sys/dev/acpica/acpi_cmbat.c

   1 /*-
   2  * Copyright (c) 2000 Munehiro Matsuda
   3  * Copyright (c) 2000 Takanori Watanabe
   4  * Copyright (c) 2000 Mitsuru IWASAKI <iwasaki@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD$
  29  */
  30
  31 #include "opt_acpi.h"
  32 #include <sys/param.h>
  33 #include <sys/kernel.h>
  34 #include <sys/bus.h>
  35 #include <sys/ioccom.h>
  36 #include <sys/conf.h>
  37
  38 #include <machine/bus.h>
  39 #include <machine/resource.h>
  40 #include <sys/rman.h>
  41 #include <sys/malloc.h>
  42
  43 #include  "acpi.h"
  44
  45 #include <dev/acpica/acpivar.h>
  46 #include <dev/acpica/acpiio.h>
  47
  48 MALLOC_DEFINE(M_ACPICMBAT, "acpicmbat", "ACPI control method battery data");
  49
  50 #define CMBAT_POLLRATE  (60 * hz)
  51
  52 /*
  53  * Hooks for the ACPI CA debugging infrastructure
  54  */
  55 #define _COMPONENT      ACPI_BATTERY
  56 ACPI_MODULE_NAME("BATTERY")
  57
  58 #define ACPI_BATTERY_BST_CHANGE 0x80
  59 #define ACPI_BATTERY_BIF_CHANGE 0x81
  60
  61 #define PKG_GETINT(res, tmp, idx, dest, label) do {                     \
  62         tmp = &res->Package.Elements[idx];                              \
  63         if (tmp == NULL) {                                              \
  64                 ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),     \
  65                     "%s: PKG_GETINT error, idx = %d\n.", __func__, idx); \
  66                 goto label;                                             \
  67         }                                                               \
  68         if (tmp->Type != ACPI_TYPE_INTEGER)                             \
  69                 goto label;                                             \
  70         dest = tmp->Integer.Value;                                      \
  71 } while (0)
  72
  73 #define PKG_GETSTR(res, tmp, idx, dest, size, label) do {               \
  74         size_t  length;                                                 \
  75         length = size;                                                  \
  76         tmp = &res->Package.Elements[idx];                              \
  77         if (tmp == NULL) {                                              \
  78                 ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),     \
  79                     "%s: PKG_GETSTR error, idx = %d\n.", __func__, idx); \
  80                 goto label;                                             \
  81         }                                                               \
  82         bzero(dest, sizeof(dest));                                      \
  83         switch (tmp->Type) {                                            \
  84         case ACPI_TYPE_STRING:                                          \
  85                 if (tmp->String.Length < length) {                      \
  86                         length = tmp->String.Length;                    \
  87                 }                                                       \
  88                 strncpy(dest, tmp->String.Pointer, length);             \
  89                 break;                                                  \
  90         case ACPI_TYPE_BUFFER:                                          \
  91                 if (tmp->Buffer.Length < length) {                      \
  92                         length = tmp->Buffer.Length;                    \
  93                 }                                                       \
  94                 strncpy(dest, tmp->Buffer.Pointer, length);             \
  95                 break;                                                  \
  96         default:                                                        \
  97                 goto label;                                             \
