drivers/power/olpc_battery.c

   1 /*
   2  * Battery driver for One Laptop Per Child board.
   3  *
   4  *      Copyright © 2006  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/module.h>
  12 #include <linux/err.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/power_supply.h>
  15 #include <linux/jiffies.h>
  16 #include <linux/sched.h>
  17 #include <asm/olpc.h>
  18
  19
  20 #define EC_BAT_VOLTAGE  0x10    /* uint16_t,    *9.76/32,    mV   */
  21 #define EC_BAT_CURRENT  0x11    /* int16_t,     *15.625/120, mA   */
  22 #define EC_BAT_ACR      0x12    /* int16_t,     *6250/15,    µAh  */
  23 #define EC_BAT_TEMP     0x13    /* uint16_t,    *100/256,   °C  */
  24 #define EC_AMB_TEMP     0x14    /* uint16_t,    *100/256,   °C  */
  25 #define EC_BAT_STATUS   0x15    /* uint8_t,     bitmask */
  26 #define EC_BAT_SOC      0x16    /* uint8_t,     percentage */
  27 #define EC_BAT_SERIAL   0x17    /* uint8_t[6] */
  28 #define EC_BAT_EEPROM   0x18    /* uint8_t adr as input, uint8_t output */
  29 #define EC_BAT_ERRCODE  0x1f    /* uint8_t,     bitmask */
  30
  31 #define BAT_STAT_PRESENT        0x01
  32 #define BAT_STAT_FULL           0x02
  33 #define BAT_STAT_LOW            0x04
  34 #define BAT_STAT_DESTROY        0x08
  35 #define BAT_STAT_AC             0x10
  36 #define BAT_STAT_CHARGING       0x20
  37 #define BAT_STAT_DISCHARGING    0x40
  38
  39 #define BAT_ERR_INFOFAIL        0x02
  40 #define BAT_ERR_OVERVOLTAGE     0x04
  41 #define BAT_ERR_OVERTEMP        0x05
  42 #define BAT_ERR_GAUGESTOP       0x06
  43 #define BAT_ERR_OUT_OF_CONTROL  0x07
  44 #define BAT_ERR_ID_FAIL         0x09
  45 #define BAT_ERR_ACR_FAIL        0x10
  46
  47 #define BAT_ADDR_MFR_TYPE       0x5F
  48
  49 /*********************************************************************
  50  *              Power
  51  *********************************************************************/
  52
  53 static int olpc_ac_get_prop(struct power_supply *psy,
  54                             enum power_supply_property psp,
  55                             union power_supply_propval *val)
  56 {
  57         int ret = 0;
  58         uint8_t status;
  59
  60         switch (psp) {
  61         case POWER_SUPPLY_PROP_ONLINE:
  62                 ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
  63                 if (ret)
  64                         return ret;
  65
  66                 val->intval = !!(status & BAT_STAT_AC);
  67                 break;
  68         default:
  69                 ret = -EINVAL;
  70                 break;
  71         }
  72         return ret;
  73 }
  74
  75 static enum power_supply_property olpc_ac_props[] = {
  76         POWER_SUPPLY_PROP_ONLINE,
  77 };
  78
  79 static struct power_supply olpc_ac = {
  80         .name = "olpc-ac",
  81         .type = POWER_SUPPLY_TYPE_MAINS,
  82         .properties = olpc_ac_props,
  83         .num_properties = ARRAY_SIZE(olpc_ac_props),
  84         .get_property = olpc_ac_get_prop,
  85 };
  86
  87 static char bat_serial[17]; /* Ick */
  88
  89 static int olpc_bat_get_status(union power_supply_propval *val, uint8_t ec_byte)
  90 {
  91         if (olpc_platform_info.ecver > 0x44) {
  92                 if (ec_byte & BAT_STAT_CHARGING)
  93                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
  94                 else if (ec_byte & BAT_STAT_DISCHARGING)
  95                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
  96                 else if (ec_byte & BAT_STAT_FULL)
  97                         val->intval = POWER_SUPPLY_STATUS_FULL;
  98                 else /* er,... */
  99                         val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
 100         } else {
 101                 /* Older EC didn't report charge/discharge bits */
 102                 if (!(ec_byte & BAT_STAT_AC)) /* No AC means discharging */
