drivers/iio/health/max30100.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor
   4  *
   5  * Copyright (C) 2015, 2018
   6  * Author: Matt Ranostay <matt.ranostay@konsulko.com>
   7  *
   8  * TODO: enable pulse length controls via device tree properties
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/delay.h>
  15 #include <linux/err.h>
  16 #include <linux/irq.h>
  17 #include <linux/i2c.h>
  18 #include <linux/mutex.h>
  19 #include <linux/property.h>
  20 #include <linux/regmap.h>
  21 #include <linux/iio/iio.h>
  22 #include <linux/iio/buffer.h>
  23 #include <linux/iio/kfifo_buf.h>
  24
  25 #define MAX30100_REGMAP_NAME    "max30100_regmap"
  26 #define MAX30100_DRV_NAME       "max30100"
  27
  28 #define MAX30100_REG_INT_STATUS                 0x00
  29 #define MAX30100_REG_INT_STATUS_PWR_RDY         BIT(0)
  30 #define MAX30100_REG_INT_STATUS_SPO2_RDY        BIT(4)
  31 #define MAX30100_REG_INT_STATUS_HR_RDY          BIT(5)
  32 #define MAX30100_REG_INT_STATUS_FIFO_RDY        BIT(7)
  33
  34 #define MAX30100_REG_INT_ENABLE                 0x01
  35 #define MAX30100_REG_INT_ENABLE_SPO2_EN         BIT(0)
  36 #define MAX30100_REG_INT_ENABLE_HR_EN           BIT(1)
  37 #define MAX30100_REG_INT_ENABLE_FIFO_EN         BIT(3)
  38 #define MAX30100_REG_INT_ENABLE_MASK            0xf0
  39 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT      4
  40
  41 #define MAX30100_REG_FIFO_WR_PTR                0x02
  42 #define MAX30100_REG_FIFO_OVR_CTR               0x03
  43 #define MAX30100_REG_FIFO_RD_PTR                0x04
  44 #define MAX30100_REG_FIFO_DATA                  0x05
  45 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT      16
  46 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN        4
  47
  48 #define MAX30100_REG_MODE_CONFIG                0x06
  49 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN   BIT(0)
  50 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN     BIT(1)
  51 #define MAX30100_REG_MODE_CONFIG_MODE_MASK      0x03
  52 #define MAX30100_REG_MODE_CONFIG_TEMP_EN        BIT(3)
  53 #define MAX30100_REG_MODE_CONFIG_PWR            BIT(7)
  54
  55 #define MAX30100_REG_SPO2_CONFIG                0x07
  56 #define MAX30100_REG_SPO2_CONFIG_100HZ          BIT(2)
  57 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN      BIT(6)
  58 #define MAX30100_REG_SPO2_CONFIG_1600US         0x3
  59
  60 #define MAX30100_REG_LED_CONFIG                 0x09
  61 #define MAX30100_REG_LED_CONFIG_LED_MASK        0x0f
  62 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT   4
  63
  64 #define MAX30100_REG_LED_CONFIG_24MA            0x07
  65 #define MAX30100_REG_LED_CONFIG_50MA            0x0f
  66
  67 #define MAX30100_REG_TEMP_INTEGER               0x16
  68 #define MAX30100_REG_TEMP_FRACTION              0x17
  69
  70 struct max30100_data {
  71         struct i2c_client *client;
  72         struct iio_dev *indio_dev;
  73         struct mutex lock;
  74         struct regmap *regmap;
  75
  76         __be16 buffer[2]; /* 2 16-bit channels */
  77 };
  78
  79 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg)
  80 {
  81         switch (reg) {
  82         case MAX30100_REG_INT_STATUS:
  83         case MAX30100_REG_MODE_CONFIG:
  84         case MAX30100_REG_FIFO_WR_PTR:
  85         case MAX30100_REG_FIFO_OVR_CTR:
  86         case MAX30100_REG_FIFO_RD_PTR:
  87         case MAX30100_REG_FIFO_DATA:
  88         case MAX30100_REG_TEMP_INTEGER:
  89         case MAX30100_REG_TEMP_FRACTION:
  90                 return true;
  91         default:
  92                 return false;
  93         }
  94 }
  95
  96 static const struct regmap_config max30100_regmap_config = {
  97         .name = MAX30100_REGMAP_NAME,
  98
  99         .reg_bits = 8,
 100         .val_bits = 8,
 101
 102         .max_register = MAX30100_REG_TEMP_FRACTION,
 103         .cache_type = REGCACHE_FLAT,
 104
 105         .volatile_reg = max30100_is_volatile_reg,
 106 };
 107
 108 static const unsigned int max30100_led_current_mapping[] = {
 109         4400, 7600, 11000, 14200, 17400,
 110         20800, 24000, 27100, 30600, 33800,
 111         37000, 40200, 43600, 46800, 50000
 112 };
 113
 114 static const unsigned long max30100_scan_masks[] = {0x3, 0};
 115
 116 static const struct iio_chan_spec max30100_channels[] = {
 117         {
 118                 .type = IIO_INTENSITY,
 119                 .channel2 = IIO_MOD_LIGHT_IR,
 120                 .modified = 1,
 121
 122                 .scan_index = 0,
 123                 .scan_type = {
 124                         .sign = 'u',
