olpc_battery.c revision 8e552c36d90c03d2cabf5373788998966751b609 
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/module.h>
12#include <linux/err.h>
13#include <linux/platform_device.h>
14#include <linux/power_supply.h>
15#include <linux/jiffies.h>
16#include <linux/sched.h>
17#include <asm/olpc.h>
18
19
20#define EC_BAT_VOLTAGE	0x10	/* uint16_t,	*9.76/32,    mV   */
21#define EC_BAT_CURRENT	0x11	/* int16_t,	*15.625/120, mA   */
22#define EC_BAT_ACR	0x12	/* int16_t,	*416.7,      µAh  */
23#define EC_BAT_TEMP	0x13	/* uint16_t,	*100/256,   °C  */
24#define EC_AMB_TEMP	0x14	/* uint16_t,	*100/256,   °C  */
25#define EC_BAT_STATUS	0x15	/* uint8_t,	bitmask */
26#define EC_BAT_SOC	0x16	/* uint8_t,	percentage */
27#define EC_BAT_SERIAL	0x17	/* uint8_t[6] */
28#define EC_BAT_EEPROM	0x18	/* uint8_t adr as input, uint8_t output */
29#define EC_BAT_ERRCODE	0x1f	/* uint8_t,	bitmask */
30
31#define BAT_STAT_PRESENT	0x01
32#define BAT_STAT_FULL		0x02
33#define BAT_STAT_LOW		0x04
34#define BAT_STAT_DESTROY	0x08
35#define BAT_STAT_AC		0x10
36#define BAT_STAT_CHARGING	0x20
37#define BAT_STAT_DISCHARGING	0x40
38
39#define BAT_ERR_INFOFAIL	0x02
40#define BAT_ERR_OVERVOLTAGE	0x04
41#define BAT_ERR_OVERTEMP	0x05
42#define BAT_ERR_GAUGESTOP	0x06
43#define BAT_ERR_OUT_OF_CONTROL	0x07
44#define BAT_ERR_ID_FAIL		0x09
45#define BAT_ERR_ACR_FAIL	0x10
46
47#define BAT_ADDR_MFR_TYPE	0x5F
48
49/*********************************************************************
50 *		Power
51 *********************************************************************/
52
53static int olpc_ac_get_prop(struct power_supply *psy,
54			    enum power_supply_property psp,
55			    union power_supply_propval *val)
56{
57	int ret = 0;
58	uint8_t status;
59
60	switch (psp) {
61	case POWER_SUPPLY_PROP_ONLINE:
62		ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
63		if (ret)
64			return ret;
65
66		val->intval = !!(status & BAT_STAT_AC);
67		break;
68	default:
69		ret = -EINVAL;
70		break;
71	}
72	return ret;
73}
74
75static enum power_supply_property olpc_ac_props[] = {
76	POWER_SUPPLY_PROP_ONLINE,
77};
78
79static struct power_supply olpc_ac = {
80	.name = "olpc-ac",
81	.type = POWER_SUPPLY_TYPE_MAINS,
82	.properties = olpc_ac_props,
83	.num_properties = ARRAY_SIZE(olpc_ac_props),
84	.get_property = olpc_ac_get_prop,
85};
86
87static char bat_serial[17]; /* Ick */
88
89static int olpc_bat_get_status(union power_supply_propval *val, uint8_t ec_byte)
90{
91	if (olpc_platform_info.ecver > 0x44) {
92		if (ec_byte & BAT_STAT_CHARGING)
93			val->intval = POWER_SUPPLY_STATUS_CHARGING;
94		else if (ec_byte & BAT_STAT_DISCHARGING)
95			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
96		else if (ec_byte & BAT_STAT_FULL)
97			val->intval = POWER_SUPPLY_STATUS_FULL;
98		else /* er,... */
99			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
100	} else {
101		/* Older EC didn't report charge/discharge bits */
102		if (!(ec_byte & BAT_STAT_AC)) /* No AC means discharging */
103			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
104		else if (ec_byte & BAT_STAT_FULL)
105			val->intval = POWER_SUPPLY_STATUS_FULL;
106		else /* Not _necessarily_ true but EC doesn't tell all yet */
107			val->intval = POWER_SUPPLY_STATUS_CHARGING;
108	}
109
110	return 0;
111}
112
113static int olpc_bat_get_health(union power_supply_propval *val)
114{
115	uint8_t ec_byte;
116	int ret;
117
118	ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
119	if (ret)
120		return ret;
121
122	switch (ec_byte) {
123	case 0:
124		val->intval = POWER_SUPPLY_HEALTH_GOOD;
125		break;
126
127	case BAT_ERR_OVERTEMP:
128		val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
129		break;
130
131	case BAT_ERR_OVERVOLTAGE:
132		val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
133		break;
134
135	case BAT_ERR_INFOFAIL:
136	case BAT_ERR_OUT_OF_CONTROL:
137	case BAT_ERR_ID_FAIL:
138	case BAT_ERR_ACR_FAIL:
139		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
140		break;
141
142	default:
143		/* Eep. We don't know this failure code */
144		ret = -EIO;
145	}
146
147	return ret;
148}
149
150static int olpc_bat_get_mfr(union power_supply_propval *val)
151{
152	uint8_t ec_byte;
153	int ret;
