ds2760_battery.c revision 5a0e3ad6af8660be21ca98a971cd00f331318c05
1/* 2 * Driver for batteries with DS2760 chips inside. 3 * 4 * Copyright © 2007 Anton Vorontsov 5 * 2004-2007 Matt Reimer 6 * 2004 Szabolcs Gyurko 7 * 8 * Use consistent with the GNU GPL is permitted, 9 * provided that this copyright notice is 10 * preserved in its entirety in all copies and derived works. 11 * 12 * Author: Anton Vorontsov <cbou@mail.ru> 13 * February 2007 14 * 15 * Matt Reimer <mreimer@vpop.net> 16 * April 2004, 2005, 2007 17 * 18 * Szabolcs Gyurko <szabolcs.gyurko@tlt.hu> 19 * September 2004 20 */ 21 22#include <linux/module.h> 23#include <linux/param.h> 24#include <linux/jiffies.h> 25#include <linux/workqueue.h> 26#include <linux/pm.h> 27#include <linux/slab.h> 28#include <linux/platform_device.h> 29#include <linux/power_supply.h> 30 31#include "../w1/w1.h" 32#include "../w1/slaves/w1_ds2760.h" 33 34struct ds2760_device_info { 35 struct device *dev; 36 37 /* DS2760 data, valid after calling ds2760_battery_read_status() */ 38 unsigned long update_time; /* jiffies when data read */ 39 char raw[DS2760_DATA_SIZE]; /* raw DS2760 data */ 40 int voltage_raw; /* units of 4.88 mV */ 41 int voltage_uV; /* units of µV */ 42 int current_raw; /* units of 0.625 mA */ 43 int current_uA; /* units of µA */ 44 int accum_current_raw; /* units of 0.25 mAh */ 45 int accum_current_uAh; /* units of µAh */ 46 int temp_raw; /* units of 0.125 °C */ 47 int temp_C; /* units of 0.1 °C */ 48 int rated_capacity; /* units of µAh */ 49 int rem_capacity; /* percentage */ 50 int full_active_uAh; /* units of µAh */ 51 int empty_uAh; /* units of µAh */ 52 int life_sec; /* units of seconds */ 53 int charge_status; /* POWER_SUPPLY_STATUS_* */ 54 55 int full_counter; 56 struct power_supply bat; 57 struct device *w1_dev; 58 struct workqueue_struct *monitor_wqueue; 59 struct delayed_work monitor_work; 60 struct delayed_work set_charged_work; 61}; 62 63static unsigned int cache_time = 1000; 64module_param(cache_time, uint, 0644); 65MODULE_PARM_DESC(cache_time, "cache time in milliseconds"); 66 67static unsigned int pmod_enabled; 68module_param(pmod_enabled, bool, 0644); 69MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit"); 70 71static unsigned int rated_capacity; 72module_param(rated_capacity, uint, 0644); 73MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index"); 74 75static unsigned int current_accum; 76module_param(current_accum, uint, 0644); 77MODULE_PARM_DESC(current_accum, "current accumulator value"); 78 79/* Some batteries have their rated capacity stored a N * 10 mAh, while 80 * others use an index into this table. */ 81static int rated_capacities[] = { 82 0, 83 920, /* Samsung */ 84 920, /* BYD */ 85 920, /* Lishen */ 86 920, /* NEC */ 87 1440, /* Samsung */ 88 1440, /* BYD */ 89 1440, /* Lishen */ 90 1440, /* NEC */ 91 2880, /* Samsung */ 92 2880, /* BYD */ 93 2880, /* Lishen */ 94 2880 /* NEC */ 95}; 96 97/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C 98 * temp is in Celsius */ 99static int battery_interpolate(int array[], int temp) 100{ 101 int index, dt; 102 103 if (temp <= 0) 104 return array[0]; 105 if (temp >= 40) 106 return array[4]; 107 108 index = temp / 10; 109 dt = temp % 10; 110 111 return array[index] + (((array[index + 1] - array[index]) * dt) / 10); 112} 113 114static int ds2760_battery_read_status(struct ds2760_device_info *di) 115{ 116 int ret, i, start, count, scale[5]; 117 118 if (di->update_time && time_before(jiffies, di->update_time + 119 msecs_to_jiffies(cache_time))) 120 return 0; 121 122 /* The first time we read the entire contents of SRAM/EEPROM, 123 * but after that we just read the interesting bits that change. */ 124 if (di->update_time == 0) { 125 start = 0; 126 count = DS2760_DATA_SIZE; 127 } else { 128 start = DS2760_VOLTAGE_MSB; 129 count = DS2760_TEMP_LSB - start + 1; 130 } 131 132 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count); 133 if (ret != count) { 134 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n", 135 di->w1_dev); 136 return 1; 137 } 138 139 di->update_time = jiffies; 140 141 /* DS2760 reports voltage in units of 4.88mV, but the battery class 142 * reports in units of uV, so convert by multiplying by 4880. */ 143 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) | 144 (di->raw[DS2760_VOLTAGE_LSB] >> 5); 145 di->voltage_uV = di->voltage_raw * 4880; 146 147 /* DS2760 reports current in signed units of 0.625mA, but the battery 148 * class reports in units of µA, so convert by multiplying by 625. */ 149 