 125                         .realbits = 16,
 126                         .storagebits = 16,
 127                         .endianness = IIO_BE,
 128                 },
 129         },
 130         {
 131                 .type = IIO_INTENSITY,
 132                 .channel2 = IIO_MOD_LIGHT_RED,
 133                 .modified = 1,
 134
 135                 .scan_index = 1,
 136                 .scan_type = {
 137                         .sign = 'u',
 138                         .realbits = 16,
 139                         .storagebits = 16,
 140                         .endianness = IIO_BE,
 141                 },
 142         },
 143         {
 144                 .type = IIO_TEMP,
 145                 .info_mask_separate =
 146                         BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
 147                 .scan_index = -1,
 148         },
 149 };
 150
 151 static int max30100_set_powermode(struct max30100_data *data, bool state)
 152 {
 153         return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 154                                   MAX30100_REG_MODE_CONFIG_PWR,
 155                                   state ? 0 : MAX30100_REG_MODE_CONFIG_PWR);
 156 }
 157
 158 static int max30100_clear_fifo(struct max30100_data *data)
 159 {
 160         int ret;
 161
 162         ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0);
 163         if (ret)
 164                 return ret;
 165
 166         ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0);
 167         if (ret)
 168                 return ret;
 169
 170         return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0);
 171 }
 172
 173 static int max30100_buffer_postenable(struct iio_dev *indio_dev)
 174 {
 175         struct max30100_data *data = iio_priv(indio_dev);
 176         int ret;
 177
 178         ret = max30100_set_powermode(data, true);
 179         if (ret)
 180                 return ret;
 181
 182         return max30100_clear_fifo(data);
 183 }
 184
 185 static int max30100_buffer_predisable(struct iio_dev *indio_dev)
 186 {
 187         struct max30100_data *data = iio_priv(indio_dev);
 188
 189         return max30100_set_powermode(data, false);
 190 }
 191
 192 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = {
 193         .postenable = max30100_buffer_postenable,
 194         .predisable = max30100_buffer_predisable,
 195 };
 196
 197 static inline int max30100_fifo_count(struct max30100_data *data)
 198 {
 199         unsigned int val;
 200         int ret;
 201
 202         ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val);
 203         if (ret)
 204                 return ret;
 205
 206         /* FIFO is almost full */
 207         if (val & MAX30100_REG_INT_STATUS_FIFO_RDY)
 208                 return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1;
 209
 210         return 0;
 211 }
 212
 213 static int max30100_read_measurement(struct max30100_data *data)
 214 {
 215         int ret;
 216
 217         ret = i2c_smbus_read_i2c_block_data(data->client,
 218                                             MAX30100_REG_FIFO_DATA,
 219                                             MAX30100_REG_FIFO_DATA_ENTRY_LEN,
 220                                             (u8 *) &data->buffer);
 221
 222         return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret;
 223 }
 224
 225 static irqreturn_t max30100_interrupt_handler(int irq, void *private)
 226 {
 227         struct iio_dev *indio_dev = private;
 228         struct max30100_data *data = iio_priv(indio_dev);
 229         int ret, cnt = 0;
 230
 231         mutex_lock(&data->lock);
 232
 233         while (cnt || (cnt = max30100_fifo_count(data)) > 0) {
 234                 ret = max30100_read_measurement(data);
 235                 if (ret)
 236                         break;
 237
 238                 iio_push_to_buffers(data->indio_dev, data->buffer);
 239                 cnt--;
 240         }
 241
 242         mutex_unlock(&data->lock);
 243
 244         return IRQ_HANDLED;
 245 }
 246
 247 static int max30100_get_current_idx(unsigned int val, int *reg)
 248 {
 249         int idx;
 250
 251         /* LED turned off */
 252         if (val == 0) {
 253                 *reg = 0;
 254                 return 0;
 255         }
 256
 257         for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) {
 258                 if (max30100_led_current_mapping[idx] == val) {
 259                         *reg = idx + 1;
 260                         return 0;
 261                 }
 262         }
 263
