xref: /openbmc/linux/drivers/acpi/battery.c (revision 384740dc)
1 /*
2  *  battery.c - ACPI Battery Driver (Revision: 2.0)
3  *
4  *  Copyright (C) 2007 Alexey Starikovskiy <astarikovskiy@suse.de>
5  *  Copyright (C) 2004-2007 Vladimir Lebedev <vladimir.p.lebedev@intel.com>
6  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
7  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
8  *
9  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
10  *
11  *  This program is free software; you can redistribute it and/or modify
12  *  it under the terms of the GNU General Public License as published by
13  *  the Free Software Foundation; either version 2 of the License, or (at
14  *  your option) any later version.
15  *
16  *  This program is distributed in the hope that it will be useful, but
17  *  WITHOUT ANY WARRANTY; without even the implied warranty of
18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
19  *  General Public License for more details.
20  *
21  *  You should have received a copy of the GNU General Public License along
22  *  with this program; if not, write to the Free Software Foundation, Inc.,
23  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
24  *
25  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
26  */
27 
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/types.h>
32 #include <linux/jiffies.h>
33 
34 #ifdef CONFIG_ACPI_PROCFS_POWER
35 #include <linux/proc_fs.h>
36 #include <linux/seq_file.h>
37 #include <asm/uaccess.h>
38 #endif
39 
40 #include <acpi/acpi_bus.h>
41 #include <acpi/acpi_drivers.h>
42 
43 #ifdef CONFIG_ACPI_SYSFS_POWER
44 #include <linux/power_supply.h>
45 #endif
46 
47 #define ACPI_BATTERY_VALUE_UNKNOWN 0xFFFFFFFF
48 
49 #define ACPI_BATTERY_COMPONENT		0x00040000
50 #define ACPI_BATTERY_CLASS		"battery"
51 #define ACPI_BATTERY_DEVICE_NAME	"Battery"
52 #define ACPI_BATTERY_NOTIFY_STATUS	0x80
53 #define ACPI_BATTERY_NOTIFY_INFO	0x81
54 
55 #define _COMPONENT		ACPI_BATTERY_COMPONENT
56 
57 ACPI_MODULE_NAME("battery");
58 
59 MODULE_AUTHOR("Paul Diefenbaugh");
60 MODULE_AUTHOR("Alexey Starikovskiy <astarikovskiy@suse.de>");
61 MODULE_DESCRIPTION("ACPI Battery Driver");
62 MODULE_LICENSE("GPL");
63 
64 static unsigned int cache_time = 1000;
65 module_param(cache_time, uint, 0644);
66 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
67 
68 #ifdef CONFIG_ACPI_PROCFS_POWER
69 extern struct proc_dir_entry *acpi_lock_battery_dir(void);
70 extern void *acpi_unlock_battery_dir(struct proc_dir_entry *acpi_battery_dir);
71 
72 enum acpi_battery_files {
73 	info_tag = 0,
74 	state_tag,
75 	alarm_tag,
76 	ACPI_BATTERY_NUMFILES,
77 };
78 
79 #endif
80 
81 static const struct acpi_device_id battery_device_ids[] = {
82 	{"PNP0C0A", 0},
83 	{"", 0},
84 };
85 
86 MODULE_DEVICE_TABLE(acpi, battery_device_ids);
87 
88 
89 struct acpi_battery {
90 	struct mutex lock;
91 #ifdef CONFIG_ACPI_SYSFS_POWER
92 	struct power_supply bat;
93 #endif
94 	struct acpi_device *device;
95 	unsigned long update_time;
96 	int current_now;
97 	int capacity_now;
98 	int voltage_now;
99 	int design_capacity;
100 	int full_charge_capacity;
101 	int technology;
102 	int design_voltage;
103 	int design_capacity_warning;
104 	int design_capacity_low;
105 	int capacity_granularity_1;
106 	int capacity_granularity_2;
107 	int alarm;
108 	char model_number[32];
109 	char serial_number[32];
110 	char type[32];
111 	char oem_info[32];
112 	int state;
113 	int power_unit;
114 	u8 alarm_present;
115 };
