sps30.c

  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
 27enum {
 28	PM1,
 29	PM2P5,
 30	PM4,
 31	PM10,
 32};
 33
 34enum {
 35	RESET,
 36	MEASURING,
 37};
 38
 39static 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
 68static 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
 90static 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
103static 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		aligned_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_ts(indio_dev, &scan, sizeof(scan),
121				    iio_get_time_ns(indio_dev));
122err:
123	iio_trigger_notify_done(indio_dev->trig);
124
125	return IRQ_HANDLED;
126}
127
128static 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
189static 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
209static 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
227static 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
264static 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
273static IIO_DEVICE_ATTR_WO(start_cleaning, 0);
274static IIO_DEVICE_ATTR_RW(cleaning_period, 0);
275static IIO_DEVICE_ATTR_RO(cleaning_period_available, 0);
276
277static 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
284static const struct attribute_group sps30_attr_group = {
285	.attrs = sps30_attrs,
286};
287
288static 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
309static 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
317static 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
325static const unsigned long sps30_scan_masks[] = { 0x0f, 0x00 };
326
327int 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}
375EXPORT_SYMBOL_NS_GPL(sps30_probe, "IIO_SPS30");
376
377MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
378MODULE_DESCRIPTION("Sensirion SPS30 particulate matter sensor driver");
379MODULE_LICENSE("GPL v2");