154
155	ec_byte = BAT_ADDR_MFR_TYPE;
156	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
157	if (ret)
158		return ret;
159
160	switch (ec_byte >> 4) {
161	case 1:
162		val->strval = "Gold Peak";
163		break;
164	case 2:
165		val->strval = "BYD";
166		break;
167	default:
168		val->strval = "Unknown";
169		break;
170	}
171
172	return ret;
173}
174
175static int olpc_bat_get_tech(union power_supply_propval *val)
176{
177	uint8_t ec_byte;
178	int ret;
179
180	ec_byte = BAT_ADDR_MFR_TYPE;
181	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
182	if (ret)
183		return ret;
184
185	switch (ec_byte & 0xf) {
186	case 1:
187		val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
188		break;
189	case 2:
190		val->intval = POWER_SUPPLY_TECHNOLOGY_LiFe;
191		break;
192	default:
193		val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
194		break;
195	}
196
197	return ret;
198}
199
200/*********************************************************************
201 *		Battery properties
202 *********************************************************************/
203static int olpc_bat_get_property(struct power_supply *psy,
204				 enum power_supply_property psp,
205				 union power_supply_propval *val)
206{
207	int ret = 0;
208	int16_t ec_word;
209	uint8_t ec_byte;
210	uint64_t ser_buf;
211
212	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
213	if (ret)
214		return ret;
215
216	/* Theoretically there's a race here -- the battery could be
217	   removed immediately after we check whether it's present, and
218	   then we query for some other property of the now-absent battery.
219	   It doesn't matter though -- the EC will return the last-known
220	   information, and it's as if we just ran that _little_ bit faster
221	   and managed to read it out before the battery went away. */
222	if (!(ec_byte & BAT_STAT_PRESENT) && psp != POWER_SUPPLY_PROP_PRESENT)
223		return -ENODEV;
224
225	switch (psp) {
226	case POWER_SUPPLY_PROP_STATUS:
227		ret = olpc_bat_get_status(val, ec_byte);
228		if (ret)
229			return ret;
230		break;
231	case POWER_SUPPLY_PROP_PRESENT:
232		val->intval = !!(ec_byte & BAT_STAT_PRESENT);
233		break;
234
235	case POWER_SUPPLY_PROP_HEALTH:
236		if (ec_byte & BAT_STAT_DESTROY)
237			val->intval = POWER_SUPPLY_HEALTH_DEAD;
238		else {
239			ret = olpc_bat_get_health(val);
240			if (ret)
241				return ret;
242		}
243		break;
244
245	case POWER_SUPPLY_PROP_MANUFACTURER:
246		ret = olpc_bat_get_mfr(val);
247		if (ret)
248			return ret;
249		break;
250	case POWER_SUPPLY_PROP_TECHNOLOGY:
251		ret = olpc_bat_get_tech(val);
252		if (ret)
253			return ret;
254		break;
255	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
256		ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
257		if (ret)
258			return ret;
259
260		ec_word = be16_to_cpu(ec_word);
261		val->intval = ec_word * 9760L / 32;
262		break;
263	case POWER_SUPPLY_PROP_CURRENT_AVG:
264		ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
265		if (ret)
266			return ret;
267
268		ec_word = be16_to_cpu(ec_word);
269		val->intval = ec_word * 15625L / 120;
270		break;
271	case POWER_SUPPLY_PROP_CAPACITY:
272		ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
273		if (ret)
274			return ret;
275		val->intval = ec_byte;
276		break;
277	case POWER_SUPPLY_PROP_TEMP:
278		ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
279		if (ret)
280			return ret;
281		ec_word = be16_to_cpu(ec_word);
282		val->intval = ec_word * 100 / 256;
283		break;
284	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
285		ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
286		if (ret)
287			return ret;
288
289		ec_word = be16_to_cpu(ec_word);
290		val->intval = ec_word * 100 / 256;
291		break;
292	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
293		ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
294		if (ret)
295			return ret;
296
297		ec_word = be16_to_cpu(ec_word);
298		val->intval = ec_word * 4167 / 10;
299		break;
300	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
301		ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
302		if (ret)
303			return ret;
304
305		sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
