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/platform_device.h>
  28 #include <linux/power_supply.h>
  29
  30 #include "../w1/w1.h"
  31 #include "../w1/slaves/w1_ds2760.h"
  32
  33 struct ds2760_device_info {
  34         struct device *dev;
  35
  36         /* DS2760 data, valid after calling ds2760_battery_read_status() */
  37         unsigned long update_time;      /* jiffies when data read */
  38         char raw[DS2760_DATA_SIZE];     /* raw DS2760 data */
  39         int voltage_raw;                /* units of 4.88 mV */
  40         int voltage_uV;                 /* units of µV */
  41         int current_raw;                /* units of 0.625 mA */
  42         int current_uA;                 /* units of µA */
  43         int accum_current_raw;          /* units of 0.25 mAh */
  44         int accum_current_uAh;          /* units of µAh */
  45         int temp_raw;                   /* units of 0.125 °C */
  46         int temp_C;                     /* units of 0.1 °C */
  47         int rated_capacity;             /* units of µAh */
  48         int rem_capacity;               /* percentage */
  49         int full_active_uAh;            /* units of µAh */
  50         int empty_uAh;                  /* units of µAh */
  51         int life_sec;                   /* units of seconds */
  52         int charge_status;              /* POWER_SUPPLY_STATUS_* */
  53
  54         int full_counter;
  55         struct power_supply bat;
  56         struct device *w1_dev;
  57         struct workqueue_struct *monitor_wqueue;
  58         struct delayed_work monitor_work;
  59 };
  60
  61 static unsigned int cache_time = 1000;
  62 module_param(cache_time, uint, 0644);
  63 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
  64
  65 static unsigned int pmod_enabled;
  66 module_param(pmod_enabled, bool, 0644);
  67 MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
  68
  69 /* Some batteries have their rated capacity stored a N * 10 mAh, while
  70  * others use an index into this table. */
  71 static int rated_capacities[] = {
  72         0,
  73         920,    /* Samsung */
  74         920,    /* BYD */
  75         920,    /* Lishen */
  76         920,    /* NEC */
  77         1440,   /* Samsung */
  78         1440,   /* BYD */
  79         1440,   /* Lishen */
  80         1440,   /* NEC */
  81         2880,   /* Samsung */
  82         2880,   /* BYD */
  83         2880,   /* Lishen */
  84         2880    /* NEC */
  85 };
  86
  87 /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
  88  * temp is in Celsius */
  89 static int battery_interpolate(int array[], int temp)
  90 {
  91         int index, dt;
  92
  93         if (temp <= 0)
  94                 return array[0];
  95         if (temp >= 40)
  96                 return array[4];
  97
  98         index = temp / 10;
  99         dt    = temp % 10;
 100
 101         return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
 102 }
 103
 104 static int ds2760_battery_read_status(struct ds2760_device_info *di)
 105 {
 106         int ret, i, start, count, scale[5];
 107
 108         if (di->update_time && time_before(jiffies, di->update_time +
 109                                            msecs_to_jiffies(cache_time)))
 110                 return 0;
 111
 112         /* The first time we read the entire contents of SRAM/EEPROM,
 113          * but after that we just read the interesting bits that change. */
 114         if (di->update_time == 0) {
 115                 start = 0;
 116                 count = DS2760_DATA_SIZE;
 117         } else {
 118                 start = DS2760_VOLTAGE_MSB;
 119                 count = DS2760_TEMP_LSB - start + 1;
 120         }
 121
 122         ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
 123         if (ret != count) {
 124                 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
 125                          di->w1_dev);
 126                 return 1;
 127         }
 128
 129         di->update_time = jiffies;
 130
 131         /* DS2760 reports voltage in units of 4.88mV, but the battery class
 132          * reports in units of uV, so convert by multiplying by 4880. */
 133         di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
 134                           (di->raw[DS2760_VOLTAGE_LSB] >> 5);
 135         di->voltage_uV = di->voltage_raw * 4880;
 136
 137         /* DS2760 reports current in signed units of 0.625mA, but the battery
 138          * class reports in units of µA, so convert by multiplying by 625. */
 139         di->current_raw =
