drivers/power/bq27x00_battery.c

   1 /*
   2  * BQ27x00 battery driver
   3  *
   4  * Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
   5  * Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
   6  * Copyright (C) 2010-2011 Lars-Peter Clausen <lars@metafoo.de>
   7  *
   8  * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
   9  *
  10  * This package is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  *
  14  * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  16  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  17  *
  18  */
  19
  20 /*
  21  * Datasheets:
  22  * http://focus.ti.com/docs/prod/folders/print/bq27000.html
  23  * http://focus.ti.com/docs/prod/folders/print/bq27500.html
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/param.h>
  28 #include <linux/jiffies.h>
  29 #include <linux/workqueue.h>
  30 #include <linux/delay.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/power_supply.h>
  33 #include <linux/idr.h>
  34 #include <linux/i2c.h>
  35 #include <linux/slab.h>
  36 #include <asm/unaligned.h>
  37
  38 #include <linux/power/bq27x00_battery.h>
  39
  40 #define DRIVER_VERSION                  "1.2.0"
  41
  42 #define BQ27x00_REG_TEMP                0x06
  43 #define BQ27x00_REG_VOLT                0x08
  44 #define BQ27x00_REG_AI                  0x14
  45 #define BQ27x00_REG_FLAGS               0x0A
  46 #define BQ27x00_REG_TTE                 0x16
  47 #define BQ27x00_REG_TTF                 0x18
  48 #define BQ27x00_REG_TTECP               0x26
  49 #define BQ27x00_REG_NAC                 0x0C /* Nominal available capaciy */
  50 #define BQ27x00_REG_LMD                 0x12 /* Last measured discharge */
  51 #define BQ27x00_REG_CYCT                0x2A /* Cycle count total */
  52 #define BQ27x00_REG_AE                  0x22 /* Available enery */
  53
  54 #define BQ27000_REG_RSOC                0x0B /* Relative State-of-Charge */
  55 #define BQ27000_REG_ILMD                0x76 /* Initial last measured discharge */
  56 #define BQ27000_FLAG_CHGS               BIT(7)
  57 #define BQ27000_FLAG_FC                 BIT(5)
  58
  59 #define BQ27500_REG_SOC                 0x2C
  60 #define BQ27500_REG_DCAP                0x3C /* Design capacity */
  61 #define BQ27500_FLAG_DSC                BIT(0)
  62 #define BQ27500_FLAG_FC                 BIT(9)
  63
  64 #define BQ27000_RS                      20 /* Resistor sense */
  65
  66 struct bq27x00_device_info;
  67 struct bq27x00_access_methods {
  68         int (*read)(struct bq27x00_device_info *di, u8 reg, bool single);
  69 };
  70
  71 enum bq27x00_chip { BQ27000, BQ27500 };
  72
  73 struct bq27x00_reg_cache {
  74         int temperature;
  75         int time_to_empty;
  76         int time_to_empty_avg;
  77         int time_to_full;
  78         int charge_full;
  79         int charge_counter;
  80         int capacity;
  81         int flags;
  82
  83         int current_now;
  84 };
  85
  86 struct bq27x00_device_info {
  87         struct device           *dev;
  88         int                     id;
  89         enum bq27x00_chip       chip;
  90
  91         struct bq27x00_reg_cache cache;
  92         int charge_design_full;
  93
  94         unsigned long last_update;
  95         struct delayed_work work;
  96
  97         struct power_supply     bat;
  98
  99         struct bq27x00_access_methods bus;
 100
 101         struct mutex lock;
 102 };
 103
 104 static enum power_supply_property bq27x00_battery_props[] = {
 105         POWER_SUPPLY_PROP_STATUS,
 106         POWER_SUPPLY_PROP_PRESENT,
 107         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 108         POWER_SUPPLY_PROP_CURRENT_NOW,
 109         POWER_SUPPLY_PROP_CAPACITY,
 110         POWER_SUPPLY_PROP_TEMP,
 111         POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 112         POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
 113         POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
 114         POWER_SUPPLY_PROP_TECHNOLOGY,
 115         POWER_SUPPLY_PROP_CHARGE_FULL,
 116         POWER_SUPPLY_PROP_CHARGE_NOW,
 117         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 118         POWER_SUPPLY_PROP_CHARGE_COUNTER,
 119         POWER_SUPPLY_PROP_ENERGY_NOW,
 120 };
 121
 122 static unsigned int poll_interval = 360;
 123 module_param(poll_interval, uint, 0644);
 124 MODULE_PARM_DESC(poll_interval, "battery poll interval in seconds - " \
 125                                 "0 disables polling");
 126
 127 /*
 128  * Common code for BQ27x00 devices
 129  */
 130
 131 static inline int bq27x00_read(struct bq27x00_device_info *di, u8 reg,
 132                 bool single)
 133 {
 134         return di->bus.read(di, reg, single);
 135 }
 136
 137 /*
 138  * Return the battery Relative State-of-Charge
 139  * Or < 0 if something fails.
