linux/drivers/power/olpc_battery.c
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   1/*
   2 * Battery driver for One Laptop Per Child board.
   3 *
   4 *      Copyright \xC2\xA9 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,    \xC2\xB5Ah  */
  23#define EC_BAT_TEMP     0x13    /* uint16_t,    *100/256,   \xC2\xB0C  */
  24#define EC_AMB_TEMP     0x14    /* uint16_t,    *100/256,   \xC2\xB0C  */
  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
  53static 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
  75static enum power_supply_property olpc_ac_props[] = {
  76        POWER_SUPPLY_PROP_ONLINE,
  77};
  78
  79static 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
  87static char bat_serial[17]; /* Ick */
  88
  89static 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
 113static 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
 150static 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
 175static 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 *********************************************************************/
 203static 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
 312static 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
 333static 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
 359static 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
 373static struct platform_device *bat_pdev;
 374
 375static 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
 382void 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
 390static 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
 434eeprom_failed:
 435        power_supply_unregister(&olpc_bat);
 436battery_failed:
 437        power_supply_unregister(&olpc_ac);
 438ac_failed:
 439        platform_device_unregister(bat_pdev);
 440success:
 441        return ret;
 442}
 443
 444static 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
 452module_init(olpc_bat_init);
 453module_exit(olpc_bat_exit);
 454
 455MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
 456MODULE_LICENSE("GPL");
 457MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");
 458