olpc_battery.c revision 2c3c8bea608866d8bd9dcf92657d57fdcac011c5 
1/*
2 * Battery driver for One Laptop Per Child board.
3 *
4 *	Copyright © 2006  David Woodhouse <dwmw2@infradead.org>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/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
57static 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
79static enum power_supply_property olpc_ac_props[] = {
80	POWER_SUPPLY_PROP_ONLINE,
81};
82
83static 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
91static char bat_serial[17]; /* Ick */
92
93static 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
117static 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
154static 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
179static 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/*********************************************************************
205 *		Battery properties
206 *********************************************************************/
207static int olpc_bat_get_property(struct power_supply *psy,
208				 enum power_supply_property psp,
209				 union power_supply_propval *val)
210{
211	int ret = 0;
212	__be16 ec_word;
213	uint8_t ec_byte;
214	__be64 ser_buf;
215
216	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
217	if (ret)
218		return ret;
219
220	/* Theoretically there's a race here -- the battery could be
221	   removed immediately after we check whether it's present, and
222	   then we query for some other property of the now-absent battery.
223	   It doesn't matter though -- the EC will return the last-known
224	   information, and it's as if we just ran that _little_ bit faster
225	   and managed to read it out before the battery went away. */
226	if (!(ec_byte & (BAT_STAT_PRESENT | BAT_STAT_TRICKLE)) &&
227			psp != POWER_SUPPLY_PROP_PRESENT)
228		return -ENODEV;
229
230	switch (psp) {
231	case POWER_SUPPLY_PROP_STATUS:
232		ret = olpc_bat_get_status(val, ec_byte);
233		if (ret)
234			return ret;
235		break;
236	case POWER_SUPPLY_PROP_CHARGE_TYPE:
237		if (ec_byte & BAT_STAT_TRICKLE)
238			val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
239		else if (ec_byte & BAT_STAT_CHARGING)
240			val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
241		else
242			val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
243		break;
244	case POWER_SUPPLY_PROP_PRESENT:
245		val->intval = !!(ec_byte & (BAT_STAT_PRESENT |
246					    BAT_STAT_TRICKLE));
247		break;
248
249	case POWER_SUPPLY_PROP_HEALTH:
250		if (ec_byte & BAT_STAT_DESTROY)
251			val->intval = POWER_SUPPLY_HEALTH_DEAD;
252		else {
253			ret = olpc_bat_get_health(val);
254			if (ret)
255				return ret;
256		}
257		break;
258
259	case POWER_SUPPLY_PROP_MANUFACTURER:
260		ret = olpc_bat_get_mfr(val);
261		if (ret)
262			return ret;
263		break;
264	case POWER_SUPPLY_PROP_TECHNOLOGY:
265		ret = olpc_bat_get_tech(val);
266		if (ret)
267			return ret;
268		break;
269	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
270		ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
271		if (ret)
272			return ret;
273
274		val->intval = (int)be16_to_cpu(ec_word) * 9760L / 32;
275		break;
276	case POWER_SUPPLY_PROP_CURRENT_AVG:
277		ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
278		if (ret)
279			return ret;
280
281		val->intval = (int)be16_to_cpu(ec_word) * 15625L / 120;
282		break;
283	case POWER_SUPPLY_PROP_CAPACITY:
284		ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
285		if (ret)
286			return ret;
287		val->intval = ec_byte;
288		break;
289	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
290		if (ec_byte & BAT_STAT_FULL)
291			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
292		else if (ec_byte & BAT_STAT_LOW)
293			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
294		else
295			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
296		break;
297	case POWER_SUPPLY_PROP_TEMP:
298		ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
299		if (ret)
300			return ret;
301
302		val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
303		break;
304	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
305		ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
306		if (ret)
307			return ret;
308
309		val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
310		break;
311	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
312		ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
313		if (ret)
314			return ret;
315
316		val->intval = (int)be16_to_cpu(ec_word) * 6250 / 15;
317		break;
318	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
319		ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
320		if (ret)
321			return ret;
322
323		sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
324		val->strval = bat_serial;
325		break;
326	default:
327		ret = -EINVAL;
328		break;
329	}
330
331	return ret;
332}
333
334static enum power_supply_property olpc_bat_props[] = {
