xref: /linux/drivers/acpi/battery.c (revision 98366c20a275e957416e9516db5dcb7195b4e101)
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
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 #include <linux/power_supply.h>
44 
45 #define ACPI_BATTERY_VALUE_UNKNOWN 0xFFFFFFFF
46 
47 #define ACPI_BATTERY_COMPONENT		0x00040000
48 #define ACPI_BATTERY_CLASS		"battery"
49 #define ACPI_BATTERY_DEVICE_NAME	"Battery"
50 #define ACPI_BATTERY_NOTIFY_STATUS	0x80
51 #define ACPI_BATTERY_NOTIFY_INFO	0x81
52 
53 #define _COMPONENT		ACPI_BATTERY_COMPONENT
54 
55 ACPI_MODULE_NAME("battery");
56 
57 MODULE_AUTHOR("Paul Diefenbaugh");
58 MODULE_AUTHOR("Alexey Starikovskiy <astarikovskiy@suse.de>");
59 MODULE_DESCRIPTION("ACPI Battery Driver");
60 MODULE_LICENSE("GPL");
61 
62 static unsigned int cache_time = 1000;
63 module_param(cache_time, uint, 0644);
64 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
65 
66 #ifdef CONFIG_ACPI_PROCFS
67 extern struct proc_dir_entry *acpi_lock_battery_dir(void);
68 extern void *acpi_unlock_battery_dir(struct proc_dir_entry *acpi_battery_dir);
69 
70 enum acpi_battery_files {
71 	info_tag = 0,
72 	state_tag,
73 	alarm_tag,
74 	ACPI_BATTERY_NUMFILES,
75 };
76 
77 #endif
78 
79 static const struct acpi_device_id battery_device_ids[] = {
80 	{"PNP0C0A", 0},
81 	{"", 0},
82 };
83 
84 MODULE_DEVICE_TABLE(acpi, battery_device_ids);
85 
86 
87 struct acpi_battery {
88 	struct mutex lock;
89 	struct power_supply bat;
90 	struct acpi_device *device;
91 	unsigned long update_time;
92 	int current_now;
93 	int capacity_now;
94 	int voltage_now;
95 	int design_capacity;
96 	int full_charge_capacity;
97 	int technology;
98 	int design_voltage;
99 	int design_capacity_warning;
100 	int design_capacity_low;
101 	int capacity_granularity_1;
102 	int capacity_granularity_2;
103 	int alarm;
104 	char model_number[32];
105 	char serial_number[32];
106 	char type[32];
107 	char oem_info[32];
108 	int state;
109 	int power_unit;
110 	u8 alarm_present;
111 };
112 
113 #define to_acpi_battery(x) container_of(x, struct acpi_battery, bat);
114 
115 inline int acpi_battery_present(struct acpi_battery *battery)
116 {
117 	return battery->device->status.battery_present;
118 }
119 
120 static int acpi_battery_technology(struct acpi_battery *battery)
121 {
122 	if (!strcasecmp("NiCd", battery->type))
123 		return POWER_SUPPLY_TECHNOLOGY_NiCd;
124 	if (!strcasecmp("NiMH", battery->type))
125 		return POWER_SUPPLY_TECHNOLOGY_NiMH;
126 	if (!strcasecmp("LION", battery->type))
127 		return POWER_SUPPLY_TECHNOLOGY_LION;
128 	if (!strcasecmp("LI-ION", battery->type))
129 		return POWER_SUPPLY_TECHNOLOGY_LION;
130 	if (!strcasecmp("LiP", battery->type))
131 		return POWER_SUPPLY_TECHNOLOGY_LIPO;
132 	return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
133 }
134 
135 static int acpi_battery_update(struct acpi_battery *battery);
136 
137 static int acpi_battery_get_property(struct power_supply *psy,
138 				     enum power_supply_property psp,
139 				     union power_supply_propval *val)
140 {
141 	struct acpi_battery *battery = to_acpi_battery(psy);
142 
143 	if ((!acpi_battery_present(battery)) &&
144 	     psp != POWER_SUPPLY_PROP_PRESENT)
145 		return -ENODEV;
146 	acpi_battery_update(battery);
147 	switch (psp) {
148 	case POWER_SUPPLY_PROP_STATUS:
149 		if (battery->state & 0x01)
150 			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
