1 /* 2 * MAX44000 Ambient and Infrared Proximity Sensor 3 * 4 * Copyright (c) 2016, Intel Corporation. 5 * 6 * This file is subject to the terms and conditions of version 2 of 7 * the GNU General Public License. See the file COPYING in the main 8 * directory of this archive for more details. 9 * 10 * Data sheet: https://datasheets.maximintegrated.com/en/ds/MAX44000.pdf 11 * 12 * 7-bit I2C slave address 0x4a 13 */ 14 15 #include <linux/module.h> 16 #include <linux/init.h> 17 #include <linux/i2c.h> 18 #include <linux/regmap.h> 19 #include <linux/util_macros.h> 20 #include <linux/iio/iio.h> 21 #include <linux/iio/sysfs.h> 22 #include <linux/iio/buffer.h> 23 #include <linux/iio/trigger_consumer.h> 24 #include <linux/iio/triggered_buffer.h> 25 #include <linux/acpi.h> 26 27 #define MAX44000_DRV_NAME "max44000" 28 29 /* Registers in datasheet order */ 30 #define MAX44000_REG_STATUS 0x00 31 #define MAX44000_REG_CFG_MAIN 0x01 32 #define MAX44000_REG_CFG_RX 0x02 33 #define MAX44000_REG_CFG_TX 0x03 34 #define MAX44000_REG_ALS_DATA_HI 0x04 35 #define MAX44000_REG_ALS_DATA_LO 0x05 36 #define MAX44000_REG_PRX_DATA 0x16 37 #define MAX44000_REG_ALS_UPTHR_HI 0x06 38 #define MAX44000_REG_ALS_UPTHR_LO 0x07 39 #define MAX44000_REG_ALS_LOTHR_HI 0x08 40 #define MAX44000_REG_ALS_LOTHR_LO 0x09 41 #define MAX44000_REG_PST 0x0a 42 #define MAX44000_REG_PRX_IND 0x0b 43 #define MAX44000_REG_PRX_THR 0x0c 44 #define MAX44000_REG_TRIM_GAIN_GREEN 0x0f 45 #define MAX44000_REG_TRIM_GAIN_IR 0x10 46 47 /* REG_CFG bits */ 48 #define MAX44000_CFG_ALSINTE 0x01 49 #define MAX44000_CFG_PRXINTE 0x02 50 #define MAX44000_CFG_MASK 0x1c 51 #define MAX44000_CFG_MODE_SHUTDOWN 0x00 52 #define MAX44000_CFG_MODE_ALS_GIR 0x04 53 #define MAX44000_CFG_MODE_ALS_G 0x08 54 #define MAX44000_CFG_MODE_ALS_IR 0x0c 55 #define MAX44000_CFG_MODE_ALS_PRX 0x10 56 #define MAX44000_CFG_MODE_PRX 0x14 57 #define MAX44000_CFG_TRIM 0x20 58 59 /* 60 * Upper 4 bits are not documented but start as 1 on powerup 61 * Setting them to 0 causes proximity to misbehave so set them to 1 62 */ 63 #define MAX44000_REG_CFG_RX_DEFAULT 0xf0 64 65 /* REG_RX bits */ 66 #define MAX44000_CFG_RX_ALSTIM_MASK 0x0c 67 #define MAX44000_CFG_RX_ALSTIM_SHIFT 2 68 #define MAX44000_CFG_RX_ALSPGA_MASK 0x03 69 #define MAX44000_CFG_RX_ALSPGA_SHIFT 0 70 71 /* REG_TX bits */ 72 #define MAX44000_LED_CURRENT_MASK 0xf 73 #define MAX44000_LED_CURRENT_MAX 11 74 #define MAX44000_LED_CURRENT_DEFAULT 6 75 76 #define MAX44000_ALSDATA_OVERFLOW 0x4000 77 78 struct max44000_data { 79 struct mutex lock; 80 struct regmap *regmap; 81 }; 82 83 /* Default scale is set to the minimum of 0.03125 or 1 / (1 << 5) lux */ 84 #define MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 5 85 86 /* Scale can be multiplied by up to 128x via ALSPGA for measurement gain */ 87 static const int max44000_alspga_shift[] = {0, 2, 4, 7}; 88 #define MAX44000_ALSPGA_MAX_SHIFT 7 89 90 /* 91 * Scale can be multiplied by up to 64x via ALSTIM because of lost resolution 92 * 93 * This scaling factor is hidden from userspace and instead accounted for when 94 * reading raw values from the device. 