sps30.c 13 KB

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  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. #include <asm/unaligned.h>
  10. #include <linux/crc8.h>
  11. #include <linux/delay.h>
  12. #include <linux/i2c.h>
  13. #include <linux/iio/buffer.h>
  14. #include <linux/iio/iio.h>
  15. #include <linux/iio/sysfs.h>
  16. #include <linux/iio/trigger_consumer.h>
  17. #include <linux/iio/triggered_buffer.h>
  18. #include <linux/kernel.h>
  19. #include <linux/module.h>
  20. #define SPS30_CRC8_POLYNOMIAL 0x31
  21. /* max number of bytes needed to store PM measurements or serial string */
  22. #define SPS30_MAX_READ_SIZE 48
  23. /* sensor measures reliably up to 3000 ug / m3 */
  24. #define SPS30_MAX_PM 3000
  25. /* minimum and maximum self cleaning periods in seconds */
  26. #define SPS30_AUTO_CLEANING_PERIOD_MIN 0
  27. #define SPS30_AUTO_CLEANING_PERIOD_MAX 604800
  28. /* SPS30 commands */
  29. #define SPS30_START_MEAS 0x0010
  30. #define SPS30_STOP_MEAS 0x0104
  31. #define SPS30_RESET 0xd304
  32. #define SPS30_READ_DATA_READY_FLAG 0x0202
  33. #define SPS30_READ_DATA 0x0300
  34. #define SPS30_READ_SERIAL 0xd033
  35. #define SPS30_START_FAN_CLEANING 0x5607
  36. #define SPS30_AUTO_CLEANING_PERIOD 0x8004
  37. /* not a sensor command per se, used only to distinguish write from read */
  38. #define SPS30_READ_AUTO_CLEANING_PERIOD 0x8005
  39. enum {
  40. PM1,
  41. PM2P5,
  42. PM4,
  43. PM10,
  44. };
  45. enum {
  46. RESET,
  47. MEASURING,
  48. };
  49. struct sps30_state {
  50. struct i2c_client *client;
  51. /*
  52. * Guards against concurrent access to sensor registers.
  53. * Must be held whenever sequence of commands is to be executed.
  54. */
  55. struct mutex lock;
  56. int state;
  57. };
  58. DECLARE_CRC8_TABLE(sps30_crc8_table);
  59. static int sps30_write_then_read(struct sps30_state *state, u8 *txbuf,
  60. int txsize, u8 *rxbuf, int rxsize)
  61. {
  62. int ret;
  63. /*
  64. * Sensor does not support repeated start so instead of
  65. * sending two i2c messages in a row we just send one by one.
  66. */
  67. ret = i2c_master_send(state->client, txbuf, txsize);
  68. if (ret != txsize)
  69. return ret < 0 ? ret : -EIO;
  70. if (!rxbuf)
  71. return 0;
  72. ret = i2c_master_recv(state->client, rxbuf, rxsize);
  73. if (ret != rxsize)
  74. return ret < 0 ? ret : -EIO;
  75. return 0;
  76. }
  77. static int sps30_do_cmd(struct sps30_state *state, u16 cmd, u8 *data, int size)
  78. {
  79. /*
  80. * Internally sensor stores measurements in a following manner:
  81. *
  82. * PM1: upper two bytes, crc8, lower two bytes, crc8
  83. * PM2P5: upper two bytes, crc8, lower two bytes, crc8
  84. * PM4: upper two bytes, crc8, lower two bytes, crc8
  85. * PM10: upper two bytes, crc8, lower two bytes, crc8
  86. *
  87. * What follows next are number concentration measurements and
  88. * typical particle size measurement which we omit.