306		val->strval = bat_serial;
307		break;
308	default:
309		ret = -EINVAL;
310		break;
311	}
312
313	return ret;
314}
315
316static enum power_supply_property olpc_bat_props[] = {
317	POWER_SUPPLY_PROP_STATUS,
318	POWER_SUPPLY_PROP_PRESENT,
319	POWER_SUPPLY_PROP_HEALTH,
320	POWER_SUPPLY_PROP_TECHNOLOGY,
321	POWER_SUPPLY_PROP_VOLTAGE_AVG,
322	POWER_SUPPLY_PROP_CURRENT_AVG,
323	POWER_SUPPLY_PROP_CAPACITY,
324	POWER_SUPPLY_PROP_TEMP,
325	POWER_SUPPLY_PROP_TEMP_AMBIENT,
326	POWER_SUPPLY_PROP_MANUFACTURER,
327	POWER_SUPPLY_PROP_SERIAL_NUMBER,
328	POWER_SUPPLY_PROP_CHARGE_COUNTER,
329};
330
331/* EEPROM reading goes completely around the power_supply API, sadly */
332
333#define EEPROM_START	0x20
334#define EEPROM_END	0x80
335#define EEPROM_SIZE	(EEPROM_END - EEPROM_START)
336
337static ssize_t olpc_bat_eeprom_read(struct kobject *kobj,
338		struct bin_attribute *attr, char *buf, loff_t off, size_t count)
339{
340	uint8_t ec_byte;
341	int ret, end;
342
343	if (off >= EEPROM_SIZE)
344		return 0;
345	if (off + count > EEPROM_SIZE)
346		count = EEPROM_SIZE - off;
347
348	end = EEPROM_START + off + count;
349	for (ec_byte = EEPROM_START + off; ec_byte < end; ec_byte++) {
350		ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1,
351				&buf[ec_byte - EEPROM_START], 1);
352		if (ret) {
353			printk(KERN_ERR "olpc-battery:  EC command "
354					"EC_BAT_EEPROM @ 0x%x failed -"
355					" %d!\n", ec_byte, ret);
356			return -EIO;
357		}
358	}
359
360	return count;
361}
362
363static struct bin_attribute olpc_bat_eeprom = {
364	.attr = {
365		.name = "eeprom",
366		.mode = S_IRUGO,
367		.owner = THIS_MODULE,
368	},
369	.size = 0,
370	.read = olpc_bat_eeprom_read,
371};
372
373/*********************************************************************
374 *		Initialisation
375 *********************************************************************/
376
377static struct platform_device *bat_pdev;
378
379static struct power_supply olpc_bat = {
380	.properties = olpc_bat_props,
381	.num_properties = ARRAY_SIZE(olpc_bat_props),
382	.get_property = olpc_bat_get_property,
383	.use_for_apm = 1,
384};
385
386void olpc_battery_trigger_uevent(unsigned long cause)
387{
388	if (cause & EC_SCI_SRC_ACPWR)
389		kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
390	if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
391		kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
392}
393
394static int __init olpc_bat_init(void)
395{
396	int ret = 0;
397	uint8_t status;
398
399	if (!olpc_platform_info.ecver)
400		return -ENXIO;
401
402	/*
403	 * We've seen a number of EC protocol changes; this driver requires
404	 * the latest EC protocol, supported by 0x44 and above.
405	 */
406	if (olpc_platform_info.ecver < 0x44) {
407		printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
408			"battery driver.\n", olpc_platform_info.ecver);
409		return -ENXIO;
410	}
411
412	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
413	if (ret)
414		return ret;
415
416	/* Ignore the status. It doesn't actually matter */
417
418	bat_pdev = platform_device_register_simple("olpc-battery", 0, NULL, 0);
419	if (IS_ERR(bat_pdev))
420		return PTR_ERR(bat_pdev);
421
422	ret = power_supply_register(&bat_pdev->dev, &olpc_ac);
423	if (ret)
424		goto ac_failed;
425
426	olpc_bat.name = bat_pdev->name;
427
428	ret = power_supply_register(&bat_pdev->dev, &olpc_bat);
429	if (ret)
430		goto battery_failed;
431
432	ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
433	if (ret)
434		goto eeprom_failed;
435
436	goto success;
437
438eeprom_failed:
439	power_supply_unregister(&olpc_bat);
440battery_failed:
441	power_supply_unregister(&olpc_ac);
442ac_failed:
443	platform_device_unregister(bat_pdev);
444success:
445	return ret;
446}
447
448static void __exit olpc_bat_exit(void)
449{
450	device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
451	power_supply_unregister(&olpc_bat);
452	power_supply_unregister(&olpc_ac);
453	platform_device_unregister(bat_pdev);
454}
455
456module_init(olpc_bat_init);
457module_exit(olpc_bat_exit);
458
459MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
460MODULE_LICENSE("GPL");
461MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");
462