di->current_raw = 150 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) | 151 (di->raw[DS2760_CURRENT_LSB] >> 3); 152 di->current_uA = di->current_raw * 625; 153 154 /* DS2760 reports accumulated current in signed units of 0.25mAh. */ 155 di->accum_current_raw = 156 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) | 157 di->raw[DS2760_CURRENT_ACCUM_LSB]; 158 di->accum_current_uAh = di->accum_current_raw * 250; 159 160 /* DS2760 reports temperature in signed units of 0.125°C, but the 161 * battery class reports in units of 1/10 °C, so we convert by 162 * multiplying by .125 * 10 = 1.25. */ 163 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) | 164 (di->raw[DS2760_TEMP_LSB] >> 5); 165 di->temp_C = di->temp_raw + (di->temp_raw / 4); 166 167 /* At least some battery monitors (e.g. HP iPAQ) store the battery's 168 * maximum rated capacity. */ 169 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities)) 170 di->rated_capacity = rated_capacities[ 171 (unsigned int)di->raw[DS2760_RATED_CAPACITY]]; 172 else 173 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10; 174 175 di->rated_capacity *= 1000; /* convert to µAh */ 176 177 /* Calculate the full level at the present temperature. */ 178 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 | 179 di->raw[DS2760_ACTIVE_FULL + 1]; 180 181 /* If the full_active_uAh value is not given, fall back to the rated 182 * capacity. This is likely to happen when chips are not part of the 183 * battery pack and is therefore not bootstrapped. */ 184 if (di->full_active_uAh == 0) 185 di->full_active_uAh = di->rated_capacity / 1000L; 186 187 scale[0] = di->full_active_uAh; 188 for (i = 1; i < 5; i++) 189 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i]; 190 191 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10); 192 di->full_active_uAh *= 1000; /* convert to µAh */ 193 194 /* Calculate the empty level at the present temperature. */ 195 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4]; 196 for (i = 3; i >= 0; i--) 197 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i]; 198 199 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); 200 di->empty_uAh *= 1000; /* convert to µAh */ 201 202 if (di->full_active_uAh == di->empty_uAh) 203 di->rem_capacity = 0; 204 else 205 /* From Maxim Application Note 131: remaining capacity = 206 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ 207 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / 208 (di->full_active_uAh - di->empty_uAh); 209 210 if (di->rem_capacity < 0) 211 di->rem_capacity = 0; 212 if (di->rem_capacity > 100) 213 di->rem_capacity = 100; 214 215 if (di->current_uA >= 100L) 216 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L) 217 / (di->current_uA / 100L); 218 else 219 di->life_sec = 0; 220 221 return 0; 222} 223 224static void ds2760_battery_set_current_accum(struct ds2760_device_info *di, 225 unsigned int acr_val) 226{ 227 unsigned char acr[2]; 228 229 /* acr is in units of 0.25 mAh */ 230 acr_val *= 4L; 231 acr_val /= 1000; 232 233 acr[0] = acr_val >> 8; 234 acr[1] = acr_val & 0xff; 235 236 if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2) 237 dev_warn(di->dev, "ACR write failed\n"); 238} 239 240static void ds2760_battery_update_status(struct ds2760_device_info *di) 241{ 242 int old_charge_status = di->charge_status; 243 244 ds2760_battery_read_status(di); 245 246 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN) 247 di->full_counter = 0; 248 249 if (power_supply_am_i_supplied(&di->bat)) { 250 if (di->current_uA > 10000) { 251 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 252 di->full_counter = 0; 253 } else if (di->current_uA < -5000) { 254 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING) 255 dev_notice(di->dev, "not enough power to " 256 "charge\n"); 257 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING; 258 di->full_counter = 0; 259 } else if (di->current_uA < 10000 && 260 di->charge_status != POWER_SUPPLY_STATUS_FULL) { 261 262 /* Don't consider the battery to be full unless 263 * we've seen the current < 10 mA at least two 264 * consecutive times. */ 265 266 di->full_counter++; 267 268 if (di->full_counter < 2) { 269 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 270 } else { 271 di->charge_status = POWER_SUPPLY_STATUS_FULL; 272 ds2760_battery_set_current_accum(di, 273 di->full_active_uAh); 274 } 275 } 276 } else { 277 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING; 278 di->full_counter = 0; 279 } 280 281 if (di->charge_status != old_charge_status) 282 