95 * 96 * This makes it possible to cleanly expose ALSPGA as IIO_CHAN_INFO_SCALE and 97 * ALSTIM as IIO_CHAN_INFO_INT_TIME without the values affecting each other. 98 * 99 * Handling this internally is also required for buffer support because the 100 * channel's scan_type can't be modified dynamically. 101 */ 102 static const int max44000_alstim_shift[] = {0, 2, 4, 6}; 103 #define MAX44000_ALSTIM_SHIFT(alstim) (2 * (alstim)) 104 105 /* Available integration times with pretty manual alignment: */ 106 static const int max44000_int_time_avail_ns_array[] = { 107 100000000, 108 25000000, 109 6250000, 110 1562500, 111 }; 112 static const char max44000_int_time_avail_str[] = 113 "0.100 " 114 "0.025 " 115 "0.00625 " 116 "0.001625"; 117 118 /* Available scales (internal to ulux) with pretty manual alignment: */ 119 static const int max44000_scale_avail_ulux_array[] = { 120 31250, 121 125000, 122 500000, 123 4000000, 124 }; 125 static const char max44000_scale_avail_str[] = 126 "0.03125 " 127 "0.125 " 128 "0.5 " 129 "4"; 130 131 #define MAX44000_SCAN_INDEX_ALS 0 132 #define MAX44000_SCAN_INDEX_PRX 1 133 134 static const struct iio_chan_spec max44000_channels[] = { 135 { 136 .type = IIO_LIGHT, 137 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 138 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | 139 BIT(IIO_CHAN_INFO_INT_TIME), 140 .scan_index = MAX44000_SCAN_INDEX_ALS, 141 .scan_type = { 142 .sign = 'u', 143 .realbits = 14, 144 .storagebits = 16, 145 } 146 }, 147 { 148 .type = IIO_PROXIMITY, 149 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), 150 .scan_index = MAX44000_SCAN_INDEX_PRX, 151 .scan_type = { 152 .sign = 'u', 153 .realbits = 8, 154 .storagebits = 16, 155 } 156 }, 157 IIO_CHAN_SOFT_TIMESTAMP(2), 158 { 159 .type = IIO_CURRENT, 160 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | 161 BIT(IIO_CHAN_INFO_SCALE), 162 .extend_name = "led", 163 .output = 1, 164 .scan_index = -1, 165 }, 166 }; 167 168 static int max44000_read_alstim(struct max44000_data *data) 169 { 170 unsigned int val; 171 int ret; 172 173 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val); 174 if (ret < 0) 175 return ret; 176 return (val & MAX44000_CFG_RX_ALSTIM_MASK) >> MAX44000_CFG_RX_ALSTIM_SHIFT; 177 } 178 179 static int max44000_write_alstim(struct max44000_data *data, int val) 180 { 181 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX, 182 MAX44000_CFG_RX_ALSTIM_MASK, 183 val << MAX44000_CFG_RX_ALSTIM_SHIFT); 184 } 185 186 static int max44000_read_alspga(struct max44000_data *data) 187 { 188 unsigned int val; 189 int ret; 190 191 ret = regmap_read(data->regmap, MAX44000_REG_CFG_RX, &val); 192 if (ret < 0) 193 return ret; 194 return (val & MAX44000_CFG_RX_ALSPGA_MASK) >> MAX44000_CFG_RX_ALSPGA_SHIFT; 195 } 196 197 static int max44000_write_alspga(struct max44000_data *data, int val) 198 { 199 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_RX, 200 MAX44000_CFG_RX_ALSPGA_MASK, 201 val << MAX44000_CFG_RX_ALSPGA_SHIFT); 202 } 203 204 static int max44000_read_alsval(struct max44000_data *data) 205 { 206 u16 regval; 207 int alstim, ret; 208 209 ret = regmap_bulk_read(data->regmap, MAX44000_REG_ALS_DATA_HI, 210 ®val, sizeof(regval)); 211 if (ret < 0) 212 return ret; 213 alstim = ret = max44000_read_alstim(data); 214 if (ret < 0) 215 return ret; 216 217 regval = be16_to_cpu(regval); 218 219 /* 220 * Overflow is explained on datasheet page 17. 