drivers/power/olpc_battery.c

   1 /*
   2  * Battery driver for One Laptop Per Child board.
   3  *
   4  *      Copyright © 2006-2010  David Woodhouse <dwmw2@infradead.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/err.h>
  15 #include <linux/device.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/power_supply.h>
  18 #include <linux/jiffies.h>
  19 #include <linux/sched.h>
  20 #include <asm/olpc.h>
  21
  22
  23 #define EC_BAT_VOLTAGE  0x10    /* uint16_t,    *9.76/32,    mV   */
  24 #define EC_BAT_CURRENT  0x11    /* int16_t,     *15.625/120, mA   */
  25 #define EC_BAT_ACR      0x12    /* int16_t,     *6250/15,    µAh  */
  26 #define EC_BAT_TEMP     0x13    /* uint16_t,    *100/256,   °C  */
  27 #define EC_AMB_TEMP     0x14    /* uint16_t,    *100/256,   °C  */
  28 #define EC_BAT_STATUS   0x15    /* uint8_t,     bitmask */
  29 #define EC_BAT_SOC      0x16    /* uint8_t,     percentage */
  30 #define EC_BAT_SERIAL   0x17    /* uint8_t[6] */
  31 #define EC_BAT_EEPROM   0x18    /* uint8_t adr as input, uint8_t output */
  32 #define EC_BAT_ERRCODE  0x1f    /* uint8_t,     bitmask */
  33
  34 #define BAT_STAT_PRESENT        0x01
  35 #define BAT_STAT_FULL           0x02
  36 #define BAT_STAT_LOW            0x04
  37 #define BAT_STAT_DESTROY        0x08
  38 #define BAT_STAT_AC             0x10
  39 #define BAT_STAT_CHARGING       0x20
  40 #define BAT_STAT_DISCHARGING    0x40
  41 #define BAT_STAT_TRICKLE        0x80
  42
  43 #define BAT_ERR_INFOFAIL        0x02
  44 #define BAT_ERR_OVERVOLTAGE     0x04
  45 #define BAT_ERR_OVERTEMP        0x05
  46 #define BAT_ERR_GAUGESTOP       0x06
  47 #define BAT_ERR_OUT_OF_CONTROL  0x07
  48 #define BAT_ERR_ID_FAIL         0x09
  49 #define BAT_ERR_ACR_FAIL        0x10
  50
  51 #define BAT_ADDR_MFR_TYPE       0x5F
  52
  53 /*********************************************************************
  54  *              Power
  55  *********************************************************************/
  56
  57 static int olpc_ac_get_prop(struct power_supply *psy,
  58                             enum power_supply_property psp,
  59                             union power_supply_propval *val)
  60 {
  61         int ret = 0;
  62         uint8_t status;
  63
  64         switch (psp) {
  65         case POWER_SUPPLY_PROP_ONLINE:
  66                 ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
  67                 if (ret)
  68                         return ret;
  69
  70                 val->intval = !!(status & BAT_STAT_AC);
  71                 break;
  72         default:
  73                 ret = -EINVAL;
  74                 break;
  75         }
  76         return ret;
  77 }
  78
  79 static enum power_supply_property olpc_ac_props[] = {
  80         POWER_SUPPLY_PROP_ONLINE,
  81 };
  82
  83 static struct power_supply olpc_ac = {
  84         .name = "olpc-ac",
  85         .type = POWER_SUPPLY_TYPE_MAINS,
  86         .properties = olpc_ac_props,
  87         .num_properties = ARRAY_SIZE(olpc_ac_props),
  88         .get_property = olpc_ac_get_prop,
  89 };
  90
  91 static char bat_serial[17]; /* Ick */
  92
  93 static int olpc_bat_get_status(union power_supply_propval *val, uint8_t ec_byte)
  94 {
  95         if (olpc_platform_info.ecver > 0x44) {
  96                 if (ec_byte & (BAT_STAT_CHARGING | BAT_STAT_TRICKLE))
  97                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
  98                 else if (ec_byte & BAT_STAT_DISCHARGING)
  99                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
 100                 else if (ec_byte & BAT_STAT_FULL)
 101                         val->intval = POWER_SUPPLY_STATUS_FULL;
 102                 else /* er,... */
 103                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 104         } else {
 105                 /* Older EC didn't report charge/discharge bits */
 106                 if (!(ec_byte & BAT_STAT_AC)) /* No AC means discharging */
 107                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
 108                 else if (ec_byte & BAT_STAT_FULL)
 109                         val->intval = POWER_SUPPLY_STATUS_FULL;
 110                 else /* Not _necessarily_ true but EC doesn't tell all yet */
 111                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
 112         }
 113
 114         return 0;
 115 }
 116
 117 static int olpc_bat_get_health(union power_supply_propval *val)
 118 {
 119         uint8_t ec_byte;
 120         int ret;
 121
 122         ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
 123         if (ret)
 124                 return ret;
 125
 126         switch (ec_byte) {
 127         case 0:
 128                 val->intval = POWER_SUPPLY_HEALTH_GOOD;
 129                 break;
 130
 131         case BAT_ERR_OVERTEMP:
 132                 val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
