1 // SPDX-License-Identifier: GPL-2.0+ 2 // 3 // max14577_charger.c - Battery charger driver for the Maxim 14577/77836 4 // 5 // Copyright (C) 2013,2014 Samsung Electronics 6 // Krzysztof Kozlowski <krzk@kernel.org> 7 8 #include <linux/module.h> 9 #include <linux/platform_device.h> 10 #include <linux/power_supply.h> 11 #include <linux/mfd/max14577-private.h> 12 #include <linux/mfd/max14577.h> 13 14 struct max14577_charger { 15 struct device *dev; 16 struct max14577 *max14577; 17 struct power_supply *charger; 18 19 struct max14577_charger_platform_data *pdata; 20 }; 21 22 /* 23 * Helper function for mapping values of STATUS2/CHGTYP register on max14577 24 * and max77836 chipsets to enum maxim_muic_charger_type. 25 */ 26 static enum max14577_muic_charger_type maxim_get_charger_type( 27 enum maxim_device_type dev_type, u8 val) { 28 switch (val) { 29 case MAX14577_CHARGER_TYPE_NONE: 30 case MAX14577_CHARGER_TYPE_USB: 31 case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT: 32 case MAX14577_CHARGER_TYPE_DEDICATED_CHG: 33 case MAX14577_CHARGER_TYPE_SPECIAL_500MA: 34 case MAX14577_CHARGER_TYPE_SPECIAL_1A: 35 return val; 36 case MAX14577_CHARGER_TYPE_DEAD_BATTERY: 37 case MAX14577_CHARGER_TYPE_RESERVED: 38 if (dev_type == MAXIM_DEVICE_TYPE_MAX77836) 39 val |= 0x8; 40 return val; 41 default: 42 WARN_ONCE(1, "max14577: Unsupported chgtyp register value 0x%02x", val); 43 return val; 44 } 45 } 46 47 static int max14577_get_charger_state(struct max14577_charger *chg, int *val) 48 { 49 struct regmap *rmap = chg->max14577->regmap; 50 int ret; 51 u8 reg_data; 52 53 /* 54 * Charging occurs only if: 55 * - CHGCTRL2/MBCHOSTEN == 1 56 * - STATUS2/CGMBC == 1 57 * 58 * TODO: 59 * - handle FULL after Top-off timer (EOC register may be off 60 * and the charger won't be charging although MBCHOSTEN is on) 61 * - handle properly dead-battery charging (respect timer) 62 * - handle timers (fast-charge and prequal) /MBCCHGERR/ 63 */ 64 ret = max14577_read_reg(rmap, MAX14577_CHG_REG_CHG_CTRL2, ®_data); 65 if (ret < 0) 66 goto out; 67 68 if ((reg_data & CHGCTRL2_MBCHOSTEN_MASK) == 0) { 69 *val = POWER_SUPPLY_STATUS_DISCHARGING; 70 goto out; 71 } 72 73 ret = max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, ®_data); 74 if (ret < 0) 75 goto out; 76 77 if (reg_data & STATUS3_CGMBC_MASK) { 78 /* Charger or USB-cable is connected */ 79 if (reg_data & STATUS3_EOC_MASK) 80 *val = POWER_SUPPLY_STATUS_FULL; 81 else 82 *val = POWER_SUPPLY_STATUS_CHARGING; 83 goto out; 84 } 85 86 *val = POWER_SUPPLY_STATUS_DISCHARGING; 87 88 out: 89 return ret; 90 } 91 92 /* 93 * Supported charge types: 94 * - POWER_SUPPLY_CHARGE_TYPE_NONE 95 * - POWER_SUPPLY_CHARGE_TYPE_FAST 96 */ 97 static int max14577_get_charge_type(struct max14577_charger *chg, int *val) 98 { 99 int ret, charging; 100 101 /* 102 * TODO: CHARGE_TYPE_TRICKLE (VCHGR_RC or EOC)? 