  98         }                                                               \
  99         dest[sizeof(dest)-1] = '\0';                                    \
 100 } while (0)
 101
 102 struct acpi_cmbat_softc {
 103         device_t        dev;
 104
 105         struct acpi_bif bif;
 106         struct acpi_bst bst;
 107         struct timespec bif_lastupdated;
 108         struct timespec bst_lastupdated;
 109         int             bif_updating;
 110         int             bst_updating;
 111
 112         int             not_present;
 113         int             cap;
 114         int             min;
 115         int             full_charge_time;
 116 };
 117
 118 static struct timespec   acpi_cmbat_info_lastupdated;
 119
 120 /* XXX: devclass_get_maxunit() don't give us the current allocated units... */
 121 static int               acpi_cmbat_units = 0;
 122
 123 static int               acpi_cmbat_info_expired(struct timespec *);
 124 static void              acpi_cmbat_info_updated(struct timespec *);
 125 static void              acpi_cmbat_get_bst(void *);
 126 static void              acpi_cmbat_get_bif(void *);
 127 static void              acpi_cmbat_notify_handler(ACPI_HANDLE, UINT32, void *);
 128 static int               acpi_cmbat_probe(device_t);
 129 static int               acpi_cmbat_attach(device_t);
 130 static int               acpi_cmbat_resume(device_t);
 131 static int               acpi_cmbat_ioctl(u_long, caddr_t, void *);
 132 static int               acpi_cmbat_get_total_battinfo(struct acpi_battinfo *);
 133
 134 static __inline int
 135 acpi_cmbat_info_expired(struct timespec *lastupdated)
 136 {
 137         struct timespec curtime;
 138
 139         if (lastupdated == NULL) {
 140                 return (1);
 141         }
 142
 143         if (!timespecisset(lastupdated)) {
 144                 return (1);
 145         }
 146
 147         getnanotime(&curtime);
 148         timespecsub(&curtime, lastupdated);
 149         return ((curtime.tv_sec < 0 || curtime.tv_sec > acpi_battery_get_info_expire()));
 150 }
 151
 152
 153 static __inline void
 154 acpi_cmbat_info_updated(struct timespec *lastupdated)
 155 {
 156
 157         if (lastupdated != NULL) {
 158                 getnanotime(lastupdated);
 159         }
 160 }
 161
 162 static void
 163 acpi_cmbat_get_bst(void *context)
 164 {
 165         device_t        dev;
 166         struct acpi_cmbat_softc *sc;
 167         ACPI_STATUS     as;
 168         ACPI_OBJECT     *res, *tmp;
 169         ACPI_HANDLE     h;
 170         ACPI_BUFFER     bst_buffer;
 171
 172         dev = context;
 173         sc = device_get_softc(dev);
 174         h = acpi_get_handle(dev);
 175         bst_buffer.Pointer = NULL;
 176
 177         if (!acpi_cmbat_info_expired(&sc->bst_lastupdated)) {
 178                 return;
 179         }
 180
 181         if (sc->bst_updating) {
 182                 return;
 183         }
 184         sc->bst_updating = 1;
 185
 186         bst_buffer.Length = ACPI_ALLOCATE_BUFFER;
 187         if (ACPI_FAILURE(as = AcpiEvaluateObject(h, "_BST", NULL, &bst_buffer))) {
 188                 ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),
 189                     "error fetching current battery status -- %s\n",
 190                     AcpiFormatException(as));
 191                 goto end;
 192         }
 193
 194         res = (ACPI_OBJECT *)bst_buffer.Pointer;
 195
 196         if ((res->Type != ACPI_TYPE_PACKAGE) || (res->Package.Count != 4)) {
 197                 ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),
 198                     "battery status corrupted\n");
 199                 goto end;
 200         }
 201
 202         PKG_GETINT(res, tmp, 0, sc->bst.state, end);
 203         PKG_GETINT(res, tmp, 1, sc->bst.rate, end);
