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 & 0xff); 121 fallthrough; 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 struct { 234 s32 data[4]; /* PM1, PM2P5, PM4, PM10 */ 235 s64 ts; 236 } scan; 237 238 mutex_lock(&state->lock); 239 ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data)); 240 mutex_unlock(&state->lock); 241 if (ret) 242 goto err; 243 244 iio_push_to_buffers_with_timestamp(indio_dev, &scan, 245 iio_get_time_ns(indio_dev)); 246 err: 247 iio_trigger_notify_done(indio_dev->trig); 248 249 return IRQ_HANDLED; 250 } 251 252 static int sps30_read_raw(struct iio_dev *indio_dev, 253 struct iio_chan_spec const *chan, 254 int *val, int *val2, long mask) 255 { 256 struct sps30_state *state = iio_priv(indio_dev); 257 int data[4], ret = -EINVAL; 258 259 switch (mask) { 260 case IIO_CHAN_INFO_PROCESSED: 261 switch (chan->type) { 262 case IIO_MASSCONCENTRATION: 263 mutex_lock(&state->lock); 264 /* read up to the number of bytes actually needed */ 265 switch (chan->channel2) { 266 case IIO_MOD_PM1: 267 ret = sps30_do_meas(state, data, 1); 268 break; 269 case IIO_MOD_PM2P5: 270 ret = sps30_do_meas(state, data, 2); 271 break; 272 case IIO_MOD_PM4: 273 ret = sps30_do_meas(state, data, 3); 274 break; 275 case IIO_MOD_PM10: 276 ret = sps30_do_meas(state, data, 4); 277 break; 278 } 279 mutex_unlock(&state->lock); 280 if (ret) 281 return ret; 282 283 *val = data[chan->address] / 100; 284 *val2 = (data[chan->address] % 100) * 10000; 285 286 return IIO_VAL_INT_PLUS_MICRO; 287 default: 288 return -EINVAL; 289 } 290 case IIO_CHAN_INFO_SCALE: 291 switch (chan->type) { 292 case IIO_MASSCONCENTRATION: 293 switch (chan->channel2) { 294 case IIO_MOD_PM1: 295 case IIO_MOD_PM2P5: 296 case IIO_MOD_PM4: 297 case IIO_MOD_PM10: 298 *val = 0; 299 *val2 = 10000; 300 301 return IIO_VAL_INT_PLUS_MICRO; 302 default: 303 return -EINVAL; 304 } 305 default: 306 return -EINVAL; 307 } 308 } 309 310 return -EINVAL; 311 } 312 313 static int sps30_do_cmd_reset(struct sps30_state *state) 314 { 315 int ret; 316 317 ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0); 318 msleep(300); 319 /* 320 * Power-on-reset causes sensor to produce some glitch on i2c bus and 321 * some controllers end up in error state. Recover simply by placing 322 * some data on the bus, for example STOP_MEAS command, which 323 * is NOP in this case. 324 */ 325 sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0); 326 state->state = RESET; 327 328 return ret; 329 } 330 331 static ssize_t start_cleaning_store(struct device *dev, 332 struct device_attribute *attr, 333 const char *buf, size_t len) 334 { 335 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 336 struct sps30_state *state = iio_priv(indio_dev); 337 int val, ret; 338 339 if (kstrtoint(buf, 0, &val) || val != 1) 340 return -EINVAL; 341 342 mutex_lock(&state->lock); 343 ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0); 344 mutex_unlock(&state->lock); 345 if (ret) 346 return ret; 347 348 return len; 349 } 350 351 static ssize_t cleaning_period_show(struct device *dev, 352 struct device_attribute *attr, 353 char *buf) 354 { 355 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 356 struct sps30_state *state = iio_priv(indio_dev); 357 u8 tmp[4]; 358 int ret; 359 360 mutex_lock(&state->lock); 361 ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4); 362 mutex_unlock(&state->lock); 363 if (ret) 364 return ret; 365 366 return sprintf(buf, "%d\n", get_unaligned_be32(tmp)); 367 } 368 369 static ssize_t cleaning_period_store(struct device *dev, 370 struct device_attribute *attr, 371 const char *buf, size_t len) 372 { 373 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 374 struct sps30_state *state = iio_priv(indio_dev); 375 int val, ret; 376 u8 tmp[4]; 377 378 if (kstrtoint(buf, 0, &val)) 379 return -EINVAL; 380 381 if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) || 382 (val > SPS30_AUTO_CLEANING_PERIOD_MAX)) 383 return -EINVAL; 384 385 put_unaligned_be32(val, tmp); 386 387 mutex_lock(&state->lock); 388 ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0); 389 if (ret) { 390 mutex_unlock(&state->lock); 391 return ret; 392 } 393 394 msleep(20); 395 396 /* 397 * sensor requires reset in order to return up to date self