116 
117 #define to_acpi_battery(x) container_of(x, struct acpi_battery, bat);
118 
119 inline int acpi_battery_present(struct acpi_battery *battery)
120 {
121 	return battery->device->status.battery_present;
122 }
123 
124 #ifdef CONFIG_ACPI_SYSFS_POWER
125 static int acpi_battery_technology(struct acpi_battery *battery)
126 {
127 	if (!strcasecmp("NiCd", battery->type))
128 		return POWER_SUPPLY_TECHNOLOGY_NiCd;
129 	if (!strcasecmp("NiMH", battery->type))
130 		return POWER_SUPPLY_TECHNOLOGY_NiMH;
131 	if (!strcasecmp("LION", battery->type))
132 		return POWER_SUPPLY_TECHNOLOGY_LION;
133 	if (!strncasecmp("LI-ION", battery->type, 6))
134 		return POWER_SUPPLY_TECHNOLOGY_LION;
135 	if (!strcasecmp("LiP", battery->type))
136 		return POWER_SUPPLY_TECHNOLOGY_LIPO;
137 	return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
138 }
139 
140 static int acpi_battery_get_state(struct acpi_battery *battery);
141 
142 static int acpi_battery_get_property(struct power_supply *psy,
143 				     enum power_supply_property psp,
144 				     union power_supply_propval *val)
145 {
146 	struct acpi_battery *battery = to_acpi_battery(psy);
147 
148 	if (acpi_battery_present(battery)) {
149 		/* run battery update only if it is present */
150 		acpi_battery_get_state(battery);
151 	} else if (psp != POWER_SUPPLY_PROP_PRESENT)
152 		return -ENODEV;
153 	switch (psp) {
154 	case POWER_SUPPLY_PROP_STATUS:
155 		if (battery->state & 0x01)
156 			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
157 		else if (battery->state & 0x02)
158 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
159 		else if (battery->state == 0)
160 			val->intval = POWER_SUPPLY_STATUS_FULL;
161 		else
162 			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
163 		break;
164 	case POWER_SUPPLY_PROP_PRESENT:
165 		val->intval = acpi_battery_present(battery);
166 		break;
167 	case POWER_SUPPLY_PROP_TECHNOLOGY:
168 		val->intval = acpi_battery_technology(battery);
169 		break;
170 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
171 		val->intval = battery->design_voltage * 1000;
172 		break;
173 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
174 		val->intval = battery->voltage_now * 1000;
175 		break;
176 	case POWER_SUPPLY_PROP_CURRENT_NOW:
177 		val->intval = battery->current_now * 1000;
178 		break;
179 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
180 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
181 		val->intval = battery->design_capacity * 1000;
182 		break;
183 	case POWER_SUPPLY_PROP_CHARGE_FULL:
184 	case POWER_SUPPLY_PROP_ENERGY_FULL:
185 		val->intval = battery->full_charge_capacity * 1000;
186 		break;
187 	case POWER_SUPPLY_PROP_CHARGE_NOW:
188 	case POWER_SUPPLY_PROP_ENERGY_NOW:
189 		val->intval = battery->capacity_now * 1000;
190 		break;
191 	case POWER_SUPPLY_PROP_MODEL_NAME:
192 		val->strval = battery->model_number;
193 		break;
194 	case POWER_SUPPLY_PROP_MANUFACTURER:
195 		val->strval = battery->oem_info;
196 		break;
197 	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
198 		val->strval = battery->serial_number;
199 		break;
200 	default:
201 		return -EINVAL;
202 	}
203 	return 0;
204 }
205 
206 static enum power_supply_property charge_battery_props[] = {
207 	POWER_SUPPLY_PROP_STATUS,
208 	POWER_SUPPLY_PROP_PRESENT,
209 	POWER_SUPPLY_PROP_TECHNOLOGY,
210 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
211 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
212 	POWER_SUPPLY_PROP_CURRENT_NOW,