 103                         val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
 104                 else if (ec_byte & BAT_STAT_FULL)
 105                         val->intval = POWER_SUPPLY_STATUS_FULL;
 106                 else /* Not _necessarily_ true but EC doesn't tell all yet */
 107                         val->intval = POWER_SUPPLY_STATUS_CHARGING;
 108         }
 109
 110         return 0;
 111 }
 112
 113 static int olpc_bat_get_health(union power_supply_propval *val)
 114 {
 115         uint8_t ec_byte;
 116         int ret;
 117
 118         ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
 119         if (ret)
 120                 return ret;
 121
 122         switch (ec_byte) {
 123         case 0:
 124                 val->intval = POWER_SUPPLY_HEALTH_GOOD;
 125                 break;
 126
 127         case BAT_ERR_OVERTEMP:
 128                 val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
 129                 break;
 130
 131         case BAT_ERR_OVERVOLTAGE:
 132                 val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
 133                 break;
 134
 135         case BAT_ERR_INFOFAIL:
 136         case BAT_ERR_OUT_OF_CONTROL:
 137         case BAT_ERR_ID_FAIL:
 138         case BAT_ERR_ACR_FAIL:
 139                 val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
 140                 break;
 141
 142         default:
 143                 /* Eep. We don't know this failure code */
 144                 ret = -EIO;
 145         }
 146
 147         return ret;
 148 }
 149
 150 static int olpc_bat_get_mfr(union power_supply_propval *val)
 151 {
 152         uint8_t ec_byte;
 153         int ret;
 154
 155         ec_byte = BAT_ADDR_MFR_TYPE;
 156         ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
 157         if (ret)
 158                 return ret;
 159
 160         switch (ec_byte >> 4) {
 161         case 1:
 162                 val->strval = "Gold Peak";
 163                 break;
 164         case 2:
 165                 val->strval = "BYD";
 166                 break;
 167         default:
 168                 val->strval = "Unknown";
 169                 break;
 170         }
 171
 172         return ret;
 173 }
 174
 175 static int olpc_bat_get_tech(union power_supply_propval *val)
 176 {
 177         uint8_t ec_byte;
 178         int ret;
 179
 180         ec_byte = BAT_ADDR_MFR_TYPE;
 181         ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
 182         if (ret)
 183                 return ret;
 184
 185         switch (ec_byte & 0xf) {
 186         case 1:
 187                 val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
 188                 break;
 189         case 2:
 190                 val->intval = POWER_SUPPLY_TECHNOLOGY_LiFe;
 191                 break;
 192         default:
 193                 val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
 194                 break;
 195         }
 196
 197         return ret;
 198 }
 199
 200 /*********************************************************************
 201  *              Battery properties
 202  *********************************************************************/
 203 static int olpc_bat_get_property(struct power_supply *psy,
 204                                  enum power_supply_property psp,
 205                                  union power_supply_propval *val)
 206 {
 207         int ret = 0;
 208         __be16 ec_word;
 209         uint8_t ec_byte;
 210         __be64 ser_buf;
 211
 212         ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
 213         if (ret)
 214                 return ret;
 215
 216         /* Theoretically there's a race here -- the battery could be
 217            removed immediately after we check whether it's present, and
 218            then we query for some other property of the now-absent battery.