 133                 break;
 134
 135         case BAT_ERR_OVERVOLTAGE:
 136                 val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
 137                 break;
 138
 139         case BAT_ERR_INFOFAIL:
 140         case BAT_ERR_OUT_OF_CONTROL:
 141         case BAT_ERR_ID_FAIL:
 142         case BAT_ERR_ACR_FAIL:
 143                 val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
 144                 break;
 145
 146         default:
 147                 /* Eep. We don't know this failure code */
 148                 ret = -EIO;
 149         }
 150
 151         return ret;
 152 }
 153
 154 static int olpc_bat_get_mfr(union power_supply_propval *val)
 155 {
 156         uint8_t ec_byte;
 157         int ret;
 158
 159         ec_byte = BAT_ADDR_MFR_TYPE;
 160         ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
 161         if (ret)
 162                 return ret;
 163
 164         switch (ec_byte >> 4) {
 165         case 1:
 166                 val->strval = "Gold Peak";
 167                 break;
 168         case 2:
 169                 val->strval = "BYD";
 170                 break;
 171         default:
 172                 val->strval = "Unknown";
 173                 break;
 174         }
 175
 176         return ret;
 177 }
 178
 179 static int olpc_bat_get_tech(union power_supply_propval *val)
 180 {
 181         uint8_t ec_byte;
 182         int ret;
 183
 184         ec_byte = BAT_ADDR_MFR_TYPE;
 185         ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
 186         if (ret)
 187                 return ret;
 188
 189         switch (ec_byte & 0xf) {
 190         case 1:
 191                 val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
 192                 break;
 193         case 2:
 194                 val->intval = POWER_SUPPLY_TECHNOLOGY_LiFe;
 195                 break;
 196         default:
 197                 val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
 198                 break;
 199         }
 200
 201         return ret;
 202 }
 203
 204 static int olpc_bat_get_charge_full_design(union power_supply_propval *val)
 205 {
 206         uint8_t ec_byte;
 207         union power_supply_propval tech;
 208         int ret, mfr;
 209
 210         ret = olpc_bat_get_tech(&tech);
 211         if (ret)
 212                 return ret;
 213
 214         ec_byte = BAT_ADDR_MFR_TYPE;
 215         ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
 216         if (ret)
 217                 return ret;
 218
 219         mfr = ec_byte >> 4;
 220
 221         switch (tech.intval) {
 222         case POWER_SUPPLY_TECHNOLOGY_NiMH:
 223                 switch (mfr) {
 224                 case 1: /* Gold Peak */
 225                         val->intval = 3000000*.8;
 226                         break;
 227                 default:
 228                         return -EIO;
 229                 }
 230                 break;
 231
 232         case POWER_SUPPLY_TECHNOLOGY_LiFe:
 233                 switch (mfr) {
 234                 case 1: /* Gold Peak */
 235                         val->intval = 2800000;
 236                         break;
 237                 case 2: /* BYD */
 238                         val->intval = 3100000;
 239                         break;
 240                 default:
 241                         return -EIO;
 242                 }
 243                 break;
 244
 245         default:
 246                 return -EIO;
 247         }
 248
 249         return ret;
 250 }
 251
 252 static int olpc_bat_get_charge_now(union power_supply_propval *val)
 253 {
 254         uint8_t soc;
 255         union power_supply_propval full;
 256         int ret;
 257
 258         ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &soc, 1);
 259         if (ret)
 260                 return ret;
 261
 262         ret = olpc_bat_get_charge_full_design(&full);
 263         if (ret)
 264                 return ret;
 265
 266         val->intval = soc * (full.intval / 100);
 267         return 0;
 268 }
 269
 270 /*********************************************************************
 271  *              Battery properties
 272  *********************************************************************/
 273 static int olpc_bat_get_property(struct power_supply *psy,
 274                                  enum power_supply_property psp,
 275                                  union power_supply_propval *val)
 276 {
 277         int ret = 0;
 278         __be16 ec_word;
 279         uint8_t ec_byte;
 280         __be64 ser_buf;
 281
 282         ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
 283         if (ret)
 284                 return ret;
 285
 286         /* Theoretically there's a race here -- the battery could be
 287            removed immediately after we check whether it's present, and
 288            then we query for some other property of the now-absent battery.
