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
8 #include <linux/crc8.h>
9 #include <linux/delay.h>
10 #include <linux/i2c.h>
11 #include <linux/iio/buffer.h>
12 #include <linux/iio/iio.h>
13 #include <linux/iio/sysfs.h>
14 #include <linux/iio/trigger_consumer.h>
15 #include <linux/iio/triggered_buffer.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18
19 #include "sps30.h"
20
21 /* sensor measures reliably up to 3000 ug / m3 */
22 #define SPS30_MAX_PM 3000
23 /* minimum and maximum self cleaning periods in seconds */
24 #define SPS30_AUTO_CLEANING_PERIOD_MIN 0
25 #define SPS30_AUTO_CLEANING_PERIOD_MAX 604800
26
27 enum {
28 PM1,
29 PM2P5,
30 PM4,
31 PM10,
32 };
33
34 enum {
35 RESET,
36 MEASURING,
37 };
38
sps30_float_to_int_clamped(__be32 * fp)39 static s32 sps30_float_to_int_clamped(__be32 *fp)
40 {
41 int val = be32_to_cpup(fp);
42 int mantissa = val & GENMASK(22, 0);
43 /* this is fine since passed float is always non-negative */
44 int exp = val >> 23;
45 int fraction, shift;
46
47 /* special case 0 */
48 if (!exp && !mantissa)
49 return 0;
50
51 exp -= 127;
52 if (exp < 0) {
53 /* return values ranging from 1 to 99 */
54 return ((((1 << 23) + mantissa) * 100) >> 23) >> (-exp);
55 }
56
57 /* return values ranging from 100 to 300000 */
58 shift = 23 - exp;
59 val = (1 << exp) + (mantissa >> shift);
60 if (val >= SPS30_MAX_PM)
61 return SPS30_MAX_PM * 100;
62
63 fraction = mantissa & GENMASK(shift - 1, 0);
64
65 return val * 100 + ((fraction * 100) >> shift);
66 }
67
sps30_do_meas(struct sps30_state * state,s32 * data,int size)68 static int sps30_do_meas(struct sps30_state *state, s32 *data, int size)
69 {
70 int i, ret;
71
72 if (state->state == RESET) {
73 ret = state->ops->start_meas(state);
74 if (ret)
75 return ret;
76
77 state->state = MEASURING;
78 }
79
80 ret = state->ops->read_meas(state, (__be32 *)data, size);
81 if (ret)
82 return ret;
83
84 for (i = 0; i < size; i++)
85 data[i] = sps30_float_to_int_clamped((__be32 *)&data[i]);
86
87 return 0;
88 }
89
sps30_do_reset(struct sps30_state * state)90 static int sps30_do_reset(struct sps30_state *state)
91 {
92 int ret;
93
94 ret = state->ops->reset(state);
95 if (ret)
96 return ret;
97
98 state->state = RESET;
99
100 return 0;
101 }
102
sps30_trigger_handler(int irq,void * p)103 static irqreturn_t sps30_trigger_handler(int irq, void *p)
104 {
105 struct iio_poll_func *pf = p;
106 struct iio_dev *indio_dev = pf->indio_dev;
107 struct sps30_state *state = iio_priv(indio_dev);
108 int ret;
109 struct {
110 s32 data[4]; /* PM1, PM2P5, PM4, PM10 */
111 s64 ts;
112 } scan;
113
114 mutex_lock(&state->lock);
115 ret = sps30_do_meas(state, scan.data, ARRAY_SIZE(scan.data));
116 mutex_unlock(&state->lock);
117 if (ret)
118 goto err;
119
120 iio_push_to_buffers_with_timestamp(indio_dev, &scan,
121 iio_get_time_ns(indio_dev));
122 err:
123 iio_trigger_notify_done(indio_dev->trig);
124
125 return IRQ_HANDLED;
126 }
127
sps30_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)128 static int sps30_read_raw(struct iio_dev *indio_dev,
129 struct iio_chan_spec const *chan,
130 int *val, int *val2, long mask)
131 {
132 struct sps30_state *state = iio_priv(indio_dev);
133 int data[4], ret = -EINVAL;
134
135 switch (mask) {
136 case IIO_CHAN_INFO_PROCESSED:
137 switch (chan->type) {
138 case IIO_MASSCONCENTRATION:
