drivers/power/ds2760_battery.c

   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
  34 struct 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
  63 static unsigned int cache_time = 1000;
  64 module_param(cache_time, uint, 0644);
  65 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
  66
  67 static bool pmod_enabled;
  68 module_param(pmod_enabled, bool, 0644);
  69 MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
  70
  71 static unsigned int rated_capacity;
  72 module_param(rated_capacity, uint, 0644);
  73 MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index");
  74
  75 static unsigned int current_accum;
  76 module_param(current_accum, uint, 0644);
  77 MODULE_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. */
  81 static int rated_capacities[] = {
  82         0,
  83         920,    /* Samsung */
  84         920,    /* BYD */
  85         920,    /* Lishen */
  86         920,    /* NEC */
  87         1440,   /* Samsung */
  88         1440,   /* BYD */
  89 #ifdef CONFIG_MACH_H4700
  90         1800,   /* HP iPAQ hx4700 3.7V 1800mAh (359113-001) */
  91 #else
  92         1440,   /* Lishen */
  93 #endif
  94         1440,   /* NEC */
  95         2880,   /* Samsung */
  96         2880,   /* BYD */
  97         2880,   /* Lishen */
  98         2880,   /* NEC */
  99 #ifdef CONFIG_MACH_H4700
 100         0,
 101         3600,   /* HP iPAQ hx4700 3.7V 3600mAh (359114-001) */
 102 #endif
 103 };
 104
 105 /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
 106  * temp is in Celsius */
 107 static int battery_interpolate(int array[], int temp)
 108 {
 109         int index, dt;
 110
 111         if (temp <= 0)
 112                 return array[0];
 113         if (temp >= 40)
 114                 return array[4];
 115
 116         index = temp / 10;
 117         dt    = temp % 10;
 118
 119         return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
 120 }
 121
 122 static int ds2760_battery_read_status(struct ds2760_device_info *di)
 123 {
 124         int ret, i, start, count, scale[5];
 125
 126         if (di->update_time && time_before(jiffies, di->update_time +
 127                                            msecs_to_jiffies(cache_time)))
 128                 return 0;
 129
 130         /* The first time we read the entire contents of SRAM/EEPROM,
 131          * but after that we just read the interesting bits that change. */
 132         if (di->update_time == 0) {
 133                 start = 0;
 134                 count = DS2760_DATA_SIZE;
 135         } else {
 136                 start = DS2760_VOLTAGE_MSB;
 137                 count = DS2760_TEMP_LSB - start + 1;
 138         }
 139
 140         ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
 141         if (ret != count) {
 142                 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
 143                          di->w1_dev);
 144                 return 1;
 145         }
 146
 147         di->update_time = jiffies;
 148
 149         /* DS2760 reports voltage in units of 4.88mV, but the battery class
 150          * reports in units of uV, so convert by multiplying by 4880. */
 151         di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
 152                           (di->raw[DS2760_VOLTAGE_LSB] >> 5);
 153         di->voltage_uV = di->voltage_raw * 4880;
 154
 155         /* DS2760 reports current in signed units of 0.625mA, but the battery
 156          * class reports in units of µA, so convert by multiplying by 625. */
 157         di->current_raw =
 158             (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
 159                           (di->raw[DS2760_CURRENT_LSB] >> 3);
 160         di->current_uA = di->current_raw * 625;
 161
 162         /* DS2760 reports accumulated current in signed units of 0.25mAh. */
 163         di->accum_current_raw =
 164             (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
 165                            di->raw[DS2760_CURRENT_ACCUM_LSB];
 166         di->accum_current_uAh = di->accum_current_raw * 250;
 167
 168         /* DS2760 reports temperature in signed units of 0.125°C, but the
 169          * battery class reports in units of 1/10 °C, so we convert by
 170          * multiplying by .125 * 10 = 1.25. */
 171         di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
 172                                      (di->raw[DS2760_TEMP_LSB] >> 5);
