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 cnt--; 248 } 249 250 mutex_unlock(&data->lock); 251 252 return IRQ_HANDLED; 253 } 254 255 static int max30100_get_current_idx(unsigned int val, int *reg) 256 { 257 int idx; 258 259 /* LED turned off */ 260 if (val == 0) { 261 *reg = 0; 262 return 0; 263 } 264 265 for (idx = 0; idx < ARRAY_SIZE(max30100_led_current_mapping); idx++) { 266 if (max30100_led_current_mapping[idx] == val) { 267 *reg = idx + 1; 268 return 0; 269 } 270 } 271 272 return -EINVAL; 273 } 274 275 static int max30100_led_init(struct max30100_data *data) 276 { 277 struct device *dev = &data->client->dev; 278 struct device_node *np = dev->of_node; 279 unsigned int val[2]; 280 int reg, ret; 281 282 ret = of_property_read_u32_array(np, "maxim,led-current-microamp", 283 (unsigned int *) &val, 2); 284 if (ret) { 285 /* Default to 24 mA RED LED, 50 mA IR LED */ 286 reg = (MAX30100_REG_LED_CONFIG_24MA << 287 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) | 288 MAX30100_REG_LED_CONFIG_50MA; 289 dev_warn(dev, "no led-current-microamp set"); 290 291 return regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, reg); 292 } 293 294 /* RED LED current */ 295 ret = max30100_get_current_idx(val[0], ®); 296 if (ret) { 297 dev_err(dev, "invalid RED current setting %d", val[0]); 298 return ret; 299 } 300 301 ret = regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, 302 MAX30100_REG_LED_CONFIG_LED_MASK << 303 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT, 304 reg << MAX30100_REG_LED_CONFIG_RED_LED_SHIFT); 305 if (ret) 306 return ret; 307 308 /* IR LED current */ 309 ret = max30100_get_current_idx(val[1], ®); 310 if (ret) { 311 dev_err(dev, "invalid IR current setting %d", val[1]); 312 return ret; 313 } 314 315 return regmap_update_bits(data->regmap, MAX30100_REG_LED_CONFIG, 316 MAX30100_REG_LED_CONFIG_LED_MASK, reg); 317 } 318 319 static int max30100_chip_init(struct max30100_data *data) 320 { 321 int ret; 322 323 /* setup LED current settings */ 324 ret = max30100_led_init(data); 325 if (ret) 326 return ret; 327 328 /* enable hi-res SPO2 readings at 100Hz */ 329 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG, 330 MAX30100_REG_SPO2_CONFIG_HI_RES_EN | 331 MAX30100_REG_SPO2_CONFIG_100HZ); 332 if (ret) 333 return ret; 334 335 /* enable SPO2 mode */ 336 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 337 MAX30100_REG_MODE_CONFIG_MODE_MASK, 338 MAX30100_REG_MODE_CONFIG_MODE_HR_EN | 339 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN); 340 if (ret) 341 return ret; 342 343 /* enable FIFO interrupt */ 344 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE, 345 MAX30100_REG_INT_ENABLE_MASK, 346 MAX30100_REG_INT_ENABLE_FIFO_EN 347 << MAX30100_REG_INT_ENABLE_MASK_SHIFT); 348 } 349 350 static int max30100_read_temp(struct max30100_data *data, int *val) 351 { 352 int ret; 353 unsigned int reg; 354 355 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®); 356 if (ret < 0) 357 return ret; 358 *val = reg << 4; 359 360 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); 361 if (ret < 0) 362 return ret; 363 364 *val |= reg & 0xf; 365 *val = sign_extend32(*val, 11); 366 367 return 0; 368 } 369 370 static int max30100_get_temp(struct max30100_data *data, int *val) 371 { 372 int ret; 373 374 /* start acquisition */ 375 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 376 MAX30100_REG_MODE_CONFIG_TEMP_EN, 377 MAX30100_REG_MODE_CONFIG_TEMP_EN); 378 if (ret) 379 return ret; 380 381 usleep_range(35000, 50000); 382 383 return max30100_read_temp(data, val); 384 } 385 386 static