151 		else if (battery->state & 0x02)
152 			val->intval = POWER_SUPPLY_STATUS_CHARGING;
153 		else if (battery->state == 0)
154 			val->intval = POWER_SUPPLY_STATUS_FULL;
155 		break;
156 	case POWER_SUPPLY_PROP_PRESENT:
157 		val->intval = acpi_battery_present(battery);
158 		break;
159 	case POWER_SUPPLY_PROP_TECHNOLOGY:
160 		val->intval = acpi_battery_technology(battery);
161 		break;
162 	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
163 		val->intval = battery->design_voltage * 1000;
164 		break;
165 	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
166 		val->intval = battery->voltage_now * 1000;
167 		break;
168 	case POWER_SUPPLY_PROP_CURRENT_NOW:
169 		val->intval = battery->current_now * 1000;
170 		break;
171 	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
172 	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
173 		val->intval = battery->design_capacity * 1000;
174 		break;
175 	case POWER_SUPPLY_PROP_CHARGE_FULL:
176 	case POWER_SUPPLY_PROP_ENERGY_FULL:
177 		val->intval = battery->full_charge_capacity * 1000;
178 		break;
179 	case POWER_SUPPLY_PROP_CHARGE_NOW:
180 	case POWER_SUPPLY_PROP_ENERGY_NOW:
181 		val->intval = battery->capacity_now * 1000;
182 		break;
183 	case POWER_SUPPLY_PROP_MODEL_NAME:
184 		val->strval = battery->model_number;
185 		break;
186 	case POWER_SUPPLY_PROP_MANUFACTURER:
187 		val->strval = battery->oem_info;
188 		break;
189 	default:
190 		return -EINVAL;
191 	}
192 	return 0;
193 }
194 
195 static enum power_supply_property charge_battery_props[] = {
196 	POWER_SUPPLY_PROP_STATUS,
197 	POWER_SUPPLY_PROP_PRESENT,
198 	POWER_SUPPLY_PROP_TECHNOLOGY,
199 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
200 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
201 	POWER_SUPPLY_PROP_CURRENT_NOW,
202 	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
203 	POWER_SUPPLY_PROP_CHARGE_FULL,
204 	POWER_SUPPLY_PROP_CHARGE_NOW,
205 	POWER_SUPPLY_PROP_MODEL_NAME,
206 	POWER_SUPPLY_PROP_MANUFACTURER,
207 };
208 
209 static enum power_supply_property energy_battery_props[] = {
210 	POWER_SUPPLY_PROP_STATUS,
211 	POWER_SUPPLY_PROP_PRESENT,
212 	POWER_SUPPLY_PROP_TECHNOLOGY,
213 	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
214 	POWER_SUPPLY_PROP_VOLTAGE_NOW,
215 	POWER_SUPPLY_PROP_CURRENT_NOW,
216 	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
217 	POWER_SUPPLY_PROP_ENERGY_FULL,
218 	POWER_SUPPLY_PROP_ENERGY_NOW,
219 	POWER_SUPPLY_PROP_MODEL_NAME,
220 	POWER_SUPPLY_PROP_MANUFACTURER,
221 };
222 
223 #ifdef CONFIG_ACPI_PROCFS
224 inline char *acpi_battery_units(struct acpi_battery *battery)
225 {
226 	return (battery->power_unit)?"mA":"mW";
227 }
228 #endif
229 
230 /* --------------------------------------------------------------------------
231                                Battery Management
232    -------------------------------------------------------------------------- */
233 struct acpi_offsets {
234 	size_t offset;		/* offset inside struct acpi_sbs_battery */
235 	u8 mode;		/* int or string? */
236 };
237 
238 static struct acpi_offsets state_offsets[] = {
239 	{offsetof(struct acpi_battery, state), 0},
240 	{offsetof(struct acpi_battery, current_now), 0},
241 	{offsetof(struct acpi_battery, capacity_now), 0},
242 	{offsetof(struct acpi_battery, voltage_now), 0},
243 };
244 
245 static struct acpi_offsets info_offsets[] = {
246 	{offsetof(struct acpi_battery, power_unit), 0},