335	POWER_SUPPLY_PROP_STATUS,
336	POWER_SUPPLY_PROP_CHARGE_TYPE,
337	POWER_SUPPLY_PROP_PRESENT,
338	POWER_SUPPLY_PROP_HEALTH,
339	POWER_SUPPLY_PROP_TECHNOLOGY,
340	POWER_SUPPLY_PROP_VOLTAGE_AVG,
341	POWER_SUPPLY_PROP_CURRENT_AVG,
342	POWER_SUPPLY_PROP_CAPACITY,
343	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
344	POWER_SUPPLY_PROP_TEMP,
345	POWER_SUPPLY_PROP_TEMP_AMBIENT,
346	POWER_SUPPLY_PROP_MANUFACTURER,
347	POWER_SUPPLY_PROP_SERIAL_NUMBER,
348	POWER_SUPPLY_PROP_CHARGE_COUNTER,
349};
350
351/* EEPROM reading goes completely around the power_supply API, sadly */
352
353#define EEPROM_START	0x20
354#define EEPROM_END	0x80
355#define EEPROM_SIZE	(EEPROM_END - EEPROM_START)
356
357static ssize_t olpc_bat_eeprom_read(struct file *filp, struct kobject *kobj,
358		struct bin_attribute *attr, char *buf, loff_t off, size_t count)
359{
360	uint8_t ec_byte;
361	int ret;
362	int i;
363
364	if (off >= EEPROM_SIZE)
365		return 0;
366	if (off + count > EEPROM_SIZE)
367		count = EEPROM_SIZE - off;
368
369	for (i = 0; i < count; i++) {
370		ec_byte = EEPROM_START + off + i;
371		ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &buf[i], 1);
372		if (ret) {
373			pr_err("olpc-battery: "
374			       "EC_BAT_EEPROM cmd @ 0x%x failed - %d!\n",
375			       ec_byte, ret);
376			return -EIO;
377		}
378	}
379
380	return count;
381}
382
383static struct bin_attribute olpc_bat_eeprom = {
384	.attr = {
385		.name = "eeprom",
386		.mode = S_IRUGO,
387		.owner = THIS_MODULE,
388	},
389	.size = 0,
390	.read = olpc_bat_eeprom_read,
391};
392
393/* Allow userspace to see the specific error value pulled from the EC */
394
395static ssize_t olpc_bat_error_read(struct device *dev,
396		struct device_attribute *attr, char *buf)
397{
398	uint8_t ec_byte;
399	ssize_t ret;
400
401	ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
402	if (ret < 0)
403		return ret;
404
405	return sprintf(buf, "%d\n", ec_byte);
406}
407
408static struct device_attribute olpc_bat_error = {
409	.attr = {
410		.name = "error",
411		.mode = S_IRUGO,
412	},
413	.show = olpc_bat_error_read,
414};
415
416/*********************************************************************
417 *		Initialisation
418 *********************************************************************/
419
420static struct platform_device *bat_pdev;
421
422static struct power_supply olpc_bat = {
423	.properties = olpc_bat_props,
424	.num_properties = ARRAY_SIZE(olpc_bat_props),
425	.get_property = olpc_bat_get_property,
426	.use_for_apm = 1,
427};
428
429void olpc_battery_trigger_uevent(unsigned long cause)
430{
431	if (cause & EC_SCI_SRC_ACPWR)
432		kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
433	if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
434		kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
435}
436
437static int __init olpc_bat_init(void)
438{
439	int ret = 0;
440	uint8_t status;
441
442	if (!olpc_platform_info.ecver)
443		return -ENXIO;
444
445	/*
446	 * We've seen a number of EC protocol changes; this driver requires
447	 * the latest EC protocol, supported by 0x44 and above.
448	 */
449	if (olpc_platform_info.ecver < 0x44) {
450		printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
451			"battery driver.\n", olpc_platform_info.ecver);
452		return -ENXIO;
453	}
454
455	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
456	if (ret)
457		return ret;
458
459	/* Ignore the status. It doesn't actually matter */
460
461	bat_pdev = platform_device_register_simple("olpc-battery", 0, NULL, 0);
462	if (IS_ERR(bat_pdev))
463		return PTR_ERR(bat_pdev);
464
465	ret = power_supply_register(&bat_pdev->dev, &olpc_ac);
466	if (ret)
467		goto ac_failed;
468
469	olpc_bat.name = bat_pdev->name;
470
471	ret = power_supply_register(&bat_pdev->dev, &olpc_bat);
472	if (ret)
473		goto battery_failed;
474
475	ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
476	if (ret)
477		goto eeprom_failed;
478
479	ret = device_create_file(olpc_bat.dev, &olpc_bat_error);
480	if (ret)
481		goto error_failed;
482
483	goto success;
484
485error_failed:
486	device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
487eeprom_failed:
488	power_supply_unregister(&olpc_bat);
489battery_failed:
490	power_supply_unregister(&olpc_ac);
491ac_failed:
492	platform_device_unregister(bat_pdev);
493success:
494	return ret;
495}
496
497static void __exit olpc_bat_exit(void)
498{
499	device_remove_file(olpc_bat.dev, &olpc_bat_error);
500	device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
501	power_supply_unregister(&olpc_bat);
502	power_supply_unregister(&olpc_ac);
503	platform_device_unregister(bat_pdev);
504}
505
506module_init(olpc_bat_init);
507module_exit(olpc_bat_exit);
508
509MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
510MODULE_LICENSE("GPL");
511MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");
512