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: allow LED current and 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/regmap.h> 28 #include <linux/iio/iio.h> 29 #include <linux/iio/buffer.h> 30 #include <linux/iio/kfifo_buf.h> 31 32 #define MAX30100_REGMAP_NAME "max30100_regmap" 33 #define MAX30100_DRV_NAME "max30100" 34 35 #define MAX30100_REG_INT_STATUS 0x00 36 #define MAX30100_REG_INT_STATUS_PWR_RDY BIT(0) 37 #define MAX30100_REG_INT_STATUS_SPO2_RDY BIT(4) 38 #define MAX30100_REG_INT_STATUS_HR_RDY BIT(5) 39 #define MAX30100_REG_INT_STATUS_FIFO_RDY BIT(7) 40 41 #define MAX30100_REG_INT_ENABLE 0x01 42 #define MAX30100_REG_INT_ENABLE_SPO2_EN BIT(0) 43 #define MAX30100_REG_INT_ENABLE_HR_EN BIT(1) 44 #define MAX30100_REG_INT_ENABLE_FIFO_EN BIT(3) 45 #define MAX30100_REG_INT_ENABLE_MASK 0xf0 46 #define MAX30100_REG_INT_ENABLE_MASK_SHIFT 4 47 48 #define MAX30100_REG_FIFO_WR_PTR 0x02 49 #define MAX30100_REG_FIFO_OVR_CTR 0x03 50 #define MAX30100_REG_FIFO_RD_PTR 0x04 51 #define MAX30100_REG_FIFO_DATA 0x05 52 #define MAX30100_REG_FIFO_DATA_ENTRY_COUNT 16 53 #define MAX30100_REG_FIFO_DATA_ENTRY_LEN 4 54 55 #define MAX30100_REG_MODE_CONFIG 0x06 56 #define MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN BIT(0) 57 #define MAX30100_REG_MODE_CONFIG_MODE_HR_EN BIT(1) 58 #define MAX30100_REG_MODE_CONFIG_MODE_MASK 0x03 59 #define MAX30100_REG_MODE_CONFIG_TEMP_EN BIT(3) 60 #define MAX30100_REG_MODE_CONFIG_PWR BIT(7) 61 62 #define MAX30100_REG_SPO2_CONFIG 0x07 63 #define MAX30100_REG_SPO2_CONFIG_100HZ BIT(2) 64 #define MAX30100_REG_SPO2_CONFIG_HI_RES_EN BIT(6) 65 #define MAX30100_REG_SPO2_CONFIG_1600US 0x3 66 67 #define MAX30100_REG_LED_CONFIG 0x09 68 #define MAX30100_REG_LED_CONFIG_RED_LED_SHIFT 4 69 70 #define MAX30100_REG_LED_CONFIG_24MA 0x07 71 #define MAX30100_REG_LED_CONFIG_50MA 0x0f 72 73 #define MAX30100_REG_TEMP_INTEGER 0x16 74 #define MAX30100_REG_TEMP_FRACTION 0x17 75 76 struct max30100_data { 77 struct i2c_client *client; 78 struct iio_dev *indio_dev; 79 struct mutex lock; 80 struct regmap *regmap; 81 82 __be16 buffer[2]; /* 2 16-bit channels */ 83 }; 84 85 static bool max30100_is_volatile_reg(struct device *dev, unsigned int reg) 86 { 87 switch (reg) { 88 case MAX30100_REG_INT_STATUS: 89 case MAX30100_REG_MODE_CONFIG: 90 case MAX30100_REG_FIFO_WR_PTR: 91 case MAX30100_REG_FIFO_OVR_CTR: 92 case MAX30100_REG_FIFO_RD_PTR: 93 case MAX30100_REG_FIFO_DATA: 94 case MAX30100_REG_TEMP_INTEGER: 95 case MAX30100_REG_TEMP_FRACTION: 96 return true; 97 default: 98 return false; 99 } 100 } 101 102 static const struct regmap_config max30100_regmap_config = { 103 .name = MAX30100_REGMAP_NAME, 104 105 .reg_bits = 8, 106 .val_bits = 8, 107 108 .max_register = MAX30100_REG_TEMP_FRACTION, 109 .cache_type = REGCACHE_FLAT, 110 111 .volatile_reg = max30100_is_volatile_reg, 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 } 240 241 mutex_unlock(&data->lock); 242 243 return IRQ_HANDLED; 244 } 245 246 static int max30100_chip_init(struct max30100_data *data) 247 { 248 int ret; 249 250 /* RED IR LED = 24mA, IR LED = 50mA */ 251 ret = regmap_write(data->regmap, MAX30100_REG_LED_CONFIG, 252 (MAX30100_REG_LED_CONFIG_24MA << 253 MAX30100_REG_LED_CONFIG_RED_LED_SHIFT) | 254 MAX30100_REG_LED_CONFIG_50MA); 255 if (ret) 256 return ret; 257 258 /* enable hi-res SPO2 readings at 100Hz */ 259 ret = regmap_write(data->regmap, MAX30100_REG_SPO2_CONFIG, 260 MAX30100_REG_SPO2_CONFIG_HI_RES_EN | 261 MAX30100_REG_SPO2_CONFIG_100HZ); 262 if (ret) 263 return ret; 264 265 /* enable SPO2 mode */ 266 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 267 MAX30100_REG_MODE_CONFIG_MODE_MASK, 268 MAX30100_REG_MODE_CONFIG_MODE_HR_EN | 269 MAX30100_REG_MODE_CONFIG_MODE_SPO2_EN); 270 if (ret) 271 return ret; 272 273 /* enable FIFO interrupt */ 274 return regmap_update_bits(data->regmap, MAX30100_REG_INT_ENABLE, 275 MAX30100_REG_INT_ENABLE_MASK, 276 MAX30100_REG_INT_ENABLE_FIFO_EN 277 << MAX30100_REG_INT_ENABLE_MASK_SHIFT); 278 } 279 280 static int max30100_read_temp(struct max30100_data *data, int *val) 281 { 282 int ret; 283 unsigned int reg; 284 285 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_INTEGER, ®); 286 if (ret < 0) 287 return ret; 288 *val = reg << 4; 289 290 ret = regmap_read(data->regmap, MAX30100_REG_TEMP_FRACTION, ®); 291 if (ret < 0) 292 return ret; 293 294 *val |= reg & 0xf; 295 *val = sign_extend32(*val, 11); 296 297 return 0; 298 } 299 300 static int max30100_get_temp(struct max30100_data *data, int *val) 301 { 302 int ret; 303 304 /* start acquisition */ 305 ret = regmap_update_bits(data->regmap, MAX30100_REG_MODE_CONFIG, 306 MAX30100_REG_MODE_CONFIG_TEMP_EN, 307 MAX30100_REG_MODE_CONFIG_TEMP_EN); 308 if (ret) 309 return ret; 310 311 usleep_range(35000, 50000); 312 313 return max30100_read_temp(data, val); 314 } 315 316 static int max30100_read_raw(struct iio_dev *indio_dev, 317 struct iio_chan_spec const *chan, 318 int *val, int *val2, long mask) 319 { 320 struct max30100_data *data = iio_priv(indio_dev); 321 int ret = -EINVAL; 322 323 switch (mask) { 324 case IIO_CHAN_INFO_RAW: 325 /* 326 * Temperature reading can only be acquired while engine 327 * is running 328 */ 329 mutex_lock(&indio_dev->mlock); 330 331 if (!iio_buffer_enabled(indio_dev)) 332 ret = -EAGAIN; 333 else { 334 ret = max30100_get_temp(data, val); 335 if (!ret) 336 ret = IIO_VAL_INT; 337 338 } 339 340 mutex_unlock(&indio_dev->mlock); 341 break; 342 case IIO_CHAN_INFO_SCALE: 343 *val = 1; /* 0.0625 */ 344 *val2 = 16; 345 ret = IIO_VAL_FRACTIONAL; 346 break; 347 } 348 349 return ret; 350 } 351 352 static const struct iio_info max30100_info = { 353 .driver_module = THIS_MODULE, 354 .read_raw = max30100_read_raw, 355 }; 