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  * Copyright (C) 2011 Pali Rohár <pali.rohar@gmail.com>
   8  *
   9  * Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
  10  *
  11  * This package is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14  *
  15  * THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  *
  19  */
  20
  21 /*
  22  * Datasheets:
  23  * http://focus.ti.com/docs/prod/folders/print/bq27000.html
  24  * http://focus.ti.com/docs/prod/folders/print/bq27500.html
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/param.h>
  29 #include <linux/jiffies.h>
  30 #include <linux/workqueue.h>
  31 #include <linux/delay.h>
  32 #include <linux/platform_device.h>
  33 #include <linux/power_supply.h>
  34 #include <linux/idr.h>
  35 #include <linux/i2c.h>
  36 #include <linux/slab.h>
  37 #include <asm/unaligned.h>
  38
  39 #include <linux/power/bq27x00_battery.h>
  40
  41 #define DRIVER_VERSION                  "1.2.0"
  42
  43 #define BQ27x00_REG_TEMP                0x06
  44 #define BQ27x00_REG_VOLT                0x08
  45 #define BQ27x00_REG_AI                  0x14
  46 #define BQ27x00_REG_FLAGS               0x0A
  47 #define BQ27x00_REG_TTE                 0x16
  48 #define BQ27x00_REG_TTF                 0x18
  49 #define BQ27x00_REG_TTECP               0x26
  50 #define BQ27x00_REG_NAC                 0x0C /* Nominal available capacity */
  51 #define BQ27x00_REG_LMD                 0x12 /* Last measured discharge */
  52 #define BQ27x00_REG_CYCT                0x2A /* Cycle count total */
  53 #define BQ27x00_REG_AE                  0x22 /* Available energy */
  54
  55 #define BQ27000_REG_RSOC                0x0B /* Relative State-of-Charge */
  56 #define BQ27000_REG_ILMD                0x76 /* Initial last measured discharge */
  57 #define BQ27000_FLAG_EDVF               BIT(0) /* Final End-of-Discharge-Voltage flag */
  58 #define BQ27000_FLAG_EDV1               BIT(1) /* First End-of-Discharge-Voltage flag */
  59 #define BQ27000_FLAG_CI                 BIT(4) /* Capacity Inaccurate flag */
  60 #define BQ27000_FLAG_FC                 BIT(5)
  61 #define BQ27000_FLAG_CHGS               BIT(7) /* Charge state flag */
  62
  63 #define BQ27500_REG_SOC                 0x2C
  64 #define BQ27500_REG_DCAP                0x3C /* Design capacity */
  65 #define BQ27500_FLAG_DSC                BIT(0)
  66 #define BQ27500_FLAG_SOCF               BIT(1) /* State-of-Charge threshold final */
  67 #define BQ27500_FLAG_SOC1               BIT(2) /* State-of-Charge threshold 1 */
  68 #define BQ27500_FLAG_FC                 BIT(9)
  69
  70 #define BQ27000_RS                      20 /* Resistor sense */
  71
  72 struct bq27x00_device_info;
  73 struct bq27x00_access_methods {
  74         int (*read)(struct bq27x00_device_info *di, u8 reg, bool single);
  75 };
  76
  77 enum bq27x00_chip { BQ27000, BQ27500 };
  78
  79 struct bq27x00_reg_cache {
  80         int temperature;
  81         int time_to_empty;
  82         int time_to_empty_avg;
  83         int time_to_full;
  84         int charge_full;
  85         int cycle_count;
  86         int capacity;
  87         int energy;
  88         int flags;
  89 };
  90
  91 struct bq27x00_device_info {
  92         struct device           *dev;
  93         int                     id;
  94         enum bq27x00_chip       chip;
  95
  96         struct bq27x00_reg_cache cache;
  97         int charge_design_full;
  98
