { 170 u16 fifo_watermark = ~0, cur_watermark, sip = 0, fifo_th_mask; 171 struct st_lsm6dsx_hw *hw = sensor->hw; 172 struct st_lsm6dsx_sensor *cur_sensor; 173 int i, err, data; 174 __le16 wdata; 175 176 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 177 cur_sensor = iio_priv(hw->iio_devs[i]); 178 179 if (!(hw->enable_mask & BIT(cur_sensor->id))) 180 continue; 181 182 cur_watermark = (cur_sensor == sensor) ? watermark 183 : cur_sensor->watermark; 184 185 fifo_watermark = min_t(u16, fifo_watermark, cur_watermark); 186 sip += cur_sensor->sip; 187 } 188 189 if (!sip) 190 return 0; 191 192 fifo_watermark = max_t(u16, fifo_watermark, sip); 193 fifo_watermark = (fifo_watermark / sip) * sip; 194 fifo_watermark = fifo_watermark * hw->settings->fifo_ops.th_wl; 195 196 err = regmap_read(hw->regmap, hw->settings->fifo_ops.fifo_th.addr + 1, 197 &data); 198 if (err < 0) 199 return err; 200 201 fifo_th_mask = hw->settings->fifo_ops.fifo_th.mask; 202 fifo_watermark = ((data << 8) & ~fifo_th_mask) | 203 (fifo_watermark & fifo_th_mask); 204 205 wdata = cpu_to_le16(fifo_watermark); 206 return regmap_bulk_write(hw->regmap, 207 hw->settings->fifo_ops.fifo_th.addr, 208 &wdata, sizeof(wdata)); 209 } 210 211 /* 212 * Set max bulk read to ST_LSM6DSX_MAX_WORD_LEN in order to avoid 213 * a kmalloc for each bus access 214 */ 215 static inline int st_lsm6dsx_read_block(struct st_lsm6dsx_hw *hw, u8 *data, 216 unsigned int data_len) 217 { 218 unsigned int word_len, read_len = 0; 219 int err; 220 221 while (read_len < data_len) { 222 word_len = min_t(unsigned int, data_len - read_len, 223 ST_LSM6DSX_MAX_WORD_LEN); 224 err = regmap_bulk_read(hw->regmap, 225 ST_LSM6DSX_REG_FIFO_OUTL_ADDR, 226 data + read_len, word_len); 227 if (err < 0) 228 return err; 229 read_len += word_len; 230 } 231 return 0; 232 } 233 234 /** 235 * st_lsm6dsx_read_fifo() - LSM6DS3-LSM6DS3H-LSM6DSL-LSM6DSM read FIFO routine 236 * @hw: Pointer to instance of struct st_lsm6dsx_hw. 237 * 238 * Read samples from the hw FIFO and push them to IIO buffers. 239 * 240 * Return: Number of bytes read from the FIFO 241 */ 242 static int st_lsm6dsx_read_fifo(struct st_lsm6dsx_hw *hw) 243 { 244 u16 fifo_len, pattern_len = hw->sip * ST_LSM6DSX_SAMPLE_SIZE; 245 u16 fifo_diff_mask = hw->settings->fifo_ops.fifo_diff.mask; 246 int err, acc_sip, gyro_sip, read_len, samples, offset; 247 struct st_lsm6dsx_sensor *acc_sensor, *gyro_sensor; 248 s64 acc_ts, acc_delta_ts, gyro_ts, gyro_delta_ts; 249 u8 iio_buff[ALIGN(ST_LSM6DSX_SAMPLE_SIZE, sizeof(s64)) + sizeof(s64)]; 250 __le16 fifo_status; 251 252 err = regmap_bulk_read(hw->regmap, 253 hw->settings->fifo_ops.fifo_diff.addr, 254 &fifo_status, sizeof(fifo_status)); 255 if (err < 0) 256 return err; 257 258 if (fifo_status & cpu_to_le16(ST_LSM6DSX_FIFO_EMPTY_MASK)) 259 return 0; 260 261 fifo_len = (le16_to_cpu(fifo_status) & fifo_diff_mask) * 262 ST_LSM6DSX_CHAN_SIZE; 263 samples = fifo_len / ST_LSM6DSX_SAMPLE_SIZE; 264 fifo_len = (fifo_len / pattern_len) * pattern_len; 265 266 /* 267 * compute delta timestamp between two consecutive samples 268 * in order to estimate queueing time of data generated 269 * by the sensor 270 */ 271 acc_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_ACC]); 272 acc_ts = acc_sensor->ts - acc_sensor->delta_ts; 273 acc_delta_ts = div_s64(acc_sensor->delta_ts * acc_sensor->decimator, 274 samples); 275 276 gyro_sensor = iio_priv(hw->iio_devs[ST_LSM6DSX_ID_GYRO]); 277 gyro_ts = gyro_sensor->ts - gyro_sensor->delta_ts; 278 gyro_delta_ts = div_s64(gyro_sensor->delta_ts * gyro_sensor->decimator, 279 samples); 280 281 for (read_len = 0; read_len < fifo_len; read_len += pattern_len) { 282 err = st_lsm6dsx_read_block(hw, hw->buff, pattern_len); 283 if (err < 0) 284 return err; 285 286 /* 287 * Data are written to the FIFO with a specific pattern 288 * depending on the configured ODRs. The first sequence of data 289 * stored in FIFO contains the data of all enabled sensors 290 * (e.g. Gx, Gy, Gz, Ax, Ay, Az), then data are repeated 291 * depending on the value of the decimation factor set for each 292 * sensor. 293 * 294 * Supposing the FIFO is storing data from gyroscope and 295 * accelerometer at different ODRs: 296 * - gyroscope ODR = 208Hz, accelerometer ODR = 104Hz 297 * Since the gyroscope ODR is twice the accelerometer one, the 298 * following pattern is repeated every 9 samples: 299 * - Gx, Gy, Gz, Ax, Ay, Az, Gx, Gy, Gz 300 */ 301 gyro_sip = gyro_sensor->sip; 302 acc_sip = acc_sensor->sip; 303 offset = 0; 304 305 while (acc_sip > 0 || gyro_sip > 0) { 306 if (gyro_sip-- > 0) { 307 memcpy(iio_buff, &hw->buff[offset], 308 ST_LSM6DSX_SAMPLE_SIZE); 309 iio_push_to_buffers_with_timestamp( 310 hw->iio_devs[ST_LSM6DSX_ID_GYRO], 311 iio_buff, gyro_ts); 312 offset += ST_LSM6DSX_SAMPLE_SIZE; 313 gyro_ts += gyro_delta_ts; 314 } 315 316 if (acc_sip-- > 0) { 317 memcpy(iio_buff, &hw->buff[offset], 318 ST_LSM6DSX_SAMPLE_SIZE); 319 iio_push_to_buffers_with_timestamp( 320 hw->iio_devs[ST_LSM6DSX_ID_ACC], 321 iio_buff, acc_ts); 322 offset += ST_LSM6DSX_SAMPLE_SIZE; 323 acc_ts += acc_delta_ts; 324 } 325 } 326 } 327 328 return read_len; 329 } 330 331 int st_lsm6dsx_flush_fifo(struct st_lsm6dsx_hw *hw) 332 { 333 int err; 334 335 mutex_lock(&hw->fifo_lock); 336 337 st_lsm6dsx_read_fifo(hw); 338 err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_BYPASS); 339 340 mutex_unlock(&hw->fifo_lock); 341 342 return err; 343 } 344 345 static int st_lsm6dsx_update_fifo(struct iio_dev *iio_dev, bool enable) 346 { 347 struct st_lsm6dsx_sensor *sensor = iio_priv(iio_dev); 348 struct st_lsm6dsx_hw *hw = sensor->hw; 349 int err; 350 351 mutex_lock(&hw->conf_lock); 352 353 if (hw->fifo_mode != ST_LSM6DSX_FIFO_BYPASS) { 354 err = st_lsm6dsx_flush_fifo(hw); 355 if (err < 0) 356 goto out; 357 } 358 359 if (enable) { 360 err = st_lsm6dsx_sensor_enable(sensor); 361 if (err < 0) 362 goto out; 363 } else { 364 err = st_lsm6dsx_sensor_disable(sensor); 365 if (err < 0) 366 goto out; 367 } 368 369 err = st_lsm6dsx_set_fifo_odr(sensor, enable); 370 if (err < 0) 371 goto out; 372 373 err = st_lsm6dsx_update_decimators(hw); 374 if (err < 0) 375 goto out; 376 377 err = st_lsm6dsx_update_watermark(sensor, sensor->watermark); 378 if (err < 0) 379 goto out; 380 381 if (hw->enable_mask) { 382 err = st_lsm6dsx_set_fifo_mode(hw, ST_LSM6DSX_FIFO_CONT); 383 if (err < 0) 384 goto out; 385 386 /* 387 * store enable buffer timestamp as reference to compute 388 * first delta timestamp 389 */ 390 sensor->ts = iio_get_time_ns(iio_dev); 