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 /* Some batteries have their rated capacity stored a N * 10 mAh, while
  66  * others use an index into this table. */
  67 static int rated_capacities[] = {
  68         0,
  69         920,    /* Samsung */
  70         920,    /* BYD */
  71         920,    /* Lishen */
  72         920,    /* NEC */
  73         1440,   /* Samsung */
  74         1440,   /* BYD */
  75         1440,   /* Lishen */
  76         1440,   /* NEC */
  77         2880,   /* Samsung */
  78         2880,   /* BYD */
  79         2880,   /* Lishen */
  80         2880    /* NEC */
  81 };
  82
  83 /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
  84  * temp is in Celsius */
  85 static int battery_interpolate(int array[], int temp)
  86 {
  87         int index, dt;
  88
  89         if (temp <= 0)
  90                 return array[0];
  91         if (temp >= 40)
  92                 return array[4];
  93
  94         index = temp / 10;
  95         dt    = temp % 10;
  96
  97         return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
  98 }
  99
 100 static int ds2760_battery_read_status(struct ds2760_device_info *di)
 101 {
 102         int ret, i, start, count, scale[5];
 103
 104         if (di->update_time && time_before(jiffies, di->update_time +
 105                                            msecs_to_jiffies(cache_time)))
 106                 return 0;
 107
 108         /* The first time we read the entire contents of SRAM/EEPROM,
 109          * but after that we just read the interesting bits that change. */
 110         if (di->update_time == 0) {
 111                 start = 0;
 112                 count = DS2760_DATA_SIZE;
 113         } else {
 114                 start = DS2760_VOLTAGE_MSB;
 115                 count = DS2760_TEMP_LSB - start + 1;
 116         }
 117
 118         ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
 119         if (ret != count) {
 120                 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
 121                          di->w1_dev);
 122                 return 1;
 123         }
 124
 125         di->update_time = jiffies;
 126
 127         /* DS2760 reports voltage in units of 4.88mV, but the battery class
 128          * reports in units of uV, so convert by multiplying by 4880. */
 129         di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
 130                           (di->raw[DS2760_VOLTAGE_LSB] >> 5);
 131         di->voltage_uV = di->voltage_raw * 4880;
 132
 133         /* DS2760 reports current in signed units of 0.625mA, but the battery
 134          * class reports in units of µA, so convert by multiplying by 625. */
 135         di->current_raw =
 136             (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
 137                           (di->raw[DS2760_CURRENT_LSB] >> 3);
 138         di->current_uA = di->current_raw * 625;
 139
 140         /* DS2760 reports accumulated current in signed units of 0.25mAh. */
 141         di->accum_current_raw =
 142             (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
 143                            di->raw[DS2760_CURRENT_ACCUM_LSB];
 144         di->accum_current_uAh = di->accum_current_raw * 250;
 145
 146         /* DS2760 reports temperature in signed units of 0.125°C, but the
 147          * battery class reports in units of 1/10 °C, so we convert by
 148          * multiplying by .125 * 10 = 1.25. */
 149         di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
 150                                      (di->raw[DS2760_TEMP_LSB] >> 5);
 151         di->temp_C = di->temp_raw + (di->temp_raw / 4);
 152
 153         /* At least some battery monitors (e.g. HP iPAQ) store the battery's
 154          * maximum rated capacity. */
 155         if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
 156                 di->rated_capacity = rated_capacities[
 157                         (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
 158         else
 159                 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
 160
 161         di->rated_capacity *= 1000; /* convert to µAh */
 162
 163         /* Calculate the full level at the present temperature. */
 164         di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
 165                               di->raw[DS2760_ACTIVE_FULL + 1];
 166
 167         scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 |
 168                    di->raw[DS2760_ACTIVE_FULL + 1];
 169         for (i = 1; i < 5; i++)
 170                 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
 171
 172         di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
 173         di->full_active_uAh *= 1000; /* convert to µAh */
 174
 175         /* Calculate the empty level at the present temperature. */
 176         scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
 177         for (i = 3; i >= 0; i--)
 178                 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
 179
 180         di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
 181         di->empty_uAh *= 1000; /* convert to µAh */
 182
 183         if (di->full_active_uAh == di->empty_uAh)
 184                 di->rem_capacity = 0;
 185         else
 186                 /* From Maxim Application Note 131: remaining capacity =