  99         unsigned long last_update;
 100         struct delayed_work work;
 101
 102         struct power_supply     bat;
 103
 104         struct bq27x00_access_methods bus;
 105
 106         struct mutex lock;
 107 };
 108
 109 static enum power_supply_property bq27x00_battery_props[] = {
 110         POWER_SUPPLY_PROP_STATUS,
 111         POWER_SUPPLY_PROP_PRESENT,
 112         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 113         POWER_SUPPLY_PROP_CURRENT_NOW,
 114         POWER_SUPPLY_PROP_CAPACITY,
 115         POWER_SUPPLY_PROP_CAPACITY_LEVEL,
 116         POWER_SUPPLY_PROP_TEMP,
 117         POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
 118         POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
 119         POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
 120         POWER_SUPPLY_PROP_TECHNOLOGY,
 121         POWER_SUPPLY_PROP_CHARGE_FULL,
 122         POWER_SUPPLY_PROP_CHARGE_NOW,
 123         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 124         POWER_SUPPLY_PROP_CYCLE_COUNT,
 125         POWER_SUPPLY_PROP_ENERGY_NOW,
 126 };
 127
 128 static unsigned int poll_interval = 360;
 129 module_param(poll_interval, uint, 0644);
 130 MODULE_PARM_DESC(poll_interval, "battery poll interval in seconds - " \
 131                                 "0 disables polling");
 132
 133 /*
 134  * Common code for BQ27x00 devices
 135  */
 136
 137 static inline int bq27x00_read(struct bq27x00_device_info *di, u8 reg,
 138                 bool single)
 139 {
 140         return di->bus.read(di, reg, single);
 141 }
 142
 143 /*
 144  * Return the battery Relative State-of-Charge
 145  * Or < 0 if something fails.
 146  */
 147 static int bq27x00_battery_read_rsoc(struct bq27x00_device_info *di)
 148 {
 149         int rsoc;
 150
 151         if (di->chip == BQ27500)
 152                 rsoc = bq27x00_read(di, BQ27500_REG_SOC, false);
 153         else
 154                 rsoc = bq27x00_read(di, BQ27000_REG_RSOC, true);
 155
 156         if (rsoc < 0)
 157                 dev_dbg(di->dev, "error reading relative State-of-Charge\n");
 158
 159         return rsoc;
 160 }
 161
 162 /*
 163  * Return a battery charge value in µAh
 164  * Or < 0 if something fails.
 165  */
 166 static int bq27x00_battery_read_charge(struct bq27x00_device_info *di, u8 reg)
 167 {
 168         int charge;
 169
 170         charge = bq27x00_read(di, reg, false);
 171         if (charge < 0) {
 172                 dev_dbg(di->dev, "error reading charge register %02x: %d\n",
 173                         reg, charge);
 174                 return charge;
 175         }
 176
 177         if (di->chip == BQ27500)
 178                 charge *= 1000;
 179         else
 180                 charge = charge * 3570 / BQ27000_RS;
 181
 182         return charge;
 183 }
 184
 185 /*
 186  * Return the battery Nominal available capaciy in µAh
 187  * Or < 0 if something fails.
 188  */
 189 static inline int bq27x00_battery_read_nac(struct bq27x00_device_info *di)
 190 {
 191         return bq27x00_battery_read_charge(di, BQ27x00_REG_NAC);
 192 }
 193
 194 /*
 195  * Return the battery Last measured discharge in µAh
 196  * Or < 0 if something fails.
 197  */
 198 static inline int bq27x00_battery_read_lmd(struct bq27x00_device_info *di)
 199 {
 200         return bq27x00_battery_read_charge(di, BQ27x00_REG_LMD);
 201 }
 202
 203 /*
 204  * Return the battery Initial last measured discharge in µAh
 205  * Or < 0 if something fails.