  89. */
  90. u8 buf[SPS30_MAX_READ_SIZE] = { cmd >> 8, cmd };
  91. int i, ret = 0;
  92. switch (cmd) {
  93. case SPS30_START_MEAS:
  94. buf[2] = 0x03;
  95. buf[3] = 0x00;
  96. buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
  97. ret = sps30_write_then_read(state, buf, 5, NULL, 0);
  98. break;
  99. case SPS30_STOP_MEAS:
  100. case SPS30_RESET:
  101. case SPS30_START_FAN_CLEANING:
  102. ret = sps30_write_then_read(state, buf, 2, NULL, 0);
  103. break;
  104. case SPS30_READ_AUTO_CLEANING_PERIOD:
  105. buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8;
  106. buf[1] = (u8)(SPS30_AUTO_CLEANING_PERIOD & 0xff);
  107. fallthrough;
  108. case SPS30_READ_DATA_READY_FLAG:
  109. case SPS30_READ_DATA:
  110. case SPS30_READ_SERIAL:
  111. /* every two data bytes are checksummed */
  112. size += size / 2;
  113. ret = sps30_write_then_read(state, buf, 2, buf, size);
  114. break;
  115. case SPS30_AUTO_CLEANING_PERIOD:
  116. buf[2] = data[0];
  117. buf[3] = data[1];
  118. buf[4] = crc8(sps30_crc8_table, &buf[2], 2, CRC8_INIT_VALUE);
  119. buf[5] = data[2];
  120. buf[6] = data[3];
  121. buf[7] = crc8(sps30_crc8_table, &buf[5], 2, CRC8_INIT_VALUE);
  122. ret = sps30_write_then_read(state, buf, 8, NULL, 0);
  123. break;
  124. }
  125. if (ret)
  126. return ret;
  127. /* validate received data and strip off crc bytes */
  128. for (i = 0; i < size; i += 3) {
  129. u8 crc = crc8(sps30_crc8_table, &buf[i], 2, CRC8_INIT_VALUE);
  130. if (crc != buf[i + 2]) {
  131. dev_err(&state->client->dev,
  132. "data integrity check failed\n");
  133. return -EIO;
  134. }
  135. *data++ = buf[i];
  136. *data++ = buf[i + 1];
  137. }
  138. return 0;
  139. }
  140. static s32 sps30_float_to_int_clamped(const u8 *fp)
  141. {
  142. int val = get_unaligned_be32(fp);
  143. int mantissa = val & GENMASK(22, 0);
  144. /* this is fine since passed float is always non-negative */
  145. int exp = val >> 23;
  146. int fraction, shift;
  147. /* special case 0 */
  148. if (!exp && !mantissa)
  149. return 0;
  150. exp -= 127;
  151. if (exp < 0) {
  152. /* return values ranging from 1 to 99 */
  153. return ((((1 << 23) + mantissa) * 100) >> 23) >> (-exp);
  154. }
  155. /* return values ranging from 100 to 300000 */
  156. shift = 23 - exp;
  157. val = (1 << exp) + (mantissa >> shift);
  158. if (val >= SPS30_MAX_PM)
  159. return SPS30_MAX_PM * 100;
  160. fraction = mantissa & GENMASK(shift - 1, 0);
  161. return val * 100 + ((fraction * 100) >> shift);
  162. }
  163. static int sps30_do_meas(struct sps30_state *state, s32 *data, int size)
  164. {
  165. int i, ret, tries = 5;
  166. u8 tmp[16];
  167. if (state->state == RESET) {
  168. ret = sps30_do_cmd(state, SPS30_START_MEAS, NULL, 0);
  169. if (ret)
  170. return ret;
  171. state->state = MEASURING;
  172. }
  173. while (tries--) {
  174. ret = sps30_do_cmd(state, SPS30_READ_DATA_READY_FLAG, tmp, 2);
  175. if (ret)
  176. return -EIO;
  177. /* new measurements ready to be read */
  178. if (tmp[1] == 1)
  179. break;
  180. msleep_interruptible(300);
  181. }
  182. if (tries == -1)
  183. return -ETIMEDOUT;
  184. ret = sps30_do_cmd(state, SPS30_READ_DATA, tmp, sizeof(int) * size);
  185. if (ret)
  186. return ret;
  187. for (i = 0; i < size; i++)
  188. data[i] = sps30_float_to_int_clamped(&tmp[4 * i]);
  189. return 0;
  190. }
  191. static irqreturn_t sps30_trigger_handler(int irq, void *p)
  192. {
  193. struct iio_poll_func *pf = p;
  194. struct iio_dev *indio_dev = pf->indio_dev;
  195. struct sps30_state *state = iio_priv(indio_dev);
  196. int ret;
  197. struct {
  198. s32 data[4]; /* PM1, PM2P5, PM4, PM10 */
  199. s64 ts;
  200. } scan;
  201. mutex_lock(&state->lock);
  202. ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
  203. mutex_unlock(&state->lock);
  204. if (ret)
  205. goto err;
  206. iio_push_to_buffers_with_timestamp(indio_dev, &scan,
  207. iio_get_time_ns(indio_dev));
  208. err:
  209. iio_trigger_notify_done(indio_dev->trig);
  210. return IRQ_HANDLED;
  211. }
  212. static int sps30_read_raw(struct iio_dev *indio_dev,
  213. struct iio_chan_spec const *chan,
  214. int *val, int *val2, long mask)
