1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Sensirion SPS30 particulate matter sensor driver 4 * 5 * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com> 6 * 7 * I2C slave address: 0x69 8 */ 9 10 #include <asm/unaligned.h> 11 #include <linux/crc8.h> 12 #include <linux/delay.h> 13 #include <linux/i2c.h> 14 #include <linux/iio/buffer.h> 15 #include <linux/iio/iio.h> 16 #include <linux/iio/sysfs.h> 17 #include <linux/iio/trigger_consumer.h> 18 #include <linux/iio/triggered_buffer.h> 19 #include <linux/kernel.h> 20 #include <linux/module.h> 21 22 #define SPS30_CRC8_POLYNOMIAL 0x31 23 /* max number of bytes needed to store PM measurements or serial string */ 24 #define SPS30_MAX_READ_SIZE 48 25 /* sensor measures reliably up to 3000 ug / m3 */ 26 #define SPS30_MAX_PM 3000 27 /* minimum and maximum self cleaning periods in seconds */ 28 #define SPS30_AUTO_CLEANING_PERIOD_MIN 0 29 #define SPS30_AUTO_CLEANING_PERIOD_MAX 604800 30 31 /* SPS30 commands */ 32 #define SPS30_START_MEAS 0x0010 33 #define SPS30_STOP_MEAS 0x0104 34 #define SPS30_RESET 0xd304 35 #define SPS30_READ_DATA_READY_FLAG 0x0202 36 #define SPS30_READ_DATA 0x0300 37 #define SPS30_READ_SERIAL 0xd033 38 #define SPS30_START_FAN_CLEANING 0x5607 39 #define SPS30_AUTO_CLEANING_PERIOD 0x8004 40 /* not a sensor command per se, used only to distinguish write from read */ 41 #define SPS30_READ_AUTO_CLEANING_PERIOD 0x8005 42 43 enum { 44 PM1, 45 PM2P5, 46 PM4, 47 PM10, 48 }; 49 50 enum { 51 RESET, 52 MEASURING, 53 }; 54 55 struct sps30_state { 56 struct i2c_client *client; 57 /* 58 * Guards against concurrent access to sensor registers. 59 * Must be held whenever sequence of commands is to be executed. 60 */ 61 struct mutex lock; 62 int state; 63 }; 64 65 DECLARE_CRC8_TABLE(sps30_crc8_table); 66 67 static int sps30_write_then_read(struct sps30_state *state, u8 *txbuf, 68 int txsize, u8 *rxbuf, int rxsize) 69 { 70 int ret; 71 72 /* 73 * Sensor does not support repeated start so instead of 74 * sending two i2c messages in a row we just send one by one. 75 */ 76 ret = i2c_master_send(state->client, txbuf, txsize); 77 if (ret != txsize) 78 return ret < 0 ? ret : -EIO; 79 80 if (!rxbuf) 81 return 0; 82 83 ret = i2c_master_recv(state->client, rxbuf, rxsize); 84 if (ret != rxsize) 85 return ret < 0 ? ret : -EIO; 86 87 return 0; 88 } 89 90 static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size) 91 { 92 /* 93 * Internally sensor stores measurements in a following manner: 94 * 95 * PM1: upper two bytes, crc8, lower two bytes, crc8 96 * PM2P5: upper two bytes, crc8, lower two bytes, crc8 97 * PM4: upper two bytes, crc8, lower two bytes, crc8 98 * PM10: upper two bytes, crc8, lower two bytes, crc8 99 * 100 * What follows next are number concentration measurements and 101 * typical particle size measurement which we omit. 102 */ 103 u8 buf[SPS30_MAX_READ_SIZE] = { cmd >> 8, cmd }; 104 int i, ret = 0; 105 106 switch (cmd) { 107 case SPS30_START_MEAS: 108 buf[2] = 0x03; 109 buf[3] = 0x00; 110 buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE); 111 ret = sps30_write_then_read(state, buf, 5, NULL, 0); 112 break; 113 case SPS30_STOP_MEAS: 114 case SPS30_RESET: 115 case SPS30_START_FAN_CLEANING: 116 ret = sps30_write_then_read(state, buf, 2, NULL, 0); 117 break; 118 case SPS30_READ_AUTO_CLEANING_PERIOD: 119 buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8; 120 buf[1] = (u8)SPS30_AUTO_CLEANING_PERIOD; 121 /* fall through */ 122 case SPS30_READ_DATA_READY_FLAG: 123 case SPS30_READ_DATA: 124 case SPS30_READ_SERIAL: 125 /* every two data bytes are checksummed */ 126 size += size / 2; 127 ret = sps30_write_then_read(state, buf, 