olpc_battery.c revision b294a290d24d1196d68399cc3a9b8c50bfb55abd 
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/err.h>
14#include <linux/platform_device.h>
15#include <linux/power_supply.h>
16#include <linux/jiffies.h>
17#include <linux/sched.h>
18#include <asm/olpc.h>
19
20
21#define EC_BAT_VOLTAGE	0x10	/* uint16_t,	*9.76/32,    mV   */
22#define EC_BAT_CURRENT	0x11	/* int16_t,	*15.625/120, mA   */
23#define EC_BAT_ACR	0x12	/* int16_t,	*6250/15,    µAh  */
24#define EC_BAT_TEMP	0x13	/* uint16_t,	*100/256,   °C  */
25#define EC_AMB_TEMP	0x14	/* uint16_t,	*100/256,   °C  */
26#define EC_BAT_STATUS	0x15	/* uint8_t,	bitmask */
27#define EC_BAT_SOC	0x16	/* uint8_t,	percentage */
28#define EC_BAT_SERIAL	0x17	/* uint8_t[6] */
29#define EC_BAT_EEPROM	0x18	/* uint8_t adr as input, uint8_t output */
30#define EC_BAT_ERRCODE	0x1f	/* uint8_t,	bitmask */
31
32#define BAT_STAT_PRESENT	0x01
33#define BAT_STAT_FULL		0x02
34#define BAT_STAT_LOW		0x04
35#define BAT_STAT_DESTROY	0x08
36#define BAT_STAT_AC		0x10
37#define BAT_STAT_CHARGING	0x20
38#define BAT_STAT_DISCHARGING	0x40
39#define BAT_STAT_TRICKLE	0x80
40
41#define BAT_ERR_INFOFAIL	0x02
42#define BAT_ERR_OVERVOLTAGE	0x04
43#define BAT_ERR_OVERTEMP	0x05
44#define BAT_ERR_GAUGESTOP	0x06
45#define BAT_ERR_OUT_OF_CONTROL	0x07
46#define BAT_ERR_ID_FAIL		0x09
47#define BAT_ERR_ACR_FAIL	0x10
48
49#define BAT_ADDR_MFR_TYPE	0x5F
50
51/*********************************************************************
52 *		Power
53 *********************************************************************/
54
55static int olpc_ac_get_prop(struct power_supply *psy,
56			    enum power_supply_property psp,
57			    union power_supply_propval *val)
58{
59	int ret = 0;
60	uint8_t status;
61
62	switch (psp) {
63	case POWER_SUPPLY_PROP_ONLINE:
64		ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
65		if (ret)
66			return ret;
67
68		val->intval = !!(status & BAT_STAT_AC);
69		break;
70	default:
71		ret = -EINVAL;
72		break;
73	}
74	return ret;
75}
76
77static enum power_supply_property olpc_ac_props[] = {
78	POWER_SUPPLY_PROP_ONLINE,
79};
80
81static struct power_supply olpc_ac = {
82	.name = "olpc-ac",
83	.type = POWER_SUPPLY_TYPE_MAINS,
84	.properties = olpc_ac_props,
85	.num_properties = ARRAY_SIZE(olpc_ac_props),
86	.get_property = olpc_ac_get_prop,
87};
88
89static char bat_serial[17]; /* Ick */
90
91static int olpc_bat_get_status(union power_supply_propval *val, uint8_t ec_byte)
92{
93	if (olpc_platform_info.ecver > 0x44) {
94		if (ec_byte & (BAT_STAT_CHARGING | BAT_STAT_TRICKLE))
95			val->intval = POWER_SUPPLY_STATUS_CHARGING;
96		else if (ec_byte & BAT_STAT_DISCHARGING)
97			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
98		else if (ec_byte & BAT_STAT_FULL)
99			val->intval = POWER_SUPPLY_STATUS_FULL;
100		else /* er,... */
101			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
102	} else {
103		/* Older EC didn't report charge/discharge bits */
104		if (!(ec_byte & BAT_STAT_AC)) /* No AC means discharging */
105			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
106		else if (ec_byte & BAT_STAT_FULL)
107			val->intval = POWER_SUPPLY_STATUS_FULL;
108		else /* Not _necessarily_ true but EC doesn't tell all yet */
109			val->intval = POWER_SUPPLY_STATUS_CHARGING;
110	}
111
112	return 0;
113}
114
115static int olpc_bat_get_health(union power_supply_propval *val)
116{
117	uint8_t ec_byte;
118	int ret;
119
120	ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
121	if (ret)
122		return ret;
123
124	switch (ec_byte) {
125	case 0:
126		val->intval = POWER_SUPPLY_HEALTH_GOOD;
127		break;
128
129	case BAT_ERR_OVERTEMP:
130		val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
131		break;
132
133	case BAT_ERR_OVERVOLTAGE:
134		val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
135		break;
136
137	case BAT_ERR_INFOFAIL:
138	case BAT_ERR_OUT_OF_CONTROL:
139	case BAT_ERR_ID_FAIL:
140	case BAT_ERR_ACR_FAIL:
141		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
142		break;
143
144	default:
145		/* Eep. We don't know this failure code */
146		ret = -EIO;
147	}
148
149	return ret;
150}
151
152static int olpc_bat_get_mfr(union power_supply_propval *val)
153{
154	uint8_t ec_byte;
155	int ret;
156
157	ec_byte = BAT_ADDR_MFR_TYPE;
158	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
159	if (ret)
160		return ret;
161
162	switch (ec_byte >> 4) {
163	case 1:
164		val->strval = "Gold Peak";
165		break;
166	case 2:
167		val->strval = "BYD";
168		break;
169	default:
170		val->strval = "Unknown";
171		break;
172	}
173
174	return ret;
175}
176
177static int olpc_bat_get_tech(union power_supply_propval *val)
178{
179	uint8_t ec_byte;
180	int ret;
181
182	ec_byte = BAT_ADDR_MFR_TYPE;
183	ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
184	if (ret)
185		return ret;
186
187	switch (ec_byte & 0xf) {
188	case 1:
189		val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
190		break;
191	case 2:
192		val->intval = POWER_SUPPLY_TECHNOLOGY_LiFe;
193		break;
194	default:
195		val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
196		break;
197	}
198
199	return ret;
200}
201
202/*********************************************************************
203 *		Battery properties
204 *********************************************************************/
205static int olpc_bat_get_property(struct power_supply *psy,
206				 enum power_supply_property psp,
207				 union power_supply_propval *val)
208{
209	int ret = 0;
210	__be16 ec_word;
211	uint8_t ec_byte;
212	__be64 ser_buf;
213
214	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
215	if (ret)
216		return ret;
217
218	/* Theoretically there's a race here -- the battery could be
219	   removed immediately after we check whether it's present, and
220	   then we query for some other property of the now-absent battery.
221	   It doesn't matter though -- the EC will return the last-known
222	   information, and it's as if we just ran that _little_ bit faster
223	   and managed to read it out before the battery went away. */
224	if (!(ec_byte & (BAT_STAT_PRESENT | BAT_STAT_TRICKLE)) &&
225			psp != POWER_SUPPLY_PROP_PRESENT)
226		return -ENODEV;
227
228	switch (psp) {
229	case POWER_SUPPLY_PROP_STATUS:
230		ret = olpc_bat_get_status(val, ec_byte);
231		if (ret)
232			return ret;
233		break;
234	case POWER_SUPPLY_PROP_PRESENT:
235		val->intval = !!(ec_byte & (BAT_STAT_PRESENT |
236					    BAT_STAT_TRICKLE));
237		break;
238
239	case POWER_SUPPLY_PROP_HEALTH:
240		if (ec_byte & BAT_STAT_DESTROY)
241			val->intval = POWER_SUPPLY_HEALTH_DEAD;
242		else {
243			ret = olpc_bat_get_health(val);
244			if (ret)
245				return ret;
246		}
247		break;
248
249	case POWER_SUPPLY_PROP_MANUFACTURER:
250		ret = olpc_bat_get_mfr(val);
251		if (ret)
252			return ret;
253		break;
254	case POWER_SUPPLY_PROP_TECHNOLOGY:
255		ret = olpc_bat_get_tech(val);
256		if (ret)
257			return ret;
258		break;
259	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
260		ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
261		if (ret)
262			return ret;
263
264		val->intval = (int)be16_to_cpu(ec_word) * 9760L / 32;