  215. {
  216. struct sps30_state *state = iio_priv(indio_dev);
  217. int data[4], ret = -EINVAL;
  218. switch (mask) {
  219. case IIO_CHAN_INFO_PROCESSED:
  220. switch (chan->type) {
  221. case IIO_MASSCONCENTRATION:
  222. mutex_lock(&state->lock);
  223. /* read up to the number of bytes actually needed */
  224. switch (chan->channel2) {
  225. case IIO_MOD_PM1:
  226. ret = sps30_do_meas(state, data, 1);
  227. break;
  228. case IIO_MOD_PM2P5:
  229. ret = sps30_do_meas(state, data, 2);
  230. break;
  231. case IIO_MOD_PM4:
  232. ret = sps30_do_meas(state, data, 3);
  233. break;
  234. case IIO_MOD_PM10:
  235. ret = sps30_do_meas(state, data, 4);
  236. break;
  237. }
  238. mutex_unlock(&state->lock);
  239. if (ret)
  240. return ret;
  241. *val = data[chan->address] / 100;
  242. *val2 = (data[chan->address] % 100) * 10000;
  243. return IIO_VAL_INT_PLUS_MICRO;
  244. default:
  245. return -EINVAL;
  246. }
  247. case IIO_CHAN_INFO_SCALE:
  248. switch (chan->type) {
  249. case IIO_MASSCONCENTRATION:
  250. switch (chan->channel2) {
  251. case IIO_MOD_PM1:
  252. case IIO_MOD_PM2P5:
  253. case IIO_MOD_PM4:
  254. case IIO_MOD_PM10:
  255. *val = 0;
  256. *val2 = 10000;
  257. return IIO_VAL_INT_PLUS_MICRO;
  258. default:
  259. return -EINVAL;
  260. }
  261. default:
  262. return -EINVAL;
  263. }
  264. }
  265. return -EINVAL;
  266. }
  267. static int sps30_do_cmd_reset(struct sps30_state *state)
  268. {
  269. int ret;
  270. ret = sps30_do_cmd(state, SPS30_RESET, NULL, 0);
  271. msleep(300);
  272. /*
  273. * Power-on-reset causes sensor to produce some glitch on i2c bus and
  274. * some controllers end up in error state. Recover simply by placing
  275. * some data on the bus, for example STOP_MEAS command, which
  276. * is NOP in this case.
  277. */
  278. sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
  279. state->state = RESET;
  280. return ret;
  281. }
  282. static ssize_t start_cleaning_store(struct device *dev,
  283. struct device_attribute *attr,
  284. const char *buf, size_t len)
  285. {
  286. struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  287. struct sps30_state *state = iio_priv(indio_dev);
  288. int val, ret;
  289. if (kstrtoint(buf, 0, &val) || val != 1)
  290. return -EINVAL;
  291. mutex_lock(&state->lock);
  292. ret = sps30_do_cmd(state, SPS30_START_FAN_CLEANING, NULL, 0);
  293. mutex_unlock(&state->lock);
  294. if (ret)
  295. return ret;
  296. return len;
  297. }
  298. static ssize_t cleaning_period_show(struct device *dev,
  299. struct device_attribute *attr,
  300. char *buf)
  301. {
  302. struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  303. struct sps30_state *state = iio_priv(indio_dev);
  304. u8 tmp[4];
  305. int ret;
  306. mutex_lock(&state->lock);
  307. ret = sps30_do_cmd(state, SPS30_READ_AUTO_CLEANING_PERIOD, tmp, 4);
  308. mutex_unlock(&state->lock);
  309. if (ret)
  310. return ret;
  311. return sprintf(buf, "%d\n", get_unaligned_be32(tmp));
  312. }
  313. static ssize_t cleaning_period_store(struct device *dev,
  314. struct device_attribute *attr,
  315. const char *buf, size_t len)
  316. {
  317. struct iio_dev *indio_dev = dev_to_iio_dev(dev);
  318. struct sps30_state *state = iio_priv(indio_dev);
  319. int val, ret;
  320. u8 tmp[4];
  321. if (kstrtoint(buf, 0, &val))
  322. return -EINVAL;
  323. if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) ||
  324. (val > SPS30_AUTO_CLEANING_PERIOD_MAX))
  325. return -EINVAL;
  326. put_unaligned_be32(val, tmp);
  327. mutex_lock(&state->lock);
  328. ret = sps30_do_cmd(state, SPS30_AUTO_CLEANING_PERIOD, tmp, 0);
  329. if (ret) {
  330. mutex_unlock(&state->lock);
  331. return ret;
  332. }
  333. msleep(20);
  334. /*
  335. * sensor requires reset in order to return up to date self cleaning
  336. * period
  337. */
  338. ret = sps30_do_cmd_reset(state);
  339. if (ret)
  340. dev_warn(dev,
  341. "period changed but reads will return the old value\n");
  342. mutex_unlock(&state->lock);
  343. return len;
  344. }
  345. static ssize_t cleaning_period_available_show(struct device *dev,