 206  */
 207 static int bq27x00_battery_read_ilmd(struct bq27x00_device_info *di)
 208 {
 209         int ilmd;
 210
 211         if (di->chip == BQ27500)
 212                 ilmd = bq27x00_read(di, BQ27500_REG_DCAP, false);
 213         else
 214                 ilmd = bq27x00_read(di, BQ27000_REG_ILMD, true);
 215
 216         if (ilmd < 0) {
 217                 dev_dbg(di->dev, "error reading initial last measured discharge\n");
 218                 return ilmd;
 219         }
 220
 221         if (di->chip == BQ27500)
 222                 ilmd *= 1000;
 223         else
 224                 ilmd = ilmd * 256 * 3570 / BQ27000_RS;
 225
 226         return ilmd;
 227 }
 228
 229 /*
 230  * Return the battery Available energy in µWh
 231  * Or < 0 if something fails.
 232  */
 233 static int bq27x00_battery_read_energy(struct bq27x00_device_info *di)
 234 {
 235         int ae;
 236
 237         ae = bq27x00_read(di, BQ27x00_REG_AE, false);
 238         if (ae < 0) {
 239                 dev_dbg(di->dev, "error reading available energy\n");
 240                 return ae;
 241         }
 242
 243         if (di->chip == BQ27500)
 244                 ae *= 1000;
 245         else
 246                 ae = ae * 29200 / BQ27000_RS;
 247
 248         return ae;
 249 }
 250
 251 /*
 252  * Return the battery temperature in tenths of degree Celsius
 253  * Or < 0 if something fails.
 254  */
 255 static int bq27x00_battery_read_temperature(struct bq27x00_device_info *di)
 256 {
 257         int temp;
 258
 259         temp = bq27x00_read(di, BQ27x00_REG_TEMP, false);
 260         if (temp < 0) {
 261                 dev_err(di->dev, "error reading temperature\n");
 262                 return temp;
 263         }
 264
 265         if (di->chip == BQ27500)
 266                 temp -= 2731;
 267         else
 268                 temp = ((temp * 5) - 5463) / 2;
 269
 270         return temp;
 271 }
 272
 273 /*
 274  * Return the battery Cycle count total
 275  * Or < 0 if something fails.
 276  */
 277 static int bq27x00_battery_read_cyct(struct bq27x00_device_info *di)
 278 {
 279         int cyct;
 280
 281         cyct = bq27x00_read(di, BQ27x00_REG_CYCT, false);
 282         if (cyct < 0)
 283                 dev_err(di->dev, "error reading cycle count total\n");
 284
 285         return cyct;
 286 }
 287
 288 /*
 289  * Read a time register.
 290  * Return < 0 if something fails.
 291  */
 292 static int bq27x00_battery_read_time(struct bq27x00_device_info *di, u8 reg)
 293 {
 294         int tval;
 295
 296         tval = bq27x00_read(di, reg, false);
 297         if (tval < 0) {
 298                 dev_dbg(di->dev, "error reading time register %02x: %d\n",
 299                         reg, tval);
 300                 return tval;
 301         }
 302
 303         if (tval == 65535)
 304                 return -ENODATA;
 305
 306         return tval * 60;
 307 }
 308
 309 static void bq27x00_update(struct bq27x00_device_info *di)
 310 {
 311         struct bq27x00_reg_cache cache = {0, };
 312         bool is_bq27500 = di->chip == BQ27500;
 313
 314         cache.flags = bq27x00_read(di, BQ27x00_REG_FLAGS, !is_bq27500);
 315         if (cache.flags >= 0) {
 316                 if (!is_bq27500 && (cache.flags & BQ27000_FLAG_CI)) {
 317                         dev_info(di->dev, "battery is not calibrated! ignoring capacity values\n");
 318                         cache.capacity = -ENODATA;
 319                         cache.energy = -ENODATA;
 320                         cache.time_to_empty = -ENODATA;
 321                         cache.time_to_empty_avg = -ENODATA;
 322                         cache.time_to_full = -ENODATA;
 323                         cache.charge_full = -ENODATA;
 324                 } else {
 325                         cache.capacity = bq27x00_battery_read_rsoc(di);
 326                         cache.energy = bq27x00_battery_read_energy(di);
 327                         cache.time_to_empty = bq27x00_battery_read_time(di, BQ27x00_REG_TTE);
 328                         cache.time_to_empty_avg = bq27x00_battery_read_time(di, BQ27x00_REG_TTECP);
 329                         cache.time_to_full = bq27x00_battery_read_time(di, BQ27x00_REG_TTF);
 330                         cache.charge_full = bq27x00_battery_read_lmd(di);
 331                 }
 332                 cache.temperature = bq27x00_battery_read_temperature(di);
 333                 cache.cycle_count = bq27x00_battery_read_cyct(di);
 334
 335                 /* We only have to read charge design full once */
 336                 if (di->charge_design_full <= 0)