 187                  * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
 188                 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
 189                                     (di->full_active_uAh - di->empty_uAh);
 190
 191         if (di->rem_capacity < 0)
 192                 di->rem_capacity = 0;
 193         if (di->rem_capacity > 100)
 194                 di->rem_capacity = 100;
 195
 196         if (di->current_uA)
 197                 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
 198                                  3600L) / di->current_uA;
 199         else
 200                 di->life_sec = 0;
 201
 202         return 0;
 203 }
 204
 205 static void ds2760_battery_update_status(struct ds2760_device_info *di)
 206 {
 207         int old_charge_status = di->charge_status;
 208
 209         ds2760_battery_read_status(di);
 210
 211         if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
 212                 di->full_counter = 0;
 213
 214         if (power_supply_am_i_supplied(&di->bat)) {
 215                 if (di->current_uA > 10000) {
 216                         di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
 217                         di->full_counter = 0;
 218                 } else if (di->current_uA < -5000) {
 219                         if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
 220                                 dev_notice(di->dev, "not enough power to "
 221                                            "charge\n");
 222                         di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
 223                         di->full_counter = 0;
 224                 } else if (di->current_uA < 10000 &&
 225                             di->charge_status != POWER_SUPPLY_STATUS_FULL) {
 226
 227                         /* Don't consider the battery to be full unless
 228                          * we've seen the current < 10 mA at least two
 229                          * consecutive times. */
 230
 231                         di->full_counter++;
 232
 233                         if (di->full_counter < 2) {
 234                                 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
 235                         } else {
 236                                 unsigned char acr[2];
 237                                 int acr_val;
 238
 239                                 /* acr is in units of 0.25 mAh */
 240                                 acr_val = di->full_active_uAh * 4L / 1000;
 241
 242                                 acr[0] = acr_val >> 8;
 243                                 acr[1] = acr_val & 0xff;
 244
 245                                 if (w1_ds2760_write(di->w1_dev, acr,
 246                                     DS2760_CURRENT_ACCUM_MSB, 2) < 2)
 247                                         dev_warn(di->dev,
 248                                                  "ACR reset failed\n");
 249
 250                                 di->charge_status = POWER_SUPPLY_STATUS_FULL;
 251                         }
 252                 }
 253         } else {
 254                 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
 255                 di->full_counter = 0;
 256         }
 257
 258         if (di->charge_status != old_charge_status)
 259                 power_supply_changed(&di->bat);
 260 }
 261
 262 static void ds2760_battery_work(struct work_struct *work)
 263 {
 264         struct ds2760_device_info *di = container_of(work,
 265                 struct ds2760_device_info, monitor_work.work);
 266         const int interval = HZ * 60;
 267
 268         dev_dbg(di->dev, "%s\n", __func__);
 269
 270         ds2760_battery_update_status(di);
 271         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
 272 }
 273
 274 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
 275                                               bat);
 276
 277 static void ds2760_battery_external_power_changed(struct power_supply *psy)
 278 {
 279         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 280
 281         dev_dbg(di->dev, "%s\n", __func__);
 282
 283         cancel_delayed_work(&di->monitor_work);
 284         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
 285 }
 286
 287 static int ds2760_battery_get_property(struct power_supply *psy,
 288                                        enum power_supply_property psp,
 289                                        union power_supply_propval *val)
 290 {
 291         struct ds2760_device_info *di = to_ds2760_device_info(psy);
 292
 293         switch (psp) {
 294         case POWER_SUPPLY_PROP_STATUS:
 295                 val->intval = di->charge_status;
 296                 return 0;
 297         default:
 298                 break;
 299         }
 300
 301         ds2760_battery_read_status(di);
 302
 303         switch (psp) {
 304         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 305                 val->intval = di->voltage_uV;
 306                 break;
 307         case POWER_SUPPLY_PROP_CURRENT_NOW:
 308                 val->intval = di->current_uA;
 309                 break;
 310         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 311                 val->intval = di->rated_capacity;
 312                 break;