103 * As spec says: 104 * [after reaching EOC interrupt] 105 * "When the battery is fully charged, the 30-minute (typ) 106 * top-off timer starts. The device continues to trickle 107 * charge the battery until the top-off timer runs out." 108 */ 109 ret = max14577_get_charger_state(chg, &charging); 110 if (ret < 0) 111 return ret; 112 113 if (charging == POWER_SUPPLY_STATUS_CHARGING) 114 *val = POWER_SUPPLY_CHARGE_TYPE_FAST; 115 else 116 *val = POWER_SUPPLY_CHARGE_TYPE_NONE; 117 118 return 0; 119 } 120 121 static int max14577_get_online(struct max14577_charger *chg, int *val) 122 { 123 struct regmap *rmap = chg->max14577->regmap; 124 u8 reg_data; 125 int ret; 126 enum max14577_muic_charger_type chg_type; 127 128 ret = max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, ®_data); 129 if (ret < 0) 130 return ret; 131 132 reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT); 133 chg_type = maxim_get_charger_type(chg->max14577->dev_type, reg_data); 134 switch (chg_type) { 135 case MAX14577_CHARGER_TYPE_USB: 136 case MAX14577_CHARGER_TYPE_DEDICATED_CHG: 137 case MAX14577_CHARGER_TYPE_SPECIAL_500MA: 138 case MAX14577_CHARGER_TYPE_SPECIAL_1A: 139 case MAX14577_CHARGER_TYPE_DEAD_BATTERY: 140 case MAX77836_CHARGER_TYPE_SPECIAL_BIAS: 141 *val = 1; 142 break; 143 case MAX14577_CHARGER_TYPE_NONE: 144 case MAX14577_CHARGER_TYPE_DOWNSTREAM_PORT: 145 case MAX14577_CHARGER_TYPE_RESERVED: 146 case MAX77836_CHARGER_TYPE_RESERVED: 147 default: 148 *val = 0; 149 } 150 151 return 0; 152 } 153 154 /* 155 * Supported health statuses: 156 * - POWER_SUPPLY_HEALTH_DEAD 157 * - POWER_SUPPLY_HEALTH_OVERVOLTAGE 158 * - POWER_SUPPLY_HEALTH_GOOD 159 */ 160 static int max14577_get_battery_health(struct max14577_charger *chg, int *val) 161 { 162 struct regmap *rmap = chg->max14577->regmap; 163 int ret; 164 u8 reg_data; 165 enum max14577_muic_charger_type chg_type; 166 167 ret = max14577_read_reg(rmap, MAX14577_MUIC_REG_STATUS2, ®_data); 168 if (ret < 0) 169 goto out; 170 171 reg_data = ((reg_data & STATUS2_CHGTYP_MASK) >> STATUS2_CHGTYP_SHIFT); 172 chg_type = maxim_get_charger_type(chg->max14577->dev_type, reg_data); 173 if (chg_type == MAX14577_CHARGER_TYPE_DEAD_BATTERY) { 174 *val = POWER_SUPPLY_HEALTH_DEAD; 175 goto out; 176 } 177 178 ret = max14577_read_reg(rmap, MAX14577_CHG_REG_STATUS3, ®_data); 179 if (ret < 0) 180 goto out; 181 182 if (reg_data & STATUS3_OVP_MASK) { 183 *val = POWER_SUPPLY_HEALTH_OVERVOLTAGE; 184 goto out; 185 } 186 187 /* Not dead, not overvoltage */ 188 *val = POWER_SUPPLY_HEALTH_GOOD; 189 190 out: 191 return ret; 192 } 193 194 /* 195 * Always returns 1. 196 * The max14577 chip doesn't report any status of battery presence. 197 * Lets assume that it will always be used with some battery. 198 */ 199 static int max14577_get_present(struct max14577_charger *chg, int *val) 200 { 201 *val = 1; 202 203 return 0; 204 } 205 206 static int max14577_set_fast_charge_timer(struct max14577_charger *chg, 207 unsigned long hours) 208 { 209 u8 reg_data; 210 211 switch (hours) { 212 case 5 ... 