2, buf, size); 128 break; 129 case SPS30_AUTO_CLEANING_PERIOD: 130 buf[2] = data[0]; 131 buf[3] = data[1]; 132 buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE); 133 buf[5] = data[2]; 134 buf[6] = data[3]; 135 buf[7] = crc8(sps30_crc8_table, &buf[5], 2, CRC8_INIT_VALUE); 136 ret = sps30_write_then_read(state, buf, 8, NULL, 0); 137 break; 138 } 139 140 if (ret) 141 return ret; 142 143 /* validate received data and strip off crc bytes */ 144 for (i = 0; i < size; i += 3) { 145 u8 crc = crc8(sps30_crc8_table, &buf[i], 2, CRC8_INIT_VALUE); 146 147 if (crc != buf[i + 2]) { 148 dev_err(&state->client->dev, 149 "data integrity check failed\n"); 150 return -EIO; 151 } 152 153 *data++ = buf[i]; 154 *data++ = buf[i + 1]; 155 } 156 157 return 0; 158 } 159 160 static s32 sps30_float_to_int_clamped(const u8 *fp) 161 { 162 int val = get_unaligned_be32(fp); 163 int mantissa = val & GENMASK(22, 0); 164 /* this is fine since passed float is always non-negative */ 165 int exp = val >> 23; 166 int fraction, shift; 167 168 /* special case 0 */ 169 if (!exp && !mantissa) 170 return 0; 171 172 exp -= 127; 173 if (exp < 0) { 174 /* return values ranging from 1 to 99 */ 175 return ((((1 << 23) + mantissa) * 100) >> 23) >> (-exp); 176 } 177 178 /* return values ranging from 100 to 300000 */ 179 shift = 23 - exp; 180 val = (1 << exp) + (mantissa >> shift); 181 if (val >= SPS30_MAX_PM) 182 return SPS30_MAX_PM * 100; 183 184 fraction = mantissa & GENMASK(shift - 1, 0); 185 186 return val * 100 + ((fraction * 100) >> shift); 187 } 188 189 static int sps30_do_meas(struct sps30_state *state, s32 *data, int size) 190 { 191 int i, ret, tries = 5; 192 u8 tmp[16]; 193 194 if (state->state == RESET) { 195 ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0); 196 if (ret) 197 return ret; 198 199 state->state = MEASURING; 200 } 201 202 while (tries--) { 203 ret = sps30_do_cmd(state, SPS30_READ_DATA_READY_FLAG, tmp, 2); 204 if (ret) 205 return -EIO; 206 207 /* new measurements ready to be read */ 208 if (tmp[1] == 1) 209 break; 210 211 msleep_interruptible(300); 212 } 213 214 if (tries == -1) 215 return -ETIMEDOUT; 216 217 ret = sps30_do_cmd(state, SPS30_READ_DATA, tmp, sizeof(int) * size); 218 if (ret) 219 return ret; 220 221 for (i = 0; i < size; i++) 222 data[i] = sps30_float_to_int_clamped(&tmp[4 * i]); 223 224 return 0; 225 } 226 227 static irqreturn_t sps30_trigger_handler(int irq, void *p) 228 { 229 struct iio_poll_func *pf = p; 230 struct iio_dev *indio_dev = pf->indio_dev; 231 struct sps30_state *state = iio_priv(indio_dev); 232 int ret; 233 s32 data[4 + 2]; /* PM1, PM2P5, PM4, PM10, timestamp */ 234 235 mutex_lock(&state->lock); 236 ret = sps30_do_meas(state, data, 4); 237 mutex_unlock(&state->lock); 238 if (ret) 239 goto err; 240 241 iio_push_to_buffers_with_timestamp(indio_dev, data, 242 iio_get_time_ns(indio_dev)); 243 err: 244 iio_trigger_notify_done(indio_dev->trig); 245 246 return IRQ_HANDLED; 247 } 248 249 static int sps30_read_raw(struct iio_dev *indio_dev, 250 struct iio_chan_spec const *chan, 251 int *val, int *val2, long mask) 252 { 253 struct sps30_state *state = iio_priv(indio_dev); 254 int data[4], ret = -EINVAL; 255 256 switch (mask) { 257 case IIO_CHAN_INFO_PROCESSED: 258 switch (chan->type) { 259 case IIO_MASSCONCENTRATION: 260 mutex_lock(&state->lock); 261 /* read up to the number of bytes actually needed */ 262 switch (chan->channel2) { 263 case IIO_MOD_PM1: 264 ret = sps30_do_meas(state, data, 1); 265 break; 266 case IIO_MOD_PM2P5: 267 ret = sps30_do_meas(state, data, 2); 268 break; 269 case IIO_MOD_PM4: 270 ret = sps30_do_meas(state, data, 3); 271 break; 272 