247 	{offsetof(struct acpi_battery, design_capacity), 0},
248 	{offsetof(struct acpi_battery, full_charge_capacity), 0},
249 	{offsetof(struct acpi_battery, technology), 0},
250 	{offsetof(struct acpi_battery, design_voltage), 0},
251 	{offsetof(struct acpi_battery, design_capacity_warning), 0},
252 	{offsetof(struct acpi_battery, design_capacity_low), 0},
253 	{offsetof(struct acpi_battery, capacity_granularity_1), 0},
254 	{offsetof(struct acpi_battery, capacity_granularity_2), 0},
255 	{offsetof(struct acpi_battery, model_number), 1},
256 	{offsetof(struct acpi_battery, serial_number), 1},
257 	{offsetof(struct acpi_battery, type), 1},
258 	{offsetof(struct acpi_battery, oem_info), 1},
259 };
260 
261 static int extract_package(struct acpi_battery *battery,
262 			   union acpi_object *package,
263 			   struct acpi_offsets *offsets, int num)
264 {
265 	int i;
266 	union acpi_object *element;
267 	if (package->type != ACPI_TYPE_PACKAGE)
268 		return -EFAULT;
269 	for (i = 0; i < num; ++i) {
270 		if (package->package.count <= i)
271 			return -EFAULT;
272 		element = &package->package.elements[i];
273 		if (offsets[i].mode) {
274 			u8 *ptr = (u8 *)battery + offsets[i].offset;
275 			if (element->type == ACPI_TYPE_STRING ||
276 			    element->type == ACPI_TYPE_BUFFER)
277 				strncpy(ptr, element->string.pointer, 32);
278 			else if (element->type == ACPI_TYPE_INTEGER) {
279 				strncpy(ptr, (u8 *)&element->integer.value,
280 					sizeof(acpi_integer));
281 				ptr[sizeof(acpi_integer)] = 0;
282 			} else return -EFAULT;
283 		} else {
284 			if (element->type == ACPI_TYPE_INTEGER) {
285 				int *x = (int *)((u8 *)battery +
286 						offsets[i].offset);
287 				*x = element->integer.value;
288 			} else return -EFAULT;
289 		}
290 	}
291 	return 0;
292 }
293 
294 static int acpi_battery_get_status(struct acpi_battery *battery)
295 {
296 	if (acpi_bus_get_status(battery->device)) {
297 		ACPI_EXCEPTION((AE_INFO, AE_ERROR, "Evaluating _STA"));
298 		return -ENODEV;
299 	}
300 	return 0;
301 }
302 
303 static int acpi_battery_get_info(struct acpi_battery *battery)
304 {
305 	int result = -EFAULT;
306 	acpi_status status = 0;
307 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
308 
309 	if (!acpi_battery_present(battery))
310 		return 0;
311 	mutex_lock(&battery->lock);
312 	status = acpi_evaluate_object(battery->device->handle, "_BIF",
313 				      NULL, &buffer);
314 	mutex_unlock(&battery->lock);
315 
316 	if (ACPI_FAILURE(status)) {
317 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BIF"));
318 		return -ENODEV;
319 	}
320 
321 	result = extract_package(battery, buffer.pointer,
322 				 info_offsets, ARRAY_SIZE(info_offsets));
323 	kfree(buffer.pointer);
324 	return result;
325 }
326 
327 static int acpi_battery_get_state(struct acpi_battery *battery)
328 {
329 	int result = 0;
330 	acpi_status status = 0;
331 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
332 
333 	if (!acpi_battery_present(battery))
334 		return 0;
335 
336 	if (battery->update_time &&
337 	    time_before(jiffies, battery->update_time +
338 			msecs_to_jiffies(cache_time)))
339 		return 0;
340 
341 	mutex_lock(&battery->lock);
342 	status = acpi_evaluate_object(battery->device->handle, "_BST",
343 				      NULL, &buffer);
344 	mutex_unlock(&battery->lock);
345 
346 	if (ACPI_FAILURE(status)) {
347 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BST"));