7: 213 reg_data = hours - 3; 214 break; 215 case 0: 216 /* Disable */ 217 reg_data = 0x7; 218 break; 219 default: 220 dev_err(chg->dev, "Wrong value for Fast-Charge Timer: %lu\n", 221 hours); 222 return -EINVAL; 223 } 224 reg_data <<= CHGCTRL1_TCHW_SHIFT; 225 226 return max14577_update_reg(chg->max14577->regmap, 227 MAX14577_REG_CHGCTRL1, CHGCTRL1_TCHW_MASK, reg_data); 228 } 229 230 static int max14577_init_constant_voltage(struct max14577_charger *chg, 231 unsigned int uvolt) 232 { 233 u8 reg_data; 234 235 if (uvolt < MAXIM_CHARGER_CONSTANT_VOLTAGE_MIN || 236 uvolt > MAXIM_CHARGER_CONSTANT_VOLTAGE_MAX) 237 return -EINVAL; 238 239 if (uvolt == 4200000) 240 reg_data = 0x0; 241 else if (uvolt == MAXIM_CHARGER_CONSTANT_VOLTAGE_MAX) 242 reg_data = 0x1f; 243 else if (uvolt <= 4280000) { 244 unsigned int val = uvolt; 245 246 val -= MAXIM_CHARGER_CONSTANT_VOLTAGE_MIN; 247 val /= MAXIM_CHARGER_CONSTANT_VOLTAGE_STEP; 248 if (uvolt <= 4180000) 249 reg_data = 0x1 + val; 250 else 251 reg_data = val; /* Fix for gap between 4.18V and 4.22V */ 252 } else 253 return -EINVAL; 254 255 reg_data <<= CHGCTRL3_MBCCVWRC_SHIFT; 256 257 return max14577_write_reg(chg->max14577->regmap, 258 MAX14577_CHG_REG_CHG_CTRL3, reg_data); 259 } 260 261 static int max14577_init_eoc(struct max14577_charger *chg, 262 unsigned int uamp) 263 { 264 unsigned int current_bits; 265 u8 reg_data; 266 267 switch (chg->max14577->dev_type) { 268 case MAXIM_DEVICE_TYPE_MAX77836: 269 if (uamp < 5000) 270 return -EINVAL; /* Requested current is too low */ 271 272 if (uamp >= 7500 && uamp < 10000) 273 current_bits = 0x0; 274 else if (uamp <= 50000) { 275 /* <5000, 7499> and <10000, 50000> */ 276 current_bits = uamp / 5000; 277 } else { 278 uamp = min(uamp, 100000U) - 50000U; 279 current_bits = 0xa + uamp / 10000; 280 } 281 break; 282 283 case MAXIM_DEVICE_TYPE_MAX14577: 284 default: 285 if (uamp < MAX14577_CHARGER_EOC_CURRENT_LIMIT_MIN) 286 return -EINVAL; /* Requested current is too low */ 287 288 uamp = min(uamp, MAX14577_CHARGER_EOC_CURRENT_LIMIT_MAX); 289 uamp -= MAX14577_CHARGER_EOC_CURRENT_LIMIT_MIN; 290 current_bits = uamp / MAX14577_CHARGER_EOC_CURRENT_LIMIT_STEP; 291 break; 292 } 293 294 reg_data = current_bits << CHGCTRL5_EOCS_SHIFT; 295 296 return max14577_update_reg(chg->max14577->regmap, 297 MAX14577_CHG_REG_CHG_CTRL5, CHGCTRL5_EOCS_MASK, 298 reg_data); 299 } 300 301 static int max14577_init_fast_charge(struct max14577_charger *chg, 302 unsigned int uamp) 303 { 304 u8 reg_data; 305 int ret; 306 const struct maxim_charger_current *limits = 307 &maxim_charger_currents[chg->max14577->dev_type]; 308 309 ret = maxim_charger_calc_reg_current(limits, uamp, uamp, ®_data); 310 if (ret) { 311 dev_err(chg->dev, "Wrong value for fast charge: %u\n", uamp); 312 return ret; 313 } 314 315 return max14577_update_reg(chg->max14577->regmap, 316 MAX14577_CHG_REG_CHG_CTRL4, 317 CHGCTRL4_MBCICHWRCL_MASK | CHGCTRL4_MBCICHWRCH_MASK, 318 reg_data); 319 } 320 321 /* 322 * Sets charger registers to proper and safe default values. 323 * Some of these values are equal to defaults in MAX14577E 324 * data sheet but there are minor differences. 