 313         case POWER_SUPPLY_PROP_CHARGE_FULL:
 314                 val->intval = di->full_active_uAh;
 315                 break;
 316         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 317                 val->intval = di->empty_uAh;
 318                 break;
 319         case POWER_SUPPLY_PROP_CHARGE_NOW:
 320                 val->intval = di->accum_current_uAh;
 321                 break;
 322         case POWER_SUPPLY_PROP_TEMP:
 323                 val->intval = di->temp_C;
 324                 break;
 325         default:
 326                 return -EINVAL;
 327         }
 328
 329         return 0;
 330 }
 331
 332 static enum power_supply_property ds2760_battery_props[] = {
 333         POWER_SUPPLY_PROP_STATUS,
 334         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 335         POWER_SUPPLY_PROP_CURRENT_NOW,
 336         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 337         POWER_SUPPLY_PROP_CHARGE_FULL,
 338         POWER_SUPPLY_PROP_CHARGE_EMPTY,
 339         POWER_SUPPLY_PROP_CHARGE_NOW,
 340         POWER_SUPPLY_PROP_TEMP,
 341 };
 342
 343 static int ds2760_battery_probe(struct platform_device *pdev)
 344 {
 345         int retval = 0;
 346         struct ds2760_device_info *di;
 347         struct ds2760_platform_data *pdata;
 348
 349         di = kzalloc(sizeof(*di), GFP_KERNEL);
 350         if (!di) {
 351                 retval = -ENOMEM;
 352                 goto di_alloc_failed;
 353         }
 354
 355         platform_set_drvdata(pdev, di);
 356
 357         pdata = pdev->dev.platform_data;
 358         di->dev         = &pdev->dev;
 359         di->w1_dev           = pdev->dev.parent;
 360         di->bat.name       = dev_name(&pdev->dev);
 361         di->bat.type       = POWER_SUPPLY_TYPE_BATTERY;
 362         di->bat.properties     = ds2760_battery_props;
 363         di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
 364         di->bat.get_property   = ds2760_battery_get_property;
 365         di->bat.external_power_changed =
 366                                   ds2760_battery_external_power_changed;
 367
 368         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 369
 370         retval = power_supply_register(&pdev->dev, &di->bat);
 371         if (retval) {
 372                 dev_err(di->dev, "failed to register battery\n");
 373                 goto batt_failed;
 374         }
 375
 376         INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
 377         di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
 378         if (!di->monitor_wqueue) {
 379                 retval = -ESRCH;
 380                 goto workqueue_failed;
 381         }
 382         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
 383
 384         goto success;
 385
 386 workqueue_failed:
 387         power_supply_unregister(&di->bat);
 388 batt_failed:
 389         kfree(di);
 390 di_alloc_failed:
 391 success:
 392         return retval;
 393 }
 394
 395 static int ds2760_battery_remove(struct platform_device *pdev)
 396 {
 397         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 398
 399         cancel_rearming_delayed_workqueue(di->monitor_wqueue,
 400                                           &di->monitor_work);
 401         destroy_workqueue(di->monitor_wqueue);
 402         power_supply_unregister(&di->bat);
 403
 404         return 0;
 405 }
 406
 407 #ifdef CONFIG_PM
 408
 409 static int ds2760_battery_suspend(struct platform_device *pdev,
 410                                   pm_message_t state)
 411 {
 412         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 413
 414         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 415
 416         return 0;
 417 }
 418
 419 static int ds2760_battery_resume(struct platform_device *pdev)
 420 {
 421         struct ds2760_device_info *di = platform_get_drvdata(pdev);
 422
 423         di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
 424         power_supply_changed(&di->bat);
 425
 426         cancel_delayed_work(&di->monitor_work);
 427         queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
 428
 429         return 0;
 430 }
 431
 432 #else
 433
 434 #define ds2760_battery_suspend NULL
 435 #define ds2760_battery_resume NULL
 436
 437 #endif /* CONFIG_PM */
 438
 439 MODULE_ALIAS("platform:ds2760-battery");
 440
 441 static struct platform_driver ds2760_battery_driver = {
 442         .driver = {
 443                 .name = "ds2760-battery",
 444         },
 445         .probe    = ds2760_battery_probe,
 446         .remove   = ds2760_battery_remove,
 447         .suspend  = ds2760_battery_suspend,
 448         .resume   = ds2760_battery_resume,
 449 };
 450
 451 static int __init ds2760_battery_init(void)
 452 {
 453         return platform_driver_register(&ds2760_battery_driver);
 454 }
 455
 456 static void __exit ds2760_battery_exit(void)
 457 {
 458         platform_driver_unregister(&ds2760_battery_driver);
 459 }
 460
 461 module_init(ds2760_battery_init);
 462 module_exit(ds2760_battery_exit);
 463
 464 MODULE_LICENSE("GPL");
 465 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
 466               "Matt Reimer <mreimer@vpop.net>, "
 467               "Anton Vorontsov <cbou@mail.ru>");
 468 MODULE_DESCRIPTION("ds2760 battery driver");