 204         PKG_GETINT(res, tmp, 2, sc->bst.cap, end);
 205         PKG_GETINT(res, tmp, 3, sc->bst.volt, end);
 206         acpi_cmbat_info_updated(&sc->bst_lastupdated);
 207 end:
 208         if (bst_buffer.Pointer != NULL)
 209                 AcpiOsFree(bst_buffer.Pointer);
 210         sc->bst_updating = 0;
 211 }
 212
 213 static void
 214 acpi_cmbat_get_bif(void *context)
 215 {
 216         device_t        dev;
 217         struct acpi_cmbat_softc *sc;
 218         ACPI_STATUS     as;
 219         ACPI_OBJECT     *res, *tmp;
 220         ACPI_HANDLE     h;
 221         ACPI_BUFFER     bif_buffer;
 222
 223         dev = context;
 224         sc = device_get_softc(dev);
 225         h = acpi_get_handle(dev);
 226         bif_buffer.Pointer = NULL;
 227
 228         if (!acpi_cmbat_info_expired(&sc->bif_lastupdated)) {
 229                 return;
 230         }
 231
 232         if (sc->bif_updating) {
 233                 return;
 234         }
 235         sc->bif_updating = 1;
 236
 237         bif_buffer.Length = ACPI_ALLOCATE_BUFFER;
 238         if (ACPI_FAILURE(as = AcpiEvaluateObject(h, "_BIF", NULL, &bif_buffer))) {
 239                 ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),
 240                     "error fetching current battery info -- %s\n",
 241                     AcpiFormatException(as));
 242                 goto end;
 243         }
 244
 245         res = (ACPI_OBJECT *)bif_buffer.Pointer;
 246
 247         if ((res->Type != ACPI_TYPE_PACKAGE) || (res->Package.Count != 13)) {
 248                 ACPI_VPRINT(dev, acpi_device_get_parent_softc(dev),
 249                     "battery info corrupted\n");
 250                 goto end;
 251         }
 252
 253         PKG_GETINT(res, tmp,  0, sc->bif.unit, end);
 254         PKG_GETINT(res, tmp,  1, sc->bif.dcap, end);
 255         PKG_GETINT(res, tmp,  2, sc->bif.lfcap, end);
 256         PKG_GETINT(res, tmp,  3, sc->bif.btech, end);
 257         PKG_GETINT(res, tmp,  4, sc->bif.dvol, end);
 258         PKG_GETINT(res, tmp,  5, sc->bif.wcap, end);
 259         PKG_GETINT(res, tmp,  6, sc->bif.lcap, end);
 260         PKG_GETINT(res, tmp,  7, sc->bif.gra1, end);
 261         PKG_GETINT(res, tmp,  8, sc->bif.gra2, end);
 262         PKG_GETSTR(res, tmp,  9, sc->bif.model, ACPI_CMBAT_MAXSTRLEN, end);
 263         PKG_GETSTR(res, tmp, 10, sc->bif.serial, ACPI_CMBAT_MAXSTRLEN, end);
 264         PKG_GETSTR(res, tmp, 11, sc->bif.type, ACPI_CMBAT_MAXSTRLEN, end);
 265         PKG_GETSTR(res, tmp, 12, sc->bif.oeminfo, ACPI_CMBAT_MAXSTRLEN, end);
 266         acpi_cmbat_info_updated(&sc->bif_lastupdated);
 267 end:
 268         if (bif_buffer.Pointer != NULL)
 269                 AcpiOsFree(bif_buffer.Pointer);
 270         sc->bif_updating = 0;
 271 }
 272
 273 static void
 274 acpi_cmbat_notify_handler(ACPI_HANDLE h, UINT32 notify, void *context)
 275 {
 276         device_t        dev;
 277         struct acpi_cmbat_softc *sc;
 278
 279         dev = (device_t)context;
 280         if ((sc = device_get_softc(dev)) == NULL) {
 281                 return;
 282         }
 283
 284         switch (notify) {
 285         case ACPI_BATTERY_BST_CHANGE:
 286                 timespecclear(&sc->bst_lastupdated);
 287                 break;
 288         case ACPI_BATTERY_BIF_CHANGE:
 289                 timespecclear(&sc->bif_lastupdated);
 290                 AcpiOsQueueForExecution(OSD_PRIORITY_LO, acpi_cmbat_get_bif, dev);
 291                 break;
 292         default:
 293                 break;
 294         }
 295 }
 296
 297 static int
 298 acpi_cmbat_probe(device_t dev)
 299 {
 300
 301         if ((acpi_get_type(dev) == ACPI_TYPE_DEVICE) &&
 302             !acpi_disabled("cmbat") &&
 303             acpi_MatchHid(dev, "PNP0C0A")) {
 304                 /*
 305                  * Set device description.