325 */ 326 static int max14577_charger_reg_init(struct max14577_charger *chg) 327 { 328 struct regmap *rmap = chg->max14577->regmap; 329 u8 reg_data; 330 int ret; 331 332 /* 333 * Charger-Type Manual Detection, default off (set CHGTYPMAN to 0) 334 * Charger-Detection Enable, default on (set CHGDETEN to 1) 335 * Combined mask of CHGDETEN and CHGTYPMAN will zero the CHGTYPMAN bit 336 */ 337 reg_data = 0x1 << CDETCTRL1_CHGDETEN_SHIFT; 338 max14577_update_reg(rmap, MAX14577_REG_CDETCTRL1, 339 CDETCTRL1_CHGDETEN_MASK | CDETCTRL1_CHGTYPMAN_MASK, 340 reg_data); 341 342 /* 343 * Wall-Adapter Rapid Charge, default on 344 * Battery-Charger, default on 345 */ 346 reg_data = 0x1 << CHGCTRL2_VCHGR_RC_SHIFT; 347 reg_data |= 0x1 << CHGCTRL2_MBCHOSTEN_SHIFT; 348 max14577_write_reg(rmap, MAX14577_REG_CHGCTRL2, reg_data); 349 350 /* Auto Charging Stop, default off */ 351 reg_data = 0x0 << CHGCTRL6_AUTOSTOP_SHIFT; 352 max14577_write_reg(rmap, MAX14577_REG_CHGCTRL6, reg_data); 353 354 ret = max14577_init_constant_voltage(chg, chg->pdata->constant_uvolt); 355 if (ret) 356 return ret; 357 358 ret = max14577_init_eoc(chg, chg->pdata->eoc_uamp); 359 if (ret) 360 return ret; 361 362 ret = max14577_init_fast_charge(chg, chg->pdata->fast_charge_uamp); 363 if (ret) 364 return ret; 365 366 ret = max14577_set_fast_charge_timer(chg, 367 MAXIM_CHARGER_FAST_CHARGE_TIMER_DEFAULT); 368 if (ret) 369 return ret; 370 371 /* Initialize Overvoltage-Protection Threshold */ 372 switch (chg->pdata->ovp_uvolt) { 373 case 7500000: 374 reg_data = 0x0; 375 break; 376 case 6000000: 377 case 6500000: 378 case 7000000: 379 reg_data = 0x1 + (chg->pdata->ovp_uvolt - 6000000) / 500000; 380 break; 381 default: 382 dev_err(chg->dev, "Wrong value for OVP: %u\n", 383 chg->pdata->ovp_uvolt); 384 return -EINVAL; 385 } 386 reg_data <<= CHGCTRL7_OTPCGHCVS_SHIFT; 387 max14577_write_reg(rmap, MAX14577_REG_CHGCTRL7, reg_data); 388 389 return 0; 390 } 391 392 /* Support property from charger */ 393 static enum power_supply_property max14577_charger_props[] = { 394 POWER_SUPPLY_PROP_STATUS, 395 POWER_SUPPLY_PROP_CHARGE_TYPE, 396 POWER_SUPPLY_PROP_HEALTH, 397 POWER_SUPPLY_PROP_PRESENT, 398 POWER_SUPPLY_PROP_ONLINE, 399 POWER_SUPPLY_PROP_MODEL_NAME, 400 POWER_SUPPLY_PROP_MANUFACTURER, 401 }; 402 403 static const char * const model_names[] = { 404 [MAXIM_DEVICE_TYPE_UNKNOWN] = "MAX14577-like", 405 [MAXIM_DEVICE_TYPE_MAX14577] = "MAX14577", 406 [MAXIM_DEVICE_TYPE_MAX77836] = "MAX77836", 407 }; 408 static const char *manufacturer = "Maxim Integrated"; 409 410 static int max14577_charger_get_property(struct power_supply *psy, 411 enum power_supply_property psp, 412 union power_supply_propval *val) 413 { 414 struct max14577_charger *chg = power_supply_get_drvdata(psy); 415 int ret = 0; 416 417 switch (psp) { 418 case POWER_SUPPLY_PROP_STATUS: 419 ret = max14577_get_charger_state(chg, &val->intval); 420 break; 421 case POWER_SUPPLY_PROP_CHARGE_TYPE: 422 ret = max14577_get_charge_type(chg, &val->intval); 423 break; 424 case POWER_SUPPLY_PROP_HEALTH: 425 ret = max14577_get_battery_health(chg, &val->intval); 426 break; 427 case POWER_SUPPLY_PROP_PRESENT: 428 ret = max14577_get_present(chg, &val->intval); 429 break; 430 case POWER_SUPPLY_PROP_ONLINE: 431 