1 /* 2 * max30102.c - Support for MAX30102 heart rate and pulse oximeter sensor 3 * 4 * Copyright (C) 2017 Matt Ranostay <matt@ranostay.consulting> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 * 11 * This program is distributed in the hope that it will be useful, 12 * but WITHOUT ANY WARRANTY; without even the implied warranty of 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 * GNU General Public License for more details. 15 * 16 * TODO: proximity power saving feature 17 */ 18 19 #include <linux/module.h> 20 #include <linux/init.h> 21 #include <linux/interrupt.h> 22 #include <linux/delay.h> 23 #include <linux/err.h> 24 #include <linux/irq.h> 25 #include <linux/i2c.h> 26 #include <linux/mutex.h> 27 #include <linux/of.h> 28 #include <linux/regmap.h> 29 #include <linux/iio/iio.h> 30 #include <linux/iio/buffer.h> 31 #include <linux/iio/kfifo_buf.h> 32 33 #define MAX30102_REGMAP_NAME "max30102_regmap" 34 #define MAX30102_DRV_NAME "max30102" 35 #define MAX30102_PART_NUMBER 0x15 36 37 enum max3012_led_idx { 38 MAX30102_LED_RED, 39 MAX30102_LED_IR, 40 }; 41 42 #define MAX30102_REG_INT_STATUS 0x00 43 #define MAX30102_REG_INT_STATUS_PWR_RDY BIT(0) 44 #define MAX30102_REG_INT_STATUS_PROX_INT BIT(4) 45 #define MAX30102_REG_INT_STATUS_ALC_OVF BIT(5) 46 #define MAX30102_REG_INT_STATUS_PPG_RDY BIT(6) 47 #define MAX30102_REG_INT_STATUS_FIFO_RDY BIT(7) 48 49 #define MAX30102_REG_INT_ENABLE 0x02 50 #define MAX30102_REG_INT_ENABLE_PROX_INT_EN BIT(4) 51 #define MAX30102_REG_INT_ENABLE_ALC_OVF_EN BIT(5) 52 #define MAX30102_REG_INT_ENABLE_PPG_EN BIT(6) 53 #define MAX30102_REG_INT_ENABLE_FIFO_EN BIT(7) 54 #define MAX30102_REG_INT_ENABLE_MASK 0xf0 55 #define MAX30102_REG_INT_ENABLE_MASK_SHIFT 4 56 57 #define MAX30102_REG_FIFO_WR_PTR 0x04 58 #define MAX30102_REG_FIFO_OVR_CTR 0x05 59 #define MAX30102_REG_FIFO_RD_PTR 0x06 60 #define MAX30102_REG_FIFO_DATA 0x07 61 #define MAX30102_REG_FIFO_DATA_ENTRY_LEN 6 62 63 #define MAX30102_REG_FIFO_CONFIG 0x08 64 #define MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES BIT(1) 65 #define MAX30102_REG_FIFO_CONFIG_AVG_SHIFT 5 66 #define MAX30102_REG_FIFO_CONFIG_AFULL BIT(0) 67 68 #define MAX30102_REG_MODE_CONFIG 0x09 69 #define MAX30102_REG_MODE_CONFIG_MODE_NONE 0x00 70 #define MAX30102_REG_MODE_CONFIG_MODE_HR 0x02 /* red LED */ 71 #define MAX30102_REG_MODE_CONFIG_MODE_HR_SPO2 0x03 /* red + IR LED */ 72 #define MAX30102_REG_MODE_CONFIG_MODE_MULTI 0x07 /* multi-LED mode */ 73 #define MAX30102_REG_MODE_CONFIG_MODE_MASK GENMASK(2, 0) 74 #define MAX30102_REG_MODE_CONFIG_PWR BIT(7) 75 76 #define MAX30102_REG_SPO2_CONFIG 0x0a 77 #define MAX30102_REG_SPO2_CONFIG_PULSE_411_US 0x03 78 #define MAX30102_REG_SPO2_CONFIG_SR_400HZ 0x03 79 #define MAX30102_REG_SPO2_CONFIG_SR_MASK 0x07 80 #define MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT 2 81 #define MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS BIT(0) 82 #define MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT 5 83 84 #define MAX30102_REG_RED_LED_CONFIG 0x0c 85 #define MAX30102_REG_IR_LED_CONFIG 0x0d 86 87 #define MAX30102_REG_TEMP_CONFIG 0x21 88 #define MAX30102_REG_TEMP_CONFIG_TEMP_EN BIT(0) 89 90 #define MAX30102_REG_TEMP_INTEGER 0x1f 91 #define MAX30102_REG_TEMP_FRACTION 0x20 92 93 #define MAX30102_REG_REV_ID 0xfe 94 #define MAX30102_REG_PART_ID 0xff 95 96 struct max30102_data { 97 struct i2c_client *client; 98 struct iio_dev *indio_dev; 99 struct mutex lock; 100 struct regmap *regmap; 101 102 u8 buffer[8]; 103 __be32 processed_buffer[2]; /* 2 x 18-bit (padded to 32-bits) */ 104 }; 105 106 static const struct regmap_config max30102_regmap_config = { 107 .name = MAX30102_REGMAP_NAME, 108 109 .reg_bits = 8, 110 .val_bits = 8, 111 }; 112 113 static const unsigned long max30102_scan_masks[] = { 114 BIT(MAX30102_LED_RED) | BIT(MAX30102_LED_IR), 115 0 116 }; 117 118 #define MAX30102_INTENSITY_CHANNEL(_si, _mod) { \ 119 .type = IIO_INTENSITY, \ 120 .channel2 = _mod, \ 121 .modified = 1, \ 122 .scan_index = _si, \ 123 .scan_type = { \ 124 .sign = 'u', \ 125 .shift = 8, \ 126 .realbits = 18, \ 127 .storagebits = 32, \ 128 .endianness = IIO_BE, \ 129 }, \ 130 } 131 132 static const struct iio_chan_spec max30102_channels[] = { 133 MAX30102_INTENSITY_CHANNEL(MAX30102_LED_RED, IIO_MOD_LIGHT_RED), 134 MAX30102_INTENSITY_CHANNEL(MAX30102_LED_IR, IIO_MOD_LIGHT_IR), 135 { 136 .type = IIO_TEMP, 137 .info_mask_separate = 138 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), 139 .scan_index = -1, 140 }, 141 }; 142 143 static int max30102_set_power(struct max30102_data *data, bool en) 144 { 145 return regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG, 146 MAX30102_REG_MODE_CONFIG_PWR, 147 en ? 0 : MAX30102_REG_MODE_CONFIG_PWR); 148 } 149 150 static int max30102_set_powermode(struct max30102_data *data, u8 mode, bool en) 151 { 152 u8 reg = mode; 153 154 if (!en) 155 reg |= MAX30102_REG_MODE_CONFIG_PWR; 156 157 return regmap_update_bits(data->regmap, MAX30102_REG_MODE_CONFIG, 158 MAX30102_REG_MODE_CONFIG_PWR | 159 MAX30102_REG_MODE_CONFIG_MODE_MASK, reg); 160 } 161 162 static int max30102_buffer_postenable(struct iio_dev *indio_dev) 163 { 164 struct max30102_data *data = iio_priv(indio_dev); 165 u8 reg; 166 167 reg = MAX30102_REG_MODE_CONFIG_MODE_HR_SPO2; 168 169 return max30102_set_powermode(data, reg, true); 170 } 171 172 static int max30102_buffer_predisable(struct iio_dev *indio_dev) 173 { 174 struct max30102_data *data = iio_priv(indio_dev); 175 176 return max30102_set_powermode(data, MAX30102_REG_MODE_CONFIG_MODE_NONE, 177 false); 178 } 179 180 static const struct iio_buffer_setup_ops max30102_buffer_setup_ops = { 181 .postenable = max30102_buffer_postenable, 182 .predisable = max30102_buffer_predisable, 183 }; 184 185 static inline int max30102_fifo_count(struct max30102_data *data) 186 { 187 unsigned int val; 188 int ret; 189 190 ret = regmap_read(data->regmap, MAX30102_REG_INT_STATUS, &val); 191 if (ret) 192 return ret; 193 194 /* FIFO has one sample slot left */ 195 if (val & MAX30102_REG_INT_STATUS_FIFO_RDY) 196 return 1; 197 198 return 0; 199 } 200 201 static int max30102_read_measurement(struct max30102_data *data) 202 { 203 int ret; 204 u8 *buffer = (u8 *) &data->buffer; 205 206 ret = i2c_smbus_read_i2c_block_data(data->client, 207 MAX30102_REG_FIFO_DATA, 208 MAX30102_REG_FIFO_DATA_ENTRY_LEN, 209 buffer); 210 211 memcpy(&data->processed_buffer[0], &buffer[0], 3); 212 memcpy(&data->processed_buffer[1], &buffer[3], 3); 213 214 return (ret == MAX30102_REG_FIFO_DATA_ENTRY_LEN) ? 0 : -EINVAL; 215 } 216 217 static irqreturn_t max30102_interrupt_handler(int irq, void *private) 218 { 219 struct iio_dev *indio_dev = private; 220 struct max30102_data *data = iio_priv(indio_dev); 221 int ret, cnt = 0; 222 223 mutex_lock(&data->lock); 224 225 while (cnt || (cnt = max30102_fifo_count(data)) > 0) { 226 ret = max30102_read_measurement(data); 227 if (ret) 228 break; 229 230 iio_push_to_buffers(data->indio_dev, data->processed_buffer); 231 cnt--; 232 } 233 234 mutex_unlock(&data->lock); 235 236 return IRQ_HANDLED; 237 } 238 239 static int max30102_get_current_idx(unsigned int val, int *reg) 240 { 241 /* each step is 0.200 mA */ 242 *reg = val / 200; 243 244 return *reg > 0xff ? -EINVAL : 0; 245 } 246 247 static int max30102_led_init(struct max30102_data *data) 248 { 249 struct device *dev = &data->client->dev; 250 struct device_node *np = dev->of_node; 251 unsigned int val; 252 int reg, ret; 253 254 ret = of_property_read_u32(np, "maxim,red-led-current-microamp", &val); 255 if (ret) { 256 dev_info(dev, "no red-led-current-microamp set\n"); 257 258 /* Default to 7 mA RED LED */ 259 val = 7000; 260 } 261 262 ret = max30102_get_current_idx(val, ®); 263 if (ret) { 264 dev_err(dev, "invalid RED LED current setting %d\n", val); 265 return ret; 266 } 267 268 ret = regmap_write(data->regmap, MAX30102_REG_RED_LED_CONFIG, reg); 269 if (ret) 270 return ret; 271 272 ret = of_property_read_u32(np, "maxim,ir-led-current-microamp", &val); 273 if (ret) { 274 dev_info(dev, "no ir-led-current-microamp set\n"); 275 276 /* Default to 7 mA IR LED */ 277 val = 7000; 278 } 279 280 ret = max30102_get_current_idx(val, ®); 281 if (ret) { 282 dev_err(dev, "invalid IR LED current setting %d\n", val); 283 return ret; 284 } 285 286 return regmap_write(data->regmap, MAX30102_REG_IR_LED_CONFIG, reg); 287 } 288 289 static int max30102_chip_init(struct max30102_data *data) 290 { 291 int ret; 292 293 /* setup LED current settings */ 294 ret = max30102_led_init(data); 295 if (ret) 296 return ret; 297 298 /* configure 18-bit HR + SpO2 readings at 400Hz */ 299 ret = regmap_write(data->regmap, MAX30102_REG_SPO2_CONFIG, 300 (MAX30102_REG_SPO2_CONFIG_ADC_4096_STEPS 301 << MAX30102_REG_SPO2_CONFIG_ADC_MASK_SHIFT) | 302 (MAX30102_REG_SPO2_CONFIG_SR_400HZ 303 << MAX30102_REG_SPO2_CONFIG_SR_MASK_SHIFT) | 304 MAX30102_REG_SPO2_CONFIG_PULSE_411_US); 305 if (ret) 306 return ret; 307 308 /* average 4 samples + generate FIFO interrupt */ 309 ret = regmap_write(data->regmap, MAX30102_REG_FIFO_CONFIG, 310 (MAX30102_REG_FIFO_CONFIG_AVG_4SAMPLES 311 << MAX30102_REG_FIFO_CONFIG_AVG_SHIFT) | 312 MAX30102_REG_FIFO_CONFIG_AFULL); 313 if (ret) 314 return ret; 315 316 /* enable FIFO interrupt */ 317 return regmap_update_bits(data->regmap, MAX30102_REG_INT_ENABLE, 318 MAX30102_REG_INT_ENABLE_MASK, 319 MAX30102_REG_INT_ENABLE_FIFO_EN); 320 } 321 322 static int max30102_read_temp(struct max30102_data *data, int *val) 323 { 324 int ret; 325 unsigned int reg; 326 327 ret = regmap_read(data->regmap, MAX30102_REG_TEMP_INTEGER, ®); 328 if (ret < 0) 329 return ret; 330 *val = reg << 4; 331 332 ret = regmap_read(data->regmap, MAX30102_REG_TEMP_FRACTION, ®); 333 if (ret < 0) 334 return ret; 335 336 *val |= reg & 0xf; 337 *val = sign_extend32(*val, 11); 338 339 return 0; 340 } 341 342 static int max30102_get_temp(struct max30102_data *data, int *val, bool en) 343 { 344 int ret; 345 346 if (en) { 347 ret = max30102_set_power(data, true); 348 if (ret) 349 return ret; 350 } 351 352 /* start acquisition */ 353 ret = regmap_update_bits(data->regmap, MAX30102_REG_TEMP_CONFIG, 354 MAX30102_REG_TEMP_CONFIG_TEMP_EN, 355 MAX30102_REG_TEMP_CONFIG_TEMP_EN); 356 if (ret) 357 goto out; 358 359 msleep(35); 360 ret = max30102_read_temp(data, val); 361 362 out: 363 if (en) 364 max30102_set_power(data, false); 365 366 return ret; 367 } 368 369 static int max30102_read_raw(struct iio_dev *indio_dev, 370 struct iio_chan_spec const *chan, 371 int *val, int *val2, long mask) 372 { 373 struct max30102_data *data = iio_priv(indio_dev); 374 int ret = -EINVAL; 375 376 switch (mask) { 377 case IIO_CHAN_INFO_RAW: 378 /* 379 * Temperature reading can only be acquired when not in 380 * shutdown; leave shutdown briefly when buffer not running 381 */ 382 mutex_lock(&indio_dev->mlock); 383 if (!iio_buffer_enabled(indio_dev)) 384 ret = max30102_get_temp(data, val, true); 385 else 386 ret = max30102_get_temp(data, val, false); 387 mutex_unlock(&indio_dev->mlock); 388 if (ret) 389 return ret; 390 391 ret = IIO_VAL_INT; 392 break; 393 case IIO_CHAN_INFO_SCALE: 394 *val = 1; /* 0.0625 */ 395 *val2 = 16; 396 ret = IIO_VAL_FRACTIONAL; 397 break; 398 } 399 400 return ret; 401 } 402 403 static const struct iio_info max30102_info = { 404 .read_raw = max30102_read_raw, 405 }; 406 407 static int max30102_probe(struct i2c_client *client, 408 const struct i2c_device_id *id) 409 { 410 struct max30102_data *data; 411 struct iio_buffer *buffer; 412 struct iio_dev *indio_dev; 413 int ret; 414 unsigned int reg; 415 416 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 417 if (!indio_dev) 418 return -ENOMEM; 419 420 buffer = devm_iio_kfifo_allocate(&client->dev); 421 if (!buffer) 422 return -ENOMEM; 423 424 