 173         di->temp_C = di->temp_raw + (di->temp_raw / 4);
 174
 175         /* At least some battery monitors (e.g. HP iPAQ) store the battery's
 176          * maximum rated capacity. */
 177         if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
 178                 di->rated_capacity = rated_capacities[
 179                         (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
 180         else
 181                 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
 182
 183         di->rated_capacity *= 1000; /* convert to µAh */
 184
 185         /* Calculate the full level at the present temperature. */
 186         di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
 187                               di->raw[DS2760_ACTIVE_FULL + 1];
 188
 189         /* If the full_active_uAh value is not given, fall back to the rated
 190          * capacity. This is likely to happen when chips are not part of the
 191          * battery pack and is therefore not bootstrapped. */
 192         if (di->full_active_uAh == 0)
 193                 di->full_active_uAh = di->rated_capacity / 1000L;
 194
 195         scale[0] = di->full_active_uAh;
 196         for (i = 1; i < 5; i++)
 197                 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 1 + i];
 198
 199         di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
 200         di->full_active_uAh *= 1000; /* convert to µAh */
 201
 202         /* Calculate the empty level at the present temperature. */
 203         scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
 204         for (i = 3; i >= 0; i--)
 205                 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
 206
 207         di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
 208         di->empty_uAh *= 1000; /* convert to µAh */
 209
 210         if (di->full_active_uAh == di->empty_uAh)
 211                 di->rem_capacity = 0;
 212         else
 213                 /* From Maxim Application Note 131: remaining capacity =
 214                  * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
 215                 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
 216                                     (di->full_active_uAh - di->empty_uAh);
 217
 218         if (di->rem_capacity < 0)
 219                 di->rem_capacity = 0;
 220         if (di->rem_capacity > 100)
 221                 di->rem_capacity = 100;
 222
 223         if (di->current_uA < -100L)
 224                 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L)
 225                                         / (di->current_uA / 100L);
 226         else
 227                 di->life_sec = 0;
 228
 229         return 0;
 230 }
 231
 232 static void ds2760_battery_set_current_accum(struct ds2760_device_info *di,
 233                                              unsigned int acr_val)
 234 {
 235         unsigned char acr[2];
 236
 237         /* acr is in units of 0.25 mAh */
 238         acr_val *= 4L;
 239         acr_val /= 1000;
 240
 241         acr[0] = acr_val >> 8;
 242         acr[1] = acr_val & 0xff;
 243
 244         if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2)
 245                 dev_warn(di->dev, "ACR write failed\n");
 246 }
 247
 248 static void ds2760_battery_update_status(struct ds2760_device_info *di)
 249 {
 250         int old_charge_status = di->charge_status;
 251
 252         ds2760_battery_read_status(di);
 253
 254         if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
 255                 di->full_counter = 0;
 256
 257         if (power_supply_am_i_supplied(&di->bat)) {
 258                 if (di->current_uA > 10000) {
 259                         di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
 260                         di->full_counter = 0;
 261                 } else if (di->current_uA < -5000) {
 262                         if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
 263                                 dev_notice(di->dev, "not enough power to "
 264                                            "charge\n");
 265                         di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
 266                         di->full_counter = 0;
 267                 } else if (di->current_uA < 10000 &&
 268                             di->charge_status != POWER_SUPPLY_STATUS_FULL) {
 269
 270                         /* Don't consider the battery to be full unless