 306                  */
 307                 device_set_desc(dev, "Control method Battery");
 308                 return (0);
 309         }
 310         return (ENXIO);
 311 }
 312
 313 static int
 314 acpi_cmbat_attach(device_t dev)
 315 {
 316         int             error;
 317         ACPI_HANDLE     handle;
 318         struct acpi_cmbat_softc *sc;
 319
 320         if ((sc = device_get_softc(dev)) == NULL) {
 321                 return (ENXIO);
 322         }
 323
 324         handle = acpi_get_handle(dev);
 325
 326         AcpiInstallNotifyHandler(handle, ACPI_DEVICE_NOTIFY,
 327                                  acpi_cmbat_notify_handler, dev);
 328
 329         sc->bif_updating = sc->bst_updating = 0;
 330         sc->dev = dev;
 331
 332         timespecclear(&sc->bif_lastupdated);
 333         timespecclear(&sc->bst_lastupdated);
 334
 335         if (acpi_cmbat_units == 0) {
 336                 if ((error = acpi_register_ioctl(ACPIIO_CMBAT_GET_BIF,
 337                                 acpi_cmbat_ioctl, NULL)) != 0) {
 338                         return (error);
 339                 }
 340                 if ((error = acpi_register_ioctl(ACPIIO_CMBAT_GET_BST,
 341                                 acpi_cmbat_ioctl, NULL)) != 0) {
 342                         return (error);
 343                 }
 344         }
 345
 346         if ((error = acpi_battery_register(ACPI_BATT_TYPE_CMBAT,
 347                         acpi_cmbat_units)) != 0) {
 348                 return (error);
 349         }
 350
 351         acpi_cmbat_units++;
 352         timespecclear(&acpi_cmbat_info_lastupdated);
 353
 354         AcpiOsQueueForExecution(OSD_PRIORITY_LO, acpi_cmbat_get_bif, dev);
 355         return (0);
 356 }
 357
 358 static int
 359 acpi_cmbat_resume(device_t dev)
 360 {
 361
 362         AcpiOsQueueForExecution(OSD_PRIORITY_LO, acpi_cmbat_get_bif, dev);
 363         return (0);
 364 }
 365
 366 static device_method_t acpi_cmbat_methods[] = {
 367         /* Device interface */
 368         DEVMETHOD(device_probe,         acpi_cmbat_probe),
 369         DEVMETHOD(device_attach,        acpi_cmbat_attach),
 370         DEVMETHOD(device_resume,        acpi_cmbat_resume),
 371
 372         {0, 0}
 373 };
 374
 375 static driver_t acpi_cmbat_driver = {
 376         "acpi_cmbat",
 377         acpi_cmbat_methods,
 378         sizeof(struct acpi_cmbat_softc),
 379 };
 380
 381 static devclass_t acpi_cmbat_devclass;
 382 DRIVER_MODULE(acpi_cmbat, acpi, acpi_cmbat_driver, acpi_cmbat_devclass, 0, 0);
 383
 384 static int
 385 acpi_cmbat_ioctl(u_long cmd, caddr_t addr, void *arg)
 386 {
 387         device_t        dev;
 388         union acpi_battery_ioctl_arg *ioctl_arg;
 389         struct acpi_cmbat_softc *sc;
 390         struct acpi_bif *bifp;
 391         struct acpi_bst *bstp;
 392
 393         ioctl_arg = (union acpi_battery_ioctl_arg *)addr;
 394         if ((dev = devclass_get_device(acpi_cmbat_devclass,
 395                         ioctl_arg->unit)) == NULL) {
 396                 return (ENXIO);
 397         }
 398
 399         if ((sc = device_get_softc(dev)) == NULL) {
 400                 return (ENXIO);
 401         }
 402
 403         switch (cmd) {
 404         case ACPIIO_CMBAT_GET_BIF:
 405                 acpi_cmbat_get_bif(dev);
 406                 bifp = &ioctl_arg->bif;
 407                 bifp->unit = sc->bif.unit;
 408                 bifp->dcap = sc->bif.dcap;
 409                 bifp->lfcap = sc->bif.lfcap;
 410                 bifp->btech = sc->bif.btech;
 411                 bifp->dvol = sc->bif.dvol;
 412                 bifp->wcap = sc->bif.wcap;
 413                 bifp->lcap = sc->bif.lcap;
 414                 bifp->gra1 = sc->bif.gra1;
 415                 bifp->gra2 = sc->bif.gra2;