 140             (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
 141                           (di->raw[DS2760_CURRENT_LSB] >> 3);
 142         di->current_uA = di->current_raw * 625;
 143
 144         /* DS2760 reports accumulated current in signed units of 0.25mAh. */
 145         di->accum_current_raw =
 146             (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
 147                            di->raw[DS2760_CURRENT_ACCUM_LSB];
 148         di->accum_current_uAh = di->accum_current_raw * 250;
 149
 150         /* DS2760 reports temperature in signed units of 0.125°C, but the
 151          * battery class reports in units of 1/10 °C, so we convert by
 152          * multiplying by .125 * 10 = 1.25. */
 153         di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
 154                                      (di->raw[DS2760_TEMP_LSB] >> 5);
 155         di->temp_C = di->temp_raw + (di->temp_raw / 4);
 156
 157         /* At least some battery monitors (e.g. HP iPAQ) store the battery's
 158          * maximum rated capacity. */
 159         if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
 160                 di->rated_capacity = rated_capacities[
 161                         (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
 162         else
 163                 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
 164
 165         di->rated_capacity *= 1000; /* convert to µAh */
 166
 167         /* Calculate the full level at the present temperature. */
 168         di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
 169                               di->raw[DS2760_ACTIVE_FULL + 1];
 170
 171         scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 |
 172                    di->raw[DS2760_ACTIVE_FULL + 1];
 173         for (i = 1; i < 5; i++)
 174                 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
 175
 176         di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
 177         di->full_active_uAh *= 1000; /* convert to µAh */
 178
 179         /* Calculate the empty level at the present temperature. */
 180         scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
 181         for (i = 3; i >= 0; i--)
 182                 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
 183
 184         di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
 185         di->empty_uAh *= 1000; /* convert to µAh */
 186
 187         if (di->full_active_uAh == di->empty_uAh)
 188                 di->rem_capacity = 0;
 189         else
 190                 /* From Maxim Application Note 131: remaining capacity =
 191                  * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
 192                 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
 193                                     (di->full_active_uAh - di->empty_uAh);
 194
 195         if (di->rem_capacity < 0)
 196                 di->rem_capacity = 0;
 197         if (di->rem_capacity > 100)
 198                 di->rem_capacity = 100;
 199
 200         if (di->current_uA)
 201                 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
 202                                  3600L) / di->current_uA;
 203         else
 204                 di->life_sec = 0;
 205
 206         return 0;
 207 }
 208
 209 static void ds2760_battery_update_status(struct ds2760_device_info *di)
 210 {
 211         int old_charge_status = di->charge_status;
 212
 213         ds2760_battery_read_status(di);
 214
 215         if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
 216                 di->full_counter = 0;
 217
 218         if (power_supply_am_i_supplied(&di->bat)) {
 219                 if (di->current_uA > 10000) {
 220                         di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
 221                         di->full_counter = 0;
 222                 } else if (di->current_uA < -5000) {
 223                         if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
 224                                 dev_notice(di->dev, "not enough power to "
 225                                            "charge\n");
 226                         di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
 227                         di->full_counter = 0;
 228                 } else if (di->current_uA < 10000 &&
 229                             di->charge_status != POWER_SUPPLY_STATUS_FULL) {
 230
 231                         /* Don't consider the battery to be full unless
 232                          * we've seen the current < 10 mA at least two
 233                          * consecutive times. */
 234
 235                         di->full_counter++;