 140  */
 141 static int bq27x00_battery_read_rsoc(struct bq27x00_device_info *di)
 142 {
 143         int rsoc;
 144
 145         if (di->chip == BQ27500)
 146                 rsoc = bq27x00_read(di, BQ27500_REG_SOC, false);
 147         else
 148                 rsoc = bq27x00_read(di, BQ27000_REG_RSOC, true);
 149
 150         if (rsoc < 0)
 151                 dev_err(di->dev, "error reading relative State-of-Charge\n");
 152
 153         return rsoc;
 154 }
 155
 156 /*
 157  * Return a battery charge value in µAh
 158  * Or < 0 if something fails.
 159  */
 160 static int bq27x00_battery_read_charge(struct bq27x00_device_info *di, u8 reg)
 161 {
 162         int charge;
 163
 164         charge = bq27x00_read(di, reg, false);
 165         if (charge < 0) {
 166                 dev_err(di->dev, "error reading nominal available capacity\n");
 167                 return charge;
 168         }
 169
 170         if (di->chip == BQ27500)
 171                 charge *= 1000;
 172         else
 173                 charge = charge * 3570 / BQ27000_RS;
 174
 175         return charge;
 176 }
 177
 178 /*
 179  * Return the battery Nominal available capaciy in µAh
 180  * Or < 0 if something fails.
 181  */
 182 static inline int bq27x00_battery_read_nac(struct bq27x00_device_info *di)
 183 {
 184         return bq27x00_battery_read_charge(di, BQ27x00_REG_NAC);
 185 }
 186
 187 /*
 188  * Return the battery Last measured discharge in µAh
 189  * Or < 0 if something fails.
 190  */
 191 static inline int bq27x00_battery_read_lmd(struct bq27x00_device_info *di)
 192 {
 193         return bq27x00_battery_read_charge(di, BQ27x00_REG_LMD);
 194 }
 195
 196 /*
 197  * Return the battery Initial last measured discharge in µAh
 198  * Or < 0 if something fails.
 199  */
 200 static int bq27x00_battery_read_ilmd(struct bq27x00_device_info *di)
 201 {
 202         int ilmd;
 203
 204         if (di->chip == BQ27500)
 205                 ilmd = bq27x00_read(di, BQ27500_REG_DCAP, false);
 206         else
 207                 ilmd = bq27x00_read(di, BQ27000_REG_ILMD, true);
 208
 209         if (ilmd < 0) {
 210                 dev_err(di->dev, "error reading initial last measured discharge\n");
 211                 return ilmd;
 212         }
 213
 214         if (di->chip == BQ27500)
 215                 ilmd *= 1000;
 216         else
 217                 ilmd = ilmd * 256 * 3570 / BQ27000_RS;
 218
 219         return ilmd;
 220 }
 221
 222 /*
 223  * Return the battery Cycle count total
 224  * Or < 0 if something fails.
 225  */
 226 static int bq27x00_battery_read_cyct(struct bq27x00_device_info *di)
 227 {
 228         int cyct;
 229
 230         cyct = bq27x00_read(di, BQ27x00_REG_CYCT, false);
 231         if (cyct < 0)
 232                 dev_err(di->dev, "error reading cycle count total\n");
 233
 234         return cyct;
 235 }
 236
 237 /*
 238  * Read a time register.
 239  * Return < 0 if something fails.