ret = max14577_get_online(chg, &val->intval); 432 break; 433 case POWER_SUPPLY_PROP_MODEL_NAME: 434 BUILD_BUG_ON(ARRAY_SIZE(model_names) != MAXIM_DEVICE_TYPE_NUM); 435 val->strval = model_names[chg->max14577->dev_type]; 436 break; 437 case POWER_SUPPLY_PROP_MANUFACTURER: 438 val->strval = manufacturer; 439 break; 440 default: 441 return -EINVAL; 442 } 443 444 return ret; 445 } 446 447 static const struct power_supply_desc max14577_charger_desc = { 448 .name = "max14577-charger", 449 .type = POWER_SUPPLY_TYPE_BATTERY, 450 .properties = max14577_charger_props, 451 .num_properties = ARRAY_SIZE(max14577_charger_props), 452 .get_property = max14577_charger_get_property, 453 }; 454 455 #ifdef CONFIG_OF 456 static struct max14577_charger_platform_data *max14577_charger_dt_init( 457 struct platform_device *pdev) 458 { 459 struct max14577_charger_platform_data *pdata; 460 struct device_node *np = pdev->dev.of_node; 461 int ret; 462 463 if (!np) { 464 dev_err(&pdev->dev, "No charger OF node\n"); 465 return ERR_PTR(-EINVAL); 466 } 467 468 pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); 469 if (!pdata) 470 return ERR_PTR(-ENOMEM); 471 472 ret = of_property_read_u32(np, "maxim,constant-uvolt", 473 &pdata->constant_uvolt); 474 if (ret) { 475 dev_err(&pdev->dev, "Cannot parse maxim,constant-uvolt field from DT\n"); 476 return ERR_PTR(ret); 477 } 478 479 ret = of_property_read_u32(np, "maxim,fast-charge-uamp", 480 &pdata->fast_charge_uamp); 481 if (ret) { 482 dev_err(&pdev->dev, "Cannot parse maxim,fast-charge-uamp field from DT\n"); 483 return ERR_PTR(ret); 484 } 485 486 ret = of_property_read_u32(np, "maxim,eoc-uamp", &pdata->eoc_uamp); 487 if (ret) { 488 dev_err(&pdev->dev, "Cannot parse maxim,eoc-uamp field from DT\n"); 489 return ERR_PTR(ret); 490 } 491 492 ret = of_property_read_u32(np, "maxim,ovp-uvolt", &pdata->ovp_uvolt); 493 if (ret) { 494 dev_err(&pdev->dev, "Cannot parse maxim,ovp-uvolt field from DT\n"); 495 return ERR_PTR(ret); 496 } 497 498 return pdata; 499 } 500 #else /* CONFIG_OF */ 501 static struct max14577_charger_platform_data *max14577_charger_dt_init( 502 struct platform_device *pdev) 503 { 504 return NULL; 505 } 506 #endif /* CONFIG_OF */ 507 508 static ssize_t show_fast_charge_timer(struct device *dev, 509 struct device_attribute *attr, char *buf) 510 { 511 struct max14577_charger *chg = dev_get_drvdata(dev); 512 u8 reg_data; 513 int ret; 514 unsigned int val; 515 516 ret = max14577_read_reg(chg->max14577->regmap, MAX14577_REG_CHGCTRL1, 517 ®_data); 518 if (ret) 519 return ret; 520 521 reg_data &= CHGCTRL1_TCHW_MASK; 522 reg_data >>= CHGCTRL1_TCHW_SHIFT; 523 switch (reg_data) { 524 case 0x2 ... 