 236
 237                         if (di->full_counter < 2) {
 238                                 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
 239                         } else {
 240                                 unsigned char acr[2];
 241                                 int acr_val;
 242
 243                                 /* acr is in units of 0.25 mAh */
 244                                 acr_val = di->full_active_uAh * 4L / 1000;
 245
 246                                 acr[0] = acr_val >> 8;
 247                                 acr[1] = acr_val & 0xff;
 248
 249                                 if (w1_ds2760_write(di->w1_dev, acr,
 250                                     DS2760_CURRENT_ACCUM_MSB, 2) < 2)
 251                                         dev_warn(di->dev,
 252                                                  "ACR reset failed\n");
 253
 254                                 di->charge_status = POWER_SUPPLY_STATUS_FULL;
 255                         }
 256                 }
 257         } else {
 258                 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
 259                 di->full_counter = 0;
 260         }
 261
 262         if (di->charge_status != old_charge_status)
 263                 power_supply_changed(&di->bat);
 264 }
 265
 266 static void ds2760_battery_write_status(struct ds2760_device_info *di,
 267                                         char status)
 268 {
 269         if (status == di->raw[DS2760_STATUS_REG])
 270                 return;
 271
 272         w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
 273         w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 274         w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
 275 }
 276
 277 static void ds2760_battery_work(struct work_struct *work)
 278 {
 279         struct ds2760_device_info *di = container_of(work,
 280                 struct ds2760_device_info, monitor_work.work);
 281         const int interval = HZ * 60;
 282
 283         dev_dbg(di->dev, "%s\n", __func__);
 284
 285         ds2760_battery_update_status(di);
 286         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
 287 }
 288
 289 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
 290                                               bat);
 291
 292 static void ds2760_battery_external_power_changed(struct power_supply *psy)
 293 {
 294         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 295
 296         dev_dbg(di->dev, "%s\n", __func__);
 297
 298         cancel_delayed_work(&di->monitor_work);
 299         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
 300 }
 301
 302 static int ds2760_battery_get_property(struct power_supply *psy,
 303                                        enum power_supply_property psp,
 304                                        union power_supply_propval *val)
 305 {
 306         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 307
 308         switch (psp) {
 309         case POWER_SUPPLY_PROP_STATUS:
 310                 val->intval = di->charge_status;
 311                 return 0;
 312         default:
 313                 break;
 314         }
 315
 316         ds2760_battery_read_status(di);
 317
 318         switch (psp) {
 319         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 320                 val->intval = di->voltage_uV;
 321                 break;
 322         case POWER_SUPPLY_PROP_CURRENT_NOW:
 323                 val->intval = di->current_uA;
 324                 break;
 325         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 326                 val->intval = di->rated_capacity;
 327                 break;
 328         case POWER_SUPPLY_PROP_CHARGE_FULL:
 329                 val->intval = di->full_active_uAh;
 330                 break;
 331         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 332                 val->intval = di->empty_uAh;
 333                 break;
 334         case POWER_SUPPLY_PROP_CHARGE_NOW:
 335                 val->intval = di->accum_current_uAh;
 336                 break;
 337         case POWER_SUPPLY_PROP_TEMP:
 338                 val->intval = di->temp_C;
 339                 break;
 340         default:
 341                 return -EINVAL;
 342         }
 343
 344         return 0;
 345 }
 346
 347 static enum power_supply_property ds2760_battery_props[] = {
 348         POWER_SUPPLY_PROP_STATUS,
 349         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 350         POWER_SUPPLY_PROP_CURRENT_NOW,
 351         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 352         POWER_SUPPLY_PROP_CHARGE_FULL,