 219            It doesn't matter though -- the EC will return the last-known
 220            information, and it's as if we just ran that _little_ bit faster
 221            and managed to read it out before the battery went away. */
 222         if (!(ec_byte & BAT_STAT_PRESENT) && psp != POWER_SUPPLY_PROP_PRESENT)
 223                 return -ENODEV;
 224
 225         switch (psp) {
 226         case POWER_SUPPLY_PROP_STATUS:
 227                 ret = olpc_bat_get_status(val, ec_byte);
 228                 if (ret)
 229                         return ret;
 230                 break;
 231         case POWER_SUPPLY_PROP_PRESENT:
 232                 val->intval = !!(ec_byte & BAT_STAT_PRESENT);
 233                 break;
 234
 235         case POWER_SUPPLY_PROP_HEALTH:
 236                 if (ec_byte & BAT_STAT_DESTROY)
 237                         val->intval = POWER_SUPPLY_HEALTH_DEAD;
 238                 else {
 239                         ret = olpc_bat_get_health(val);
 240                         if (ret)
 241                                 return ret;
 242                 }
 243                 break;
 244
 245         case POWER_SUPPLY_PROP_MANUFACTURER:
 246                 ret = olpc_bat_get_mfr(val);
 247                 if (ret)
 248                         return ret;
 249                 break;
 250         case POWER_SUPPLY_PROP_TECHNOLOGY:
 251                 ret = olpc_bat_get_tech(val);
 252                 if (ret)
 253                         return ret;
 254                 break;
 255         case POWER_SUPPLY_PROP_VOLTAGE_AVG:
 256                 ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
 257                 if (ret)
 258                         return ret;
 259
 260                 val->intval = (int)be16_to_cpu(ec_word) * 9760L / 32;
 261                 break;
 262         case POWER_SUPPLY_PROP_CURRENT_AVG:
 263                 ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
 264                 if (ret)
 265                         return ret;
 266
 267                 val->intval = (int)be16_to_cpu(ec_word) * 15625L / 120;
 268                 break;
 269         case POWER_SUPPLY_PROP_CAPACITY:
 270                 ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
 271                 if (ret)
 272                         return ret;
 273                 val->intval = ec_byte;
 274                 break;
 275         case POWER_SUPPLY_PROP_TEMP:
 276                 ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
 277                 if (ret)
 278                         return ret;
 279
 280                 val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
 281                 break;
 282         case POWER_SUPPLY_PROP_TEMP_AMBIENT:
 283                 ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
 284                 if (ret)
 285                         return ret;
 286
 287                 val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
 288                 break;
 289         case POWER_SUPPLY_PROP_CHARGE_COUNTER:
 290                 ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
 291                 if (ret)
 292                         return ret;
 293
 294                 val->intval = (int)be16_to_cpu(ec_word) * 6250 / 15;
 295                 break;
 296         case POWER_SUPPLY_PROP_SERIAL_NUMBER:
 297                 ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
 298                 if (ret)
 299                         return ret;
 300
 301                 sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
 302                 val->strval = bat_serial;
 303                 break;
 304         default:
 305                 ret = -EINVAL;
 306                 break;
 307         }
 308
 309         return ret;
 310 }
 311
 312 static enum power_supply_property olpc_bat_props[] = {
 313         POWER_SUPPLY_PROP_STATUS,
 314         POWER_SUPPLY_PROP_PRESENT,
 315         POWER_SUPPLY_PROP_HEALTH,
 316         POWER_SUPPLY_PROP_TECHNOLOGY,
 317         POWER_SUPPLY_PROP_VOLTAGE_AVG,
 318         POWER_SUPPLY_PROP_CURRENT_AVG,
 319         POWER_SUPPLY_PROP_CAPACITY,
 320         POWER_SUPPLY_PROP_TEMP,
 321         POWER_SUPPLY_PROP_TEMP_AMBIENT,
 322         POWER_SUPPLY_PROP_MANUFACTURER,
 323         POWER_SUPPLY_PROP_SERIAL_NUMBER,
 324         POWER_SUPPLY_PROP_CHARGE_COUNTER,
 325 };
 326
 327 /* EEPROM reading goes completely around the power_supply API, sadly */
 328
 329 #define EEPROM_START    0x20
