1 /* 2 * max30100.c - Support for MAX30100 heart rate and pulse oximeter sensor 3 * 4 * Copyright (C) 2015 Matt Ranostay <mranostay@gmail.com> 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: enable pulse length controls via device tree properties 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 MAX30100_REGMAP_NAME "max30100_regmap" 34 #define MAX30100_DRV_NAME "max30100" 35 36 #define MAX30100_REG_INT_STATUS 0x00 37 #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0) 38 #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4) 39 #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5) 40 #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7) 41 42 #define MAX30100_REG_INT_ENABLE 0x01 43 #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0) 44 #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1) 45 #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3) 46 #define MAX30100_REG_INT_ENABLE_MASK 0xf0 47 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4 48 49 #define MAX30100_REG_FIFO_WR_PTR 0x02 50 #define MAX30100_REG_FIFO_OVR_CTR 0x03 51 #define MAX30100_REG_FIFO_RD_PTR 0x04 52 #define MAX30100_REG_FIFO_DATA 0x05 53 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16 54 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4 55 56 #define MAX30100_REG_MODE_CONFIG 0x06 57 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0) 58 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1) 59 #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03 60 #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3) 61 #define MAX30100_REG_MODE_CONFIG_PWR BIT(7) 62 63 #define MAX30100_REG_SPO2_CONFIG 0x07 64 #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2) 65 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6) 66 #define MAX30100_REG_SPO2_CONFIG_1600US 0x3 67 68 #define MAX30100_REG_LED_CONFIG 0x09 69 #define MAX30100_REG_LED_CONFIG_LED_MASK 0x0f 70 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4 71 72 #define MAX30100_REG_LED_CONFIG_24MA 0x07 73 #define MAX30100_REG_LED_CONFIG_50MA 0x0f 74 75 #define MAX30100_REG_TEMP_INTEGER 0x16 76 #define MAX30100_REG_TEMP_FRACTION 0x17 77 78 struct max30100_data { 79 struct i2c_client *client; 80 struct iio_dev *indio_dev; 81 struct mutex lock; 82 struct regmap *regmap; 83 84 __be16 buffer[2]; /* 2 16-bit channels */ 85 }; 86 87 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg) 88 { 89 switch (reg) { 90 case MAX30100_REG_INT_STATUS: 91 case MAX30100_REG_MODE_CONFIG: 92 case MAX30100_REG_FIFO_WR_PTR: 93 case MAX30100_REG_FIFO_OVR_CTR: 94 case MAX30100_REG_FIFO_RD_PTR: 95 case MAX30100_REG_FIFO_DATA: 96 case MAX30100_REG_TEMP_INTEGER: 97 case MAX30100_REG_TEMP_FRACTION: 98 return true; 99 default: 100 return false; 101 } 102 } 103 104 static const struct regmap_config max30100_regmap_config = { 105 .name = MAX30100_REGMAP_NAME, 106 107 .reg_bits = 8, 108 .val_bits = 8, 109 110 .max_register = MAX30100_REG_TEMP_FRACTION, 111 .cache_type = REGCACHE_FLAT, 112 113 .volatile_reg = max30100_is_volatile_reg, 114 }; 115 116 static const unsigned int max30100_led_current_mapping[] = { 117 4400, 7600, 11000, 14200, 17400, 118 20800, 24000, 27100, 30600, 33800, 119 37000, 40200, 43600, 46800, 50000 120 }; 121 122 static const unsigned long max30100_scan_masks[] = {0x3, 0}; 123 124 static const struct iio_chan_spec max30100_channels[] = { 125 { 126 .type = IIO_INTENSITY, 127 .channel2 = IIO_MOD_LIGHT_IR, 128 .modified = 1, 129 130 .scan_index = 0, 131 .scan_type = { 132 .sign = 'u', 133 .realbits = 16, 134 .storagebits = 16, 135 .endianness = IIO_BE, 136 }, 137 }, 138 { 139 .type = IIO_INTENSITY, 140 .channel2 = IIO_MOD_LIGHT_RED, 141 .modified = 1, 142 143 .scan_index = 1, 144 .scan_type = { 145 .sign = 'u', 146 .realbits = 16, 147 .storagebits = 16, 148 .endianness = IIO_BE, 149 }, 150 }, 151 { 152 .type = IIO_TEMP, 153 .info_mask_separate = 154 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), 155 .scan_index = -1, 156 }, 157 }; 158 159 static int max30100_set_powermode(struct max30100_data *data, bool state) 160 { 161 return regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 162 MAX30100_REG_MODE_CONFIG_PWR, 163 state ? 0 : MAX30100_REG_MODE_CONFIG_PWR); 164 } 165 166 static int max30100_clear_fifo(struct max30100_data *data) 167 { 168 int ret; 169 170 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_WR_PTR, 0); 171 if (ret) 172 return ret; 173 174 ret = regmap_write(data->regmap, MAX30100_REG_FIFO_OVR_CTR, 0); 175 if (ret) 176 return ret; 177 178 return regmap_write(data->regmap, MAX30100_REG_FIFO_RD_PTR, 0); 179 } 180 181 static int max30100_buffer_postenable(struct iio_dev *indio_dev) 182 { 183 struct max30100_data *data = iio_priv(indio_dev); 184 int ret; 185 186 ret = max30100_set_powermode(data, true); 187 if (ret) 188 return ret; 189 190 return max30100_clear_fifo(data); 191 } 192 193 static int max30100_buffer_predisable(struct iio_dev *indio_dev) 194 { 195 struct max30100_data *data = iio_priv(indio_dev); 196 197 return max30100_set_powermode(data, false); 198 } 199 200 static const struct iio_buffer_setup_ops max30100_buffer_setup_ops = { 201 .postenable = max30100_buffer_postenable, 202 .predisable = max30100_buffer_predisable, 203 }; 204 205 static inline int max30100_fifo_count(struct max30100_data *data) 206 { 207 unsigned int val; 208 int ret; 209 210 ret = regmap_read(data->regmap, MAX30100_REG_INT_STATUS, &val); 211 if (ret) 212 return ret; 213 214 /* FIFO is almost full */ 215 if (val & MAX30100_REG_INT_STATUS_FIFO_RDY) 216 return MAX30100_REG_FIFO_DATA_ENTRY_COUNT - 1; 217 218 return 0; 219 } 220 221 static int max30100_read_measurement(struct max30100_data *data) 222 { 223 int ret; 224 225 ret = i2c_smbus_read_i2c_block_data(data->client, 226 MAX30100_REG_FIFO_DATA, 227 MAX30100_REG_FIFO_DATA_ENTRY_LEN, 228 (u8 *) &data->buffer); 229 230 return (ret == MAX30100_REG_FIFO_DATA_ENTRY_LEN) ? 0 : ret; 231 } 232 233 static irqreturn_t max30100_interrupt_handler(int irq, void *private) 234 { 235 struct iio_dev *indio_dev = private; 236 struct max30100_data *data = iio_priv(indio_dev); 237 int ret, cnt = 0; 238 239 mutex_lock(&data->lock); 240 241 while (cnt-- || (cnt = max30100_fifo_count(data) > 0)) { 242 ret = max30100_read_measurement(data); 243 if (ret) 244 break; 245 246 iio_push_to_buffers(data->indio_dev, data->buffer); 247 } 248 249 mutex_unlock(&data->lock); 250 251 return IRQ_HANDLED; 252 } 253 254 static int max30100_get_current_idx(unsigned int val, int *reg) 255 { 256 int idx; 257 258 /* LED turned off */ 259 if (val == 0) { 260 *reg = 0; 261 return 0; 262 } 263 264 for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) { 265 if (max30100_led_current_mapping[idx] == val) { 266 *reg = idx + 1; 267 return 0; 268 } 269 } 