 289            It doesn't matter though -- the EC will return the last-known
 290            information, and it's as if we just ran that _little_ bit faster
 291            and managed to read it out before the battery went away. */
 292         if (!(ec_byte & (BAT_STAT_PRESENT | BAT_STAT_TRICKLE)) &&
 293                         psp != POWER_SUPPLY_PROP_PRESENT)
 294                 return -ENODEV;
 295
 296         switch (psp) {
 297         case POWER_SUPPLY_PROP_STATUS:
 298                 ret = olpc_bat_get_status(val, ec_byte);
 299                 if (ret)
 300                         return ret;
 301                 break;
 302         case POWER_SUPPLY_PROP_CHARGE_TYPE:
 303                 if (ec_byte & BAT_STAT_TRICKLE)
 304                         val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
 305                 else if (ec_byte & BAT_STAT_CHARGING)
 306                         val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
 307                 else
 308                         val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
 309                 break;
 310         case POWER_SUPPLY_PROP_PRESENT:
 311                 val->intval = !!(ec_byte & (BAT_STAT_PRESENT |
 312                                             BAT_STAT_TRICKLE));
 313                 break;
 314
 315         case POWER_SUPPLY_PROP_HEALTH:
 316                 if (ec_byte & BAT_STAT_DESTROY)
 317                         val->intval = POWER_SUPPLY_HEALTH_DEAD;
 318                 else {
 319                         ret = olpc_bat_get_health(val);
 320                         if (ret)
 321                                 return ret;
 322                 }
 323                 break;
 324
 325         case POWER_SUPPLY_PROP_MANUFACTURER:
 326                 ret = olpc_bat_get_mfr(val);
 327                 if (ret)
 328                         return ret;
 329                 break;
 330         case POWER_SUPPLY_PROP_TECHNOLOGY:
 331                 ret = olpc_bat_get_tech(val);
 332                 if (ret)
 333                         return ret;
 334                 break;
 335         case POWER_SUPPLY_PROP_VOLTAGE_AVG:
 336                 ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
 337                 if (ret)
 338                         return ret;
 339
 340                 val->intval = (s16)be16_to_cpu(ec_word) * 9760L / 32;
 341                 break;
 342         case POWER_SUPPLY_PROP_CURRENT_AVG:
 343                 ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
 344                 if (ret)
 345                         return ret;
 346
 347                 val->intval = (s16)be16_to_cpu(ec_word) * 15625L / 120;
 348                 break;
 349         case POWER_SUPPLY_PROP_CAPACITY:
 350                 ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
 351                 if (ret)
 352                         return ret;
 353                 val->intval = ec_byte;
 354                 break;
 355         case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
 356                 if (ec_byte & BAT_STAT_FULL)
 357                         val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
 358                 else if (ec_byte & BAT_STAT_LOW)
 359                         val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
 360                 else
 361                         val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
 362                 break;
 363         case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
 364                 ret = olpc_bat_get_charge_full_design(val);
 365                 if (ret)
 366                         return ret;
 367                 break;
 368         case POWER_SUPPLY_PROP_CHARGE_NOW:
 369                 ret = olpc_bat_get_charge_now(val);
 370                 if (ret)
 371                         return ret;
 372                 break;
 373         case POWER_SUPPLY_PROP_TEMP:
 374                 ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
 375                 if (ret)
 376                         return ret;
 377
 378                 val->intval = (s16)be16_to_cpu(ec_word) * 100 / 256;