221 * 222 * It's a warning that either the G or IR channel has become saturated 223 * and that the value in the register is likely incorrect. 224 * 225 * The recommendation is to change the scale (ALSPGA). 226 * The driver just returns the max representable value. 227 */ 228 if (regval & MAX44000_ALSDATA_OVERFLOW) 229 return 0x3FFF; 230 231 return regval << MAX44000_ALSTIM_SHIFT(alstim); 232 } 233 234 static int max44000_write_led_current_raw(struct max44000_data *data, int val) 235 { 236 /* Maybe we should clamp the value instead? */ 237 if (val < 0 || val > MAX44000_LED_CURRENT_MAX) 238 return -ERANGE; 239 if (val >= 8) 240 val += 4; 241 return regmap_write_bits(data->regmap, MAX44000_REG_CFG_TX, 242 MAX44000_LED_CURRENT_MASK, val); 243 } 244 245 static int max44000_read_led_current_raw(struct max44000_data *data) 246 { 247 unsigned int regval; 248 int ret; 249 250 ret = regmap_read(data->regmap, MAX44000_REG_CFG_TX, ®val); 251 if (ret < 0) 252 return ret; 253 regval &= MAX44000_LED_CURRENT_MASK; 254 if (regval >= 8) 255 regval -= 4; 256 return regval; 257 } 258 259 static int max44000_read_raw(struct iio_dev *indio_dev, 260 struct iio_chan_spec const *chan, 261 int *val, int *val2, long mask) 262 { 263 struct max44000_data *data = iio_priv(indio_dev); 264 int alstim, alspga; 265 unsigned int regval; 266 int ret; 267 268 switch (mask) { 269 case IIO_CHAN_INFO_RAW: 270 switch (chan->type) { 271 case IIO_LIGHT: 272 mutex_lock(&data->lock); 273 ret = max44000_read_alsval(data); 274 mutex_unlock(&data->lock); 275 if (ret < 0) 276 return ret; 277 *val = ret; 278 return IIO_VAL_INT; 279 280 case IIO_PROXIMITY: 281 mutex_lock(&data->lock); 282 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val); 283 mutex_unlock(&data->lock); 284 if (ret < 0) 285 return ret; 286 *val = regval; 287 return IIO_VAL_INT; 288 289 case IIO_CURRENT: 290 mutex_lock(&data->lock); 291 ret = max44000_read_led_current_raw(data); 292 mutex_unlock(&data->lock); 293 if (ret < 0) 294 return ret; 295 *val = ret; 296 return IIO_VAL_INT; 297 298 default: 299 return -EINVAL; 300 } 301 302 case IIO_CHAN_INFO_SCALE: 303 switch (chan->type) { 304 case IIO_CURRENT: 305 /* Output register is in 10s of miliamps */ 306 *val = 10; 307 return IIO_VAL_INT; 308 309 case IIO_LIGHT: 310 mutex_lock(&data->lock); 311 alspga = ret = max44000_read_alspga(data); 312 mutex_unlock(&data->lock); 313 if (ret < 0) 314 return ret; 315 316 /* Avoid negative shifts */ 317 *val = (1 << MAX44000_ALSPGA_MAX_SHIFT); 318 *val2 = MAX44000_ALS_TO_LUX_DEFAULT_FRACTION_LOG2 319 + MAX44000_ALSPGA_MAX_SHIFT 320 - max44000_alspga_shift[alspga]; 321 return IIO_VAL_FRACTIONAL_LOG2; 322 323 default: 324 return -EINVAL; 325 } 326 327 case IIO_CHAN_INFO_INT_TIME: 328 mutex_lock(&data->lock); 329 alstim = ret = max44000_read_alstim(data); 330 mutex_unlock(&data->lock); 331 332 if (ret < 0) 333 return ret; 334 *val = 0; 335 *val2 = max44000_int_time_avail_ns_array[alstim]; 336 return IIO_VAL_INT_PLUS_NANO; 337 338 default: 339 return -EINVAL; 340 } 341 } 342 343 static int max44000_write_raw(struct iio_dev *indio_dev, 344 struct iio_chan_spec const *chan, 345 int val, int val2, long mask) 346 { 347 struct max44000_data *data = iio_priv(indio_dev); 348 int ret; 349 350 if (mask == IIO_CHAN_INFO_RAW && chan->type == IIO_CURRENT) { 351 mutex_lock(&data->lock); 352 ret = max44000_write_led_current_raw(data, val); 353 mutex_unlock(&data->lock); 354 return ret; 355 } else if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) { 356 s64 valns = val * NSEC_PER_SEC + val2; 357 int alstim = find_closest_descending(valns, 358 max44000_int_time_avail_ns_array, 359 ARRAY_SIZE(max44000_int_time_avail_ns_array)); 360 mutex_lock(&data->lock); 361 ret = max44000_write_alstim(data, alstim); 362 mutex_unlock(&data->lock); 363 return ret; 364 } else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) { 365 s64 valus = val * USEC_PER_SEC + val2; 366 int alspga = find_closest(valus, 367 max44000_scale_avail_ulux_array, 368 ARRAY_SIZE(max44000_scale_avail_ulux_array)); 369 mutex_lock(&data->lock); 370 ret = max44000_write_alspga(data, alspga); 371 mutex_unlock(&data->lock); 372 return ret; 373 } 374 375 return -EINVAL; 376 } 377 378 static int max44000_write_raw_get_fmt(struct iio_dev *indio_dev, 379 struct iio_chan_spec const *chan, 380 long mask) 381 { 382 if (mask == IIO_CHAN_INFO_INT_TIME && chan->type == IIO_LIGHT) 383 return IIO_VAL_INT_PLUS_NANO; 384 else if (mask == IIO_CHAN_INFO_SCALE && chan->type == IIO_LIGHT) 385 return IIO_VAL_INT_PLUS_MICRO; 386 else 387 return IIO_VAL_INT; 388 } 389 390 static IIO_CONST_ATTR(illuminance_integration_time_available, max44000_int_time_avail_str); 391 static IIO_CONST_ATTR(illuminance_scale_available, max44000_scale_avail_str); 392 393 static struct attribute *max44000_attributes[] = { 394 &iio_const_attr_illuminance_integration_time_available.dev_attr.attr, 395 &iio_const_attr_illuminance_scale_available.dev_attr.attr, 396 NULL 397 }; 398 399 static const struct attribute_group max44000_attribute_group = { 400 .attrs = max44000_attributes, 401 }; 402 403 static const struct iio_info max44000_info = { 404 .driver_module = THIS_MODULE, 405 .read_raw = max44000_read_raw, 406 .write_raw = max44000_write_raw, 407 .write_raw_get_fmt = max44000_write_raw_get_fmt, 408 .attrs = &max44000_attribute_group, 409 }; 410 411 static bool max44000_readable_reg(struct device *dev, unsigned int reg) 412 { 413 switch (reg) { 414 case MAX44000_REG_STATUS: 415 case MAX44000_REG_CFG_MAIN: 416 case MAX44000_REG_CFG_RX: 417 case MAX44000_REG_CFG_TX: 418 case MAX44000_REG_ALS_DATA_HI: 419 case MAX44000_REG_ALS_DATA_LO: 420 case MAX44000_REG_PRX_DATA: 421 case MAX44000_REG_ALS_UPTHR_HI: 422 case MAX44000_REG_ALS_UPTHR_LO: 423 case MAX44000_REG_ALS_LOTHR_HI: 424 case MAX44000_REG_ALS_LOTHR_LO: 425 case MAX44000_REG_PST: 426 case MAX44000_REG_PRX_IND: 