348 		return -ENODEV;
349 	}
350 
351 	result = extract_package(battery, buffer.pointer,
352 				 state_offsets, ARRAY_SIZE(state_offsets));
353 	battery->update_time = jiffies;
354 	kfree(buffer.pointer);
355 	return result;
356 }
357 
358 static int acpi_battery_set_alarm(struct acpi_battery *battery)
359 {
360 	acpi_status status = 0;
361 	union acpi_object arg0 = { .type = ACPI_TYPE_INTEGER };
362 	struct acpi_object_list arg_list = { 1, &arg0 };
363 
364 	if (!acpi_battery_present(battery)|| !battery->alarm_present)
365 		return -ENODEV;
366 
367 	arg0.integer.value = battery->alarm;
368 
369 	mutex_lock(&battery->lock);
370 	status = acpi_evaluate_object(battery->device->handle, "_BTP",
371 				 &arg_list, NULL);
372 	mutex_unlock(&battery->lock);
373 
374 	if (ACPI_FAILURE(status))
375 		return -ENODEV;
376 
377 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Alarm set to %d\n", battery->alarm));
378 	return 0;
379 }
380 
381 static int acpi_battery_init_alarm(struct acpi_battery *battery)
382 {
383 	acpi_status status = AE_OK;
384 	acpi_handle handle = NULL;
385 
386 	/* See if alarms are supported, and if so, set default */
387 	status = acpi_get_handle(battery->device->handle, "_BTP", &handle);
388 	if (ACPI_FAILURE(status)) {
389 		battery->alarm_present = 0;
390 		return 0;
391 	}
392 	battery->alarm_present = 1;
393 	if (!battery->alarm)
394 		battery->alarm = battery->design_capacity_warning;
395 	return acpi_battery_set_alarm(battery);
396 }
397 
398 static ssize_t acpi_battery_alarm_show(struct device *dev,
399 					struct device_attribute *attr,
400 					char *buf)
401 {
402 	struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));
403 	return sprintf(buf, "%d\n", battery->alarm * 1000);
404 }
405 
406 static ssize_t acpi_battery_alarm_store(struct device *dev,
407 					struct device_attribute *attr,
408 					const char *buf, size_t count)
409 {
410 	unsigned long x;
411 	struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));
412 	if (sscanf(buf, "%ld\n", &x) == 1)
413 		battery->alarm = x/1000;
414 	if (acpi_battery_present(battery))
415 		acpi_battery_set_alarm(battery);
416 	return count;
417 }
418 
419 static struct device_attribute alarm_attr = {
420 	.attr = {.name = "alarm", .mode = 0644, .owner = THIS_MODULE},
421 	.show = acpi_battery_alarm_show,
422 	.store = acpi_battery_alarm_store,
423 };
424 
425 static int sysfs_add_battery(struct acpi_battery *battery)
426 {
427 	int result;
428 
429 	battery->update_time = 0;
430 	result = acpi_battery_get_info(battery);
431 	acpi_battery_init_alarm(battery);
432 	if (result)
433 		return result;
434 	if (battery->power_unit) {
435 		battery->bat.properties = charge_battery_props;
436 		battery->bat.num_properties =
437 			ARRAY_SIZE(charge_battery_props);
438 	} else {
439 		battery->bat.properties = energy_battery_props;
440 		battery->bat.num_properties =
441 			ARRAY_SIZE(energy_battery_props);
442 	}
443 
444 	battery->bat.name = acpi_device_bid(battery->device);
445 	battery->bat.type = POWER_SUPPLY_TYPE_BATTERY;
446 	battery->bat.get_property = acpi_battery_get_property;
447 
448 	result = power_supply_register(&battery->device->dev, &battery->bat);
449 	if (result)
450 		return result;
451 	return device_create_file(battery->bat.dev, &alarm_attr);
452 }
453 
454 static void sysfs_remove_battery(struct acpi_battery *battery)
