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Add linux-next specific files for 20110831
[linux-2.6/next.git] / drivers / power / olpc_battery.c
blob46a2f07edab10cf47ef40eee8438e66d9474ac0c
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 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
337 ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
338 if (ret)
339 return ret;
340
341 val->intval = (s16)be16_to_cpu(ec_word) * 9760L / 32;
342 break;
343 case POWER_SUPPLY_PROP_CURRENT_AVG:
344 case POWER_SUPPLY_PROP_CURRENT_NOW:
345 ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
346 if (ret)
347 return ret;
348
349 val->intval = (s16)be16_to_cpu(ec_word) * 15625L / 120;
350 break;
351 case POWER_SUPPLY_PROP_CAPACITY:
352 ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
353 if (ret)
354 return ret;
355 val->intval = ec_byte;
356 break;
357 case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
358 if (ec_byte & BAT_STAT_FULL)
359 val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
360 else if (ec_byte & BAT_STAT_LOW)
361 val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
362 else
363 val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
364 break;
365 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
366 ret = olpc_bat_get_charge_full_design(val);
367 if (ret)
368 return ret;
369 break;
370 case POWER_SUPPLY_PROP_CHARGE_NOW:
371 ret = olpc_bat_get_charge_now(val);
372 if (ret)
373 return ret;
374 break;
375 case POWER_SUPPLY_PROP_TEMP:
376 ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
377 if (ret)
378 return ret;
379
380 val->intval = (s16)be16_to_cpu(ec_word) * 100 / 256;
381 break;
382 case POWER_SUPPLY_PROP_TEMP_AMBIENT:
383 ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
384 if (ret)
385 return ret;
386
387 val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
388 break;
389 case POWER_SUPPLY_PROP_CHARGE_COUNTER:
390 ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
391 if (ret)
392 return ret;
393
394 val->intval = (s16)be16_to_cpu(ec_word) * 6250 / 15;
395 break;
396 case POWER_SUPPLY_PROP_SERIAL_NUMBER:
397 ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
398 if (ret)
399 return ret;
400
401 sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
402 val->strval = bat_serial;
403 break;
404 default:
405 ret = -EINVAL;
406 break;
407 }
408
409 return ret;
410 }
411
412 static enum power_supply_property olpc_xo1_bat_props[] = {
413 POWER_SUPPLY_PROP_STATUS,
414 POWER_SUPPLY_PROP_CHARGE_TYPE,
415 POWER_SUPPLY_PROP_PRESENT,
416 POWER_SUPPLY_PROP_HEALTH,
417 POWER_SUPPLY_PROP_TECHNOLOGY,
418 POWER_SUPPLY_PROP_VOLTAGE_AVG,
419 POWER_SUPPLY_PROP_VOLTAGE_NOW,
420 POWER_SUPPLY_PROP_CURRENT_AVG,
421 POWER_SUPPLY_PROP_CURRENT_NOW,
422 POWER_SUPPLY_PROP_CAPACITY,
423 POWER_SUPPLY_PROP_CAPACITY_LEVEL,
424 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
425 POWER_SUPPLY_PROP_CHARGE_NOW,
426 POWER_SUPPLY_PROP_TEMP,
427 POWER_SUPPLY_PROP_TEMP_AMBIENT,
428 POWER_SUPPLY_PROP_MANUFACTURER,
429 POWER_SUPPLY_PROP_SERIAL_NUMBER,
430 POWER_SUPPLY_PROP_CHARGE_COUNTER,
431 };
432
433 /* XO-1.5 does not have ambient temperature property */
434 static enum power_supply_property olpc_xo15_bat_props[] = {
435 POWER_SUPPLY_PROP_STATUS,
436 POWER_SUPPLY_PROP_CHARGE_TYPE,
437 POWER_SUPPLY_PROP_PRESENT,
438 POWER_SUPPLY_PROP_HEALTH,
439 POWER_SUPPLY_PROP_TECHNOLOGY,
440 POWER_SUPPLY_PROP_VOLTAGE_AVG,
441 POWER_SUPPLY_PROP_VOLTAGE_NOW,
442 POWER_SUPPLY_PROP_CURRENT_AVG,
443 POWER_SUPPLY_PROP_CURRENT_NOW,
444 POWER_SUPPLY_PROP_CAPACITY,
445 POWER_SUPPLY_PROP_CAPACITY_LEVEL,
446 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
447 POWER_SUPPLY_PROP_CHARGE_NOW,
448 POWER_SUPPLY_PROP_TEMP,
449 POWER_SUPPLY_PROP_MANUFACTURER,
450 POWER_SUPPLY_PROP_SERIAL_NUMBER,
451 POWER_SUPPLY_PROP_CHARGE_COUNTER,
452 };
453
454 /* EEPROM reading goes completely around the power_supply API, sadly */
455
456 #define EEPROM_START 0x20
457 #define EEPROM_END 0x80
458 #define EEPROM_SIZE (EEPROM_END - EEPROM_START)
459
460 static ssize_t olpc_bat_eeprom_read(struct file *filp, struct kobject *kobj,
461 struct bin_attribute *attr, char *buf, loff_t off, size_t count)
462 {
463 uint8_t ec_byte;
464 int ret;
465 int i;
466
467 if (off >= EEPROM_SIZE)
468 return 0;
469 if (off + count > EEPROM_SIZE)
470 count = EEPROM_SIZE - off;
471
472 for (i = 0; i < count; i++) {
473 ec_byte = EEPROM_START + off + i;
474 ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &buf[i], 1);
475 if (ret) {
476 pr_err("olpc-battery: "
477 "EC_BAT_EEPROM cmd @ 0x%x failed - %d!\n",
478 ec_byte, ret);
479 return -EIO;
480 }
481 }
482
483 return count;
484 }
485
486 static struct bin_attribute olpc_bat_eeprom = {
487 .attr = {
