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232e0f6d TD |
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 | |
232e0f6d TD |
8 | */ |
9 | ||
232e0f6d TD |
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> | |
62129a08 | 19 | #include <linux/kernel.h> |
232e0f6d TD |
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 | |
62129a08 TD |
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 | |
232e0f6d TD |
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 | |
c546d496 | 38 | #define SPS30_START_FAN_CLEANING 0x5607 |
62129a08 TD |
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 | |
232e0f6d TD |
42 | |
43 | enum { | |
44 | PM1, | |
45 | PM2P5, | |
46 | PM4, | |
47 | PM10, | |
48 | }; | |
49 | ||
62129a08 TD |
50 | enum { |
51 | RESET, | |
52 | MEASURING, | |
53 | }; | |
54 | ||
232e0f6d TD |
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; | |
62129a08 | 62 | int state; |
232e0f6d TD |
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: | |
c546d496 | 115 | case SPS30_START_FAN_CLEANING: |
232e0f6d TD |
116 | ret = sps30_write_then_read(state, buf, 2, NULL, 0); |
117 | break; | |
62129a08 TD |
118 | case SPS30_READ_AUTO_CLEANING_PERIOD: |
119 | buf[0] = SPS30_AUTO_CLEANING_PERIOD >> 8; | |
120 | buf[1] = (u8)SPS30_AUTO_CLEANING_PERIOD; | |
59b9bb0a | 121 | /* fall through */ |
232e0f6d TD |
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; | |
62129a08 TD |
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; | |
232e0f6d TD |
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 | ||
62129a08 TD |
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 | ||
232e0f6d TD |
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 | ||
905889b4 | 214 | if (tries == -1) |
232e0f6d TD |
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; | |
59b9bb0a JC |
299 | default: |
300 | return -EINVAL; | |
232e0f6d TD |
301 | } |
302 | default: | |
303 | return -EINVAL; | |
304 | } | |
305 | } | |
306 | ||
307 | return -EINVAL; | |
308 | } | |
309 | ||
62129a08 TD |
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 | ||
c546d496 TD |
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 | ||
62129a08 TD |
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 | ||
c546d496 | 416 | static IIO_DEVICE_ATTR_WO(start_cleaning, 0); |
62129a08 TD |
417 | static IIO_DEVICE_ATTR_RW(cleaning_period, 0); |
418 | static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0); | |
c546d496 TD |
419 | |
420 | static struct attribute *sps30_attrs[] = { | |
421 | &iio_dev_attr_start_cleaning.dev_attr.attr, | |
62129a08 TD |
422 | &iio_dev_attr_cleaning_period.dev_attr.attr, |
423 | &iio_dev_attr_cleaning_period_available.dev_attr.attr, | |
c546d496 TD |
424 | NULL |
425 | }; | |
426 | ||
427 | static const struct attribute_group sps30_attr_group = { | |
428 | .attrs = sps30_attrs, | |
429 | }; | |
430 | ||
232e0f6d | 431 | static const struct iio_info sps30_info = { |
c546d496 | 432 | .attrs = &sps30_attr_group, |
232e0f6d TD |
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; | |
62129a08 | 486 | state->state = RESET; |
232e0f6d TD |
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 | ||
62129a08 | 498 | ret = sps30_do_cmd_reset(state); |
232e0f6d TD |
499 | if (ret) { |
500 | dev_err(&client->dev, "failed to reset device\n"); | |
501 | return ret; | |
502 | } | |
232e0f6d TD |
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 | ||
232e0f6d TD |
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"); |