427 case MAX44000_REG_PRX_THR: 428 case MAX44000_REG_TRIM_GAIN_GREEN: 429 case MAX44000_REG_TRIM_GAIN_IR: 430 return true; 431 default: 432 return false; 433 } 434 } 435 436 static bool max44000_writeable_reg(struct device *dev, unsigned int reg) 437 { 438 switch (reg) { 439 case MAX44000_REG_CFG_MAIN: 440 case MAX44000_REG_CFG_RX: 441 case MAX44000_REG_CFG_TX: 442 case MAX44000_REG_ALS_UPTHR_HI: 443 case MAX44000_REG_ALS_UPTHR_LO: 444 case MAX44000_REG_ALS_LOTHR_HI: 445 case MAX44000_REG_ALS_LOTHR_LO: 446 case MAX44000_REG_PST: 447 case MAX44000_REG_PRX_IND: 448 case MAX44000_REG_PRX_THR: 449 case MAX44000_REG_TRIM_GAIN_GREEN: 450 case MAX44000_REG_TRIM_GAIN_IR: 451 return true; 452 default: 453 return false; 454 } 455 } 456 457 static bool max44000_volatile_reg(struct device *dev, unsigned int reg) 458 { 459 switch (reg) { 460 case MAX44000_REG_STATUS: 461 case MAX44000_REG_ALS_DATA_HI: 462 case MAX44000_REG_ALS_DATA_LO: 463 case MAX44000_REG_PRX_DATA: 464 return true; 465 default: 466 return false; 467 } 468 } 469 470 static bool max44000_precious_reg(struct device *dev, unsigned int reg) 471 { 472 return reg == MAX44000_REG_STATUS; 473 } 474 475 static const struct regmap_config max44000_regmap_config = { 476 .reg_bits = 8, 477 .val_bits = 8, 478 479 .max_register = MAX44000_REG_PRX_DATA, 480 .readable_reg = max44000_readable_reg, 481 .writeable_reg = max44000_writeable_reg, 482 .volatile_reg = max44000_volatile_reg, 483 .precious_reg = max44000_precious_reg, 484 485 .use_single_rw = 1, 486 .cache_type = REGCACHE_RBTREE, 487 }; 488 489 static irqreturn_t max44000_trigger_handler(int irq, void *p) 490 { 491 struct iio_poll_func *pf = p; 492 struct iio_dev *indio_dev = pf->indio_dev; 493 struct max44000_data *data = iio_priv(indio_dev); 494 u16 buf[8]; /* 2x u16 + padding + 8 bytes timestamp */ 495 int index = 0; 496 unsigned int regval; 497 int ret; 498 499 mutex_lock(&data->lock); 500 if (test_bit(MAX44000_SCAN_INDEX_ALS, indio_dev->active_scan_mask)) { 501 ret = max44000_read_alsval(data); 502 if (ret < 0) 503 goto out_unlock; 504 buf[index++] = ret; 505 } 506 if (test_bit(MAX44000_SCAN_INDEX_PRX, indio_dev->active_scan_mask)) { 507 ret = regmap_read(data->regmap, MAX44000_REG_PRX_DATA, ®val); 508 if (ret < 0) 509 goto out_unlock; 510 buf[index] = regval; 511 } 512 mutex_unlock(&data->lock); 513 514 iio_push_to_buffers_with_timestamp(indio_dev, buf, 515 iio_get_time_ns(indio_dev)); 516 iio_trigger_notify_done(indio_dev->trig); 517 return IRQ_HANDLED; 518 519 out_unlock: 520 mutex_unlock(&data->lock); 521 iio_trigger_notify_done(indio_dev->trig); 522 return IRQ_HANDLED; 523 } 524 525 static int max44000_probe(struct i2c_client *client, 526 const struct i2c_device_id *id) 527 { 528 struct max44000_data *data; 529 struct iio_dev *indio_dev; 530 int ret, reg; 531 532 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); 533 if (!indio_dev) 534 return -ENOMEM; 535 data = iio_priv(indio_dev); 536 data->regmap = devm_regmap_init_i2c(client, &max44000_regmap_config); 537 if (IS_ERR(data->regmap)) { 538 dev_err(&client->dev, "regmap_init failed!