455 {
456 	if (!battery->bat.dev)
457 		return;
458 	device_remove_file(battery->bat.dev, &alarm_attr);
459 	power_supply_unregister(&battery->bat);
460 }
461 
462 static int acpi_battery_update(struct acpi_battery *battery)
463 {
464 	int result = acpi_battery_get_status(battery);
465 	if (result)
466 		return result;
467 	if (!acpi_battery_present(battery)) {
468 		sysfs_remove_battery(battery);
469 		return 0;
470 	}
471 	if (!battery->bat.dev)
472 		sysfs_add_battery(battery);
473 	return acpi_battery_get_state(battery);
474 }
475 
476 /* --------------------------------------------------------------------------
477                               FS Interface (/proc)
478    -------------------------------------------------------------------------- */
479 
480 #ifdef CONFIG_ACPI_PROCFS
481 static struct proc_dir_entry *acpi_battery_dir;
482 
483 static int acpi_battery_print_info(struct seq_file *seq, int result)
484 {
485 	struct acpi_battery *battery = seq->private;
486 
487 	if (result)
488 		goto end;
489 
490 	seq_printf(seq, "present:                 %s\n",
491 		   acpi_battery_present(battery)?"yes":"no");
492 	if (!acpi_battery_present(battery))
493 		goto end;
494 	if (battery->design_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
495 		seq_printf(seq, "design capacity:         unknown\n");
496 	else
497 		seq_printf(seq, "design capacity:         %d %sh\n",
498 			   battery->design_capacity,
499 			   acpi_battery_units(battery));
500 
501 	if (battery->full_charge_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
502 		seq_printf(seq, "last full capacity:      unknown\n");
503 	else
504 		seq_printf(seq, "last full capacity:      %d %sh\n",
505 			   battery->full_charge_capacity,
506 			   acpi_battery_units(battery));
507 
508 	seq_printf(seq, "battery technology:      %srechargeable\n",
509 		   (!battery->technology)?"non-":"");
510 
511 	if (battery->design_voltage == ACPI_BATTERY_VALUE_UNKNOWN)
512 		seq_printf(seq, "design voltage:          unknown\n");
513 	else
514 		seq_printf(seq, "design voltage:          %d mV\n",
515 			   battery->design_voltage);
516 	seq_printf(seq, "design capacity warning: %d %sh\n",
517 		   battery->design_capacity_warning,
518 		   acpi_battery_units(battery));
519 	seq_printf(seq, "design capacity low:     %d %sh\n",
520 		   battery->design_capacity_low,
521 		   acpi_battery_units(battery));
522 	seq_printf(seq, "capacity granularity 1:  %d %sh\n",
523 		   battery->capacity_granularity_1,
524 		   acpi_battery_units(battery));
525 	seq_printf(seq, "capacity granularity 2:  %d %sh\n",
526 		   battery->capacity_granularity_2,
527 		   acpi_battery_units(battery));
528 	seq_printf(seq, "model number:            %s\n", battery->model_number);
529 	seq_printf(seq, "serial number:           %s\n", battery->serial_number);
530 	seq_printf(seq, "battery type:            %s\n", battery->type);
531 	seq_printf(seq, "OEM info:                %s\n", battery->oem_info);
532       end:
533 	if (result)
534 		seq_printf(seq, "ERROR: Unable to read battery info\n");
535 	return result;
536 }
537 
538 static int acpi_battery_print_state(struct seq_file *seq, int result)
539 {
540 	struct acpi_battery *battery = seq->private;
541 
542 	if (result)
543 		goto end;
544 
545 	seq_printf(seq, "present:                 %s\n",
546 		   acpi_battery_present(battery)?"yes":"no");