 240  */
 241 static int bq27x00_battery_read_time(struct bq27x00_device_info *di, u8 reg)
 242 {
 243         int tval;
 244
 245         tval = bq27x00_read(di, reg, false);
 246         if (tval < 0) {
 247                 dev_err(di->dev, "error reading register %02x: %d\n", reg, tval);
 248                 return tval;
 249         }
 250
 251         if (tval == 65535)
 252                 return -ENODATA;
 253
 254         return tval * 60;
 255 }
 256
 257 static void bq27x00_update(struct bq27x00_device_info *di)
 258 {
 259         struct bq27x00_reg_cache cache = {0, };
 260         bool is_bq27500 = di->chip == BQ27500;
 261
 262         cache.flags = bq27x00_read(di, BQ27x00_REG_FLAGS, is_bq27500);
 263         if (cache.flags >= 0) {
 264                 cache.capacity = bq27x00_battery_read_rsoc(di);
 265                 cache.temperature = bq27x00_read(di, BQ27x00_REG_TEMP, false);
 266                 cache.time_to_empty = bq27x00_battery_read_time(di, BQ27x00_REG_TTE);
 267                 cache.time_to_empty_avg = bq27x00_battery_read_time(di, BQ27x00_REG_TTECP);
 268                 cache.time_to_full = bq27x00_battery_read_time(di, BQ27x00_REG_TTF);
 269                 cache.charge_full = bq27x00_battery_read_lmd(di);
 270                 cache.charge_counter = bq27x00_battery_read_cyct(di);
 271
 272                 if (!is_bq27500)
 273                         cache.current_now = bq27x00_read(di, BQ27x00_REG_AI, false);
 274
 275                 /* We only have to read charge design full once */
 276                 if (di->charge_design_full <= 0)
 277                         di->charge_design_full = bq27x00_battery_read_ilmd(di);
 278         }
 279
 280         /* Ignore current_now which is a snapshot of the current battery state
 281          * and is likely to be different even between two consecutive reads */
 282         if (memcmp(&di->cache, &cache, sizeof(cache) - sizeof(int)) != 0) {
 283                 di->cache = cache;
 284                 power_supply_changed(&di->bat);
 285         }
 286
 287         di->last_update = jiffies;
 288 }
 289
 290 static void bq27x00_battery_poll(struct work_struct *work)
 291 {
 292         struct bq27x00_device_info *di =
 293                 container_of(work, struct bq27x00_device_info, work.work);
 294
 295         bq27x00_update(di);
 296
 297         if (poll_interval > 0) {
 298                 /* The timer does not have to be accurate. */
 299                 set_timer_slack(&di->work.timer, poll_interval * HZ / 4);
 300                 schedule_delayed_work(&di->work, poll_interval * HZ);
 301         }
 302 }
 303
 304
 305 /*
 306  * Return the battery temperature in tenths of degree Celsius
 307  * Or < 0 if something fails.
 308  */
 309 static int bq27x00_battery_temperature(struct bq27x00_device_info *di,
 310         union power_supply_propval *val)
 311 {
 312         if (di->cache.temperature < 0)
 313                 return di->cache.temperature;
 314
 315         if (di->chip == BQ27500)
 316                 val->intval = di->cache.temperature - 2731;
 317         else
 318                 val->intval = ((di->cache.temperature * 5) - 5463) / 2;
 319
 320         return 0;
 321 }
 322
 323 /*
 324  * Return the battery average current in µA
 325  * Note that current can be negative signed as well
 326  * Or 0 if something fails.
