drivers/iio/chemical/pms7003.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Plantower PMS7003 particulate matter sensor driver
   4  *
   5  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
   6  */
   7
   8 #include <asm/unaligned.h>
   9 #include <linux/completion.h>
  10 #include <linux/device.h>
  11 #include <linux/errno.h>
  12 #include <linux/iio/buffer.h>
  13 #include <linux/iio/iio.h>
  14 #include <linux/iio/trigger_consumer.h>
  15 #include <linux/iio/triggered_buffer.h>
  16 #include <linux/jiffies.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mod_devicetable.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/serdev.h>
  22
  23 #define PMS7003_DRIVER_NAME "pms7003"
  24
  25 #define PMS7003_MAGIC 0x424d
  26 /* last 2 data bytes hold frame checksum */
  27 #define PMS7003_MAX_DATA_LENGTH 28
  28 #define PMS7003_CHECKSUM_LENGTH 2
  29 #define PMS7003_PM10_OFFSET 10
  30 #define PMS7003_PM2P5_OFFSET 8
  31 #define PMS7003_PM1_OFFSET 6
  32
  33 #define PMS7003_TIMEOUT msecs_to_jiffies(6000)
  34 #define PMS7003_CMD_LENGTH 7
  35 #define PMS7003_PM_MAX 1000
  36 #define PMS7003_PM_MIN 0
  37
  38 enum {
  39         PM1,
  40         PM2P5,
  41         PM10,
  42 };
  43
  44 enum pms7003_cmd {
  45         CMD_WAKEUP,
  46         CMD_ENTER_PASSIVE_MODE,
  47         CMD_READ_PASSIVE,
  48         CMD_SLEEP,
  49 };
  50
  51 /*
  52  * commands have following format:
  53  *
  54  * +------+------+-----+------+-----+-----------+-----------+
  55  * | 0x42 | 0x4d | cmd | 0x00 | arg | cksum msb | cksum lsb |
  56  * +------+------+-----+------+-----+-----------+-----------+
  57  */
  58 static const u8 pms7003_cmd_tbl[][PMS7003_CMD_LENGTH] = {
  59         [CMD_WAKEUP] = { 0x42, 0x4d, 0xe4, 0x00, 0x01, 0x01, 0x74 },
  60         [CMD_ENTER_PASSIVE_MODE] = { 0x42, 0x4d, 0xe1, 0x00, 0x00, 0x01, 0x70 },
  61         [CMD_READ_PASSIVE] = { 0x42, 0x4d, 0xe2, 0x00, 0x00, 0x01, 0x71 },
  62         [CMD_SLEEP] = { 0x42, 0x4d, 0xe4, 0x00, 0x00, 0x01, 0x73 },
  63 };
  64
  65 struct pms7003_frame {
  66         u8 data[PMS7003_MAX_DATA_LENGTH];
  67         u16 expected_length;
  68         u16 length;
  69 };
  70
  71 struct pms7003_state {
  72         struct serdev_device *serdev;
  73         struct pms7003_frame frame;
  74         struct completion frame_ready;
  75         struct mutex lock; /* must be held whenever state gets touched */
  76 };
  77
  78 static int pms7003_do_cmd(struct pms7003_state *state, enum pms7003_cmd cmd)
  79 {
  80         int ret;
  81
  82         ret = serdev_device_write(state->serdev, pms7003_cmd_tbl[cmd],
  83                                   PMS7003_CMD_LENGTH, PMS7003_TIMEOUT);
  84         if (ret < PMS7003_CMD_LENGTH)
  85                 return ret < 0 ? ret : -EIO;
  86
  87         ret = wait_for_completion_interruptible_timeout(&state->frame_ready,
  88                                                         PMS7003_TIMEOUT);
  89         if (!ret)
  90                 ret = -ETIMEDOUT;
  91
  92         return ret < 0 ? ret : 0;
  93 }
  94
  95 static u16 pms7003_get_pm(const u8 *data)
  96 {
  97         return clamp_val(get_unaligned_be16(data),
  98                          PMS7003_PM_MIN, PMS7003_PM_MAX);
  99 }
 100
 101 static irqreturn_t pms7003_trigger_handler(int irq, void *p)
 102 {
 103         struct iio_poll_func *pf = p;
 104         struct iio_dev *indio_dev = pf->indio_dev;
 105         struct pms7003_state *state = iio_priv(indio_dev);
 106         struct pms7003_frame *frame = &state->frame;
 107         u16 data[3 + 1 + 4]; /* PM1, PM2P5, PM10, padding, timestamp */
 108         int ret;
 109
 110         mutex_lock(&state->lock);
 111         ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
 112         if (ret) {
 113                 mutex_unlock(&state->lock);
 114                 goto err;
 115         }
 116
 117         data[PM1] = pms7003_get_pm(frame->data + PMS7003_PM1_OFFSET);
 118         data[PM2P5] = pms7003_get_pm(frame->data + PMS7003_PM2P5_OFFSET);
 119         data[PM10] = pms7003_get_pm(frame->data + PMS7003_PM10_OFFSET);