case IIO_MOD_PM10: 273 ret = sps30_do_meas(state, data, 4); 274 break; 275 } 276 mutex_unlock(&state->lock); 277 if (ret) 278 return ret; 279 280 *val = data[chan->address] / 100; 281 *val2 = (data[chan->address] % 100) * 10000; 282 283 return IIO_VAL_INT_PLUS_MICRO; 284 default: 285 return -EINVAL; 286 } 287 case IIO_CHAN_INFO_SCALE: 288 switch (chan->type) { 289 case IIO_MASSCONCENTRATION: 290 switch (chan->channel2) { 291 case IIO_MOD_PM1: 292 case IIO_MOD_PM2P5: 293 case IIO_MOD_PM4: 294 case IIO_MOD_PM10: 295 *val = 0; 296 *val2 = 10000; 297 298 return IIO_VAL_INT_PLUS_MICRO; 299 default: 300 return -EINVAL; 301 } 302 default: 303 return -EINVAL; 304 } 305 } 306 307 return -EINVAL; 308 } 309 310 static int sps30_do_cmd_reset(struct sps30_state *state) 311 { 312 int ret; 313 314 ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0); 315 msleep(300); 316 /* 317 * Power-on-reset causes sensor to produce some glitch on i2c bus and 318 * some controllers end up in error state. Recover simply by placing 319 * some data on the bus, for example STOP_MEAS command, which 320 * is NOP in this case. 321 */ 322 sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0); 323 state->state = RESET; 324 325 return ret; 326 } 327 328 static ssize_t start_cleaning_store(struct device *dev, 329 struct device_attribute *attr, 330 const char *buf, size_t len) 331 { 332 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 333 struct sps30_state *state = iio_priv(indio_dev); 334 int val, ret; 335 336 if (kstrtoint(buf, 0, &val) || val != 1) 337 return -EINVAL; 338 339 mutex_lock(&state->lock); 340 ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0); 341 mutex_unlock(&state->lock); 342 if (ret) 343 return ret; 344 345 return len; 346 } 347 348 static ssize_t cleaning_period_show(struct device *dev, 349 struct device_attribute *attr, 350 char *buf) 351 { 352 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 353 struct sps30_state *state = iio_priv(indio_dev); 354 u8 tmp[4]; 355 int ret; 356 357 mutex_lock(&state->lock); 358 ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4); 359 mutex_unlock(&state->lock); 360 if (ret) 361 return ret; 362 363 return sprintf(buf, "%d\n", get_unaligned_be32(tmp)); 364 } 365 366 static ssize_t cleaning_period_store(struct device *dev, 367 struct device_attribute *attr, 368 const char *buf, size_t len) 369 { 370 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 371 struct sps30_state *state = iio_priv(indio_dev); 372 int val, ret; 373 u8 tmp[4]; 374 375 if (kstrtoint(buf, 0, &val)) 376 return -EINVAL; 377 378 if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) || 379 (val > SPS30_AUTO_CLEANING_PERIOD_MAX)) 380 return -EINVAL; 381 382 put_unaligned_be32(val, tmp); 383 384 mutex_lock(&state->lock); 385 ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0); 386 if (ret) { 387 mutex_unlock(&state->lock); 388 return ret; 389 } 390 391 msleep(20); 392 393 /* 394 * sensor requires reset in order to return up to date self cleaning 395 * period 396 */ 397 ret = sps30_do_cmd_reset(state); 398 if (ret) 399 dev_warn(dev, 400 "period changed but reads will return the old value\n"); 401 402 mutex_unlock(&state->lock); 403 404 return len; 405 } 406 407 static ssize_t cleaning_period_available_show(struct device *dev, 408 struct device_attribute *attr, 409 char *buf) 410 { 411 return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n", 412 SPS30_AUTO_CLEANING_PERIOD_MIN, 1, 413 SPS30_AUTO_CLEANING_PERIOD_MAX); 414 } 415 416 static IIO_DEVICE_ATTR_WO(start_cleaning, 0); 417 static IIO_DEVICE_ATTR_RW(cleaning_period, 0); 418 