 327  */
 328 static int bq27x00_battery_current(struct bq27x00_device_info *di,
 329         union power_supply_propval *val)
 330 {
 331         int curr;
 332
 333         if (di->chip == BQ27500)
 334             curr = bq27x00_read(di, BQ27x00_REG_AI, false);
 335         else
 336             curr = di->cache.current_now;
 337
 338         if (curr < 0)
 339                 return curr;
 340
 341         if (di->chip == BQ27500) {
 342                 /* bq27500 returns signed value */
 343                 val->intval = (int)((s16)curr) * 1000;
 344         } else {
 345                 if (di->cache.flags & BQ27000_FLAG_CHGS) {
 346                         dev_dbg(di->dev, "negative current!\n");
 347                         curr = -curr;
 348                 }
 349
 350                 val->intval = curr * 3570 / BQ27000_RS;
 351         }
 352
 353         return 0;
 354 }
 355
 356 static int bq27x00_battery_status(struct bq27x00_device_info *di,
 357         union power_supply_propval *val)
 358 {
 359         int status;
 360
 361         if (di->chip == BQ27500) {
 362                 if (di->cache.flags & BQ27500_FLAG_FC)
 363                         status = POWER_SUPPLY_STATUS_FULL;
 364                 else if (di->cache.flags & BQ27500_FLAG_DSC)
 365                         status = POWER_SUPPLY_STATUS_DISCHARGING;
 366                 else
 367                         status = POWER_SUPPLY_STATUS_CHARGING;
 368         } else {
 369                 if (di->cache.flags & BQ27000_FLAG_FC)
 370                         status = POWER_SUPPLY_STATUS_FULL;
 371                 else if (di->cache.flags & BQ27000_FLAG_CHGS)
 372                         status = POWER_SUPPLY_STATUS_CHARGING;
 373                 else if (power_supply_am_i_supplied(&di->bat))
 374                         status = POWER_SUPPLY_STATUS_NOT_CHARGING;
 375                 else
 376                         status = POWER_SUPPLY_STATUS_DISCHARGING;
 377         }
 378
 379         val->intval = status;
 380
 381         return 0;
 382 }
 383
 384 /*
 385  * Return the battery Voltage in milivolts
 386  * Or < 0 if something fails.
 387  */
 388 static int bq27x00_battery_voltage(struct bq27x00_device_info *di,
 389         union power_supply_propval *val)
 390 {
 391         int volt;
 392
 393         volt = bq27x00_read(di, BQ27x00_REG_VOLT, false);
 394         if (volt < 0)
 395                 return volt;
 396
 397         val->intval = volt * 1000;
 398
 399         return 0;
 400 }
 401
 402 /*
 403  * Return the battery Available energy in µWh
 404  * Or < 0 if something fails.
 405  */
 406 static int bq27x00_battery_energy(struct bq27x00_device_info *di,
 407         union power_supply_propval *val)
 408 {
 409         int ae;
 410
 411         ae = bq27x00_read(di, BQ27x00_REG_AE, false);
 412         if (ae < 0) {
 413                 dev_err(di->dev, "error reading available energy\n");
 414                 return ae;
 415         }
 416
 417         if (di->chip == BQ27500)
 418                 ae *= 1000;
 419         else
 420                 ae = ae * 29200 / BQ27000_RS;
 421
 422         val->intval = ae;
 423
 424         return 0;
 425 }
 426
 427
 428 static int bq27x00_simple_value(int value,
 429         union power_supply_propval *val)
 430 {
 431         if (value < 0)
 432                 return value;
 433
 434         val->intval = value;
 435
 436         return 0;
 437 }
 438
 439 #define to_bq27x00_device_info(x) container_of((x), \
 440                                 struct bq27x00_device_info, bat);
 441
 442 static int bq27x00_battery_get_property(struct power_supply *psy,
 443                                         enum power_supply_property psp,
 444                                         union power_supply_propval *val)
 445 {
 446         int ret = 0;
 447         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 448
 449         mutex_lock(&di->lock);
 450         if (time_is_before_jiffies(di->last_update + 5 * HZ)) {
 451                 cancel_delayed_work_sync(&di->work);
 452                 bq27x00_battery_poll(&di->work.work);
 453         }
 454         mutex_unlock(&di->lock);