int max30100_read_raw(struct iio_dev *indio_dev, 387 struct iio_chan_spec const *chan, 388 int *val, int *val2, long mask) 389 { 390 struct max30100_data *data = iio_priv(indio_dev); 391 int ret = -EINVAL; 392 393 switch (mask) { 394 case IIO_CHAN_INFO_RAW: 395 /* 396 * Temperature reading can only be acquired while engine 397 * is running 398 */ 399 mutex_lock(&indio_dev->mlock); 400 401 if (!iio_buffer_enabled(indio_dev)) 402 ret = -EAGAIN; 403 else { 404 ret = max30100_get_temp(data, val); 405 if (!ret) 406 ret = IIO_VAL_INT; 407 408 } 409 410 mutex_unlock(&indio_dev->mlock); 411 break; 412 case IIO_CHAN_INFO_SCALE: 413 *val = 1; /* 0.0625 */ 414 *val2 = 16; 415 ret = IIO_VAL_FRACTIONAL; 416 break; 417 } 418 419 return ret; 420 } 421 422 static const struct iio_info max30100_info = { 423 .driver_module = THIS_MODULE, 424 .read_raw = max30100_read_raw, 425 }; 426 427 static int max30100_probe(struct i2c_client *client, 428 const struct i2c_device_id *id) 429 { 430 struct max30100_data *data; 431 struct iio_buffer *buffer; 432 struct iio_dev *indio_dev; 433 int ret; 434 435 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 436 if (!indio_dev) 437 return -ENOMEM; 438 439 buffer = devm_iio_kfifo_allocate(&client->dev); 440 if (!buffer) 441 return -ENOMEM; 442 443 iio_device_attach_buffer(indio_dev, buffer); 444 445 indio_dev->name = MAX30100_DRV_NAME; 446 indio_dev->channels = max30100_channels; 447 indio_dev->info = &max30100_info; 448 indio_dev->num_channels = ARRAY_SIZE(max30100_channels); 449 indio_dev->available_scan_masks = max30100_scan_masks; 450 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE); 451 indio_dev->setup_ops = &max30100_buffer_setup_ops; 452 453 data = iio_priv(indio_dev); 454 data->indio_dev = indio_dev; 455 data->client = client; 456 457 mutex_init(&data->lock); 458 i2c_set_clientdata(client, indio_dev); 459 460 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config); 461 if (IS_ERR(data->regmap)) { 462 dev_err(&client->dev, "regmap initialization failed.\n"); 463 return PTR_ERR(data->regmap); 464 } 465 max30100_set_powermode(data, false); 466 467 ret = max30100_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 ret = devm_request_threaded_irq(&client->dev, client->irq, 476 NULL, max30100_interrupt_handler, 477 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 478 "max30100_irq", indio_dev); 479 if (ret) { 480 dev_err(&client->dev, "request irq (%d) failed\n", client->irq); 481 return ret; 482 } 483 484 return iio_device_register(indio_dev); 485 } 486 487 static int max30100_remove(struct i2c_client *client) 488 { 489 struct iio_dev *indio_dev = i2c_get_clientdata(client); 490 struct max30100_data *data = iio_priv(indio_dev); 491 492 iio_device_unregister(indio_dev); 493 max30100_set_powermode(data, false); 494 495 return 0; 496 } 497 498 static const struct i2c_device_id max30100_id[] = { 499 { "max30100", 0 }, 500 {} 501 }; 502 MODULE_DEVICE_TABLE(i2c, max30100_id); 503 504 static const struct of_device_id max30100_dt_ids[] = { 505 { .compatible = "maxim,max30100" }, 506 { } 507 }; 508 MODULE_DEVICE_TABLE(of, max30100_dt_ids); 509 510 static struct i2c_driver max30100_driver = { 511 .driver = { 512 .name = MAX30100_DRV_NAME, 513 .of_match_table = of_match_ptr(max30100_dt_ids), 514 }, 515 .probe = max30100_probe, 516 .remove = max30100_remove, 517 .id_table = max30100_id, 518 }; 519 module_i2c_driver(max30100_driver); 520 521 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); 522 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); 523 MODULE_LICENSE("GPL"); 524