\n"); 539 return PTR_ERR(data->regmap); 540 } 541 542 i2c_set_clientdata(client, indio_dev); 543 mutex_init(&data->lock); 544 indio_dev->dev.parent = &client->dev; 545 indio_dev->info = &max44000_info; 546 indio_dev->name = MAX44000_DRV_NAME; 547 indio_dev->channels = max44000_channels; 548 indio_dev->num_channels = ARRAY_SIZE(max44000_channels); 549 550 /* 551 * The device doesn't have a reset function so we just clear some 552 * important bits at probe time to ensure sane operation. 553 * 554 * Since we don't support interrupts/events the threshold values are 555 * not important. We also don't touch trim values. 556 */ 557 558 /* Reset ALS scaling bits */ 559 ret = regmap_write(data->regmap, MAX44000_REG_CFG_RX, 560 MAX44000_REG_CFG_RX_DEFAULT); 561 if (ret < 0) { 562 dev_err(&client->dev, "failed to write default CFG_RX: %d\n", 563 ret); 564 return ret; 565 } 566 567 /* 568 * By default the LED pulse used for the proximity sensor is disabled. 569 * Set a middle value so that we get some sort of valid data by default. 570 */ 571 ret = max44000_write_led_current_raw(data, MAX44000_LED_CURRENT_DEFAULT); 572 if (ret < 0) { 573 dev_err(&client->dev, "failed to write init config: %d\n", ret); 574 return ret; 575 } 576 577 /* Reset CFG bits to ALS_PRX mode which allows easy reading of both values. */ 578 reg = MAX44000_CFG_TRIM | MAX44000_CFG_MODE_ALS_PRX; 579 ret = regmap_write(data->regmap, MAX44000_REG_CFG_MAIN, reg); 580 if (ret < 0) { 581 dev_err(&client->dev, "failed to write init config: %d\n", ret); 582 return ret; 583 } 584 585 /* Read status at least once to clear any stale interrupt bits. */ 586 ret = regmap_read(data->regmap, MAX44000_REG_STATUS, ®); 587 if (ret < 0) { 588 dev_err(&client->dev, "failed to read init status: %d\n", ret); 589 return ret; 590 } 591 592 ret = iio_triggered_buffer_setup(indio_dev, NULL, max44000_trigger_handler, NULL); 593 if (ret < 0) { 594 dev_err(&client->dev, "iio triggered buffer setup failed\n"); 595 return ret; 596 } 597 598 return iio_device_register(indio_dev); 599 } 600 601 static int max44000_remove(struct i2c_client *client) 602 { 603 struct iio_dev *indio_dev = i2c_get_clientdata(client); 604 605 iio_device_unregister(indio_dev); 606 iio_triggered_buffer_cleanup(indio_dev); 607 608 return 0; 609 } 610 611 static const struct i2c_device_id max44000_id[] = { 612 {"max44000", 0}, 613 { } 614 }; 615 MODULE_DEVICE_TABLE(i2c, max44000_id); 616 617 #ifdef CONFIG_ACPI 618 static const struct acpi_device_id max44000_acpi_match[] = { 619 {"MAX44000", 0}, 620 { } 621 }; 622 MODULE_DEVICE_TABLE(acpi, max44000_acpi_match); 623 #endif 624 625 static struct i2c_driver max44000_driver = { 626 .driver = { 627 .name = MAX44000_DRV_NAME, 628 .acpi_match_table = ACPI_PTR(max44000_acpi_match), 629 }, 630 .probe = max44000_probe, 631 .remove = max44000_remove, 632 .id_table = max44000_id, 633 }; 634 635 module_i2c_driver(max44000_driver); 636 637 MODULE_AUTHOR("Crestez Dan Leonard <leonard.crestez@intel.com>"); 638 MODULE_DESCRIPTION("MAX44000 Ambient and Infrared Proximity Sensor"); 639 MODULE_LICENSE("GPL v2"); 640