0x4: 525 val = reg_data + 3; 526 break; 527 case 0x7: 528 val = 0; 529 break; 530 default: 531 val = 5; 532 break; 533 } 534 535 return sysfs_emit(buf, "%u\n", val); 536 } 537 538 static ssize_t store_fast_charge_timer(struct device *dev, 539 struct device_attribute *attr, const char *buf, size_t count) 540 { 541 struct max14577_charger *chg = dev_get_drvdata(dev); 542 unsigned long val; 543 int ret; 544 545 ret = kstrtoul(buf, 10, &val); 546 if (ret) 547 return ret; 548 549 ret = max14577_set_fast_charge_timer(chg, val); 550 if (ret) 551 return ret; 552 553 return count; 554 } 555 556 static DEVICE_ATTR(fast_charge_timer, S_IRUGO | S_IWUSR, 557 show_fast_charge_timer, store_fast_charge_timer); 558 559 static int max14577_charger_probe(struct platform_device *pdev) 560 { 561 struct max14577_charger *chg; 562 struct power_supply_config psy_cfg = {}; 563 struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent); 564 int ret; 565 566 chg = devm_kzalloc(&pdev->dev, sizeof(*chg), GFP_KERNEL); 567 if (!chg) 568 return -ENOMEM; 569 570 platform_set_drvdata(pdev, chg); 571 chg->dev = &pdev->dev; 572 chg->max14577 = max14577; 573 574 chg->pdata = max14577_charger_dt_init(pdev); 575 if (IS_ERR_OR_NULL(chg->pdata)) 576 return PTR_ERR(chg->pdata); 577 578 ret = max14577_charger_reg_init(chg); 579 if (ret) 580 return ret; 581 582 ret = device_create_file(&pdev->dev, &dev_attr_fast_charge_timer); 583 if (ret) { 584 dev_err(&pdev->dev, "failed: create sysfs entry\n"); 585 return ret; 586 } 587 588 psy_cfg.drv_data = chg; 589 chg->charger = power_supply_register(&pdev->dev, &max14577_charger_desc, 590 &psy_cfg); 591 if (IS_ERR(chg->charger)) { 592 dev_err(&pdev->dev, "failed: power supply register\n"); 593 ret = PTR_ERR(chg->charger); 594 goto err; 595 } 596 597 /* Check for valid values for charger */ 598 BUILD_BUG_ON(MAX14577_CHARGER_EOC_CURRENT_LIMIT_MIN + 599 MAX14577_CHARGER_EOC_CURRENT_LIMIT_STEP * 0xf != 600 MAX14577_CHARGER_EOC_CURRENT_LIMIT_MAX); 601 return 0; 602 603 err: 604 device_remove_file(&pdev->dev, &dev_attr_fast_charge_timer); 605 606 return ret; 607 } 608 609 static void max14577_charger_remove(struct platform_device *pdev) 610 { 611 struct max14577_charger *chg = platform_get_drvdata(pdev); 612 613 device_remove_file(&pdev->dev, &dev_attr_fast_charge_timer); 614 power_supply_unregister(chg->charger); 615 } 616 617 static const struct platform_device_id max14577_charger_id[] = { 618 { "max14577-charger", MAXIM_DEVICE_TYPE_MAX14577, }, 619 { "max77836-charger", MAXIM_DEVICE_TYPE_MAX77836, }, 620 { } 621 }; 622 MODULE_DEVICE_TABLE(platform, max14577_charger_id); 623 624 static const struct of_device_id of_max14577_charger_dt_match[] = { 625 { .compatible = "maxim,max14577-charger", 626 .data = (void *)MAXIM_DEVICE_TYPE_MAX14577, }, 627 { .compatible = "maxim,max77836-charger", 628 .data = (void *)MAXIM_DEVICE_TYPE_MAX77836, }, 629 { }, 630 }; 631 MODULE_DEVICE_TABLE(of, of_max14577_charger_dt_match); 632 633 static struct platform_driver max14577_charger_driver = { 634 .driver = { 635 .name = "max14577-charger", 636 .of_match_table = of_max14577_charger_dt_match, 637 }, 638 .probe = max14577_charger_probe, 639 .remove_new = max14577_charger_remove, 640 .id_table = max14577_charger_id, 641 }; 642 module_platform_driver(max14577_charger_driver); 643 644 MODULE_AUTHOR("Krzysztof Kozlowski <krzk@kernel.org>"); 645 MODULE_DESCRIPTION("Maxim 14577/77836 charger driver"); 646 MODULE_LICENSE("GPL"); 647