139 mutex_lock(&state->lock);
140 /* read up to the number of bytes actually needed */
141 switch (chan->channel2) {
142 case IIO_MOD_PM1:
143 ret = sps30_do_meas(state, data, 1);
144 break;
145 case IIO_MOD_PM2P5:
146 ret = sps30_do_meas(state, data, 2);
147 break;
148 case IIO_MOD_PM4:
149 ret = sps30_do_meas(state, data, 3);
150 break;
151 case IIO_MOD_PM10:
152 ret = sps30_do_meas(state, data, 4);
153 break;
154 }
155 mutex_unlock(&state->lock);
156 if (ret)
157 return ret;
158
159 *val = data[chan->address] / 100;
160 *val2 = (data[chan->address] % 100) * 10000;
161
162 return IIO_VAL_INT_PLUS_MICRO;
163 default:
164 return -EINVAL;
165 }
166 case IIO_CHAN_INFO_SCALE:
167 switch (chan->type) {
168 case IIO_MASSCONCENTRATION:
169 switch (chan->channel2) {
170 case IIO_MOD_PM1:
171 case IIO_MOD_PM2P5:
172 case IIO_MOD_PM4:
173 case IIO_MOD_PM10:
174 *val = 0;
175 *val2 = 10000;
176
177 return IIO_VAL_INT_PLUS_MICRO;
178 default:
179 return -EINVAL;
180 }
181 default:
182 return -EINVAL;
183 }
184 }
185
186 return -EINVAL;
187 }
188
start_cleaning_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)189 static ssize_t start_cleaning_store(struct device *dev,
190 struct device_attribute *attr,
191 const char *buf, size_t len)
192 {
193 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
194 struct sps30_state *state = iio_priv(indio_dev);
195 int val, ret;
196
197 if (kstrtoint(buf, 0, &val) || val != 1)
198 return -EINVAL;
199
200 mutex_lock(&state->lock);
201 ret = state->ops->clean_fan(state);
202 mutex_unlock(&state->lock);
203 if (ret)
204 return ret;
205
206 return len;
207 }
208
cleaning_period_show(struct device * dev,struct device_attribute * attr,char * buf)209 static ssize_t cleaning_period_show(struct device *dev,
210 struct device_attribute *attr,
211 char *buf)
212 {
213 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
214 struct sps30_state *state = iio_priv(indio_dev);
215 __be32 val;
216 int ret;
217
218 mutex_lock(&state->lock);
219 ret = state->ops->read_cleaning_period(state, &val);
220 mutex_unlock(&state->lock);
221 if (ret)
222 return ret;
223
224 return sysfs_emit(buf, "%d\n", be32_to_cpu(val));
225 }
226
cleaning_period_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)227 static ssize_t cleaning_period_store(struct device *dev, struct device_attribute *attr,
228 const char *buf, size_t len)
229 {
230 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
231 struct sps30_state *state = iio_priv(indio_dev);
232 int val, ret;
233
234 if (kstrtoint(buf, 0, &val))
235 return -EINVAL;
236
237 if ((val < SPS30_AUTO_CLEANING_PERIOD_MIN) ||
238 (val > SPS30_AUTO_CLEANING_PERIOD_MAX))
239 return -EINVAL;
240
241 mutex_lock(&state->lock);
242 ret = state->ops->write_cleaning_period(state, cpu_to_be32(val));
243 if (ret) {
244 mutex_unlock(&state->lock);
245 return ret;
246 }
247
248 msleep(20);
249
250 /*
251 * sensor requires reset in order to return up to date self cleaning
252 * period
253 */
254 ret = sps30_do_reset(state);
255 if (ret)
256 dev_warn(dev,
257 "period changed but reads will return the old value\n");
258
259 mutex_unlock(&state->lock);
260
261 return len;
262 }
263
cleaning_period_available_show(struct device * dev,struct device_attribute * attr,char * buf)264 static ssize_t cleaning_period_available_show(struct device *dev,