 120         mutex_unlock(&state->lock);
 121
 122         iio_push_to_buffers_with_timestamp(indio_dev, data,
 123                                            iio_get_time_ns(indio_dev));
 124 err:
 125         iio_trigger_notify_done(indio_dev->trig);
 126
 127         return IRQ_HANDLED;
 128 }
 129
 130 static int pms7003_read_raw(struct iio_dev *indio_dev,
 131                             struct iio_chan_spec const *chan,
 132                             int *val, int *val2, long mask)
 133 {
 134         struct pms7003_state *state = iio_priv(indio_dev);
 135         struct pms7003_frame *frame = &state->frame;
 136         int ret;
 137
 138         switch (mask) {
 139         case IIO_CHAN_INFO_PROCESSED:
 140                 switch (chan->type) {
 141                 case IIO_MASSCONCENTRATION:
 142                         mutex_lock(&state->lock);
 143                         ret = pms7003_do_cmd(state, CMD_READ_PASSIVE);
 144                         if (ret) {
 145                                 mutex_unlock(&state->lock);
 146                                 return ret;
 147                         }
 148
 149                         *val = pms7003_get_pm(frame->data + chan->address);
 150                         mutex_unlock(&state->lock);
 151
 152                         return IIO_VAL_INT;
 153                 default:
 154                         return -EINVAL;
 155                 }
 156         }
 157
 158         return -EINVAL;
 159 }
 160
 161 static const struct iio_info pms7003_info = {
 162         .read_raw = pms7003_read_raw,
 163 };
 164
 165 #define PMS7003_CHAN(_index, _mod, _addr) { \
 166         .type = IIO_MASSCONCENTRATION, \
 167         .modified = 1, \
 168         .channel2 = IIO_MOD_ ## _mod, \
 169         .address = _addr, \
 170         .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
 171         .scan_index = _index, \
 172         .scan_type = { \
 173                 .sign = 'u', \
 174                 .realbits = 10, \
 175                 .storagebits = 16, \
 176                 .endianness = IIO_CPU, \
 177         }, \
 178 }
 179
 180 static const struct iio_chan_spec pms7003_channels[] = {
 181         PMS7003_CHAN(0, PM1, PMS7003_PM1_OFFSET),
 182         PMS7003_CHAN(1, PM2P5, PMS7003_PM2P5_OFFSET),
 183         PMS7003_CHAN(2, PM10, PMS7003_PM10_OFFSET),
 184         IIO_CHAN_SOFT_TIMESTAMP(3),
 185 };
 186
 187 static u16 pms7003_calc_checksum(struct pms7003_frame *frame)
 188 {
 189         u16 checksum = (PMS7003_MAGIC >> 8) + (u8)(PMS7003_MAGIC & 0xff) +
 190                        (frame->length >> 8) + (u8)frame->length;
 191         int i;
 192
 193         for (i = 0; i < frame->length - PMS7003_CHECKSUM_LENGTH; i++)
 194                 checksum += frame->data[i];
 195
 196         return checksum;
 197 }
 198
 199 static bool pms7003_frame_is_okay(struct pms7003_frame *frame)
 200 {
 201         int offset = frame->length - PMS7003_CHECKSUM_LENGTH;
 202         u16 checksum = get_unaligned_be16(frame->data + offset);
 203
 204         return checksum == pms7003_calc_checksum(frame);
 205 }
 206
 207 static int pms7003_receive_buf(struct serdev_device *serdev,
 208                                const unsigned char *buf, size_t size)
 209 {
 210         struct iio_dev *indio_dev = serdev_device_get_drvdata(serdev);
 211         struct pms7003_state *state = iio_priv(indio_dev);
 212         struct pms7003_frame *frame = &state->frame;
 213         int num;
 214
 215         if (!frame->expected_length) {
 216                 u16 magic;
 217
 218                 /* wait for SOF and data length */
 219                 if (size < 4)
 220                         return 0;
 221
 222                 magic = get_unaligned_be16(buf);
 223                 if (magic != PMS7003_MAGIC)
 224                         return 2;
 225
 226                 num = get_unaligned_be16(buf + 2);
 227                 if (num <= PMS7003_MAX_DATA_LENGTH) {
 228                         frame->expected_length = num;
 229                         frame->length = 0;
 230                 }
 231
 232                 return 4;