 330 #define EEPROM_END      0x80
 331 #define EEPROM_SIZE     (EEPROM_END - EEPROM_START)
 332
 333 static ssize_t olpc_bat_eeprom_read(struct kobject *kobj,
 334                 struct bin_attribute *attr, char *buf, loff_t off, size_t count)
 335 {
 336         uint8_t ec_byte;
 337         int ret, end;
 338
 339         if (off >= EEPROM_SIZE)
 340                 return 0;
 341         if (off + count > EEPROM_SIZE)
 342                 count = EEPROM_SIZE - off;
 343
 344         end = EEPROM_START + off + count;
 345         for (ec_byte = EEPROM_START + off; ec_byte < end; ec_byte++) {
 346                 ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1,
 347                                 &buf[ec_byte - EEPROM_START], 1);
 348                 if (ret) {
 349                         printk(KERN_ERR "olpc-battery:  EC command "
 350                                         "EC_BAT_EEPROM @ 0x%x failed -"
 351                                         " %d!\n", ec_byte, ret);
 352                         return -EIO;
 353                 }
 354         }
 355
 356         return count;
 357 }
 358
 359 static struct bin_attribute olpc_bat_eeprom = {
 360         .attr = {
 361                 .name = "eeprom",
 362                 .mode = S_IRUGO,
 363                 .owner = THIS_MODULE,
 364         },
 365         .size = 0,
 366         .read = olpc_bat_eeprom_read,
 367 };
 368
 369 /*********************************************************************
 370  *              Initialisation
 371  *********************************************************************/
 372
 373 static struct platform_device *bat_pdev;
 374
 375 static struct power_supply olpc_bat = {
 376         .properties = olpc_bat_props,
 377         .num_properties = ARRAY_SIZE(olpc_bat_props),
 378         .get_property = olpc_bat_get_property,
 379         .use_for_apm = 1,
 380 };
 381
 382 void olpc_battery_trigger_uevent(unsigned long cause)
 383 {
 384         if (cause & EC_SCI_SRC_ACPWR)
 385                 kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
 386         if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
 387                 kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
 388 }
 389
 390 static int __init olpc_bat_init(void)
 391 {
 392         int ret = 0;
 393         uint8_t status;
 394
 395         if (!olpc_platform_info.ecver)
 396                 return -ENXIO;
 397
 398         /*
 399          * We've seen a number of EC protocol changes; this driver requires
 400          * the latest EC protocol, supported by 0x44 and above.
 401          */
 402         if (olpc_platform_info.ecver < 0x44) {
 403                 printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
 404                         "battery driver.\n", olpc_platform_info.ecver);
 405                 return -ENXIO;
 406         }
 407
 408         ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
 409         if (ret)
 410                 return ret;
 411
 412         /* Ignore the status. It doesn't actually matter */
 413
 414         bat_pdev = platform_device_register_simple("olpc-battery", 0, NULL, 0);
 415         if (IS_ERR(bat_pdev))
 416                 return PTR_ERR(bat_pdev);
 417
 418         ret = power_supply_register(&bat_pdev->dev, &olpc_ac);
 419         if (ret)
 420                 goto ac_failed;
 421
 422         olpc_bat.name = bat_pdev->name;
 423
 424         ret = power_supply_register(&bat_pdev->dev, &olpc_bat);
 425         if (ret)
 426                 goto battery_failed;
 427
 428         ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
 429         if (ret)
 430                 goto eeprom_failed;
 431
 432         goto success;
 433
 434 eeprom_failed:
 435         power_supply_unregister(&olpc_bat);
 436 battery_failed:
 437         power_supply_unregister(&olpc_ac);
 438 ac_failed:
 439         platform_device_unregister(bat_pdev);
 440 success:
 441         return ret;
 442 }
 443
 444 static void __exit olpc_bat_exit(void)
 445 {
 446         device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
 447         power_supply_unregister(&olpc_bat);
 448         power_supply_unregister(&olpc_ac);
 449         platform_device_unregister(bat_pdev);
 450 }
 451
 452 module_init(olpc_bat_init);
 453 module_exit(olpc_bat_exit);
 454
 455 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 456 MODULE_LICENSE("GPL");
 457 MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");