 455
 456         if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0)
 457                 return -ENODEV;
 458
 459         switch (psp) {
 460         case POWER_SUPPLY_PROP_STATUS:
 461                 ret = bq27x00_battery_status(di, val);
 462                 break;
 463         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 464                 ret = bq27x00_battery_voltage(di, val);
 465                 break;
 466         case POWER_SUPPLY_PROP_PRESENT:
 467                 val->intval = di->cache.flags < 0 ? 0 : 1;
 468                 break;
 469         case POWER_SUPPLY_PROP_CURRENT_NOW:
 470                 ret = bq27x00_battery_current(di, val);
 471                 break;
 472         case POWER_SUPPLY_PROP_CAPACITY:
 473                 ret = bq27x00_simple_value(di->cache.capacity, val);
 474                 break;
 475         case POWER_SUPPLY_PROP_TEMP:
 476                 ret = bq27x00_battery_temperature(di, val);
 477                 break;
 478         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
 479                 ret = bq27x00_simple_value(di->cache.time_to_empty, val);
 480                 break;
 481         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 482                 ret = bq27x00_simple_value(di->cache.time_to_empty_avg, val);
 483                 break;
 484         case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
 485                 ret = bq27x00_simple_value(di->cache.time_to_full, val);
 486                 break;
 487         case POWER_SUPPLY_PROP_TECHNOLOGY:
 488                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 489                 break;
 490         case POWER_SUPPLY_PROP_CHARGE_NOW:
 491                 ret = bq27x00_simple_value(bq27x00_battery_read_nac(di), val);
 492                 break;
 493         case POWER_SUPPLY_PROP_CHARGE_FULL:
 494                 ret = bq27x00_simple_value(di->cache.charge_full, val);
 495                 break;
 496         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 497                 ret = bq27x00_simple_value(di->charge_design_full, val);
 498                 break;
 499         case POWER_SUPPLY_PROP_CHARGE_COUNTER:
 500                 ret = bq27x00_simple_value(di->cache.charge_counter, val);
 501                 break;
 502         case POWER_SUPPLY_PROP_ENERGY_NOW:
 503                 ret = bq27x00_battery_energy(di, val);
 504                 break;
 505         default:
 506                 return -EINVAL;
 507         }
 508
 509         return ret;
 510 }
 511
 512 static void bq27x00_external_power_changed(struct power_supply *psy)
 513 {
 514         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 515
 516         cancel_delayed_work_sync(&di->work);
 517         schedule_delayed_work(&di->work, 0);
 518 }
 519
 520 static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
 521 {
 522         int ret;
 523
 524         di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
 525         di->bat.properties = bq27x00_battery_props;
 526         di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
 527         di->bat.get_property = bq27x00_battery_get_property;
 528         di->bat.external_power_changed = bq27x00_external_power_changed;
 529
 530         INIT_DELAYED_WORK(&di->work, bq27x00_battery_poll);
 531         mutex_init(&di->lock);
 532
 533         ret = power_supply_register(di->dev, &di->bat);
 534         if (ret) {
 535                 dev_err(di->dev, "failed to register battery: %d\n", ret);
 536                 return ret;
 537         }
 538
 539         dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 540
 541         bq27x00_update(di);
 542
 543         return 0;
 544 }
 545
 546 static void bq27x00_powersupply_unregister(struct bq27x00_device_info *di)
 547 {
 548         cancel_delayed_work_sync(&di->work);
 549
 550         power_supply_unregister(&di->bat);
 551
 552         mutex_destroy(&di->lock);
 553 }
 554
 555
 556 /* i2c specific code */
 557 #ifdef CONFIG_BATTERY_BQ27X00_I2C
 558
 559 /* If the system has several batteries we need a different name for each
 560  * of them...