 271                          * we've seen the current < 10 mA at least two
 272                          * consecutive times. */
 273
 274                         di->full_counter++;
 275
 276                         if (di->full_counter < 2) {
 277                                 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
 278                         } else {
 279                                 di->charge_status = POWER_SUPPLY_STATUS_FULL;
 280                                 ds2760_battery_set_current_accum(di,
 281                                                 di->full_active_uAh);
 282                         }
 283                 }
 284         } else {
 285                 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
 286                 di->full_counter = 0;
 287         }
 288
 289         if (di->charge_status != old_charge_status)
 290                 power_supply_changed(&di->bat);
 291 }
 292
 293 static void ds2760_battery_write_status(struct ds2760_device_info *di,
 294                                         char status)
 295 {
 296         if (status == di->raw[DS2760_STATUS_REG])
 297                 return;
 298
 299         w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
 300         w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 301         w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 302 }
 303
 304 static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di,
 305                                                 unsigned char rated_capacity)
 306 {
 307         if (rated_capacity == di->raw[DS2760_RATED_CAPACITY])
 308                 return;
 309
 310         w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1);
 311         w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 312         w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 313 }
 314
 315 static void ds2760_battery_write_active_full(struct ds2760_device_info *di,
 316                                              int active_full)
 317 {
 318         unsigned char tmp[2] = {
 319                 active_full >> 8,
 320                 active_full & 0xff
 321         };
 322
 323         if (tmp[0] == di->raw[DS2760_ACTIVE_FULL] &&
 324             tmp[1] == di->raw[DS2760_ACTIVE_FULL + 1])
 325                 return;
 326
 327         w1_ds2760_write(di->w1_dev, tmp, DS2760_ACTIVE_FULL, sizeof(tmp));
 328         w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK0);
 329         w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK0);
 330
 331         /* Write to the di->raw[] buffer directly - the DS2760_ACTIVE_FULL
 332          * values won't be read back by ds2760_battery_read_status() */
 333         di->raw[DS2760_ACTIVE_FULL] = tmp[0];
 334         di->raw[DS2760_ACTIVE_FULL + 1] = tmp[1];
 335 }
 336
 337 static void ds2760_battery_work(struct work_struct *work)
 338 {
 339         struct ds2760_device_info *di = container_of(work,
 340                 struct ds2760_device_info, monitor_work.work);
 341         const int interval = HZ * 60;
 342
 343         dev_dbg(di->dev, "%s\n", __func__);
 344
 345         ds2760_battery_update_status(di);
 346         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
 347 }
 348
 349 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
 350                                               bat);
 351
 352 static void ds2760_battery_external_power_changed(struct power_supply *psy)
 353 {
 354         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 355
 356         dev_dbg(di->dev, "%s\n", __func__);
 357
 358         cancel_delayed_work(&di->monitor_work);
 359         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
 360 }
 361
 362
 363 static void ds2760_battery_set_charged_work(struct work_struct *work)
 364 {
 365         char bias;
 366         struct ds2760_device_info *di = container_of(work,
 367                 struct ds2760_device_info, set_charged_work.work);
 368
 369         dev_dbg(di->dev, "%s\n", __func__);
 370
 371         ds2760_battery_read_status(di);
 372
 373         /* When we get notified by external circuitry that the battery is
 374          * considered fully charged now, we know that there is no current
 375          * flow any more. However, the ds2760's internal current meter is
 376          * too inaccurate to rely on - spec say something ~15% failure.
 377          * Hence, we use the current offset bias register to compensate
 378          * that error.