 379                 break;
 380         case POWER_SUPPLY_PROP_TEMP_AMBIENT:
 381                 ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
 382                 if (ret)
 383                         return ret;
 384
 385                 val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
 386                 break;
 387         case POWER_SUPPLY_PROP_CHARGE_COUNTER:
 388                 ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
 389                 if (ret)
 390                         return ret;
 391
 392                 val->intval = (s16)be16_to_cpu(ec_word) * 6250 / 15;
 393                 break;
 394         case POWER_SUPPLY_PROP_SERIAL_NUMBER:
 395                 ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
 396                 if (ret)
 397                         return ret;
 398
 399                 sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
 400                 val->strval = bat_serial;
 401                 break;
 402         default:
 403                 ret = -EINVAL;
 404                 break;
 405         }
 406
 407         return ret;
 408 }
 409
 410 static enum power_supply_property olpc_xo1_bat_props[] = {
 411         POWER_SUPPLY_PROP_STATUS,
 412         POWER_SUPPLY_PROP_CHARGE_TYPE,
 413         POWER_SUPPLY_PROP_PRESENT,
 414         POWER_SUPPLY_PROP_HEALTH,
 415         POWER_SUPPLY_PROP_TECHNOLOGY,
 416         POWER_SUPPLY_PROP_VOLTAGE_AVG,
 417         POWER_SUPPLY_PROP_CURRENT_AVG,
 418         POWER_SUPPLY_PROP_CAPACITY,
 419         POWER_SUPPLY_PROP_CAPACITY_LEVEL,
 420         POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
 421         POWER_SUPPLY_PROP_CHARGE_NOW,
 422         POWER_SUPPLY_PROP_TEMP,
 423         POWER_SUPPLY_PROP_TEMP_AMBIENT,
 424         POWER_SUPPLY_PROP_MANUFACTURER,
 425         POWER_SUPPLY_PROP_SERIAL_NUMBER,
 426         POWER_SUPPLY_PROP_CHARGE_COUNTER,
 427 };
 428
 429 /* XO-1.5 does not have ambient temperature property */
 430 static enum power_supply_property olpc_xo15_bat_props[] = {
 431         POWER_SUPPLY_PROP_STATUS,
 432         POWER_SUPPLY_PROP_CHARGE_TYPE,
 433         POWER_SUPPLY_PROP_PRESENT,
 434         POWER_SUPPLY_PROP_HEALTH,
 435         POWER_SUPPLY_PROP_TECHNOLOGY,
 436         POWER_SUPPLY_PROP_VOLTAGE_AVG,
 437         POWER_SUPPLY_PROP_CURRENT_AVG,
 438         POWER_SUPPLY_PROP_CAPACITY,
 439         POWER_SUPPLY_PROP_CAPACITY_LEVEL,
 440         POWER_SUPPLY_PROP_TEMP,
 441         POWER_SUPPLY_PROP_MANUFACTURER,
 442         POWER_SUPPLY_PROP_SERIAL_NUMBER,
 443         POWER_SUPPLY_PROP_CHARGE_COUNTER,
 444 };
 445
 446 /* EEPROM reading goes completely around the power_supply API, sadly */
 447
 448 #define EEPROM_START    0x20
 449 #define EEPROM_END      0x80
 450 #define EEPROM_SIZE     (EEPROM_END - EEPROM_START)
 451
 452 static ssize_t olpc_bat_eeprom_read(struct file *filp, struct kobject *kobj,
 453                 struct bin_attribute *attr, char *buf, loff_t off, size_t count)
 454 {
 455         uint8_t ec_byte;
 456         int ret;
 457         int i;
 458
 459         if (off >= EEPROM_SIZE)
 460                 return 0;
 461         if (off + count > EEPROM_SIZE)
 462                 count = EEPROM_SIZE - off;
 463
 464         for (i = 0; i < count; i++) {
 465                 ec_byte = EEPROM_START + off + i;
 466                 ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &buf[i], 1);
 467                 if (ret) {
 468                         pr_err("olpc-battery: "
 469                                "EC_BAT_EEPROM cmd @ 0x%x failed - %d!\n",
 470                                ec_byte, ret);
 471                         return -EIO;
 472                 }
 473         }
 474
 475         return count;
 476 }
 477
 478 static struct bin_attribute olpc_bat_eeprom = {
 479         .attr = {
 480                 .name = "eeprom",
 481                 .mode = S_IRUGO,
 482         },
 483         .size = 0,
 484         .read = olpc_bat_eeprom_read,
 485 };
 486
 487 /* Allow userspace to see the specific error value pulled from the EC */
 488
 489 static ssize_t olpc_bat_error_read(struct device *dev,
 490                 struct device_attribute *attr, char *buf)