488 .name = "eeprom",
489 .mode = S_IRUGO,
490 },
491 .size = 0,
492 .read = olpc_bat_eeprom_read,
493 };
494
495 /* Allow userspace to see the specific error value pulled from the EC */
496
497 static ssize_t olpc_bat_error_read(struct device *dev,
498 struct device_attribute *attr, char *buf)
499 {
500 uint8_t ec_byte;
501 ssize_t ret;
502
503 ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
504 if (ret < 0)
505 return ret;
506
507 return sprintf(buf, "%d\n", ec_byte);
508 }
509
510 static struct device_attribute olpc_bat_error = {
511 .attr = {
512 .name = "error",
513 .mode = S_IRUGO,
514 },
515 .show = olpc_bat_error_read,
516 };
517
518 /*********************************************************************
519 * Initialisation
520 *********************************************************************/
521
522 static struct power_supply olpc_bat = {
523 .name = "olpc-battery",
524 .get_property = olpc_bat_get_property,
525 .use_for_apm = 1,
526 };
527
528 void olpc_battery_trigger_uevent(unsigned long cause)
529 {
530 if (cause & EC_SCI_SRC_ACPWR)
531 kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
532 if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
533 kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
534 }
535
536 static int olpc_battery_suspend(struct platform_device *pdev,
537 pm_message_t state)
538 {
539 if (device_may_wakeup(olpc_ac.dev))
540 olpc_ec_wakeup_set(EC_SCI_SRC_ACPWR);
541 else
542 olpc_ec_wakeup_clear(EC_SCI_SRC_ACPWR);
543
544 if (device_may_wakeup(olpc_bat.dev))
545 olpc_ec_wakeup_set(EC_SCI_SRC_BATTERY | EC_SCI_SRC_BATSOC
546 | EC_SCI_SRC_BATERR);
547 else
548 olpc_ec_wakeup_clear(EC_SCI_SRC_BATTERY | EC_SCI_SRC_BATSOC
549 | EC_SCI_SRC_BATERR);
550
551 return 0;
552 }
553
554 static int __devinit olpc_battery_probe(struct platform_device *pdev)
555 {
556 int ret;
557 uint8_t status;
558
559 /*
560 * We've seen a number of EC protocol changes; this driver requires
561 * the latest EC protocol, supported by 0x44 and above.
562 */
563 if (olpc_platform_info.ecver < 0x44) {
564 printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
565 "battery driver.\n", olpc_platform_info.ecver);
566 return -ENXIO;
567 }
568
569 ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
570 if (ret)
571 return ret;
572
573 /* Ignore the status. It doesn't actually matter */
574
575 ret = power_supply_register(&pdev->dev, &olpc_ac);
576 if (ret)
577 return ret;
578
579 if (olpc_board_at_least(olpc_board_pre(0xd0))) { /* XO-1.5 */
580 olpc_bat.properties = olpc_xo15_bat_props;
581 olpc_bat.num_properties = ARRAY_SIZE(olpc_xo15_bat_props);
582 } else { /* XO-1 */
583 olpc_bat.properties = olpc_xo1_bat_props;
584 olpc_bat.num_properties = ARRAY_SIZE(olpc_xo1_bat_props);
585 }
586
587 ret = power_supply_register(&pdev->dev, &olpc_bat);
588 if (ret)
589 goto battery_failed;
590
591 ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
592 if (ret)
593 goto eeprom_failed;
594
595 ret = device_create_file(olpc_bat.dev, &olpc_bat_error);
596 if (ret)
597 goto error_failed;
598
599 if (olpc_ec_wakeup_available()) {
600 device_set_wakeup_capable(olpc_ac.dev, true);
601 device_set_wakeup_capable(olpc_bat.dev, true);
602 }
603
604 return 0;
605
606 error_failed:
607 device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
608 eeprom_failed:
609 power_supply_unregister(&olpc_bat);
610 battery_failed:
611 power_supply_unregister(&olpc_ac);
612 return ret;
613 }
614
615 static int __devexit olpc_battery_remove(struct platform_device *pdev)
616 {
617 device_remove_file(olpc_bat.dev, &olpc_bat_error);
618 device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
619 power_supply_unregister(&olpc_bat);
620 power_supply_unregister(&olpc_ac);
621 return 0;
622 }
623
624 static const struct of_device_id olpc_battery_ids[] __devinitconst = {
625 { .compatible = "olpc,xo1-battery" },
626 {}
627 };
628 MODULE_DEVICE_TABLE(of, olpc_battery_ids);
629
630 static struct platform_driver olpc_battery_drv = {
631 .driver = {
632 .name = "olpc-battery",
633 .owner = THIS_MODULE,
634 .of_match_table = olpc_battery_ids,
635 },
636 .probe = olpc_battery_probe,
637 .remove = __devexit_p(olpc_battery_remove),
638 .suspend = olpc_battery_suspend,
639 };
640
641 static int __init olpc_bat_init(void)
642 {
643 return platform_driver_register(&olpc_battery_drv);
644 }
645 module_init(olpc_bat_init);
646
647 static void __exit olpc_bat_exit(void)
648 {
649 platform_driver_unregister(&olpc_battery_drv);
650 }
651 module_exit(olpc_bat_exit);
652
653 MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
654 MODULE_LICENSE("GPL");
655 MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");
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