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 unsigned int 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         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 */
  99 static 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
 114 static 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
 224 static 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
 240 static 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
 285 static 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
 296 static 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
 307 static 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
 322 static 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
 333 static 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
 368 static 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
 378 static 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
 429 static 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
 442 static 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
 506 workqueue_failed:
 507         power_supply_unregister(&di->bat);
 508 batt_failed:
 509         kfree(di);
 510 di_alloc_failed:
 511 success:
 512         return retval;
 513 }
 514
 515 static 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
 531 static 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
 541 static 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
 561 MODULE_ALIAS("platform:ds2760-battery");
 562
 563 static 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
 573 static int __init ds2760_battery_init(void)
 574 {
 575         return platform_driver_register(&ds2760_battery_driver);
 576 }
 577
 578 static void __exit ds2760_battery_exit(void)
 579 {
 580         platform_driver_unregister(&ds2760_battery_driver);
 581 }
 582
 583 module_init(ds2760_battery_init);
 584 module_exit(ds2760_battery_exit);
 585
 586 MODULE_LICENSE("GPL");
 587 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
 588               "Matt Reimer <mreimer@vpop.net>, "
 589               "Anton Vorontsov <cbou@mail.ru>");
 590 MODULE_DESCRIPTION("ds2760 battery driver");