213 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
214 	POWER_SUPPLY_PROP_CHARGE_FULL,
215 	POWER_SUPPLY_PROP_CHARGE_NOW,
216 	POWER_SUPPLY_PROP_MODEL_NAME,
217 	POWER_SUPPLY_PROP_MANUFACTURER,
218 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
219 };
220 
221 static enum power_supply_property energy_battery_props[] = {
222 	POWER_SUPPLY_PROP_STATUS,
223 	POWER_SUPPLY_PROP_PRESENT,
224 	POWER_SUPPLY_PROP_TECHNOLOGY,
225 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
226 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
227 	POWER_SUPPLY_PROP_CURRENT_NOW,
228 	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
229 	POWER_SUPPLY_PROP_ENERGY_FULL,
230 	POWER_SUPPLY_PROP_ENERGY_NOW,
231 	POWER_SUPPLY_PROP_MODEL_NAME,
232 	POWER_SUPPLY_PROP_MANUFACTURER,
233 	POWER_SUPPLY_PROP_SERIAL_NUMBER,
234 };
235 #endif
236 
237 #ifdef CONFIG_ACPI_PROCFS_POWER
238 inline char *acpi_battery_units(struct acpi_battery *battery)
239 {
240 	return (battery->power_unit)?"mA":"mW";
241 }
242 #endif
243 
244 /* --------------------------------------------------------------------------
245                                Battery Management
246    -------------------------------------------------------------------------- */
247 struct acpi_offsets {
248 	size_t offset;		/* offset inside struct acpi_sbs_battery */
249 	u8 mode;		/* int or string? */
250 };
251 
252 static struct acpi_offsets state_offsets[] = {
253 	{offsetof(struct acpi_battery, state), 0},
254 	{offsetof(struct acpi_battery, current_now), 0},
255 	{offsetof(struct acpi_battery, capacity_now), 0},
256 	{offsetof(struct acpi_battery, voltage_now), 0},
257 };
258 
259 static struct acpi_offsets info_offsets[] = {
260 	{offsetof(struct acpi_battery, power_unit), 0},
261 	{offsetof(struct acpi_battery, design_capacity), 0},
262 	{offsetof(struct acpi_battery, full_charge_capacity), 0},
263 	{offsetof(struct acpi_battery, technology), 0},
264 	{offsetof(struct acpi_battery, design_voltage), 0},
265 	{offsetof(struct acpi_battery, design_capacity_warning), 0},
266 	{offsetof(struct acpi_battery, design_capacity_low), 0},
267 	{offsetof(struct acpi_battery, capacity_granularity_1), 0},
268 	{offsetof(struct acpi_battery, capacity_granularity_2), 0},
269 	{offsetof(struct acpi_battery, model_number), 1},
270 	{offsetof(struct acpi_battery, serial_number), 1},
271 	{offsetof(struct acpi_battery, type), 1},
272 	{offsetof(struct acpi_battery, oem_info), 1},
273 };
274 
275 static int extract_package(struct acpi_battery *battery,
276 			   union acpi_object *package,
277 			   struct acpi_offsets *offsets, int num)
278 {
279 	int i;
280 	union acpi_object *element;
281 	if (package->type != ACPI_TYPE_PACKAGE)
282 		return -EFAULT;
283 	for (i = 0; i < num; ++i) {
284 		if (package->package.count <= i)
285 			return -EFAULT;
286 		element = &package->package.elements[i];
287 		if (offsets[i].mode) {
288 			u8 *ptr = (u8 *)battery + offsets[i].offset;
289 			if (element->type == ACPI_TYPE_STRING ||
290 			    element->type == ACPI_TYPE_BUFFER)
291 				strncpy(ptr, element->string.pointer, 32);
292 			else if (element->type == ACPI_TYPE_INTEGER) {
293 				strncpy(ptr, (u8 *)&element->integer.value,
294 					sizeof(acpi_integer));
295 				ptr[sizeof(acpi_integer)] = 0;
296 			} else
297 				*ptr = 0; /* don't have value */
298 		} else {
299 			int *x = (int *)((u8 *)battery + offsets[i].offset);
300 			*x = (element->type == ACPI_TYPE_INTEGER) ?
