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], ®); 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], ®); 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, ®); 347 if (ret < 0) 348 return ret; 349 *val = reg << 4; 350 351 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); 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 if (iio_device_claim_buffer_mode(indio_dev)) { 391 /* 392 * Replacing -EBUSY or other error code 393 * returned by iio_device_claim_buffer_mode() 394 * because user space may rely on the current 395 * one. 396 */ 397 ret = -EAGAIN; 398 } else { 399 ret = max30100_get_temp(data, val); 400 if (!ret) 401 ret = IIO_VAL_INT; 402 403 iio_device_release_buffer_mode(indio_dev); 404 } 405 break; 406 case IIO_CHAN_INFO_SCALE: 407 *val = 1; /* 0.0625 */ 408 *val2 = 16; 409 ret = IIO_VAL_FRACTIONAL; 410 break; 411 } 412 413 return ret; 414 } 415 416 static const struct iio_info max30100_info = { 417 .read_raw = max30100_read_raw, 418 }; 419 420 static int max30100_probe(struct i2c_client *client) 421 { 422 struct max30100_data *data; 423 struct iio_dev *indio_dev; 424 int ret; 425 426 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 427 if (!indio_dev) 428 return -ENOMEM; 429 430 indio_dev->name = MAX30100_DRV_NAME; 431 indio_dev->channels = max30100_channels; 432 indio_dev->info = &max30100_info; 433 indio_dev->num_channels = ARRAY_SIZE(max30100_channels); 434 indio_dev->available_scan_masks = max30100_scan_masks; 435 indio_dev->modes = INDIO_DIRECT_MODE; 436 437 ret = devm_iio_kfifo_buffer_setup(&client->dev, indio_dev, 438 &max30100_buffer_setup_ops); 439 if (ret) 440 return ret; 441 442 data = iio_priv(indio_dev); 443 data->indio_dev = indio_dev; 444 data->client = client; 445 446 mutex_init(&data->lock); 447 i2c_set_clientdata(client, indio_dev); 448 449 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config); 450 if (IS_ERR(data->regmap)) { 451 dev_err(&client->dev, "regmap initialization failed.\n"); 452 return PTR_ERR(data->regmap); 453 } 454 max30100_set_powermode(data, false); 455 456 ret = max30100_chip_init(data); 457 if (ret) 458 return ret; 459 460 if (client->irq <= 0) { 461 dev_err(&client->dev, "no valid irq defined\n"); 462 return -EINVAL; 463 } 464 ret = devm_request_threaded_irq(&client->dev, client->irq, 465 NULL, max30100_interrupt_handler, 466 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 467 "max30100_irq", indio_dev); 468 if (ret) { 469 dev_err(&client->dev, "request irq (%d) failed\n", client->irq); 470 return ret; 471 } 472 473 return iio_device_register(indio_dev); 474 } 475 476 static void max30100_remove(struct i2c_client *client) 477 { 478 struct iio_dev *indio_dev = i2c_get_clientdata(client); 479 struct max30100_data *data = iio_priv(indio_dev); 480 481 iio_device_unregister(indio_dev); 482 max30100_set_powermode(data, false); 483 } 484 485 static const struct i2c_device_id max30100_id[] = { 486 { "max30100", 0 }, 487 {} 488 }; 489 MODULE_DEVICE_TABLE(i2c, max30100_id); 490 491 static const struct of_device_id max30100_dt_ids[] = { 492 { .compatible = "maxim,max30100" }, 493 { } 494 }; 495 MODULE_DEVICE_TABLE(of, max30100_dt_ids); 496 497 static struct i2c_driver max30100_driver = { 498 .driver = { 499 .name = MAX30100_DRV_NAME, 500 .of_match_table = max30100_dt_ids, 501 }, 502 .probe = max30100_probe, 503 .remove = max30100_remove, 504 .id_table = max30100_id, 505 }; 506 module_i2c_driver(max30100_driver); 507 508 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>"); 509 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); 510 MODULE_LICENSE("GPL"); 511