static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0); 419 420 static struct attribute *sps30_attrs[] = { 421 &iio_dev_attr_start_cleaning.dev_attr.attr, 422 &iio_dev_attr_cleaning_period.dev_attr.attr, 423 &iio_dev_attr_cleaning_period_available.dev_attr.attr, 424 NULL 425 }; 426 427 static const struct attribute_group sps30_attr_group = { 428 .attrs = sps30_attrs, 429 }; 430 431 static const struct iio_info sps30_info = { 432 .attrs = &sps30_attr_group, 433 .read_raw = sps30_read_raw, 434 }; 435 436 #define SPS30_CHAN(_index, _mod) { \ 437 .type = IIO_MASSCONCENTRATION, \ 438 .modified = 1, \ 439 .channel2 = IIO_MOD_ ## _mod, \ 440 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ 441 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 442 .address = _mod, \ 443 .scan_index = _index, \ 444 .scan_type = { \ 445 .sign = 'u', \ 446 .realbits = 19, \ 447 .storagebits = 32, \ 448 .endianness = IIO_CPU, \ 449 }, \ 450 } 451 452 static const struct iio_chan_spec sps30_channels[] = { 453 SPS30_CHAN(0, PM1), 454 SPS30_CHAN(1, PM2P5), 455 SPS30_CHAN(2, PM4), 456 SPS30_CHAN(3, PM10), 457 IIO_CHAN_SOFT_TIMESTAMP(4), 458 }; 459 460 static void sps30_stop_meas(void *data) 461 { 462 struct sps30_state *state = data; 463 464 sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0); 465 } 466 467 static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 }; 468 469 static int sps30_probe(struct i2c_client *client) 470 { 471 struct iio_dev *indio_dev; 472 struct sps30_state *state; 473 u8 buf[32]; 474 int ret; 475 476 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 477 return -EOPNOTSUPP; 478 479 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*state)); 480 if (!indio_dev) 481 return -ENOMEM; 482 483 state = iio_priv(indio_dev); 484 i2c_set_clientdata(client, indio_dev); 485 state->client = client; 486 state->state = RESET; 487 indio_dev->dev.parent = &client->dev; 488 indio_dev->info = &sps30_info; 489 indio_dev->name = client->name; 490 indio_dev->channels = sps30_channels; 491 indio_dev->num_channels = ARRAY_SIZE(sps30_channels); 492 indio_dev->modes = INDIO_DIRECT_MODE; 493 indio_dev->available_scan_masks = sps30_scan_masks; 494 495 mutex_init(&state->lock); 496 crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL); 497 498 ret = sps30_do_cmd_reset(state); 499 if (ret) { 500 dev_err(&client->dev, "failed to reset device\n"); 501 return ret; 502 } 503 504 ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf)); 505 if (ret) { 506 dev_err(&client->dev, "failed to read serial number\n"); 507 return ret; 508 } 509 /* returned serial number is already NUL terminated */ 510 dev_info(&client->dev, "serial number: %s\n", buf); 511 512 ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state); 513 if (ret) 514 return ret; 515 516 ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL, 517 sps30_trigger_handler, NULL); 518 if (ret) 519 return ret; 520 521 return devm_iio_device_register(&client->dev, indio_dev); 522 } 523 524 static const struct i2c_device_id sps30_id[] = { 525 { "sps30" }, 526 { } 527 }; 528 MODULE_DEVICE_TABLE(i2c, sps30_id); 529 530 static const struct of_device_id sps30_of_match[] = { 531 { .compatible = "sensirion,sps30" }, 532 { } 533 }; 534 MODULE_DEVICE_TABLE(of, sps30_of_match); 535 536 static struct i2c_driver sps30_driver = { 537 .driver = { 538 .name = "sps30", 539 .of_match_table = sps30_of_match, 540 }, 541 .id_table = sps30_id, 542 .probe_new = sps30_probe, 543 }; 544 module_i2c_driver(sps30_driver); 545 546 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>"); 547 MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver"); 548 MODULE_LICENSE("GPL v2"); 549