301 				element->integer.value : -1;
302 		}
303 	}
304 	return 0;
305 }
306 
307 static int acpi_battery_get_status(struct acpi_battery *battery)
308 {
309 	if (acpi_bus_get_status(battery->device)) {
310 		ACPI_EXCEPTION((AE_INFO, AE_ERROR, "Evaluating _STA"));
311 		return -ENODEV;
312 	}
313 	return 0;
314 }
315 
316 static int acpi_battery_get_info(struct acpi_battery *battery)
317 {
318 	int result = -EFAULT;
319 	acpi_status status = 0;
320 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
321 
322 	if (!acpi_battery_present(battery))
323 		return 0;
324 	mutex_lock(&battery->lock);
325 	status = acpi_evaluate_object(battery->device->handle, "_BIF",
326 				      NULL, &buffer);
327 	mutex_unlock(&battery->lock);
328 
329 	if (ACPI_FAILURE(status)) {
330 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BIF"));
331 		return -ENODEV;
332 	}
333 
334 	result = extract_package(battery, buffer.pointer,
335 				 info_offsets, ARRAY_SIZE(info_offsets));
336 	kfree(buffer.pointer);
337 	return result;
338 }
339 
340 static int acpi_battery_get_state(struct acpi_battery *battery)
341 {
342 	int result = 0;
343 	acpi_status status = 0;
344 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
345 
346 	if (!acpi_battery_present(battery))
347 		return 0;
348 
349 	if (battery->update_time &&
350 	    time_before(jiffies, battery->update_time +
351 			msecs_to_jiffies(cache_time)))
352 		return 0;
353 
354 	mutex_lock(&battery->lock);
355 	status = acpi_evaluate_object(battery->device->handle, "_BST",
356 				      NULL, &buffer);
357 	mutex_unlock(&battery->lock);
358 
359 	if (ACPI_FAILURE(status)) {
360 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BST"));
361 		return -ENODEV;
362 	}
363 
364 	result = extract_package(battery, buffer.pointer,
365 				 state_offsets, ARRAY_SIZE(state_offsets));
366 	battery->update_time = jiffies;
367 	kfree(buffer.pointer);
368 	return result;
369 }
370 
371 static int acpi_battery_set_alarm(struct acpi_battery *battery)
372 {
373 	acpi_status status = 0;
374 	union acpi_object arg0 = { .type = ACPI_TYPE_INTEGER };
375 	struct acpi_object_list arg_list = { 1, &arg0 };
376 
377 	if (!acpi_battery_present(battery)|| !battery->alarm_present)
378 		return -ENODEV;
379 
380 	arg0.integer.value = battery->alarm;
381 
382 	mutex_lock(&battery->lock);
383 	status = acpi_evaluate_object(battery->device->handle, "_BTP",
384 				 &arg_list, NULL);
385 	mutex_unlock(&battery->lock);
386 
387 	if (ACPI_FAILURE(status))
388 		return -ENODEV;
389 
390 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Alarm set to %d\n", battery->alarm));
391 	return 0;
392 }
393 
394 static int acpi_battery_init_alarm(struct acpi_battery *battery)
395 {
396 	acpi_status status = AE_OK;
397 	acpi_handle handle = NULL;
398 
399 	/* See if alarms are supported, and if so, set default */
400 	status = acpi_get_handle(battery->device->handle, "_BTP", &handle);
401 	if (ACPI_FAILURE(status)) {
402 		battery->alarm_present = 0;
403 		return 0;
404 	}
405 	battery->alarm_present = 1;
406 	if (!battery->alarm)
407 		battery->alarm = battery->design_capacity_warning;
408 	return acpi_battery_set_alarm(battery);
409 }
410 
411 #ifdef CONFIG_ACPI_SYSFS_POWER
412 static ssize_t acpi_battery_alarm_show(struct device *dev,
413 					struct device_attribute *attr,
414 					char *buf)
415 {
416 	struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));
417 	return sprintf(buf, "%d\n", battery->alarm * 1000);
418 }
419 
420 static ssize_t acpi_battery_alarm_store(struct device *dev,
421 					struct device_attribute *attr,
422 					const char *buf, size_t count)
423 {
424 	unsigned long x;
425 	struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));
426 	if (sscanf(buf, "%ld\n", &x) == 1)
427 		battery->alarm = x/1000;