 561  */
 562 static DEFINE_IDR(battery_id);
 563 static DEFINE_MUTEX(battery_mutex);
 564
 565 static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg, bool single)
 566 {
 567         struct i2c_client *client = to_i2c_client(di->dev);
 568         struct i2c_msg msg[2];
 569         unsigned char data[2];
 570         int ret;
 571
 572         if (!client->adapter)
 573                 return -ENODEV;
 574
 575         msg[0].addr = client->addr;
 576         msg[0].flags = 0;
 577         msg[0].buf = &reg;
 578         msg[0].len = sizeof(reg);
 579         msg[1].addr = client->addr;
 580         msg[1].flags = I2C_M_RD;
 581         msg[1].buf = data;
 582         if (single)
 583                 msg[1].len = 1;
 584         else
 585                 msg[1].len = 2;
 586
 587         ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
 588         if (ret < 0)
 589                 return ret;
 590
 591         if (!single)
 592                 ret = get_unaligned_le16(data);
 593         else
 594                 ret = data[0];
 595
 596         return ret;
 597 }
 598
 599 static int bq27x00_battery_probe(struct i2c_client *client,
 600                                  const struct i2c_device_id *id)
 601 {
 602         char *name;
 603         struct bq27x00_device_info *di;
 604         int num;
 605         int retval = 0;
 606
 607         /* Get new ID for the new battery device */
 608         retval = idr_pre_get(&battery_id, GFP_KERNEL);
 609         if (retval == 0)
 610                 return -ENOMEM;
 611         mutex_lock(&battery_mutex);
 612         retval = idr_get_new(&battery_id, client, &num);
 613         mutex_unlock(&battery_mutex);
 614         if (retval < 0)
 615                 return retval;
 616
 617         name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
 618         if (!name) {
 619                 dev_err(&client->dev, "failed to allocate device name\n");
 620                 retval = -ENOMEM;
 621                 goto batt_failed_1;
 622         }
 623
 624         di = kzalloc(sizeof(*di), GFP_KERNEL);
 625         if (!di) {
 626                 dev_err(&client->dev, "failed to allocate device info data\n");
 627                 retval = -ENOMEM;
 628                 goto batt_failed_2;
 629         }
 630
 631         di->id = num;
 632         di->dev = &client->dev;
 633         di->chip = id->driver_data;
 634         di->bat.name = name;
 635         di->bus.read = &bq27x00_read_i2c;
 636
 637         if (bq27x00_powersupply_init(di))
 638                 goto batt_failed_3;
 639
 640         i2c_set_clientdata(client, di);
 641
 642         return 0;
 643
 644 batt_failed_3:
 645         kfree(di);
 646 batt_failed_2:
 647         kfree(name);
 648 batt_failed_1:
 649         mutex_lock(&battery_mutex);
 650         idr_remove(&battery_id, num);
 651         mutex_unlock(&battery_mutex);
 652
 653         return retval;
 654 }
 655
 656 static int bq27x00_battery_remove(struct i2c_client *client)
 657 {
 658         struct bq27x00_device_info *di = i2c_get_clientdata(client);
 659
 660         bq27x00_powersupply_unregister(di);
 661
 662         kfree(di->bat.name);
 663
 664         mutex_lock(&battery_mutex);
 665         idr_remove(&battery_id, di->id);
 666         mutex_unlock(&battery_mutex);
 667
 668         kfree(di);
 669
 670         return 0;
 671 }
 672
 673 static const struct i2c_device_id bq27x00_id[] = {
 674         { "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */
 675         { "bq27500", BQ27500 },
 676         {},
 677 };
 678 MODULE_DEVICE_TABLE(i2c, bq27x00_id);
 679
 680 static struct i2c_driver bq27x00_battery_driver = {
 681         .driver = {
 682                 .name = "bq27x00-battery",
 683         },
 684         .probe = bq27x00_battery_probe,
 685         .remove = bq27x00_battery_remove,
 686         .id_table = bq27x00_id,
 687 };
 688
 689 static inline int bq27x00_battery_i2c_init(void)
 690 {
 691         int ret = i2c_add_driver(&bq27x00_battery_driver);
 692         if (ret)
 693                 printk(KERN_ERR "Unable to register BQ27x00 i2c driver\n");
 694
 695         return ret;
 696 }
 697
 698 static inline void bq27x00_battery_i2c_exit(void)
 699 {
 700         i2c_del_driver(&bq27x00_battery_driver);
 701 }
 702
 703 #else
 704
 705 static inline int bq27x00_battery_i2c_init(void) { return 0; }
 706 static inline void bq27x00_battery_i2c_exit(void) {};
 707
 708 #endif
 709
 710 /* platform specific code */
 711 #ifdef CONFIG_BATTERY_BQ27X00_PLATFORM