 337                         di->charge_design_full = bq27x00_battery_read_ilmd(di);
 338         }
 339
 340         if (memcmp(&di->cache, &cache, sizeof(cache)) != 0) {
 341                 di->cache = cache;
 342                 power_supply_changed(&di->bat);
 343         }
 344
 345         di->last_update = jiffies;
 346 }
 347
 348 static void bq27x00_battery_poll(struct work_struct *work)
 349 {
 350         struct bq27x00_device_info *di =
 351                 container_of(work, struct bq27x00_device_info, work.work);
 352
 353         bq27x00_update(di);
 354
 355         if (poll_interval > 0) {
 356                 /* The timer does not have to be accurate. */
 357                 set_timer_slack(&di->work.timer, poll_interval * HZ / 4);
 358                 schedule_delayed_work(&di->work, poll_interval * HZ);
 359         }
 360 }
 361
 362 /*
 363  * Return the battery average current in µA
 364  * Note that current can be negative signed as well
 365  * Or 0 if something fails.
 366  */
 367 static int bq27x00_battery_current(struct bq27x00_device_info *di,
 368         union power_supply_propval *val)
 369 {
 370         int curr;
 371         int flags;
 372
 373         curr = bq27x00_read(di, BQ27x00_REG_AI, false);
 374         if (curr < 0) {
 375                 dev_err(di->dev, "error reading current\n");
 376                 return curr;
 377         }
 378
 379         if (di->chip == BQ27500) {
 380                 /* bq27500 returns signed value */
 381                 val->intval = (int)((s16)curr) * 1000;
 382         } else {
 383                 flags = bq27x00_read(di, BQ27x00_REG_FLAGS, false);
 384                 if (flags & BQ27000_FLAG_CHGS) {
 385                         dev_dbg(di->dev, "negative current!\n");
 386                         curr = -curr;
 387                 }
 388
 389                 val->intval = curr * 3570 / BQ27000_RS;
 390         }
 391
 392         return 0;
 393 }
 394
 395 static int bq27x00_battery_status(struct bq27x00_device_info *di,
 396         union power_supply_propval *val)
 397 {
 398         int status;
 399
 400         if (di->chip == BQ27500) {
 401                 if (di->cache.flags & BQ27500_FLAG_FC)
 402                         status = POWER_SUPPLY_STATUS_FULL;
 403                 else if (di->cache.flags & BQ27500_FLAG_DSC)
 404                         status = POWER_SUPPLY_STATUS_DISCHARGING;
 405                 else
 406                         status = POWER_SUPPLY_STATUS_CHARGING;
 407         } else {
 408                 if (di->cache.flags & BQ27000_FLAG_FC)
 409                         status = POWER_SUPPLY_STATUS_FULL;
 410                 else if (di->cache.flags & BQ27000_FLAG_CHGS)
 411                         status = POWER_SUPPLY_STATUS_CHARGING;
 412                 else if (power_supply_am_i_supplied(&di->bat))
 413                         status = POWER_SUPPLY_STATUS_NOT_CHARGING;
 414                 else
 415                         status = POWER_SUPPLY_STATUS_DISCHARGING;
 416         }
 417
 418         val->intval = status;
 419
 420         return 0;
 421 }
 422
 423 static int bq27x00_battery_capacity_level(struct bq27x00_device_info *di,
 424         union power_supply_propval *val)
 425 {
 426         int level;
 427
 428         if (di->chip == BQ27500) {
 429                 if (di->cache.flags & BQ27500_FLAG_FC)
 430                         level = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
 431                 else if (di->cache.flags & BQ27500_FLAG_SOC1)
 432                         level = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
 433                 else if (di->cache.flags & BQ27500_FLAG_SOCF)
 434                         level = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
 435                 else
 436                         level = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
 437         } else {
 438                 if (di->cache.flags & BQ27000_FLAG_FC)
 439                         level = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
 440                 else if (di->cache.flags & BQ27000_FLAG_EDV1)
 441                         level = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
 442                 else if (di->cache.flags & BQ27000_FLAG_EDVF)
 443                         level = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
 444                 else
 445                         level = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
 446         }
 447
 448         val->intval = level;
 449
 450         return 0;
 451 }
 452
 453 /*
 454  * Return the battery Voltage in milivolts
 455  * Or < 0 if something fails.