428 	if (acpi_battery_present(battery))
429 		acpi_battery_set_alarm(battery);
430 	return count;
431 }
432 
433 static struct device_attribute alarm_attr = {
434 	.attr = {.name = "alarm", .mode = 0644, .owner = THIS_MODULE},
435 	.show = acpi_battery_alarm_show,
436 	.store = acpi_battery_alarm_store,
437 };
438 
439 static int sysfs_add_battery(struct acpi_battery *battery)
440 {
441 	int result;
442 
443 	if (battery->power_unit) {
444 		battery->bat.properties = charge_battery_props;
445 		battery->bat.num_properties =
446 			ARRAY_SIZE(charge_battery_props);
447 	} else {
448 		battery->bat.properties = energy_battery_props;
449 		battery->bat.num_properties =
450 			ARRAY_SIZE(energy_battery_props);
451 	}
452 
453 	battery->bat.name = acpi_device_bid(battery->device);
454 	battery->bat.type = POWER_SUPPLY_TYPE_BATTERY;
455 	battery->bat.get_property = acpi_battery_get_property;
456 
457 	result = power_supply_register(&battery->device->dev, &battery->bat);
458 	if (result)
459 		return result;
460 	return device_create_file(battery->bat.dev, &alarm_attr);
461 }
462 
463 static void sysfs_remove_battery(struct acpi_battery *battery)
464 {
465 	if (!battery->bat.dev)
466 		return;
467 	device_remove_file(battery->bat.dev, &alarm_attr);
468 	power_supply_unregister(&battery->bat);
469 	battery->bat.dev = NULL;
470 }
471 #endif
472 
473 static int acpi_battery_update(struct acpi_battery *battery)
474 {
475 	int result;
476 	result = acpi_battery_get_status(battery);
477 	if (result)
478 		return result;
479 #ifdef CONFIG_ACPI_SYSFS_POWER
480 	if (!acpi_battery_present(battery)) {
481 		sysfs_remove_battery(battery);
482 		battery->update_time = 0;
483 		return 0;
484 	}
485 #endif
486 	if (!battery->update_time) {
487 		result = acpi_battery_get_info(battery);
488 		if (result)
489 			return result;
490 		acpi_battery_init_alarm(battery);
491 	}
492 #ifdef CONFIG_ACPI_SYSFS_POWER
493 	if (!battery->bat.dev)
494 		sysfs_add_battery(battery);
495 #endif
496 	return acpi_battery_get_state(battery);
497 }
498 
499 /* --------------------------------------------------------------------------
500                               FS Interface (/proc)
501    -------------------------------------------------------------------------- */
502 
503 #ifdef CONFIG_ACPI_PROCFS_POWER
504 static struct proc_dir_entry *acpi_battery_dir;
505 
506 static int acpi_battery_print_info(struct seq_file *seq, int result)
507 {
508 	struct acpi_battery *battery = seq->private;
509 
510 	if (result)
511 		goto end;
512 
513 	seq_printf(seq, "present:                 %s\n",
514 		   acpi_battery_present(battery)?"yes":"no");
515 	if (!acpi_battery_present(battery))
516 		goto end;
517 	if (battery->design_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
518 		seq_printf(seq, "design capacity:         unknown\n");
519 	else
520 		seq_printf(seq, "design capacity:         %d %sh\n",
521 			   battery->design_capacity,
522 			   acpi_battery_units(battery));
523 
524 	if (battery->full_charge_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
525 		seq_printf(seq, "last full capacity:      unknown\n");
526 	else
527 		seq_printf(seq, "last full capacity:      %d %sh\n",
528 			   battery->full_charge_capacity,
529 			   acpi_battery_units(battery));
530 
531 	seq_printf(seq, "battery technology:      %srechargeable\n",
532 		   (!battery->technology)?"non-":"");
533 
534 	if (battery->design_voltage == ACPI_BATTERY_VALUE_UNKNOWN)
535 		seq_printf(seq, "design voltage:          unknown\n");
536 	else
537 		seq_printf(seq, "design voltage:          %d mV\n",
538 			   battery->design_voltage);
539 	seq_printf(seq, "design capacity warning: %d %sh\n",
540 		   battery->design_capacity_warning,
541 		   acpi_battery_units(battery));