 379          */
 380
 381         if (!power_supply_am_i_supplied(&di->bat))
 382                 return;
 383
 384         bias = (signed char) di->current_raw +
 385                 (signed char) di->raw[DS2760_CURRENT_OFFSET_BIAS];
 386
 387         dev_dbg(di->dev, "%s: bias = %d\n", __func__, bias);
 388
 389         w1_ds2760_write(di->w1_dev, &bias, DS2760_CURRENT_OFFSET_BIAS, 1);
 390         w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 391         w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 392
 393         /* Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS
 394          * value won't be read back by ds2760_battery_read_status() */
 395         di->raw[DS2760_CURRENT_OFFSET_BIAS] = bias;
 396 }
 397
 398 static void ds2760_battery_set_charged(struct power_supply *psy)
 399 {
 400         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 401
 402         /* postpone the actual work by 20 secs. This is for debouncing GPIO
 403          * signals and to let the current value settle. See AN4188. */
 404         cancel_delayed_work(&di->set_charged_work);
 405         queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
 406 }
 407
 408 static int ds2760_battery_get_property(struct power_supply *psy,
 409                                        enum power_supply_property psp,
 410                                        union power_supply_propval *val)
 411 {
 412         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 413
 414         switch (psp) {
 415         case POWER_SUPPLY_PROP_STATUS:
 416                 val->intval = di->charge_status;
 417                 return 0;
 418         default:
 419                 break;
 420         }
 421
 422         ds2760_battery_read_status(di);
 423
 424         switch (psp) {
 425         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 426                 val->intval = di->voltage_uV;
 427                 break;
 428         case POWER_SUPPLY_PROP_CURRENT_NOW:
 429                 val->intval = di->current_uA;
 430                 break;
 431         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 432                 val->intval = di->rated_capacity;
 433                 break;
 434         case POWER_SUPPLY_PROP_CHARGE_FULL:
 435                 val->intval = di->full_active_uAh;
 436                 break;
 437         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 438                 val->intval = di->empty_uAh;
 439                 break;
 440         case POWER_SUPPLY_PROP_CHARGE_NOW:
 441                 val->intval = di->accum_current_uAh;
 442                 break;
 443         case POWER_SUPPLY_PROP_TEMP:
 444                 val->intval = di->temp_C;
 445                 break;
 446         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
 447                 val->intval = di->life_sec;
 448                 break;
 449         case POWER_SUPPLY_PROP_CAPACITY:
 450                 val->intval = di->rem_capacity;
 451                 break;
 452         default:
 453                 return -EINVAL;
 454         }
 455
 456         return 0;
 457 }
 458
 459 static int ds2760_battery_set_property(struct power_supply *psy,
 460                                        enum power_supply_property psp,
 461                                        const union power_supply_propval *val)
 462 {
 463         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 464
 465         switch (psp) {
 466         case POWER_SUPPLY_PROP_CHARGE_FULL:
 467                 /* the interface counts in uAh, convert the value */
 468                 ds2760_battery_write_active_full(di, val->intval / 1000L);
 469                 break;
 470
 471         case POWER_SUPPLY_PROP_CHARGE_NOW:
 472                 /* ds2760_battery_set_current_accum() does the conversion */
 473                 ds2760_battery_set_current_accum(di, val->intval);
 474                 break;
 475
 476         default:
 477                 return -EPERM;
 478         }
 479
 480         return 0;
 481 }
 482
 483 static int ds2760_battery_property_is_writeable(struct power_supply *psy,
 484                                                 enum power_supply_property psp)
 485 {
 486         switch (psp) {
 487         case POWER_SUPPLY_PROP_CHARGE_FULL:
 488         case POWER_SUPPLY_PROP_CHARGE_NOW:
 489                 return 1;
 490
 491         default:
 492                 break;
 493         }
 494
 495         return 0;
 496 }
 497
 498 static enum power_supply_property ds2760_battery_props[] = {
 499         POWER_SUPPLY_PROP_STATUS,
 500         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 501         POWER_SUPPLY_PROP_CURRENT_NOW,
 502         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 503         POWER_SUPPLY_PROP_CHARGE_FULL,
 504         POWER_SUPPLY_PROP_CHARGE_EMPTY,
 505         POWER_SUPPLY_PROP_CHARGE_NOW,
 506         POWER_SUPPLY_PROP_TEMP,
 507         POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 508         POWER_SUPPLY_PROP_CAPACITY,
 509 };
 510
 511 static int ds2760_battery_probe(struct platform_device *pdev)
 512 {
 513         char status;
 514         int retval = 0;
 515         struct ds2760_device_info *di;
 516
 517         di = kzalloc(sizeof(*di), GFP_KERNEL);
 518         if (!di) {
 519                 retval = -ENOMEM;
 520                 goto di_alloc_failed;
 521         }
 522
 523         platform_set_drvdata(pdev, di);
 524
 525         di->dev                 = &pdev->dev;
 526         di->w1_dev              = pdev->dev.parent;
 527         di->bat.name            = dev_name(&pdev->dev);
 528         di->bat.type            = POWER_SUPPLY_TYPE_BATTERY;
 529         di->bat.properties      = ds2760_battery_props;
 530         di->bat.num_properties  = ARRAY_SIZE(ds2760_battery_props);
 531         di->bat.get_property    = ds2760_battery_get_property;
 532         di->bat.set_property    = ds2760_battery_set_property;
 533         di->bat.property_is_writeable =
 534                                   ds2760_battery_property_is_writeable;
 535         di->bat.set_charged     = ds2760_battery_set_charged;
 536         di->bat.external_power_changed =
 537                                   ds2760_battery_external_power_changed;
 538
 539         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 540
 541         /* enable sleep mode feature */
 542         ds2760_battery_read_status(di);
 543         status = di->raw[DS2760_STATUS_REG];
 544         if (pmod_enabled)
 545                 status |= DS2760_STATUS_PMOD;
 546         else
 547                 status &= ~DS2760_STATUS_PMOD;
 548
 549         ds2760_battery_write_status(di, status);
 550
 551         /* set rated capacity from module param */
 552         if (rated_capacity)
 553                 ds2760_battery_write_rated_capacity(di, rated_capacity);
 554
 555         /* set current accumulator if given as parameter.