 416                 strncpy(bifp->model, sc->bif.model, sizeof(sc->bif.model));
 417                 strncpy(bifp->serial, sc->bif.serial, sizeof(sc->bif.serial));
 418                 strncpy(bifp->type, sc->bif.type, sizeof(sc->bif.type));
 419                 strncpy(bifp->oeminfo, sc->bif.oeminfo, sizeof(sc->bif.oeminfo));
 420                 break;
 421
 422         case ACPIIO_CMBAT_GET_BST:
 423                 acpi_cmbat_get_bst(dev);
 424                 bstp = &ioctl_arg->bst;
 425                 bstp->state = sc->bst.state;
 426                 bstp->rate = sc->bst.rate;
 427                 bstp->cap = sc->bst.cap;
 428                 bstp->volt = sc->bst.volt;
 429                 break;
 430         }
 431
 432         return (0);
 433 }
 434
 435 static int
 436 acpi_cmbat_get_total_battinfo(struct acpi_battinfo *battinfo)
 437 {
 438         int             i;
 439         int             error;
 440         int             batt_stat;
 441         int             valid_rate, valid_units;
 442         int             cap, min;
 443         int             total_cap, total_min, total_full;
 444         device_t        dev;
 445         struct acpi_cmbat_softc *sc;
 446         static int      bat_units = 0;
 447         static struct acpi_cmbat_softc **bat = NULL;
 448
 449         cap = min = -1;
 450         batt_stat = ACPI_BATT_STAT_NOT_PRESENT;
 451         error = 0;
 452
 453         /* Allocate array of softc pointers */
 454         if (bat_units != acpi_cmbat_units) {
 455                 if (bat != NULL) {
 456                         free(bat, M_ACPICMBAT);
 457                         bat = NULL;
 458                 }
 459                 bat_units = 0;
 460         }
 461         if (bat == NULL) {
 462                 bat_units = acpi_cmbat_units;
 463                 bat = malloc(sizeof(struct acpi_cmbat_softc *) * bat_units,
 464                              M_ACPICMBAT, M_NOWAIT);
 465                 if (bat == NULL) {
 466                         error = ENOMEM;
 467                         goto out;
 468                 }
 469
 470                 /* Collect softc pointers */
 471                 for (i = 0; i < acpi_cmbat_units; i++) {
 472                         if ((dev = devclass_get_device(acpi_cmbat_devclass, i)) == NULL) {
 473                                 error = ENXIO;
 474                                 goto out;
 475                         }
 476
 477                         if ((sc = device_get_softc(dev)) == NULL) {
 478                                 error = ENXIO;
 479                                 goto out;
 480                         }
 481
 482                         bat[i] = sc;
 483                 }
 484         }
 485
 486         /* Get battery status, valid rate and valid units */
 487         batt_stat = valid_rate = valid_units = 0;
 488         for (i = 0; i < acpi_cmbat_units; i++) {
 489                 bat[i]->not_present = 0;
 490                 acpi_cmbat_get_bst(bat[i]->dev);
 491
 492                 /* If battey not installed, we get strange values */
 493                 if (bat[i]->bst.state >= ACPI_BATT_STAT_MAX ||
 494                     bat[i]->bst.cap == 0xffffffff ||
 495                     bat[i]->bst.volt == 0xffffffff ||
 496                     bat[i]->bif.lfcap == 0) {
 497                         bat[i]->not_present = 1;
 498                         continue;
 499                 }
 500
 501                 valid_units++;
 502
 503                 bat[i]->cap = 100 * bat[i]->bst.cap / bat[i]->bif.lfcap;
 504
 505                 batt_stat |= bat[i]->bst.state;
 506
 507                 if (bat[i]->bst.rate > 0) {
 508                         /*
 509                          * XXX Hack to calculate total battery time.