542 	seq_printf(seq, "design capacity low:     %d %sh\n",
543 		   battery->design_capacity_low,
544 		   acpi_battery_units(battery));
545 	seq_printf(seq, "capacity granularity 1:  %d %sh\n",
546 		   battery->capacity_granularity_1,
547 		   acpi_battery_units(battery));
548 	seq_printf(seq, "capacity granularity 2:  %d %sh\n",
549 		   battery->capacity_granularity_2,
550 		   acpi_battery_units(battery));
551 	seq_printf(seq, "model number:            %s\n", battery->model_number);
552 	seq_printf(seq, "serial number:           %s\n", battery->serial_number);
553 	seq_printf(seq, "battery type:            %s\n", battery->type);
554 	seq_printf(seq, "OEM info:                %s\n", battery->oem_info);
555       end:
556 	if (result)
557 		seq_printf(seq, "ERROR: Unable to read battery info\n");
558 	return result;
559 }
560 
561 static int acpi_battery_print_state(struct seq_file *seq, int result)
562 {
563 	struct acpi_battery *battery = seq->private;
564 
565 	if (result)
566 		goto end;
567 
568 	seq_printf(seq, "present:                 %s\n",
569 		   acpi_battery_present(battery)?"yes":"no");
570 	if (!acpi_battery_present(battery))
571 		goto end;
572 
573 	seq_printf(seq, "capacity state:          %s\n",
574 			(battery->state & 0x04)?"critical":"ok");
575 	if ((battery->state & 0x01) && (battery->state & 0x02))
576 		seq_printf(seq,
577 			   "charging state:          charging/discharging\n");
578 	else if (battery->state & 0x01)
579 		seq_printf(seq, "charging state:          discharging\n");
580 	else if (battery->state & 0x02)
581 		seq_printf(seq, "charging state:          charging\n");
582 	else
583 		seq_printf(seq, "charging state:          charged\n");
584 
585 	if (battery->current_now == ACPI_BATTERY_VALUE_UNKNOWN)
586 		seq_printf(seq, "present rate:            unknown\n");
587 	else
588 		seq_printf(seq, "present rate:            %d %s\n",
589 			   battery->current_now, acpi_battery_units(battery));
590 
591 	if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN)
592 		seq_printf(seq, "remaining capacity:      unknown\n");
593 	else
594 		seq_printf(seq, "remaining capacity:      %d %sh\n",
595 			   battery->capacity_now, acpi_battery_units(battery));
596 	if (battery->voltage_now == ACPI_BATTERY_VALUE_UNKNOWN)
597 		seq_printf(seq, "present voltage:         unknown\n");
598 	else
599 		seq_printf(seq, "present voltage:         %d mV\n",
600 			   battery->voltage_now);
601       end:
602 	if (result)
603 		seq_printf(seq, "ERROR: Unable to read battery state\n");
604 
605 	return result;
606 }
607 
608 static int acpi_battery_print_alarm(struct seq_file *seq, int result)
609 {
610 	struct acpi_battery *battery = seq->private;
611 
612 	if (result)
613 		goto end;
614 
615 	if (!acpi_battery_present(battery)) {
616 		seq_printf(seq, "present:                 no\n");
617 		goto end;
618 	}
619 	seq_printf(seq, "alarm:                   ");
620 	if (!battery->alarm)
621 		seq_printf(seq, "unsupported\n");
622 	else
623 		seq_printf(seq, "%u %sh\n", battery->alarm,
624 				acpi_battery_units(battery));
625       end:
626 	if (result)
627 		seq_printf(seq, "ERROR: Unable to read battery alarm\n");
628 	return result;
629 }
630 
631 static ssize_t acpi_battery_write_alarm(struct file *file,
632 					const char __user * buffer,
633 					size_t count, loff_t * ppos)
634 {
635 	int result = 0;
636 	char alarm_string[12] = { '\0' };
637 	struct seq_file *m = file->private_data;
638 	struct acpi_battery *battery = m->private;
639 
640 	if (!battery || (count > sizeof(alarm_string) - 1))
641 		return -EINVAL;
642 	if (!acpi_battery_present(battery)) {
643 		result = -ENODEV;
644 		goto end;
645 	}
646 	if (copy_from_user(alarm_string, buffer, count)) {
647 		result = -EFAULT;
648 		goto end;
649 	}
650 	alarm_string[count] = '\0';