547 	if (!acpi_battery_present(battery))
548 		goto end;
549 
550 	seq_printf(seq, "capacity state:          %s\n",
551 			(battery->state & 0x04)?"critical":"ok");
552 	if ((battery->state & 0x01) && (battery->state & 0x02))
553 		seq_printf(seq,
554 			   "charging state:          charging/discharging\n");
555 	else if (battery->state & 0x01)
556 		seq_printf(seq, "charging state:          discharging\n");
557 	else if (battery->state & 0x02)
558 		seq_printf(seq, "charging state:          charging\n");
559 	else
560 		seq_printf(seq, "charging state:          charged\n");
561 
562 	if (battery->current_now == ACPI_BATTERY_VALUE_UNKNOWN)
563 		seq_printf(seq, "present rate:            unknown\n");
564 	else
565 		seq_printf(seq, "present rate:            %d %s\n",
566 			   battery->current_now, acpi_battery_units(battery));
567 
568 	if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN)
569 		seq_printf(seq, "remaining capacity:      unknown\n");
570 	else
571 		seq_printf(seq, "remaining capacity:      %d %sh\n",
572 			   battery->capacity_now, acpi_battery_units(battery));
573 	if (battery->voltage_now == ACPI_BATTERY_VALUE_UNKNOWN)
574 		seq_printf(seq, "present voltage:         unknown\n");
575 	else
576 		seq_printf(seq, "present voltage:         %d mV\n",
577 			   battery->voltage_now);
578       end:
579 	if (result)
580 		seq_printf(seq, "ERROR: Unable to read battery state\n");
581 
582 	return result;
583 }
584 
585 static int acpi_battery_print_alarm(struct seq_file *seq, int result)
586 {
587 	struct acpi_battery *battery = seq->private;
588 
589 	if (result)
590 		goto end;
591 
592 	if (!acpi_battery_present(battery)) {
593 		seq_printf(seq, "present:                 no\n");
594 		goto end;
595 	}
596 	seq_printf(seq, "alarm:                   ");
597 	if (!battery->alarm)
598 		seq_printf(seq, "unsupported\n");
599 	else
600 		seq_printf(seq, "%u %sh\n", battery->alarm,
601 				acpi_battery_units(battery));
602       end:
603 	if (result)
604 		seq_printf(seq, "ERROR: Unable to read battery alarm\n");
605 	return result;
606 }
607 
608 static ssize_t acpi_battery_write_alarm(struct file *file,
609 					const char __user * buffer,
610 					size_t count, loff_t * ppos)
611 {
612 	int result = 0;
613 	char alarm_string[12] = { '\0' };
614 	struct seq_file *m = file->private_data;
615 	struct acpi_battery *battery = m->private;
616 
617 	if (!battery || (count > sizeof(alarm_string) - 1))
618 		return -EINVAL;
619 	if (!acpi_battery_present(battery)) {
620 		result = -ENODEV;
621 		goto end;
622 	}
623 	if (copy_from_user(alarm_string, buffer, count)) {
624 		result = -EFAULT;
625 		goto end;
626 	}
627 	alarm_string[count] = '\0';
628 	battery->alarm = simple_strtol(alarm_string, NULL, 0);
629 	result = acpi_battery_set_alarm(battery);
630       end:
631 	if (!result)
632 		return count;
633 	return result;
634 }
635 
636 typedef int(*print_func)(struct seq_file *seq, int result);
637 
638 static print_func acpi_print_funcs[ACPI_BATTERY_NUMFILES] = {
639 	acpi_battery_print_info,
640 	acpi_battery_print_state,
641 	acpi_battery_print_alarm,
642 };
643 
644 static int acpi_battery_read(int fid, struct seq_file *seq)
645 {
646 	struct acpi_battery *battery = seq->private;
647 	int result = acpi_battery_update(battery);
648 	return acpi_print_funcs[fid](seq, result);
649 }
650 
651 #define DECLARE_FILE_FUNCTIONS(_name) \