power_supply_changed(&di->bat); 283} 284 285static void ds2760_battery_write_status(struct ds2760_device_info *di, 286 char status) 287{ 288 if (status == di->raw[DS2760_STATUS_REG]) 289 return; 290 291 w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1); 292 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 293 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 294} 295 296static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di, 297 unsigned char rated_capacity) 298{ 299 if (rated_capacity == di->raw[DS2760_RATED_CAPACITY]) 300 return; 301 302 w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1); 303 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 304 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 305} 306 307static void ds2760_battery_work(struct work_struct *work) 308{ 309 struct ds2760_device_info *di = container_of(work, 310 struct ds2760_device_info, monitor_work.work); 311 const int interval = HZ * 60; 312 313 dev_dbg(di->dev, "%s\n", __func__); 314 315 ds2760_battery_update_status(di); 316 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval); 317} 318 319#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \ 320 bat); 321 322static void ds2760_battery_external_power_changed(struct power_supply *psy) 323{ 324 struct ds2760_device_info *di = to_ds2760_device_info(psy); 325 326 dev_dbg(di->dev, "%s\n", __func__); 327 328 cancel_delayed_work(&di->monitor_work); 329 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10); 330} 331 332 333static void ds2760_battery_set_charged_work(struct work_struct *work) 334{ 335 char bias; 336 struct ds2760_device_info *di = container_of(work, 337 struct ds2760_device_info, set_charged_work.work); 338 339 dev_dbg(di->dev, "%s\n", __func__); 340 341 ds2760_battery_read_status(di); 342 343 /* When we get notified by external circuitry that the battery is 344 * considered fully charged now, we know that there is no current 345 * flow any more. However, the ds2760's internal current meter is 346 * too inaccurate to rely on - spec say something ~15% failure. 347 * Hence, we use the current offset bias register to compensate 348 * that error. 349 */ 350 351 if (!power_supply_am_i_supplied(&di->bat)) 352 return; 353 354 bias = (signed char) di->current_raw + 355 (signed char) di->raw[DS2760_CURRENT_OFFSET_BIAS]; 356 357 dev_dbg(di->dev, "%s: bias = %d\n", __func__, bias); 358 359 w1_ds2760_write(di->w1_dev, &bias, DS2760_CURRENT_OFFSET_BIAS, 1); 360 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 361 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 362 363 /* Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS 364 * value won't be read back by ds2760_battery_read_status() */ 365 di->raw[DS2760_CURRENT_OFFSET_BIAS] = bias; 366} 367 368static void ds2760_battery_set_charged(struct power_supply *psy) 369{ 370 struct ds2760_device_info *di = to_ds2760_device_info(psy); 371 372 /* postpone the actual work by 20 secs. This is for debouncing GPIO 373 * signals and to let the current value settle. See AN4188. */ 374 cancel_delayed_work(&di->set_charged_work); 375 queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20); 376} 377 378static int ds2760_battery_get_property(struct power_supply *psy, 379 enum power_supply_property psp, 380 union power_supply_propval *val) 381{ 382 struct ds2760_device_info *di = to_ds2760_device_info(psy); 383 384 switch (psp) { 385 case POWER_SUPPLY_PROP_STATUS: 386 val->intval = di->charge_status; 387 return 0; 388 default: 389 break; 390 } 391 392 ds2760_battery_read_status(di); 393 394 switch (psp) { 395 case POWER_SUPPLY_PROP_VOLTAGE_NOW: 396 val->intval = di->voltage_uV; 397 break; 398 case POWER_SUPPLY_PROP_CURRENT_NOW: 399 val->intval = di->current_uA; 400 break; 401 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: 402 val->intval = di->rated_capacity; 403 break; 404 case POWER_SUPPLY_PROP_CHARGE_FULL: 405 val->intval = di->full_active_uAh; 406 break; 407 case POWER_SUPPLY_PROP_CHARGE_EMPTY: 408 val->intval = di->empty_uAh; 409 break; 410 case POWER_SUPPLY_PROP_CHARGE_NOW: 411 val->intval = di->accum_current_uAh; 412 break; 413 case POWER_SUPPLY_PROP_TEMP: 414 val->intval = di->temp_C; 415 break; 416 case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: 417 val->intval = di->life_sec; 418 break; 419 case POWER_SUPPLY_PROP_CAPACITY: 420 val->intval = di->rem_capacity; 421 break; 422 default: 423 return -EINVAL; 424 } 425 426 return 0; 427} 428 429static enum power_supply_property ds2760_battery_props[] = { 430 