651 	battery->alarm = simple_strtol(alarm_string, NULL, 0);
652 	result = acpi_battery_set_alarm(battery);
653       end:
654 	if (!result)
655 		return count;
656 	return result;
657 }
658 
659 typedef int(*print_func)(struct seq_file *seq, int result);
660 
661 static print_func acpi_print_funcs[ACPI_BATTERY_NUMFILES] = {
662 	acpi_battery_print_info,
663 	acpi_battery_print_state,
664 	acpi_battery_print_alarm,
665 };
666 
667 static int acpi_battery_read(int fid, struct seq_file *seq)
668 {
669 	struct acpi_battery *battery = seq->private;
670 	int result = acpi_battery_update(battery);
671 	return acpi_print_funcs[fid](seq, result);
672 }
673 
674 #define DECLARE_FILE_FUNCTIONS(_name) \
675 static int acpi_battery_read_##_name(struct seq_file *seq, void *offset) \
676 { \
677 	return acpi_battery_read(_name##_tag, seq); \
678 } \
679 static int acpi_battery_##_name##_open_fs(struct inode *inode, struct file *file) \
680 { \
681 	return single_open(file, acpi_battery_read_##_name, PDE(inode)->data); \
682 }
683 
684 DECLARE_FILE_FUNCTIONS(info);
685 DECLARE_FILE_FUNCTIONS(state);
686 DECLARE_FILE_FUNCTIONS(alarm);
687 
688 #undef DECLARE_FILE_FUNCTIONS
689 
690 #define FILE_DESCRIPTION_RO(_name) \
691 	{ \
692 	.name = __stringify(_name), \
693 	.mode = S_IRUGO, \
694 	.ops = { \
695 		.open = acpi_battery_##_name##_open_fs, \
696 		.read = seq_read, \
697 		.llseek = seq_lseek, \
698 		.release = single_release, \
699 		.owner = THIS_MODULE, \
700 		}, \
701 	}
702 
703 #define FILE_DESCRIPTION_RW(_name) \
704 	{ \
705 	.name = __stringify(_name), \
706 	.mode = S_IFREG | S_IRUGO | S_IWUSR, \
707 	.ops = { \
708 		.open = acpi_battery_##_name##_open_fs, \
709 		.read = seq_read, \
710 		.llseek = seq_lseek, \
711 		.write = acpi_battery_write_##_name, \
712 		.release = single_release, \
713 		.owner = THIS_MODULE, \
714 		}, \
715 	}
716 
717 static struct battery_file {
718 	struct file_operations ops;
719 	mode_t mode;
720 	char *name;
721 } acpi_battery_file[] = {
722 	FILE_DESCRIPTION_RO(info),
723 	FILE_DESCRIPTION_RO(state),
724 	FILE_DESCRIPTION_RW(alarm),
725 };
726 
727 #undef FILE_DESCRIPTION_RO
728 #undef FILE_DESCRIPTION_RW
729 
730 static int acpi_battery_add_fs(struct acpi_device *device)
731 {
732 	struct proc_dir_entry *entry = NULL;
733 	int i;
734 
735 	if (!acpi_device_dir(device)) {
736 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
737 						     acpi_battery_dir);
738 		if (!acpi_device_dir(device))
739 			return -ENODEV;
740 		acpi_device_dir(device)->owner = THIS_MODULE;
741 	}
742 
743 	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i) {
744 		entry = proc_create_data(acpi_battery_file[i].name,
745 					 acpi_battery_file[i].mode,
746 					 acpi_device_dir(device),
747 					 &acpi_battery_file[i].ops,
748 					 acpi_driver_data(device));
749 		if (!entry)
750 			return -ENODEV;
751 	}
752 	return 0;
753 }
754 
755 static void acpi_battery_remove_fs(struct acpi_device *device)
756 {
757 	int i;
758 	if (!acpi_device_dir(device))
759 		return;
760 	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i)
761 		remove_proc_entry(acpi_battery_file[i].name,
762 				  acpi_device_dir(device));
763 
764 	remove_proc_entry(acpi_device_bid(device), acpi_battery_dir);
765 	acpi_device_dir(device) = NULL;
766 }
767 
768 #endif
769 
770 /* --------------------------------------------------------------------------
771                                  Driver Interface
772    -------------------------------------------------------------------------- */
773 
774 static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
775 {
776 	struct acpi_battery *battery = data;
777 	struct acpi_device *device;
778 	if (!battery)
779 		return;
780 	device = battery->device;
781 	acpi_battery_update(battery);