652 static int acpi_battery_read_##_name(struct seq_file *seq, void *offset) \
653 { \
654 	return acpi_battery_read(_name##_tag, seq); \
655 } \
656 static int acpi_battery_##_name##_open_fs(struct inode *inode, struct file *file) \
657 { \
658 	return single_open(file, acpi_battery_read_##_name, PDE(inode)->data); \
659 }
660 
661 DECLARE_FILE_FUNCTIONS(info);
662 DECLARE_FILE_FUNCTIONS(state);
663 DECLARE_FILE_FUNCTIONS(alarm);
664 
665 #undef DECLARE_FILE_FUNCTIONS
666 
667 #define FILE_DESCRIPTION_RO(_name) \
668 	{ \
669 	.name = __stringify(_name), \
670 	.mode = S_IRUGO, \
671 	.ops = { \
672 		.open = acpi_battery_##_name##_open_fs, \
673 		.read = seq_read, \
674 		.llseek = seq_lseek, \
675 		.release = single_release, \
676 		.owner = THIS_MODULE, \
677 		}, \
678 	}
679 
680 #define FILE_DESCRIPTION_RW(_name) \
681 	{ \
682 	.name = __stringify(_name), \
683 	.mode = S_IFREG | S_IRUGO | S_IWUSR, \
684 	.ops = { \
685 		.open = acpi_battery_##_name##_open_fs, \
686 		.read = seq_read, \
687 		.llseek = seq_lseek, \
688 		.write = acpi_battery_write_##_name, \
689 		.release = single_release, \
690 		.owner = THIS_MODULE, \
691 		}, \
692 	}
693 
694 static struct battery_file {
695 	struct file_operations ops;
696 	mode_t mode;
697 	char *name;
698 } acpi_battery_file[] = {
699 	FILE_DESCRIPTION_RO(info),
700 	FILE_DESCRIPTION_RO(state),
701 	FILE_DESCRIPTION_RW(alarm),
702 };
703 
704 #undef FILE_DESCRIPTION_RO
705 #undef FILE_DESCRIPTION_RW
706 
707 static int acpi_battery_add_fs(struct acpi_device *device)
708 {
709 	struct proc_dir_entry *entry = NULL;
710 	int i;
711 
712 	if (!acpi_device_dir(device)) {
713 		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
714 						     acpi_battery_dir);
715 		if (!acpi_device_dir(device))
716 			return -ENODEV;
717 		acpi_device_dir(device)->owner = THIS_MODULE;
718 	}
719 
720 	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i) {
721 		entry = create_proc_entry(acpi_battery_file[i].name,
722 				  acpi_battery_file[i].mode, acpi_device_dir(device));
723 		if (!entry)
724 			return -ENODEV;
725 		else {
726 			entry->proc_fops = &acpi_battery_file[i].ops;
727 			entry->data = acpi_driver_data(device);
728 			entry->owner = THIS_MODULE;
729 		}
730 	}
731 	return 0;
732 }
733 
734 static void acpi_battery_remove_fs(struct acpi_device *device)
735 {
736 	int i;
737 	if (!acpi_device_dir(device))
738 		return;
739 	for (i = 0; i < ACPI_BATTERY_NUMFILES; ++i)
740 		remove_proc_entry(acpi_battery_file[i].name,
741 				  acpi_device_dir(device));
742 
743 	remove_proc_entry(acpi_device_bid(device), acpi_battery_dir);
744 	acpi_device_dir(device) = NULL;
745 }
746 
747 #endif
748 
749 /* --------------------------------------------------------------------------
750                                  Driver Interface
751    -------------------------------------------------------------------------- */
752 
753 static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
754 {
755 	struct acpi_battery *battery = data;
756 	struct acpi_device *device;
757 	if (!battery)
758 		return;
759 	device = battery->device;
760 	acpi_battery_update(battery);
761 	acpi_bus_generate_proc_event(device, event,
762 				     acpi_battery_present(battery));
763 	acpi_bus_generate_netlink_event(device->pnp.device_class,
764 					device->dev.bus_id, event,
765 					acpi_battery_present(battery));
766 	/* acpi_batter_update could remove power_supply object */