iio_device_attach_buffer(indio_dev, buffer); 425 426 indio_dev->name = MAX30102_DRV_NAME; 427 indio_dev->channels = max30102_channels; 428 indio_dev->info = &max30102_info; 429 indio_dev->num_channels = ARRAY_SIZE(max30102_channels); 430 indio_dev->available_scan_masks = max30102_scan_masks; 431 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE); 432 indio_dev->setup_ops = &max30102_buffer_setup_ops; 433 indio_dev->dev.parent = &client->dev; 434 435 data = iio_priv(indio_dev); 436 data->indio_dev = indio_dev; 437 data->client = client; 438 439 mutex_init(&data->lock); 440 i2c_set_clientdata(client, indio_dev); 441 442 data->regmap = devm_regmap_init_i2c(client, &max30102_regmap_config); 443 if (IS_ERR(data->regmap)) { 444 dev_err(&client->dev, "regmap initialization failed\n"); 445 return PTR_ERR(data->regmap); 446 } 447 448 /* check part ID */ 449 ret = regmap_read(data->regmap, MAX30102_REG_PART_ID, ®); 450 if (ret) 451 return ret; 452 if (reg != MAX30102_PART_NUMBER) 453 return -ENODEV; 454 455 /* show revision ID */ 456 ret = regmap_read(data->regmap, MAX30102_REG_REV_ID, ®); 457 if (ret) 458 return ret; 459 dev_dbg(&client->dev, "max3010x revision %02x\n", reg); 460 461 /* clear mode setting, chip shutdown */ 462 ret = max30102_set_powermode(data, MAX30102_REG_MODE_CONFIG_MODE_NONE, 463 false); 464 if (ret) 465 return ret; 466 467 ret = max30102_chip_init(data); 468 if (ret) 469 return ret; 470 471 if (client->irq <= 0) { 472 dev_err(&client->dev, "no valid irq defined\n"); 473 return -EINVAL; 474 } 475 476 ret = devm_request_threaded_irq(&client->dev, client->irq, 477 NULL, max30102_interrupt_handler, 478 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 479 "max30102_irq", indio_dev); 480 if (ret) { 481 dev_err(&client->dev, "request irq (%d) failed\n", client->irq); 482 return ret; 483 } 484 485 return iio_device_register(indio_dev); 486 } 487 488 static int max30102_remove(struct i2c_client *client) 489 { 490 struct iio_dev *indio_dev = i2c_get_clientdata(client); 491 struct max30102_data *data = iio_priv(indio_dev); 492 493 iio_device_unregister(indio_dev); 494 max30102_set_power(data, false); 495 496 return 0; 497 } 498 499 static const struct i2c_device_id max30102_id[] = { 500 { "max30102", 0 }, 501 {} 502 }; 503 MODULE_DEVICE_TABLE(i2c, max30102_id); 504 505 static const struct of_device_id max30102_dt_ids[] = { 506 { .compatible = "maxim,max30102" }, 507 { } 508 }; 509 MODULE_DEVICE_TABLE(of, max30102_dt_ids); 510 511 static struct i2c_driver max30102_driver = { 512 .driver = { 513 .name = MAX30102_DRV_NAME, 514 .of_match_table = of_match_ptr(max30102_dt_ids), 515 }, 516 .probe = max30102_probe, 517 .remove = max30102_remove, 518 .id_table = max30102_id, 519 }; 520 module_i2c_driver(max30102_driver); 521 522 MODULE_AUTHOR("Matt Ranostay <matt@ranostay.consulting>"); 523 MODULE_DESCRIPTION("MAX30102 heart rate and pulse oximeter sensor"); 524 MODULE_LICENSE("GPL"); 525