  346. struct device_attribute *attr,
  347. char *buf)
  348. {
  349. return snprintf(buf, PAGE_SIZE, "[%d %d %d]\n",
  350. SPS30_AUTO_CLEANING_PERIOD_MIN, 1,
  351. SPS30_AUTO_CLEANING_PERIOD_MAX);
  352. }
  353. static IIO_DEVICE_ATTR_WO(start_cleaning, 0);
  354. static IIO_DEVICE_ATTR_RW(cleaning_period, 0);
  355. static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0);
  356. static struct attribute *sps30_attrs[] = {
  357. &iio_dev_attr_start_cleaning.dev_attr.attr,
  358. &iio_dev_attr_cleaning_period.dev_attr.attr,
  359. &iio_dev_attr_cleaning_period_available.dev_attr.attr,
  360. NULL
  361. };
  362. static const struct attribute_group sps30_attr_group = {
  363. .attrs = sps30_attrs,
  364. };
  365. static const struct iio_info sps30_info = {
  366. .attrs = &sps30_attr_group,
  367. .read_raw = sps30_read_raw,
  368. };
  369. #define SPS30_CHAN(_index, _mod) { \
  370. .type = IIO_MASSCONCENTRATION, \
  371. .modified = 1, \
  372. .channel2 = IIO_MOD_ ## _mod, \
  373. .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
  374. .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
  375. .address = _mod, \
  376. .scan_index = _index, \
  377. .scan_type = { \
  378. .sign = 'u', \
  379. .realbits = 19, \
  380. .storagebits = 32, \
  381. .endianness = IIO_CPU, \
  382. }, \
  383. }
  384. static const struct iio_chan_spec sps30_channels[] = {
  385. SPS30_CHAN(0, PM1),
  386. SPS30_CHAN(1, PM2P5),
  387. SPS30_CHAN(2, PM4),
  388. SPS30_CHAN(3, PM10),
  389. IIO_CHAN_SOFT_TIMESTAMP(4),
  390. };
  391. static void sps30_stop_meas(void *data)
  392. {
  393. struct sps30_state *state = data;
  394. sps30_do_cmd(state, SPS30_STOP_MEAS, NULL, 0);
  395. }
  396. static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
  397. static int sps30_probe(struct i2c_client *client)
  398. {
  399. struct iio_dev *indio_dev;
  400. struct sps30_state *state;
  401. u8 buf[32];
  402. int ret;
  403. if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C))
  404. return -EOPNOTSUPP;
  405. indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*state));
  406. if (!indio_dev)
  407. return -ENOMEM;
  408. state = iio_priv(indio_dev);
  409. i2c_set_clientdata(client, indio_dev);
  410. state->client = client;
  411. state->state = RESET;
  412. indio_dev->info = &sps30_info;
  413. indio_dev->name = client->name;
  414. indio_dev->channels = sps30_channels;
  415. indio_dev->num_channels = ARRAY_SIZE(sps30_channels);
  416. indio_dev->modes = INDIO_DIRECT_MODE;
  417. indio_dev->available_scan_masks = sps30_scan_masks;
  418. mutex_init(&state->lock);
  419. crc8_populate_msb(sps30_crc8_table, SPS30_CRC8_POLYNOMIAL);
  420. ret = sps30_do_cmd_reset(state);
  421. if (ret) {
  422. dev_err(&client->dev, "failed to reset device\n");
  423. return ret;
  424. }
  425. ret = sps30_do_cmd(state, SPS30_READ_SERIAL, buf, sizeof(buf));
  426. if (ret) {
  427. dev_err(&client->dev, "failed to read serial number\n");
  428. return ret;
  429. }
  430. /* returned serial number is already NUL terminated */
  431. dev_info(&client->dev, "serial number: %s\n", buf);
  432. ret = devm_add_action_or_reset(&client->dev, sps30_stop_meas, state);
  433. if (ret)
  434. return ret;
  435. ret = devm_iio_triggered_buffer_setup(&client->dev, indio_dev, NULL,
  436. sps30_trigger_handler, NULL);
  437. if (ret)
  438. return ret;
  439. return devm_iio_device_register(&client->dev, indio_dev);
  440. }
  441. static const struct i2c_device_id sps30_id[] = {
  442. { "sps30" },
  443. { }
  444. };
  445. MODULE_DEVICE_TABLE(i2c, sps30_id);
  446. static const struct of_device_id sps30_of_match[] = {
  447. { .compatible = "sensirion,sps30" },
  448. { }
  449. };
  450. MODULE_DEVICE_TABLE(of, sps30_of_match);
  451. static struct i2c_driver sps30_driver = {
  452. .driver = {
  453. .name = "sps30",
  454. .of_match_table = sps30_of_match,
  455. },
  456. .id_table = sps30_id,
  457. .probe_new = sps30_probe,
  458. };
  459. module_i2c_driver(sps30_driver);
  460. MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
  461. MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");
  462. MODULE_LICENSE("GPL v2");