270 271 return -EINVAL; 272 } 273 274 static int max30100_led_init(struct max30100_data *data) 275 { 276 struct device *dev = &data->client->dev; 277 struct device_node *np = dev->of_node; 278 unsigned int val[2]; 279 int reg, ret; 280 281 ret = of_property_read_u32_array(np, "maxim,led-current-microamp", 282 (unsigned int *) &val, 2); 283 if (ret) { 284 /* Default to 24 mA RED LED, 50 mA IR LED */ 285 reg = (MAX30100_REG_LED_CONFIG_24MA << 286 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) | 287 MAX30100_REG_LED_CONFIG_50MA; 288 dev_warn(dev, "no led-current-microamp set"); 289 290 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg); 291 } 292 293 /* RED LED current */ 294 ret = max30100_get_current_idx(val[0], ®); 295 if (ret) { 296 dev_err(dev, "invalid RED current setting %d", val[0]); 297 return ret; 298 } 299 300 ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, 301 MAX30100_REG_LED_CONFIG_LED_MASK << 302 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT, 303 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT); 304 if (ret) 305 return ret; 306 307 /* IR LED current */ 308 ret = max30100_get_current_idx(val[1], ®); 309 if (ret) { 310 dev_err(dev, "invalid IR current setting %d", val[1]); 311 return ret; 312 } 313 314 return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, 315 MAX30100_REG_LED_CONFIG_LED_MASK, reg); 316 } 317 318 static int max30100_chip_init(struct max30100_data *data) 319 { 320 int ret; 321 322 /* setup LED current settings */ 323 ret = max30100_led_init(data); 324 if (ret) 325 return ret; 326 327 /* enable hi-res SPO2 readings at 100Hz */ 328 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG, 329 MAX30100_REG_SPO2_CONFIG_HI_RES_EN | 330 MAX30100_REG_SPO2_CONFIG_100HZ); 331 if (ret) 332 return ret; 333 334 /* enable SPO2 mode */ 335 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 336 MAX30100_REG_MODE_CONFIG_MODE_MASK, 337 MAX30100_REG_MODE_CONFIG_MODE_HR_EN | 338 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN); 339 if (ret) 340 return ret; 341 342 /* enable FIFO interrupt */ 343 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE, 344 MAX30100_REG_INT_ENABLE_MASK, 345 MAX30100_REG_INT_ENABLE_FIFO_EN 346 << MAX30100_REG_INT_ENABLE_MASK_SHIFT); 347 } 348 349 static int max30100_read_temp(struct max30100_data *data, int *val) 350 { 351 int ret; 352 unsigned int reg; 353 354 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®); 355 if (ret < 0) 356 return ret; 357 *val = reg << 4; 358 359 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); 360 if (ret < 0) 361 return ret; 362 363 *val |= reg & 0xf; 364 *val = sign_extend32(*val, 11); 365 366 return 0; 367 } 368 369 static int max30100_get_temp(struct max30100_data *data, int *val) 370 { 371 int ret; 372 373 /* start acquisition */ 374 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 375 MAX30100_REG_MODE_CONFIG_TEMP_EN, 376 MAX30100_REG_MODE_CONFIG_TEMP_EN); 377 if (ret) 378 return ret; 379 380 usleep_range(35000, 50000); 381 382 return max30100_read_temp(data, val); 383 } 384 385 static int max30100_read_raw(struct iio_dev *indio_dev, 386 struct iio_chan_spec const *chan, 387 int *val, int *val2, long mask) 388 { 389 struct max30100_data *data = iio_priv(indio_dev); 390 int ret = -EINVAL; 391 392 switch (mask) { 393 case IIO_CHAN_INFO_RAW: 394 /* 395 * Temperature reading can only be