 510                          * Systems with 2 or more battries, they may get used
 511                          * one by one, thus bst.rate is set only to the one
 512                          * in use. For remaining batteries bst.rate = 0, which
 513                          * makes it impossible to calculate remaining time.
 514                          * Some other systems may need sum of bst.rate in
 515                          * dis-charging state.
 516                          * There for we sum up the bst.rate that is valid
 517                          * (in dis-charging state), and use the sum to
 518                          * calcutate remaining batteries' time.
 519                          */
 520                         if (bat[i]->bst.state & ACPI_BATT_STAT_DISCHARG) {
 521                                 valid_rate += bat[i]->bst.rate;
 522                         }
 523                 }
 524         }
 525
 526         /* Calculate total battery capacity and time */
 527         total_cap = total_min = total_full = 0;
 528         for (i = 0; i < acpi_cmbat_units; i++) {
 529                 if (bat[i]->not_present) {
 530                         continue;
 531                 }
 532
 533                 if (valid_rate > 0) {
 534                         /* Use the sum of bst.rate */
 535                         bat[i]->min = 60 * bat[i]->bst.cap / valid_rate;
 536                 } else if (bat[i]->full_charge_time > 0) {
 537                         bat[i]->min = (bat[i]->full_charge_time * bat[i]->cap) / 100;
 538                 } else {
 539                         /* Couldn't find valid rate and full battery time */
 540                         bat[i]->min = 0;
 541                 }
 542                 total_min += bat[i]->min;
 543                 total_cap += bat[i]->cap;
 544                 total_full += bat[i]->full_charge_time;
 545         }
 546
 547         /* Battery life */
 548         if (valid_units == 0) {
 549                 cap = -1;
 550                 batt_stat = ACPI_BATT_STAT_NOT_PRESENT;
 551         } else {
 552                 cap = total_cap / valid_units;
 553         }
 554
 555         /* Battery time */
 556         if (valid_units == 0) {
 557                 min = -1;
 558         } else if (valid_rate == 0 || (batt_stat & ACPI_BATT_STAT_CHARGING)) {
 559                 if (total_full == 0) {
 560                         min = -1;
 561                 } else {
 562                         min = (total_full * cap) / 100;
 563                 }
 564         } else {
 565                 min = total_min;
 566         }
 567
 568         acpi_cmbat_info_updated(&acpi_cmbat_info_lastupdated);
 569 out:
 570         battinfo->cap = cap;
 571         battinfo->min = min;
 572         battinfo->state = batt_stat;
 573
 574         return (error);
 575 }
 576
 577 /*
 578  * Public interfaces.
 579  */
 580
 581 int
 582 acpi_cmbat_get_battinfo(int unit, struct acpi_battinfo *battinfo)
 583 {
 584         int             error;
 585         device_t        dev;
 586         struct acpi_cmbat_softc *sc;
 587
 588         if (unit == -1) {
 589                 return (acpi_cmbat_get_total_battinfo(battinfo));
 590         }
 591
 592         if (acpi_cmbat_info_expired(&acpi_cmbat_info_lastupdated)) {
 593                 error = acpi_cmbat_get_total_battinfo(battinfo);
 594                 if (error) {
 595                         goto out;
 596                 }
 597         }
 598
 599         error = 0;
 600         if (unit >= acpi_cmbat_units) {
 601                 error = ENXIO;
 602                 goto out;
 603         }
 604
 605         if ((dev = devclass_get_device(acpi_cmbat_devclass, unit)) == NULL) {
 606                 error = ENXIO;
 607                 goto out;
 608         }
 609
 610         if ((sc = device_get_softc(dev)) == NULL) {
 611                 error = ENXIO;
 612                 goto out;
 613         }
 614
 615         if (sc->not_present) {
 616                 battinfo->cap = -1;
 617                 battinfo->min = -1;
 618                 battinfo->state = ACPI_BATT_STAT_NOT_PRESENT;
 619         } else {
 620                 battinfo->cap = sc->cap;
 621                 battinfo->min = sc->min;
 622                 battinfo->state = sc->bst.state;
 623         }
 624 out:
 625         return (error);
 626 }
 627