356 357 static int max30100_probe(struct i2c_client *client, 358 const struct i2c_device_id *id) 359 { 360 struct max30100_data *data; 361 struct iio_buffer *buffer; 362 struct iio_dev *indio_dev; 363 int ret; 364 365 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 366 if (!indio_dev) 367 return -ENOMEM; 368 369 buffer = devm_iio_kfifo_allocate(&client->dev); 370 if (!buffer) 371 return -ENOMEM; 372 373 iio_device_attach_buffer(indio_dev, buffer); 374 375 indio_dev->name = MAX30100_DRV_NAME; 376 indio_dev->channels = max30100_channels; 377 indio_dev->info = &max30100_info; 378 indio_dev->num_channels = ARRAY_SIZE(max30100_channels); 379 indio_dev->available_scan_masks = max30100_scan_masks; 380 indio_dev->modes = (INDIO_BUFFER_SOFTWARE | INDIO_DIRECT_MODE); 381 indio_dev->setup_ops = &max30100_buffer_setup_ops; 382 383 data = iio_priv(indio_dev); 384 data->indio_dev = indio_dev; 385 data->client = client; 386 387 mutex_init(&data->lock); 388 i2c_set_clientdata(client, indio_dev); 389 390 data->regmap = devm_regmap_init_i2c(client, &max30100_regmap_config); 391 if (IS_ERR(data->regmap)) { 392 dev_err(&client->dev, "regmap initialization failed.\n"); 393 return PTR_ERR(data->regmap); 394 } 395 max30100_set_powermode(data, false); 396 397 ret = max30100_chip_init(data); 398 if (ret) 399 return ret; 400 401 if (client->irq <= 0) { 402 dev_err(&client->dev, "no valid irq defined\n"); 403 return -EINVAL; 404 } 405 ret = devm_request_threaded_irq(&client->dev, client->irq, 406 NULL, max30100_interrupt_handler, 407 IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 408 "max30100_irq", indio_dev); 409 if (ret) { 410 dev_err(&client->dev, "request irq (%d) failed\n", client->irq); 411 return ret; 412 } 413 414 return iio_device_register(indio_dev); 415 } 416 417 static int max30100_remove(struct i2c_client *client) 418 { 419 struct iio_dev *indio_dev = i2c_get_clientdata(client); 420 struct max30100_data *data = iio_priv(indio_dev); 421 422 iio_device_unregister(indio_dev); 423 max30100_set_powermode(data, false); 424 425 return 0; 426 } 427 428 static const struct i2c_device_id max30100_id[] = { 429 { "max30100", 0 }, 430 {} 431 }; 432 MODULE_DEVICE_TABLE(i2c, max30100_id); 433 434 static const struct of_device_id max30100_dt_ids[] = { 435 { .compatible = "maxim,max30100" }, 436 { } 437 }; 438 MODULE_DEVICE_TABLE(of, max30100_dt_ids); 439 440 static struct i2c_driver max30100_driver = { 441 .driver = { 442 .name = MAX30100_DRV_NAME, 443 .of_match_table = of_match_ptr(max30100_dt_ids), 444 }, 445 .probe = max30100_probe, 446 .remove = max30100_remove, 447 .id_table = max30100_id, 448 }; 449 module_i2c_driver(max30100_driver); 450 451 MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>"); 452 MODULE_DESCRIPTION("MAX30100 heart rate and pulse oximeter sensor"); 453 MODULE_LICENSE("GPL"); 454