POWER_SUPPLY_PROP_STATUS, 431 POWER_SUPPLY_PROP_VOLTAGE_NOW, 432 POWER_SUPPLY_PROP_CURRENT_NOW, 433 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 434 POWER_SUPPLY_PROP_CHARGE_FULL, 435 POWER_SUPPLY_PROP_CHARGE_EMPTY, 436 POWER_SUPPLY_PROP_CHARGE_NOW, 437 POWER_SUPPLY_PROP_TEMP, 438 POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW, 439 POWER_SUPPLY_PROP_CAPACITY, 440}; 441 442static int ds2760_battery_probe(struct platform_device *pdev) 443{ 444 char status; 445 int retval = 0; 446 struct ds2760_device_info *di; 447 448 di = kzalloc(sizeof(*di), GFP_KERNEL); 449 if (!di) { 450 retval = -ENOMEM; 451 goto di_alloc_failed; 452 } 453 454 platform_set_drvdata(pdev, di); 455 456 di->dev = &pdev->dev; 457 di->w1_dev = pdev->dev.parent; 458 di->bat.name = dev_name(&pdev->dev); 459 di->bat.type = POWER_SUPPLY_TYPE_BATTERY; 460 di->bat.properties = ds2760_battery_props; 461 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props); 462 di->bat.get_property = ds2760_battery_get_property; 463 di->bat.set_charged = ds2760_battery_set_charged; 464 di->bat.external_power_changed = 465 ds2760_battery_external_power_changed; 466 467 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 468 469 /* enable sleep mode feature */ 470 ds2760_battery_read_status(di); 471 status = di->raw[DS2760_STATUS_REG]; 472 if (pmod_enabled) 473 status |= DS2760_STATUS_PMOD; 474 else 475 status &= ~DS2760_STATUS_PMOD; 476 477 ds2760_battery_write_status(di, status); 478 479 /* set rated capacity from module param */ 480 if (rated_capacity) 481 ds2760_battery_write_rated_capacity(di, rated_capacity); 482 483 /* set current accumulator if given as parameter. 484 * this should only be done for bootstrapping the value */ 485 if (current_accum) 486 ds2760_battery_set_current_accum(di, current_accum); 487 488 retval = power_supply_register(&pdev->dev, &di->bat); 489 if (retval) { 490 dev_err(di->dev, "failed to register battery\n"); 491 goto batt_failed; 492 } 493 494 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work); 495 INIT_DELAYED_WORK(&di->set_charged_work, 496 ds2760_battery_set_charged_work); 497 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev)); 498 if (!di->monitor_wqueue) { 499 retval = -ESRCH; 500 goto workqueue_failed; 501 } 502 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1); 503 504 goto success; 505 506workqueue_failed: 507 power_supply_unregister(&di->bat); 508batt_failed: 509 kfree(di); 510di_alloc_failed: 511success: 512 return retval; 513} 514 515static int ds2760_battery_remove(struct platform_device *pdev) 516{ 517 struct ds2760_device_info *di = platform_get_drvdata(pdev); 518 519 cancel_rearming_delayed_workqueue(di->monitor_wqueue, 520 &di->monitor_work); 521 cancel_rearming_delayed_workqueue(di->monitor_wqueue, 522 &di->set_charged_work); 523 destroy_workqueue(di->monitor_wqueue); 524 power_supply_unregister(&di->bat); 525 526 return 0; 527} 528 529#ifdef CONFIG_PM 530 531static int ds2760_battery_suspend(struct platform_device *pdev, 532 pm_message_t state) 533{ 534 struct ds2760_device_info *di = platform_get_drvdata(pdev); 535 536 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 537 538 return 0; 539} 540 541static int ds2760_battery_resume(struct platform_device *pdev) 542{ 543 struct ds2760_device_info *di = platform_get_drvdata(pdev); 544 545 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 546 power_supply_changed(&di->bat); 547 548 cancel_delayed_work(&di->monitor_work); 549 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ); 550 551 return 0; 552} 553 554#else 555 556#define ds2760_battery_suspend NULL 557#define ds2760_battery_resume NULL 558 559#endif /* CONFIG_PM */ 560 561MODULE_ALIAS("platform:ds2760-battery"); 562 563static struct platform_driver ds2760_battery_driver = { 564 .driver = { 565 .name = "ds2760-battery", 566 }, 567 .probe = ds2760_battery_probe, 568 .remove = ds2760_battery_remove, 569 .suspend = ds2760_battery_suspend, 570 .resume = ds2760_battery_resume, 571}; 572 573static int __init ds2760_battery_init(void) 574{ 575 return platform_driver_register(&ds2760_battery_driver); 576} 577 578static void __exit ds2760_battery_exit(void) 579{ 580 platform_driver_unregister(&ds2760_battery_driver); 581} 582 583module_init(ds2760_battery_init); 584module_exit(ds2760_battery_exit); 585 586MODULE_LICENSE("GPL"); 587MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, " 588 "Matt Reimer <mreimer@vpop.net>, " 589 "Anton Vorontsov <cbou@mail.ru>"); 590MODULE_DESCRIPTION("ds2760 battery driver"); 591