 491 {
 492         uint8_t ec_byte;
 493         ssize_t ret;
 494
 495         ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
 496         if (ret < 0)
 497                 return ret;
 498
 499         return sprintf(buf, "%d\n", ec_byte);
 500 }
 501
 502 static struct device_attribute olpc_bat_error = {
 503         .attr = {
 504                 .name = "error",
 505                 .mode = S_IRUGO,
 506         },
 507         .show = olpc_bat_error_read,
 508 };
 509
 510 /*********************************************************************
 511  *              Initialisation
 512  *********************************************************************/
 513
 514 static struct platform_device *bat_pdev;
 515
 516 static struct power_supply olpc_bat = {
 517         .get_property = olpc_bat_get_property,
 518         .use_for_apm = 1,
 519 };
 520
 521 void olpc_battery_trigger_uevent(unsigned long cause)
 522 {
 523         if (cause & EC_SCI_SRC_ACPWR)
 524                 kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
 525         if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
 526                 kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
 527 }
 528
 529 static int __init olpc_bat_init(void)
 530 {
 531         int ret = 0;
 532         uint8_t status;
 533
 534         if (!olpc_platform_info.ecver)
 535                 return -ENXIO;
 536
 537         /*
 538          * We've seen a number of EC protocol changes; this driver requires
 539          * the latest EC protocol, supported by 0x44 and above.
 540          */
 541         if (olpc_platform_info.ecver < 0x44) {
 542                 printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
 543                         "battery driver.\n", olpc_platform_info.ecver);
 544                 return -ENXIO;
 545         }
 546
 547         ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
 548         if (ret)
 549                 return ret;
 550
 551         /* Ignore the status. It doesn't actually matter */
 552
 553         bat_pdev = platform_device_register_simple("olpc-battery", 0, NULL, 0);
 554         if (IS_ERR(bat_pdev))
 555                 return PTR_ERR(bat_pdev);
 556
 557         ret = power_supply_register(&bat_pdev->dev, &olpc_ac);
 558         if (ret)
 559                 goto ac_failed;
 560
 561         olpc_bat.name = bat_pdev->name;
 562         if (olpc_board_at_least(olpc_board_pre(0xd0))) { /* XO-1.5 */
 563                 olpc_bat.properties = olpc_xo15_bat_props;
 564                 olpc_bat.num_properties = ARRAY_SIZE(olpc_xo15_bat_props);
 565         } else { /* XO-1 */
 566                 olpc_bat.properties = olpc_xo1_bat_props;
 567                 olpc_bat.num_properties = ARRAY_SIZE(olpc_xo1_bat_props);
 568         }
 569
 570         ret = power_supply_register(&bat_pdev->dev, &olpc_bat);
 571         if (ret)
 572                 goto battery_failed;
 573
 574         ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
 575         if (ret)
 576                 goto eeprom_failed;
 577
 578         ret = device_create_file(olpc_bat.dev, &olpc_bat_error);
 579         if (ret)
 580                 goto error_failed;
 581
 582         goto success;
 583
 584 error_failed:
 585         device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
 586 eeprom_failed:
 587         power_supply_unregister(&olpc_bat);
 588 battery_failed:
 589         power_supply_unregister(&olpc_ac);
 590 ac_failed:
 591         platform_device_unregister(bat_pdev);
 592 success:
 593         return ret;
 594 }
 595
 596 static void __exit olpc_bat_exit(void)
 597 {
 598         device_remove_file(olpc_bat.dev, &olpc_bat_error);
 599         device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
 600         power_supply_unregister(&olpc_bat);
 601         power_supply_unregister(&olpc_ac);
 602         platform_device_unregister(bat_pdev);
 603 }
 604
 605 module_init(olpc_bat_init);
 606 module_exit(olpc_bat_exit);
 607
 608 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 609 MODULE_LICENSE("GPL");
 610 MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");