391 } 392 393 out: 394 mutex_unlock(&hw->conf_lock); 395 396 return err; 397 } 398 399 static irqreturn_t st_lsm6dsx_handler_irq(int irq, void *private) 400 { 401 struct st_lsm6dsx_hw *hw = private; 402 struct st_lsm6dsx_sensor *sensor; 403 int i; 404 405 if (!hw->sip) 406 return IRQ_NONE; 407 408 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 409 sensor = iio_priv(hw->iio_devs[i]); 410 411 if (sensor->sip > 0) { 412 s64 timestamp; 413 414 timestamp = iio_get_time_ns(hw->iio_devs[i]); 415 sensor->delta_ts = timestamp - sensor->ts; 416 sensor->ts = timestamp; 417 } 418 } 419 420 return IRQ_WAKE_THREAD; 421 } 422 423 static irqreturn_t st_lsm6dsx_handler_thread(int irq, void *private) 424 { 425 struct st_lsm6dsx_hw *hw = private; 426 int count; 427 428 mutex_lock(&hw->fifo_lock); 429 count = st_lsm6dsx_read_fifo(hw); 430 mutex_unlock(&hw->fifo_lock); 431 432 return !count ? IRQ_NONE : IRQ_HANDLED; 433 } 434 435 static int st_lsm6dsx_buffer_preenable(struct iio_dev *iio_dev) 436 { 437 return st_lsm6dsx_update_fifo(iio_dev, true); 438 } 439 440 static int st_lsm6dsx_buffer_postdisable(struct iio_dev *iio_dev) 441 { 442 return st_lsm6dsx_update_fifo(iio_dev, false); 443 } 444 445 static const struct iio_buffer_setup_ops st_lsm6dsx_buffer_ops = { 446 .preenable = st_lsm6dsx_buffer_preenable, 447 .postdisable = st_lsm6dsx_buffer_postdisable, 448 }; 449 450 int st_lsm6dsx_fifo_setup(struct st_lsm6dsx_hw *hw) 451 { 452 struct device_node *np = hw->dev->of_node; 453 struct st_sensors_platform_data *pdata; 454 struct iio_buffer *buffer; 455 unsigned long irq_type; 456 bool irq_active_low; 457 int i, err; 458 459 irq_type = irqd_get_trigger_type(irq_get_irq_data(hw->irq)); 460 461 switch (irq_type) { 462 case IRQF_TRIGGER_HIGH: 463 case IRQF_TRIGGER_RISING: 464 irq_active_low = false; 465 break; 466 case IRQF_TRIGGER_LOW: 467 case IRQF_TRIGGER_FALLING: 468 irq_active_low = true; 469 break; 470 default: 471 dev_info(hw->dev, "mode %lx unsupported\n", irq_type); 472 return -EINVAL; 473 } 474 475 err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_HLACTIVE_ADDR, 476 ST_LSM6DSX_REG_HLACTIVE_MASK, 477 FIELD_PREP(ST_LSM6DSX_REG_HLACTIVE_MASK, 478 irq_active_low)); 479 if (err < 0) 480 return err; 481 482 pdata = (struct st_sensors_platform_data *)hw->dev->platform_data; 483 if ((np && of_property_read_bool(np, "drive-open-drain")) || 484 (pdata && pdata->open_drain)) { 485 err = regmap_update_bits(hw->regmap, ST_LSM6DSX_REG_PP_OD_ADDR, 486 ST_LSM6DSX_REG_PP_OD_MASK, 487 FIELD_PREP(ST_LSM6DSX_REG_PP_OD_MASK, 488 1)); 489 if (err < 0) 490 return err; 491 492 irq_type |= IRQF_SHARED; 493 } 494 495 err = devm_request_threaded_irq(hw->dev, hw->irq, 496 st_lsm6dsx_handler_irq, 497 st_lsm6dsx_handler_thread, 498 irq_type | IRQF_ONESHOT, 499 "lsm6dsx", hw); 500 if (err) { 501 dev_err(hw->dev, "failed to request trigger irq %d\n", 502 hw->irq); 503 return err; 504 } 505 506 for (i = 0; i < ST_LSM6DSX_ID_MAX; i++) { 507 buffer = devm_iio_kfifo_allocate(hw->dev); 508 if (!buffer) 509 return -ENOMEM; 510 511 iio_device_attach_buffer(hw->iio_devs[i], buffer); 512 hw->iio_devs[i]->modes |= INDIO_BUFFER_SOFTWARE; 513 hw->iio_devs[i]->setup_ops = &st_lsm6dsx_buffer_ops; 514 } 515 516 return 0; 517 } 518