 353         POWER_SUPPLY_PROP_CHARGE_EMPTY,
 354         POWER_SUPPLY_PROP_CHARGE_NOW,
 355         POWER_SUPPLY_PROP_TEMP,
 356 };
 357
 358 static int ds2760_battery_probe(struct platform_device *pdev)
 359 {
 360         char status;
 361         int retval = 0;
 362         struct ds2760_device_info *di;
 363
 364         di = kzalloc(sizeof(*di), GFP_KERNEL);
 365         if (!di) {
 366                 retval = -ENOMEM;
 367                 goto di_alloc_failed;
 368         }
 369
 370         platform_set_drvdata(pdev, di);
 371
 372         di->dev                 = &pdev->dev;
 373         di->w1_dev              = pdev->dev.parent;
 374         di->bat.name            = dev_name(&pdev->dev);
 375         di->bat.type            = POWER_SUPPLY_TYPE_BATTERY;
 376         di->bat.properties      = ds2760_battery_props;
 377         di->bat.num_properties  = ARRAY_SIZE(ds2760_battery_props);
 378         di->bat.get_property    = ds2760_battery_get_property;
 379         di->bat.external_power_changed =
 380                                   ds2760_battery_external_power_changed;
 381
 382         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 383
 384         retval = power_supply_register(&pdev->dev, &di->bat);
 385         if (retval) {
 386                 dev_err(di->dev, "failed to register battery\n");
 387                 goto batt_failed;
 388         }
 389
 390         /* enable sleep mode feature */
 391         ds2760_battery_read_status(di);
 392         status = di->raw[DS2760_STATUS_REG];
 393         if (pmod_enabled)
 394                 status |= DS2760_STATUS_PMOD;
 395         else
 396                 status &= ~DS2760_STATUS_PMOD;
 397
 398         ds2760_battery_write_status(di, status);
 399
 400         INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
 401         di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
 402         if (!di->monitor_wqueue) {
 403                 retval = -ESRCH;
 404                 goto workqueue_failed;
 405         }
 406         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
 407
 408         goto success;
 409
 410 workqueue_failed:
 411         power_supply_unregister(&di->bat);
 412 batt_failed:
 413         kfree(di);
 414 di_alloc_failed:
 415 success:
 416         return retval;
 417 }
 418
 419 static int ds2760_battery_remove(struct platform_device *pdev)
 420 {
 421         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 422
 423         cancel_rearming_delayed_workqueue(di->monitor_wqueue,
 424                                           &di->monitor_work);
 425         destroy_workqueue(di->monitor_wqueue);
 426         power_supply_unregister(&di->bat);
 427
 428         return 0;
 429 }
 430
 431 #ifdef CONFIG_PM
 432
 433 static int ds2760_battery_suspend(struct platform_device *pdev,
 434                                   pm_message_t state)
 435 {
 436         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 437
 438         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 439
 440         return 0;
 441 }
 442
 443 static int ds2760_battery_resume(struct platform_device *pdev)
 444 {
 445         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 446
 447         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 448         power_supply_changed(&di->bat);
 449
 450         cancel_delayed_work(&di->monitor_work);
 451         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
 452
 453         return 0;
 454 }
 455
 456 #else
 457
 458 #define ds2760_battery_suspend NULL
 459 #define ds2760_battery_resume NULL
 460
 461 #endif /* CONFIG_PM */
 462
 463 MODULE_ALIAS("platform:ds2760-battery");
 464
 465 static struct platform_driver ds2760_battery_driver = {
 466         .driver = {
 467                 .name = "ds2760-battery",
 468         },
 469         .probe    = ds2760_battery_probe,
 470         .remove   = ds2760_battery_remove,
 471         .suspend  = ds2760_battery_suspend,
 472         .resume   = ds2760_battery_resume,
 473 };
 474
 475 static int __init ds2760_battery_init(void)
 476 {
 477         return platform_driver_register(&ds2760_battery_driver);
 478 }
 479
 480 static void __exit ds2760_battery_exit(void)
 481 {
 482         platform_driver_unregister(&ds2760_battery_driver);
 483 }
 484
 485 module_init(ds2760_battery_init);
 486 module_exit(ds2760_battery_exit);
 487
 488 MODULE_LICENSE("GPL");
 489 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
 490               "Matt Reimer <mreimer@vpop.net>, "
 491               "Anton Vorontsov <cbou@mail.ru>");
 492 MODULE_DESCRIPTION("ds2760 battery driver");