 233         }
 234
 235         num = min(size, (size_t)(frame->expected_length - frame->length));
 236         memcpy(frame->data + frame->length, buf, num);
 237         frame->length += num;
 238
 239         if (frame->length == frame->expected_length) {
 240                 if (pms7003_frame_is_okay(frame))
 241                         complete(&state->frame_ready);
 242
 243                 frame->expected_length = 0;
 244         }
 245
 246         return num;
 247 }
 248
 249 static const struct serdev_device_ops pms7003_serdev_ops = {
 250         .receive_buf = pms7003_receive_buf,
 251         .write_wakeup = serdev_device_write_wakeup,
 252 };
 253
 254 static void pms7003_stop(void *data)
 255 {
 256         struct pms7003_state *state = data;
 257
 258         pms7003_do_cmd(state, CMD_SLEEP);
 259 }
 260
 261 static const unsigned long pms7003_scan_masks[] = { 0x07, 0x00 };
 262
 263 static int pms7003_probe(struct serdev_device *serdev)
 264 {
 265         struct pms7003_state *state;
 266         struct iio_dev *indio_dev;
 267         int ret;
 268
 269         indio_dev = devm_iio_device_alloc(&serdev->dev, sizeof(*state));
 270         if (!indio_dev)
 271                 return -ENOMEM;
 272
 273         state = iio_priv(indio_dev);
 274         serdev_device_set_drvdata(serdev, indio_dev);
 275         state->serdev = serdev;
 276         indio_dev->dev.parent = &serdev->dev;
 277         indio_dev->info = &pms7003_info;
 278         indio_dev->name = PMS7003_DRIVER_NAME;
 279         indio_dev->channels = pms7003_channels,
 280         indio_dev->num_channels = ARRAY_SIZE(pms7003_channels);
 281         indio_dev->modes = INDIO_DIRECT_MODE;
 282         indio_dev->available_scan_masks = pms7003_scan_masks;
 283
 284         mutex_init(&state->lock);
 285         init_completion(&state->frame_ready);
 286
 287         serdev_device_set_client_ops(serdev, &pms7003_serdev_ops);
 288         ret = devm_serdev_device_open(&serdev->dev, serdev);
 289         if (ret)
 290                 return ret;
 291
 292         serdev_device_set_baudrate(serdev, 9600);
 293         serdev_device_set_flow_control(serdev, false);
 294
 295         ret = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE);
 296         if (ret)
 297                 return ret;
 298
 299         ret = pms7003_do_cmd(state, CMD_WAKEUP);
 300         if (ret) {
 301                 dev_err(&serdev->dev, "failed to wakeup sensor\n");
 302                 return ret;
 303         }
 304
 305         ret = pms7003_do_cmd(state, CMD_ENTER_PASSIVE_MODE);
 306         if (ret) {
 307                 dev_err(&serdev->dev, "failed to enter passive mode\n");
 308                 return ret;
 309         }
 310
 311         ret = devm_add_action_or_reset(&serdev->dev, pms7003_stop, state);
 312         if (ret)
 313                 return ret;
 314
 315         ret = devm_iio_triggered_buffer_setup(&serdev->dev, indio_dev, NULL,
 316                                               pms7003_trigger_handler, NULL);
 317         if (ret)
 318                 return ret;
 319
 320         return devm_iio_device_register(&serdev->dev, indio_dev);
 321 }
 322
 323 static const struct of_device_id pms7003_of_match[] = {
 324         { .compatible = "plantower,pms1003" },
 325         { .compatible = "plantower,pms3003" },
 326         { .compatible = "plantower,pms5003" },
 327         { .compatible = "plantower,pms6003" },
 328         { .compatible = "plantower,pms7003" },
 329         { .compatible = "plantower,pmsa003" },
 330         { }
 331 };
 332 MODULE_DEVICE_TABLE(of, pms7003_of_match);
 333
 334 static struct serdev_device_driver pms7003_driver = {
 335         .driver = {
 336                 .name = PMS7003_DRIVER_NAME,
 337                 .of_match_table = pms7003_of_match,
 338         },
 339         .probe = pms7003_probe,
 340 };
 341 module_serdev_device_driver(pms7003_driver);
 342
 343 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
 344 MODULE_DESCRIPTION("Plantower PMS7003 particulate matter sensor driver");
 345 MODULE_LICENSE("GPL v2");