 556          * this should only be done for bootstrapping the value */
 557         if (current_accum)
 558                 ds2760_battery_set_current_accum(di, current_accum);
 559
 560         retval = power_supply_register(&pdev->dev, &di->bat);
 561         if (retval) {
 562                 dev_err(di->dev, "failed to register battery\n");
 563                 goto batt_failed;
 564         }
 565
 566         INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
 567         INIT_DELAYED_WORK(&di->set_charged_work,
 568                           ds2760_battery_set_charged_work);
 569         di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
 570         if (!di->monitor_wqueue) {
 571                 retval = -ESRCH;
 572                 goto workqueue_failed;
 573         }
 574         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
 575
 576         goto success;
 577
 578 workqueue_failed:
 579         power_supply_unregister(&di->bat);
 580 batt_failed:
 581         kfree(di);
 582 di_alloc_failed:
 583 success:
 584         return retval;
 585 }
 586
 587 static int ds2760_battery_remove(struct platform_device *pdev)
 588 {
 589         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 590
 591         cancel_delayed_work_sync(&di->monitor_work);
 592         cancel_delayed_work_sync(&di->set_charged_work);
 593         destroy_workqueue(di->monitor_wqueue);
 594         power_supply_unregister(&di->bat);
 595         kfree(di);
 596
 597         return 0;
 598 }
 599
 600 #ifdef CONFIG_PM
 601
 602 static int ds2760_battery_suspend(struct platform_device *pdev,
 603                                   pm_message_t state)
 604 {
 605         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 606
 607         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 608
 609         return 0;
 610 }
 611
 612 static int ds2760_battery_resume(struct platform_device *pdev)
 613 {
 614         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 615
 616         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 617         power_supply_changed(&di->bat);
 618
 619         cancel_delayed_work(&di->monitor_work);
 620         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
 621
 622         return 0;
 623 }
 624
 625 #else
 626
 627 #define ds2760_battery_suspend NULL
 628 #define ds2760_battery_resume NULL
 629
 630 #endif /* CONFIG_PM */
 631
 632 MODULE_ALIAS("platform:ds2760-battery");
 633
 634 static struct platform_driver ds2760_battery_driver = {
 635         .driver = {
 636                 .name = "ds2760-battery",
 637         },
 638         .probe    = ds2760_battery_probe,
 639         .remove   = ds2760_battery_remove,
 640         .suspend  = ds2760_battery_suspend,
 641         .resume   = ds2760_battery_resume,
 642 };
 643
 644 module_platform_driver(ds2760_battery_driver);
 645
 646 MODULE_LICENSE("GPL");
 647 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
 648               "Matt Reimer <mreimer@vpop.net>, "
 649               "Anton Vorontsov <cbou@mail.ru>");
 650 MODULE_DESCRIPTION("ds2760 battery driver");