 456  */
 457 static int bq27x00_battery_voltage(struct bq27x00_device_info *di,
 458         union power_supply_propval *val)
 459 {
 460         int volt;
 461
 462         volt = bq27x00_read(di, BQ27x00_REG_VOLT, false);
 463         if (volt < 0) {
 464                 dev_err(di->dev, "error reading voltage\n");
 465                 return volt;
 466         }
 467
 468         val->intval = volt * 1000;
 469
 470         return 0;
 471 }
 472
 473 static int bq27x00_simple_value(int value,
 474         union power_supply_propval *val)
 475 {
 476         if (value < 0)
 477                 return value;
 478
 479         val->intval = value;
 480
 481         return 0;
 482 }
 483
 484 #define to_bq27x00_device_info(x) container_of((x), \
 485                                 struct bq27x00_device_info, bat);
 486
 487 static int bq27x00_battery_get_property(struct power_supply *psy,
 488                                         enum power_supply_property psp,
 489                                         union power_supply_propval *val)
 490 {
 491         int ret = 0;
 492         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 493
 494         mutex_lock(&di->lock);
 495         if (time_is_before_jiffies(di->last_update + 5 * HZ)) {
 496                 cancel_delayed_work_sync(&di->work);
 497                 bq27x00_battery_poll(&di->work.work);
 498         }
 499         mutex_unlock(&di->lock);
 500
 501         if (psp != POWER_SUPPLY_PROP_PRESENT && di->cache.flags < 0)
 502                 return -ENODEV;
 503
 504         switch (psp) {
 505         case POWER_SUPPLY_PROP_STATUS:
 506                 ret = bq27x00_battery_status(di, val);
 507                 break;
 508         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 509                 ret = bq27x00_battery_voltage(di, val);
 510                 break;
 511         case POWER_SUPPLY_PROP_PRESENT:
 512                 val->intval = di->cache.flags < 0 ? 0 : 1;
 513                 break;
 514         case POWER_SUPPLY_PROP_CURRENT_NOW:
 515                 ret = bq27x00_battery_current(di, val);
 516                 break;
 517         case POWER_SUPPLY_PROP_CAPACITY:
 518                 ret = bq27x00_simple_value(di->cache.capacity, val);
 519                 break;
 520         case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
 521                 ret = bq27x00_battery_capacity_level(di, val);
 522                 break;
 523         case POWER_SUPPLY_PROP_TEMP:
 524                 ret = bq27x00_simple_value(di->cache.temperature, val);
 525                 break;
 526         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
 527                 ret = bq27x00_simple_value(di->cache.time_to_empty, val);
 528                 break;
 529         case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG:
 530                 ret = bq27x00_simple_value(di->cache.time_to_empty_avg, val);
 531                 break;
 532         case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW:
 533                 ret = bq27x00_simple_value(di->cache.time_to_full, val);
 534                 break;
 535         case POWER_SUPPLY_PROP_TECHNOLOGY:
 536                 val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
 537                 break;
 538         case POWER_SUPPLY_PROP_CHARGE_NOW:
 539                 ret = bq27x00_simple_value(bq27x00_battery_read_nac(di), val);
 540                 break;
 541         case POWER_SUPPLY_PROP_CHARGE_FULL:
 542                 ret = bq27x00_simple_value(di->cache.charge_full, val);
 543                 break;
 544         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 545                 ret = bq27x00_simple_value(di->charge_design_full, val);
 546                 break;
 547         case POWER_SUPPLY_PROP_CYCLE_COUNT:
 548                 ret = bq27x00_simple_value(di->cache.cycle_count, val);
 549                 break;
 550         case POWER_SUPPLY_PROP_ENERGY_NOW:
 551                 ret = bq27x00_simple_value(di->cache.energy, val);
 552                 break;
 553         default:
 554                 return -EINVAL;
 555         }
 556
 557         return ret;
 558 }
 559
 560 static void bq27x00_external_power_changed(struct power_supply *psy)
 561 {
 562         struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
 563
 564         cancel_delayed_work_sync(&di->work);
 565         schedule_delayed_work(&di->work, 0);
 566 }
 567
 568 static int bq27x00_powersupply_init(struct bq27x00_device_info *di)
 569 {
 570         int ret;
 571
 572         di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
 573         di->bat.properties = bq27x00_battery_props;
 574         di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
 575         di->bat.get_property = bq27x00_battery_get_property;
 576         di->bat.external_power_changed = bq27x00_external_power_changed;
 577
 578         INIT_DELAYED_WORK(&di->work, bq27x00_battery_poll);
 579         mutex_init(&di->lock);
 580
 581         ret = power_supply_register(di->dev, &di->bat);
 582         if (ret) {
 583                 dev_err(di->dev, "failed to register battery: %d\n", ret);
 584                 return ret;
 585         }
 586
 587         dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 588
 589         bq27x00_update(di);
 590
 591         return 0;
 592 }
 593
 594 static void bq27x00_powersupply_unregister(struct bq27x00_device_info *di)
 595 {
 596         /*
 597          * power_supply_unregister call bq27x00_battery_get_property which
 598          * call bq27x00_battery_poll.
 599          * Make sure that bq27x00_battery_poll will not call
 600          * schedule_delayed_work again after unregister (which cause OOPS).
 601          */
 602         poll_interval = 0;
 603
 604         cancel_delayed_work_sync(&di->work);
 605
 606         power_supply_unregister(&di->bat);
 607
 608         mutex_destroy(&di->lock);
 609 }
 610
 611
 612 /* i2c specific code */
 613 #ifdef CONFIG_BATTERY_BQ27X00_I2C
 614
 615 /* If the system has several batteries we need a different name for each
 616  * of them...
 617  */
 618 static DEFINE_IDR(battery_id);
 619 static DEFINE_MUTEX(battery_mutex);
 620
 621 static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg, bool single)
 622 {
 623         struct i2c_client *client = to_i2c_client(di->dev);
 624         struct i2c_msg msg[2];
 625         unsigned char data[2];
 626         int ret;
 627
 628         if (!client->adapter)
 629                 return -ENODEV;
 630
 631         msg[0].addr = client->addr;
 632         msg[0].flags = 0;
 633         msg[0].buf = &reg;
 634         msg[0].len = sizeof(reg);
 635         msg[1].addr = client->addr;
 636         msg[1].flags = I2C_M_RD;
 637         msg[1].buf = data;
 638         if (single)
 639                 msg[1].len = 1;
 640         else
 641                 msg[1].len = 2;
 642
 643         ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
 644         if (ret < 0)
 645                 return ret;
 646
 647         if (!single)
 648                 ret = get_unaligned_le16(data);
 649         else
 650                 ret = data[0];
 651
 652         return ret;
 653 }
 654
 655 static int bq27x00_battery_probe(struct i2c_client *client,
 656                                  const struct i2c_device_id *id)
 657 {
 658         char *name;
 659         struct bq27x00_device_info *di;
 660         int num;
 661         int retval = 0;
 662
 663         /* Get new ID for the new battery device */
 664         retval = idr_pre_get(&battery_id, GFP_KERNEL);
