drivers/iio/chemical/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
  27 enum {
  28         PM1,
  29         PM2P5,
  30         PM4,
  31         PM10,
  32 };
  33
  34 enum {
  35         RESET,
  36         MEASURING,
  37 };
  38
  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
  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
  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
 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
 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
 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
 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
 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
 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
 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
 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");