cleaning 398 * period 399 */ 400 ret = sps30_do_cmd_reset(state); 401 if (ret) 402 dev_warn(dev, 403 "period changed but reads will return the old value\n"); 404 405 mutex_unlock(&state->lock); 406 407 return len; 408 } 409 410 static ssize_t cleaning_period_available_show(struct device *dev, 411 struct device_attribute *attr, 412 char *buf) 413 { 414 return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n", 415 SPS30_AUTO_CLEANING_PERIOD_MIN, 1, 416 SPS30_AUTO_CLEANING_PERIOD_MAX); 417 } 418 419 static IIO_DEVICE_ATTR_WO(start_cleaning, 0); 420 static IIO_DEVICE_ATTR_RW(cleaning_period, 0); 421 static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0); 422 423 static struct attribute *sps30_attrs[] = { 424 &iio_dev_attr_start_cleaning.dev_attr.attr, 425 &iio_dev_attr_cleaning_period.dev_attr.attr, 426 &iio_dev_attr_cleaning_period_available.dev_attr.attr, 427 NULL 428 }; 429 430 static const struct attribute_group sps30_attr_group = { 431 .attrs = sps30_attrs, 432 }; 433 434 static const struct iio_info sps30_info = { 435 .attrs = &sps30_attr_group, 436 .read_raw = sps30_read_raw, 437 }; 438 439 #define SPS30_CHAN(_index, _mod) { \ 440 .type = IIO_MASSCONCENTRATION, \ 441 .modified = 1, \ 442 .channel2 = IIO_MOD_ ## _mod, \ 443 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \ 444 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ 445 .address = _mod, \ 446 .scan_index = _index, \ 447 .scan_type = { \ 448 .sign = 'u', \ 449 .realbits = 19, \ 450 .storagebits = 32, \ 451 .endianness = IIO_CPU, \ 452 }, \ 453 } 454 455 static const struct iio_chan_spec sps30_channels[] = { 456 SPS30_CHAN(0, PM1), 457 SPS30_CHAN(1, PM2P5), 458 SPS30_CHAN(2, PM4), 459 SPS30_CHAN(3, PM10), 460 IIO_CHAN_SOFT_TIMESTAMP(4), 461 }; 462 463 static void sps30_stop_meas(void *data) 464 { 465 struct sps30_state *state = data; 466 467 sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0); 468 } 469 470 static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 }; 471 472 static int sps30_probe(struct i2c_client *client) 473 { 474 struct iio_dev *indio_dev; 475 struct sps30_state *state; 476 u8 buf[32]; 477 int ret; 478 479 if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) 480 return -EOPNOTSUPP; 481 482 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*state)); 483 if (!indio_dev) 484 return -ENOMEM; 485 486 state = iio_priv(indio_dev); 487 i2c_set_clientdata(client, indio_dev); 488 state->client = client; 489 state->state = RESET; 490 indio_dev->info = &sps30_info; 491 indio_dev->name = client->name; 492 indio_dev->channels = sps30_channels; 493 indio_dev->num_channels = ARRAY_SIZE(sps30_channels); 494 indio_dev->modes = INDIO_DIRECT_MODE; 495 indio_dev->available_scan_masks = sps30_scan_masks; 496 497 mutex_init(&state->lock); 498 crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL); 499 500 ret = sps30_do_cmd_reset(state); 501 if (ret) { 502 dev_err(&client->dev, "failed to reset device\n"); 503 return ret; 504 } 505 506 ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf)); 507 if (ret) { 508 dev_err(&client->dev, "failed to read serial number\n"); 509 return ret; 510 } 511 /* returned serial number is already NUL terminated */ 512 dev_info(&client->dev, "serial number: %s\n", buf); 513 514 ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state); 515 if (ret) 516 return ret; 517 518 ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL, 519 sps30_trigger_handler, NULL); 520 if (ret) 521 return ret; 522 523 return devm_iio_device_register(&client->dev, indio_dev); 524 } 525 526 static const struct i2c_device_id sps30_id[] = { 527 { "sps30" }, 528 { } 529 }; 530 MODULE_DEVICE_TABLE(i2c, sps30_id); 531 532 static const struct of_device_id sps30_of_match[] = { 533 { .compatible = "sensirion,sps30" }, 534 { } 535 }; 536 MODULE_DEVICE_TABLE(of, sps30_of_match); 537 538 static struct i2c_driver sps30_driver = { 539 .driver = { 540 .name = "sps30", 541 .of_match_table = sps30_of_match, 542 }, 543 .id_table = sps30_id, 544 .probe_new = sps30_probe, 545 }; 546 module_i2c_driver(sps30_driver); 547 548 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>"); 549 MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver"); 550 MODULE_LICENSE("GPL v2"); 551