 665         if (retval == 0)
 666                 return -ENOMEM;
 667         mutex_lock(&battery_mutex);
 668         retval = idr_get_new(&battery_id, client, &num);
 669         mutex_unlock(&battery_mutex);
 670         if (retval < 0)
 671                 return retval;
 672
 673         name = kasprintf(GFP_KERNEL, "%s-%d", id->name, num);
 674         if (!name) {
 675                 dev_err(&client->dev, "failed to allocate device name\n");
 676                 retval = -ENOMEM;
 677                 goto batt_failed_1;
 678         }
 679
 680         di = kzalloc(sizeof(*di), GFP_KERNEL);
 681         if (!di) {
 682                 dev_err(&client->dev, "failed to allocate device info data\n");
 683                 retval = -ENOMEM;
 684                 goto batt_failed_2;
 685         }
 686
 687         di->id = num;
 688         di->dev = &client->dev;
 689         di->chip = id->driver_data;
 690         di->bat.name = name;
 691         di->bus.read = &bq27x00_read_i2c;
 692
 693         if (bq27x00_powersupply_init(di))
 694                 goto batt_failed_3;
 695
 696         i2c_set_clientdata(client, di);
 697
 698         return 0;
 699
 700 batt_failed_3:
 701         kfree(di);
 702 batt_failed_2:
 703         kfree(name);
 704 batt_failed_1:
 705         mutex_lock(&battery_mutex);
 706         idr_remove(&battery_id, num);
 707         mutex_unlock(&battery_mutex);
 708
 709         return retval;
 710 }
 711
 712 static int bq27x00_battery_remove(struct i2c_client *client)
 713 {
 714         struct bq27x00_device_info *di = i2c_get_clientdata(client);
 715
 716         bq27x00_powersupply_unregister(di);
 717
 718         kfree(di->bat.name);
 719
 720         mutex_lock(&battery_mutex);
 721         idr_remove(&battery_id, di->id);
 722         mutex_unlock(&battery_mutex);
 723
 724         kfree(di);
 725
 726         return 0;
 727 }
 728
 729 static const struct i2c_device_id bq27x00_id[] = {
 730         { "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */
 731         { "bq27500", BQ27500 },
 732         {},
 733 };
 734 MODULE_DEVICE_TABLE(i2c, bq27x00_id);
 735
 736 static struct i2c_driver bq27x00_battery_driver = {
 737         .driver = {
 738                 .name = "bq27x00-battery",
 739         },
 740         .probe = bq27x00_battery_probe,
 741         .remove = bq27x00_battery_remove,
 742         .id_table = bq27x00_id,
 743 };
 744
 745 static inline int bq27x00_battery_i2c_init(void)
 746 {
 747         int ret = i2c_add_driver(&bq27x00_battery_driver);
 748         if (ret)
 749                 printk(KERN_ERR "Unable to register BQ27x00 i2c driver\n");
 750
 751         return ret;
 752 }
 753
 754 static inline void bq27x00_battery_i2c_exit(void)
 755 {
 756         i2c_del_driver(&bq27x00_battery_driver);
 757 }
 758
 759 #else
 760
 761 static inline int bq27x00_battery_i2c_init(void) { return 0; }
 762 static inline void bq27x00_battery_i2c_exit(void) {};
 763
 764 #endif
 765
 766 /* platform specific code */
 767 #ifdef CONFIG_BATTERY_BQ27X00_PLATFORM
 768
 769 static int bq27000_read_platform(struct bq27x00_device_info *di, u8 reg,
 770                         bool single)
 771 {
 772         struct device *dev = di->dev;
 773         struct bq27000_platform_data *pdata = dev->platform_data;
 774         unsigned int timeout = 3;
 775         int upper, lower;
 776         int temp;
 777
 778         if (!single) {
 779                 /* Make sure the value has not changed in between reading the
 780                  * lower and the upper part */
 781                 upper = pdata->read(dev, reg + 1);
 782                 do {
 783                         temp = upper;
 784                         if (upper < 0)
 785                                 return upper;
 786