782 	acpi_bus_generate_proc_event(device, event,
783 				     acpi_battery_present(battery));
784 	acpi_bus_generate_netlink_event(device->pnp.device_class,
785 					device->dev.bus_id, event,
786 					acpi_battery_present(battery));
787 #ifdef CONFIG_ACPI_SYSFS_POWER
788 	/* acpi_batter_update could remove power_supply object */
789 	if (battery->bat.dev)
790 		kobject_uevent(&battery->bat.dev->kobj, KOBJ_CHANGE);
791 #endif
792 }
793 
794 static int acpi_battery_add(struct acpi_device *device)
795 {
796 	int result = 0;
797 	acpi_status status = 0;
798 	struct acpi_battery *battery = NULL;
799 	if (!device)
800 		return -EINVAL;
801 	battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
802 	if (!battery)
803 		return -ENOMEM;
804 	battery->device = device;
805 	strcpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
806 	strcpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
807 	acpi_driver_data(device) = battery;
808 	mutex_init(&battery->lock);
809 	acpi_battery_update(battery);
810 #ifdef CONFIG_ACPI_PROCFS_POWER
811 	result = acpi_battery_add_fs(device);
812 	if (result)
813 		goto end;
814 #endif
815 	status = acpi_install_notify_handler(device->handle,
816 					     ACPI_ALL_NOTIFY,
817 					     acpi_battery_notify, battery);
818 	if (ACPI_FAILURE(status)) {
819 		ACPI_EXCEPTION((AE_INFO, status, "Installing notify handler"));
820 		result = -ENODEV;
821 		goto end;
822 	}
823 	printk(KERN_INFO PREFIX "%s Slot [%s] (battery %s)\n",
824 	       ACPI_BATTERY_DEVICE_NAME, acpi_device_bid(device),
825 	       device->status.battery_present ? "present" : "absent");
826       end:
827 	if (result) {
828 #ifdef CONFIG_ACPI_PROCFS_POWER
829 		acpi_battery_remove_fs(device);
830 #endif
831 		kfree(battery);
832 	}
833 	return result;
834 }
835 
836 static int acpi_battery_remove(struct acpi_device *device, int type)
837 {
838 	acpi_status status = 0;
839 	struct acpi_battery *battery = NULL;
840 
841 	if (!device || !acpi_driver_data(device))
842 		return -EINVAL;
843 	battery = acpi_driver_data(device);
844 	status = acpi_remove_notify_handler(device->handle,
845 					    ACPI_ALL_NOTIFY,
846 					    acpi_battery_notify);
847 #ifdef CONFIG_ACPI_PROCFS_POWER
848 	acpi_battery_remove_fs(device);
849 #endif
850 #ifdef CONFIG_ACPI_SYSFS_POWER
851 	sysfs_remove_battery(battery);
852 #endif
853 	mutex_destroy(&battery->lock);
854 	kfree(battery);
855 	return 0;
856 }
857 
858 /* this is needed to learn about changes made in suspended state */
859 static int acpi_battery_resume(struct acpi_device *device)
860 {
861 	struct acpi_battery *battery;
862 	if (!device)
863 		return -EINVAL;
864 	battery = acpi_driver_data(device);
865 	battery->update_time = 0;
866 	acpi_battery_update(battery);
867 	return 0;
868 }
869 
870 static struct acpi_driver acpi_battery_driver = {
871 	.name = "battery",
872 	.class = ACPI_BATTERY_CLASS,
873 	.ids = battery_device_ids,
874 	.ops = {
875 		.add = acpi_battery_add,
876 		.resume = acpi_battery_resume,
877 		.remove = acpi_battery_remove,
878 		},
879 };
880 
881 static int __init acpi_battery_init(void)
882 {
883 	if (acpi_disabled)
884 		return -ENODEV;
885 #ifdef CONFIG_ACPI_PROCFS_POWER
886 	acpi_battery_dir = acpi_lock_battery_dir();
887 	if (!acpi_battery_dir)
888 		return -ENODEV;
889 #endif
890 	if (acpi_bus_register_driver(&acpi_battery_driver) < 0) {
891 #ifdef CONFIG_ACPI_PROCFS_POWER
892 		acpi_unlock_battery_dir(acpi_battery_dir);
893 #endif
894 		return -ENODEV;
895 	}
896 	return 0;
897 }
898 
899 static void __exit acpi_battery_exit(void)
900 {
901 	acpi_bus_unregister_driver(&acpi_battery_driver);
902 #ifdef CONFIG_ACPI_PROCFS_POWER
903 	acpi_unlock_battery_dir(acpi_battery_dir);
904 #endif
905 }
906 
907 module_init(acpi_battery_init);
908 module_exit(acpi_battery_exit);
909