 712
 713 static int bq27000_read_platform(struct bq27x00_device_info *di, u8 reg,
 714                         bool single)
 715 {
 716         struct device *dev = di->dev;
 717         struct bq27000_platform_data *pdata = dev->platform_data;
 718         unsigned int timeout = 3;
 719         int upper, lower;
 720         int temp;
 721
 722         if (!single) {
 723                 /* Make sure the value has not changed in between reading the
 724                  * lower and the upper part */
 725                 upper = pdata->read(dev, reg + 1);
 726                 do {
 727                         temp = upper;
 728                         if (upper < 0)
 729                                 return upper;
 730
 731                         lower = pdata->read(dev, reg);
 732                         if (lower < 0)
 733                                 return lower;
 734
 735                         upper = pdata->read(dev, reg + 1);
 736                 } while (temp != upper && --timeout);
 737
 738                 if (timeout == 0)
 739                         return -EIO;
 740
 741                 return (upper << 8) | lower;
 742         }
 743
 744         return pdata->read(dev, reg);
 745 }
 746
 747 static int __devinit bq27000_battery_probe(struct platform_device *pdev)
 748 {
 749         struct bq27x00_device_info *di;
 750         struct bq27000_platform_data *pdata = pdev->dev.platform_data;
 751         int ret;
 752
 753         if (!pdata) {
 754                 dev_err(&pdev->dev, "no platform_data supplied\n");
 755                 return -EINVAL;
 756         }
 757
 758         if (!pdata->read) {
 759                 dev_err(&pdev->dev, "no hdq read callback supplied\n");
 760                 return -EINVAL;
 761         }
 762
 763         di = kzalloc(sizeof(*di), GFP_KERNEL);
 764         if (!di) {
 765                 dev_err(&pdev->dev, "failed to allocate device info data\n");
 766                 return -ENOMEM;
 767         }
 768
 769         platform_set_drvdata(pdev, di);
 770
 771         di->dev = &pdev->dev;
 772         di->chip = BQ27000;
 773
 774         di->bat.name = pdata->name ?: dev_name(&pdev->dev);
 775         di->bus.read = &bq27000_read_platform;
 776
 777         ret = bq27x00_powersupply_init(di);
 778         if (ret)
 779                 goto err_free;
 780
 781         return 0;
 782
 783 err_free:
 784         platform_set_drvdata(pdev, NULL);
 785         kfree(di);
 786
 787         return ret;
 788 }
 789
 790 static int __devexit bq27000_battery_remove(struct platform_device *pdev)
 791 {
 792         struct bq27x00_device_info *di = platform_get_drvdata(pdev);
 793
 794         bq27x00_powersupply_unregister(di);
 795
 796         platform_set_drvdata(pdev, NULL);
 797         kfree(di);
 798
 799         return 0;
 800 }
 801
 802 static struct platform_driver bq27000_battery_driver = {
 803         .probe  = bq27000_battery_probe,
 804         .remove = __devexit_p(bq27000_battery_remove),
 805         .driver = {
 806                 .name = "bq27000-battery",
 807                 .owner = THIS_MODULE,
 808         },
 809 };
 810
 811 static inline int bq27x00_battery_platform_init(void)
 812 {
 813         int ret = platform_driver_register(&bq27000_battery_driver);
 814         if (ret)
 815                 printk(KERN_ERR "Unable to register BQ27000 platform driver\n");
 816
 817         return ret;
 818 }
 819
 820 static inline void bq27x00_battery_platform_exit(void)
 821 {
 822         platform_driver_unregister(&bq27000_battery_driver);
 823 }
 824
 825 #else
 826
 827 static inline int bq27x00_battery_platform_init(void) { return 0; }
 828 static inline void bq27x00_battery_platform_exit(void) {};
 829
 830 #endif
 831
 832 /*
 833  * Module stuff
 834  */
 835
 836 static int __init bq27x00_battery_init(void)
 837 {
 838         int ret;
 839
 840         ret = bq27x00_battery_i2c_init();
 841         if (ret)
 842                 return ret;
 843
 844         ret = bq27x00_battery_platform_init();
 845         if (ret)
 846                 bq27x00_battery_i2c_exit();
 847
 848         return ret;
 849 }
 850 module_init(bq27x00_battery_init);
 851
 852 static void __exit bq27x00_battery_exit(void)
 853 {
 854         bq27x00_battery_platform_exit();
 855         bq27x00_battery_i2c_exit();
 856 }
 857 module_exit(bq27x00_battery_exit);
 858
 859 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 860 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 861 MODULE_LICENSE("GPL");