 787                         lower = pdata->read(dev, reg);
 788                         if (lower < 0)
 789                                 return lower;
 790
 791                         upper = pdata->read(dev, reg + 1);
 792                 } while (temp != upper && --timeout);
 793
 794                 if (timeout == 0)
 795                         return -EIO;
 796
 797                 return (upper << 8) | lower;
 798         }
 799
 800         return pdata->read(dev, reg);
 801 }
 802
 803 static int __devinit bq27000_battery_probe(struct platform_device *pdev)
 804 {
 805         struct bq27x00_device_info *di;
 806         struct bq27000_platform_data *pdata = pdev->dev.platform_data;
 807         int ret;
 808
 809         if (!pdata) {
 810                 dev_err(&pdev->dev, "no platform_data supplied\n");
 811                 return -EINVAL;
 812         }
 813
 814         if (!pdata->read) {
 815                 dev_err(&pdev->dev, "no hdq read callback supplied\n");
 816                 return -EINVAL;
 817         }
 818
 819         di = kzalloc(sizeof(*di), GFP_KERNEL);
 820         if (!di) {
 821                 dev_err(&pdev->dev, "failed to allocate device info data\n");
 822                 return -ENOMEM;
 823         }
 824
 825         platform_set_drvdata(pdev, di);
 826
 827         di->dev = &pdev->dev;
 828         di->chip = BQ27000;
 829
 830         di->bat.name = pdata->name ?: dev_name(&pdev->dev);
 831         di->bus.read = &bq27000_read_platform;
 832
 833         ret = bq27x00_powersupply_init(di);
 834         if (ret)
 835                 goto err_free;
 836
 837         return 0;
 838
 839 err_free:
 840         platform_set_drvdata(pdev, NULL);
 841         kfree(di);
 842
 843         return ret;
 844 }
 845
 846 static int __devexit bq27000_battery_remove(struct platform_device *pdev)
 847 {
 848         struct bq27x00_device_info *di = platform_get_drvdata(pdev);
 849
 850         bq27x00_powersupply_unregister(di);
 851
 852         platform_set_drvdata(pdev, NULL);
 853         kfree(di);
 854
 855         return 0;
 856 }
 857
 858 static struct platform_driver bq27000_battery_driver = {
 859         .probe  = bq27000_battery_probe,
 860         .remove = __devexit_p(bq27000_battery_remove),
 861         .driver = {
 862                 .name = "bq27000-battery",
 863                 .owner = THIS_MODULE,
 864         },
 865 };
 866
 867 static inline int bq27x00_battery_platform_init(void)
 868 {
 869         int ret = platform_driver_register(&bq27000_battery_driver);
 870         if (ret)
 871                 printk(KERN_ERR "Unable to register BQ27000 platform driver\n");
 872
 873         return ret;
 874 }
 875
 876 static inline void bq27x00_battery_platform_exit(void)
 877 {
 878         platform_driver_unregister(&bq27000_battery_driver);
 879 }
 880
 881 #else
 882
 883 static inline int bq27x00_battery_platform_init(void) { return 0; }
 884 static inline void bq27x00_battery_platform_exit(void) {};
 885
 886 #endif
 887
 888 /*
 889  * Module stuff
 890  */
 891
 892 static int __init bq27x00_battery_init(void)
 893 {
 894         int ret;
 895
 896         ret = bq27x00_battery_i2c_init();
 897         if (ret)
 898                 return ret;
 899
 900         ret = bq27x00_battery_platform_init();
 901         if (ret)
 902                 bq27x00_battery_i2c_exit();
 903
 904         return ret;
 905 }
 906 module_init(bq27x00_battery_init);
 907
 908 static void __exit bq27x00_battery_exit(void)
 909 {
 910         bq27x00_battery_platform_exit();
 911         bq27x00_battery_i2c_exit();
 912 }
 913 module_exit(bq27x00_battery_exit);
 914
 915 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 916 MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
 917 MODULE_LICENSE("GPL");