265 struct device_attribute *attr,
266 char *buf)
267 {
268 return sysfs_emit(buf, "[%d %d %d]\n",
269 SPS30_AUTO_CLEANING_PERIOD_MIN, 1,
270 SPS30_AUTO_CLEANING_PERIOD_MAX);
271 }
272
273 static IIO_DEVICE_ATTR_WO(start_cleaning, 0);
274 static IIO_DEVICE_ATTR_RW(cleaning_period, 0);
275 static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0);
276
277 static struct attribute *sps30_attrs[] = {
278 &iio_dev_attr_start_cleaning.dev_attr.attr,
279 &iio_dev_attr_cleaning_period.dev_attr.attr,
280 &iio_dev_attr_cleaning_period_available.dev_attr.attr,
281 NULL
282 };
283
284 static const struct attribute_group sps30_attr_group = {
285 .attrs = sps30_attrs,
286 };
287
288 static const struct iio_info sps30_info = {
289 .attrs = &sps30_attr_group,
290 .read_raw = sps30_read_raw,
291 };
292
293 #define SPS30_CHAN(_index, _mod) { \
294 .type = IIO_MASSCONCENTRATION, \
295 .modified = 1, \
296 .channel2 = IIO_MOD_ ## _mod, \
297 .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
298 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
299 .address = _mod, \
300 .scan_index = _index, \
301 .scan_type = { \
302 .sign = 'u', \
303 .realbits = 19, \
304 .storagebits = 32, \
305 .endianness = IIO_CPU, \
306 }, \
307 }
308
309 static const struct iio_chan_spec sps30_channels[] = {
310 SPS30_CHAN(0, PM1),
311 SPS30_CHAN(1, PM2P5),
312 SPS30_CHAN(2, PM4),
313 SPS30_CHAN(3, PM10),
314 IIO_CHAN_SOFT_TIMESTAMP(4),
315 };
316
sps30_devm_stop_meas(void * data)317 static void sps30_devm_stop_meas(void *data)
318 {
319 struct sps30_state *state = data;
320
321 if (state->state == MEASURING)
322 state->ops->stop_meas(state);
323 }
324
325 static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
326
sps30_probe(struct device * dev,const char * name,void * priv,const struct sps30_ops * ops)327 int sps30_probe(struct device *dev, const char *name, void *priv, const struct sps30_ops *ops)
328 {
329 struct iio_dev *indio_dev;
330 struct sps30_state *state;
331 int ret;
332
333 indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
334 if (!indio_dev)
335 return -ENOMEM;
336
337 dev_set_drvdata(dev, indio_dev);
338
339 state = iio_priv(indio_dev);
340 state->dev = dev;
341 state->priv = priv;
342 state->ops = ops;
343 mutex_init(&state->lock);
344
345 indio_dev->info = &sps30_info;
346 indio_dev->name = name;
347 indio_dev->channels = sps30_channels;
348 indio_dev->num_channels = ARRAY_SIZE(sps30_channels);
349 indio_dev->modes = INDIO_DIRECT_MODE;
350 indio_dev->available_scan_masks = sps30_scan_masks;
351
352 ret = sps30_do_reset(state);
353 if (ret) {
354 dev_err(dev, "failed to reset device\n");
355 return ret;
356 }
357
358 ret = state->ops->show_info(state);
359 if (ret) {
360 dev_err(dev, "failed to read device info\n");
361 return ret;
362 }
363
364 ret = devm_add_action_or_reset(dev, sps30_devm_stop_meas, state);
365 if (ret)
366 return ret;
367
368 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
369 sps30_trigger_handler, NULL);
370 if (ret)
371 return ret;
372
373 return devm_iio_device_register(dev, indio_dev);
374 }
375 EXPORT_SYMBOL_NS_GPL(sps30_probe, IIO_SPS30);
376
377 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
378 MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");
379 MODULE_LICENSE("GPL v2");
380