 264         return -EINVAL;
 265 }
 266
 267 static int max30100_led_init(struct max30100_data *data)
 268 {
 269         struct device *dev = &data->client->dev;
 270         unsigned int val[2];
 271         int reg, ret;
 272
 273         ret = device_property_read_u32_array(dev, "maxim,led-current-microamp",
 274                                         (unsigned int *) &val, 2);
 275         if (ret) {
 276                 /* Default to 24 mA RED LED, 50 mA IR LED */
 277                 reg = (MAX30100_REG_LED_CONFIG_24MA <<
 278                         MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) |
 279                         MAX30100_REG_LED_CONFIG_50MA;
 280                 dev_warn(dev, "no led-current-microamp set");
 281
 282                 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg);
 283         }
 284
 285         /* RED LED current */
 286         ret = max30100_get_current_idx(val[0], &reg);
 287         if (ret) {
 288                 dev_err(dev, "invalid RED current setting %d", val[0]);
 289                 return ret;
 290         }
 291
 292         ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
 293                 MAX30100_REG_LED_CONFIG_LED_MASK <<
 294                 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT,
 295                 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT);
 296         if (ret)
 297                 return ret;
 298
 299         /* IR LED current */
 300         ret = max30100_get_current_idx(val[1], &reg);
 301         if (ret) {
 302                 dev_err(dev, "invalid IR current setting %d", val[1]);
 303                 return ret;
 304         }
 305
 306         return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG,
 307                 MAX30100_REG_LED_CONFIG_LED_MASK, reg);
 308 }
 309
 310 static int max30100_chip_init(struct max30100_data *data)
 311 {
 312         int ret;
 313
 314         /* setup LED current settings */
 315         ret = max30100_led_init(data);
 316         if (ret)
 317                 return ret;
 318
 319         /* enable hi-res SPO2 readings at 100Hz */
 320         ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG,
 321                                  MAX30100_REG_SPO2_CONFIG_HI_RES_EN |
 322                                  MAX30100_REG_SPO2_CONFIG_100HZ);
 323         if (ret)
 324                 return ret;
 325
 326         /* enable SPO2 mode */
 327         ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 328                                  MAX30100_REG_MODE_CONFIG_MODE_MASK,
 329                                  MAX30100_REG_MODE_CONFIG_MODE_HR_EN |
 330                                  MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN);
 331         if (ret)
 332                 return ret;
 333
 334         /* enable FIFO interrupt */
 335         return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE,
 336                                  MAX30100_REG_INT_ENABLE_MASK,
 337                                  MAX30100_REG_INT_ENABLE_FIFO_EN
 338                                  << MAX30100_REG_INT_ENABLE_MASK_SHIFT);
 339 }
 340
 341 static int max30100_read_temp(struct max30100_data *data, int *val)
 342 {
 343         int ret;
 344         unsigned int reg;
 345
 346         ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, &reg);
 347         if (ret < 0)
 348                 return ret;
 349         *val = reg << 4;
 350
 351         ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, &reg);
 352         if (ret < 0)
 353                 return ret;
 354
 355         *val |= reg & 0xf;
 356         *val = sign_extend32(*val, 11);
 357
 358         return 0;
 359 }
 360
 361 static int max30100_get_temp(struct max30100_data *data, int *val)
 362 {
 363         int ret;
 364
 365         /* start acquisition */
 366         ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG,
 367                                  MAX30100_REG_MODE_CONFIG_TEMP_EN,
 368                                  MAX30100_REG_MODE_CONFIG_TEMP_EN);
 369         if (ret)
 370                 return ret;
 371
 372         msleep(35);
 373
 374         return max30100_read_temp(data, val);
 375 }
 376
 377 static int max30100_read_raw(struct iio_dev *indio_dev,
 378                              struct iio_chan_spec const *chan,
 379                              int *val, int *val2, long mask)
 380 {
 381         struct max30100_data *data = iio_priv(indio_dev);
 382         int ret = -EINVAL;
 383
 384         switch (mask) {
 385         case IIO_CHAN_INFO_RAW:
 386                 /*
 387                  * Temperature reading can only be acquired while engine
 388                  * is running
 389                  */
 390                 mutex_lock(&indio_dev->mlock);
 391
 392                 if (!iio_buffer_enabled(indio_dev))
 393                         ret = -EAGAIN;
 394                 else {
 395                         ret = max30100_get_temp(data, val);
 396                         if (!ret)
 397                                 ret = IIO_VAL_INT;
 398
 399                 }
 400
 401                 mutex_unlock(&indio_dev->mlock);
 402                 break;
 403         case IIO_CHAN_INFO_SCALE:
 404                 *val = 1;  /* 0.0625 */
 405                 *val2 = 16;
 406                 ret = IIO_VAL_FRACTIONAL;
 407                 break;
 408         }
 409
 410         return ret;
 411 }
 412
 413 static const struct iio_info max30100_info = {
 414         .read_raw = max30100_read_raw,
 415 };
 416
 417 static int max30100_probe(struct i2c_client *client,
 418                           const struct i2c_device_id *id)
 419 {
 420         struct max30100_data *data;
 421         struct iio_buffer *buffer;
 422         struct iio_dev *indio_dev;
 423         int ret;
 424
 425         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 426         if (!indio_dev)
 427                 return -ENOMEM;
 428
 429         buffer = devm_iio_kfifo_allocate(&client->dev);
 430         if (!buffer)
 431                 return -ENOMEM;
 432
 433         iio_device_attach_buffer(indio_dev, buffer);
 434
 435         indio_dev->name = MAX30100_DRV_NAME;
 436         indio_dev->channels = max30100_channels;
 437         indio_dev->info = &max30100_info;
 438         indio_dev->num_channels = ARRAY_SIZE(max30100_channels);
 439         indio_dev->available_scan_masks = max30100_scan_masks;
 440         indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE);
 441         indio_dev->setup_ops = &max30100_buffer_setup_ops;
 442
 443         data = iio_priv(indio_dev);
 444         data->indio_dev = indio_dev;
 445         data->client = client;
 446
 447         mutex_init(&data->lock);
 448         i2c_set_clientdata(client, indio_dev);
 449
 450         data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config);
 451         if (IS_ERR(data->regmap)) {
 452                 dev_err(&client->dev, "regmap initialization failed.\n");
 453                 return PTR_ERR(data->regmap);
 454         }
 455         max30100_set_powermode(data, false);
 456
 457         ret = max30100_chip_init(data);
 458         if (ret)
 459                 return ret;
 460
 461         if (client->irq <= 0) {
 462                 dev_err(&client->dev, "no valid irq defined\n");
 463                 return -EINVAL;
 464         }
 465         ret = devm_request_threaded_irq(&client->dev, client->irq,
 466                                         NULL, max30100_interrupt_handler,
 467                                         IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 468                                         "max30100_irq", indio_dev);
 469         if (ret) {
 470                 dev_err(&client->dev, "request irq (%d) failed\n", client->irq);
 471                 return ret;
 472         }
 473
 474         return iio_device_register(indio_dev);
 475 }
 476
 477 static int max30100_remove(struct i2c_client *client)
 478 {
 479         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 480         struct max30100_data *data = iio_priv(indio_dev);
 481
 482         iio_device_unregister(indio_dev);
 483         max30100_set_powermode(data, false);
 484
 485         return 0;
 486 }
 487
 488 static const struct i2c_device_id max30100_id[] = {
 489         { "max30100", 0 },
 490         {}
 491 };
 492 MODULE_DEVICE_TABLE(i2c, max30100_id);
 493
 494 static const struct of_device_id max30100_dt_ids[] = {
 495         { .compatible = "maxim,max30100" },
 496         { }
 497 };
 498 MODULE_DEVICE_TABLE(of, max30100_dt_ids);
 499
 500 static struct i2c_driver max30100_driver = {
 501         .driver = {
 502                 .name   = MAX30100_DRV_NAME,
 503                 .of_match_table = max30100_dt_ids,
 504         },
 505         .probe          = max30100_probe,
 506         .remove         = max30100_remove,
 507         .id_table       = max30100_id,
 508 };
 509 module_i2c_driver(max30100_driver);
 510
 511 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
 512 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor");
 513 MODULE_LICENSE("GPL");