767 	if (battery->bat.dev)
768 		kobject_uevent(&battery->bat.dev->kobj, KOBJ_CHANGE);
769 }
770 
771 static int acpi_battery_add(struct acpi_device *device)
772 {
773 	int result = 0;
774 	acpi_status status = 0;
775 	struct acpi_battery *battery = NULL;
776 	if (!device)
777 		return -EINVAL;
778 	battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
779 	if (!battery)
780 		return -ENOMEM;
781 	battery->device = device;
782 	strcpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
783 	strcpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
784 	acpi_driver_data(device) = battery;
785 	mutex_init(&battery->lock);
786 	acpi_battery_update(battery);
787 #ifdef CONFIG_ACPI_PROCFS
788 	result = acpi_battery_add_fs(device);
789 	if (result)
790 		goto end;
791 #endif
792 	status = acpi_install_notify_handler(device->handle,
793 					     ACPI_ALL_NOTIFY,
794 					     acpi_battery_notify, battery);
795 	if (ACPI_FAILURE(status)) {
796 		ACPI_EXCEPTION((AE_INFO, status, "Installing notify handler"));
797 		result = -ENODEV;
798 		goto end;
799 	}
800 	printk(KERN_INFO PREFIX "%s Slot [%s] (battery %s)\n",
801 	       ACPI_BATTERY_DEVICE_NAME, acpi_device_bid(device),
802 	       device->status.battery_present ? "present" : "absent");
803       end:
804 	if (result) {
805 #ifdef CONFIG_ACPI_PROCFS
806 		acpi_battery_remove_fs(device);
807 #endif
808 		kfree(battery);
809 	}
810 	return result;
811 }
812 
813 static int acpi_battery_remove(struct acpi_device *device, int type)
814 {
815 	acpi_status status = 0;
816 	struct acpi_battery *battery = NULL;
817 
818 	if (!device || !acpi_driver_data(device))
819 		return -EINVAL;
820 	battery = acpi_driver_data(device);
821 	status = acpi_remove_notify_handler(device->handle,
822 					    ACPI_ALL_NOTIFY,
823 					    acpi_battery_notify);
824 #ifdef CONFIG_ACPI_PROCFS
825 	acpi_battery_remove_fs(device);
826 #endif
827 	sysfs_remove_battery(battery);
828 	mutex_destroy(&battery->lock);
829 	kfree(battery);
830 	return 0;
831 }
832 
833 /* this is needed to learn about changes made in suspended state */
834 static int acpi_battery_resume(struct acpi_device *device)
835 {
836 	struct acpi_battery *battery;
837 	if (!device)
838 		return -EINVAL;
839 	battery = acpi_driver_data(device);
840 	battery->update_time = 0;
841 	acpi_battery_update(battery);
842 	return 0;
843 }
844 
845 static struct acpi_driver acpi_battery_driver = {
846 	.name = "battery",
847 	.class = ACPI_BATTERY_CLASS,
848 	.ids = battery_device_ids,
849 	.ops = {
850 		.add = acpi_battery_add,
851 		.resume = acpi_battery_resume,
852 		.remove = acpi_battery_remove,
853 		},
854 };
855 
856 static int __init acpi_battery_init(void)
857 {
858 	if (acpi_disabled)
859 		return -ENODEV;
860 #ifdef CONFIG_ACPI_PROCFS
861 	acpi_battery_dir = acpi_lock_battery_dir();
862 	if (!acpi_battery_dir)
863 		return -ENODEV;
864 #endif
865 	if (acpi_bus_register_driver(&acpi_battery_driver) < 0) {
866 #ifdef CONFIG_ACPI_PROCFS
867 		acpi_unlock_battery_dir(acpi_battery_dir);
868 #endif
869 		return -ENODEV;
870 	}
871 	return 0;
872 }
873 
874 static void __exit acpi_battery_exit(void)
875 {
876 	acpi_bus_unregister_driver(&acpi_battery_driver);
877 #ifdef CONFIG_ACPI_PROCFS
878 	acpi_unlock_battery_dir(acpi_battery_dir);
879 #endif
880 }
881 
882 module_init(acpi_battery_init);
883 module_exit(acpi_battery_exit);
884