acquired while engine 396 * is running 397 */ 398 mutex_lock(&indio_dev->mlock); 399 400 if (!iio_buffer_enabled(indio_dev)) 401 ret = -EAGAIN; 402 else { 403 ret = max30100_get_temp(data, val); 404 if (!ret) 405 ret = IIO_VAL_INT; 406 407 } 408 409 mutex_unlock(&indio_dev->mlock); 410 break; 411 case IIO_CHAN_INFO_SCALE: 412 *val = 1; /* 0.0625 */ 413 *val2 = 16; 414 ret = IIO_VAL_FRACTIONAL; 415 break; 416 } 417 418 return ret; 419 } 420 421 static const struct iio_info max30100_info = { 422 .driver_module = THIS_MODULE, 423 .read_raw = max30100_read_raw, 424 }; 425 426 static int max30100_probe(struct i2c_client *client, 427 const struct i2c_device_id *id) 428 { 429 struct max30100_data *data; 430 struct iio_buffer *buffer; 431 struct iio_dev *indio_dev; 432 int ret; 433 434 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 435 if (!indio_dev) 436 return -ENOMEM; 437 438 buffer = devm_iio_kfifo_allocate(&client->dev); 439 if (!buffer) 440 return -ENOMEM; 441 442 iio_device_attach_buffer(indio_dev, buffer); 443 444 indio_dev->name = MAX30100_DRV_NAME; 445 indio_dev->channels = max30100_channels; 446 indio_dev->info = &max30100_info; 447 indio_dev->num_channels = ARRAY_SIZE(max30100_channels); 448 indio_dev->available_scan_masks = max30100_scan_masks; 449 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE); 450 indio_dev->setup_ops = &max30100_buffer_setup_ops; 451 452 data = iio_priv(indio_dev); 453 data->indio_dev = indio_dev; 454 data->client = client; 455 456 mutex_init(&data->lock); 457 i2c_set_clientdata(client, indio_dev); 458 459 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config); 460 if (IS_ERR(data->regmap)) { 461 dev_err(&client->dev, "regmap initialization failed.\n"); 462 return PTR_ERR(data->regmap); 463 } 464 max30100_set_powermode(data, false); 465 466 ret = max30100_chip_init(data); 467 if (ret) 468 return ret; 469 470 if (client->irq <= 0) { 471 dev_err(&client->dev, "no valid irq defined\n"); 472 return -EINVAL; 473 } 474 ret = devm_request_threaded_irq(&client->dev, client->irq, 475 NULL, max30100_interrupt_handler, 476 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 477 "max30100_irq", indio_dev); 478 if (ret) { 479 dev_err(&client->dev, "request irq (%d) failed\n", client->irq); 480 return ret; 481 } 482 483 return iio_device_register(indio_dev); 484 } 485 486 static int max30100_remove(struct i2c_client *client) 487 { 488 struct iio_dev *indio_dev = i2c_get_clientdata(client); 489 struct max30100_data *data = iio_priv(indio_dev); 490 491 iio_device_unregister(indio_dev); 492 max30100_set_powermode(data, false); 493 494 return 0; 495 } 496 497 static const struct i2c_device_id max30100_id[] = { 498 { "max30100", 0 }, 499 {} 500 }; 501 MODULE_DEVICE_TABLE(i2c, max30100_id); 502 503 static const struct of_device_id max30100_dt_ids[] = { 504 { .compatible = "maxim,max30100" }, 505 { } 506 }; 507 MODULE_DEVICE_TABLE(of, max30100_dt_ids); 508 509 static struct i2c_driver max30100_driver = { 510 .driver = { 511 .name = MAX30100_DRV_NAME, 512 .of_match_table = of_match_ptr(max30100_dt_ids), 513 }, 514 .probe = max30100_probe, 515 .remove = max30100_remove, 516 .id_table = max30100_id, 517 }; 518 module_i2c_driver(max30100_driver); 519 520 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); 521 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); 522 MODULE_LICENSE("GPL"); 523