265		break;
266	case POWER_SUPPLY_PROP_CURRENT_AVG:
267		ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
268		if (ret)
269			return ret;
270
271		val->intval = (int)be16_to_cpu(ec_word) * 15625L / 120;
272		break;
273	case POWER_SUPPLY_PROP_CAPACITY:
274		ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
275		if (ret)
276			return ret;
277		val->intval = ec_byte;
278		break;
279	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
280		if (ec_byte & BAT_STAT_FULL)
281			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
282		else if (ec_byte & BAT_STAT_LOW)
283			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
284		else
285			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
286		break;
287	case POWER_SUPPLY_PROP_TEMP:
288		ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
289		if (ret)
290			return ret;
291
292		val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
293		break;
294	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
295		ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
296		if (ret)
297			return ret;
298
299		val->intval = (int)be16_to_cpu(ec_word) * 100 / 256;
300		break;
301	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
302		ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
303		if (ret)
304			return ret;
305
306		val->intval = (int)be16_to_cpu(ec_word) * 6250 / 15;
307		break;
308	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
309		ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
310		if (ret)
311			return ret;
312
313		sprintf(bat_serial, "%016llx", (long long)be64_to_cpu(ser_buf));
314		val->strval = bat_serial;
315		break;
316	default:
317		ret = -EINVAL;
318		break;
319	}
320
321	return ret;
322}
323
324static enum power_supply_property olpc_bat_props[] = {
325	POWER_SUPPLY_PROP_STATUS,
326	POWER_SUPPLY_PROP_PRESENT,
327	POWER_SUPPLY_PROP_HEALTH,
328	POWER_SUPPLY_PROP_TECHNOLOGY,
329	POWER_SUPPLY_PROP_VOLTAGE_AVG,
330	POWER_SUPPLY_PROP_CURRENT_AVG,
331	POWER_SUPPLY_PROP_CAPACITY,
332	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
333	POWER_SUPPLY_PROP_TEMP,
334	POWER_SUPPLY_PROP_TEMP_AMBIENT,
335	POWER_SUPPLY_PROP_MANUFACTURER,
336	POWER_SUPPLY_PROP_SERIAL_NUMBER,
337	POWER_SUPPLY_PROP_CHARGE_COUNTER,
338};
339
340/* EEPROM reading goes completely around the power_supply API, sadly */
341
342#define EEPROM_START	0x20
343#define EEPROM_END	0x80
344#define EEPROM_SIZE	(EEPROM_END - EEPROM_START)
345
346static ssize_t olpc_bat_eeprom_read(struct kobject *kobj,
347		struct bin_attribute *attr, char *buf, loff_t off, size_t count)
348{
349	uint8_t ec_byte;
350	int ret;
351	int i;
352
353	if (off >= EEPROM_SIZE)
354		return 0;
355	if (off + count > EEPROM_SIZE)
356		count = EEPROM_SIZE - off;
357
358	for (i = 0; i < count; i++) {
359		ec_byte = EEPROM_START + off + i;
360		ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &buf[i], 1);
361		if (ret) {
362			pr_err("olpc-battery: "
363			       "EC_BAT_EEPROM cmd @ 0x%x failed - %d!\n",
364			       ec_byte, ret);
365			return -EIO;
366		}
367	}
368
369	return count;
370}
371
372static struct bin_attribute olpc_bat_eeprom = {
373	.attr = {
374		.name = "eeprom",
375		.mode = S_IRUGO,
376		.owner = THIS_MODULE,
377	},
378	.size = 0,
379	.read = olpc_bat_eeprom_read,
380};
381
382/*********************************************************************
383 *		Initialisation
384 *********************************************************************/
385
386static struct platform_device *bat_pdev;
387
388static struct power_supply olpc_bat = {
389	.properties = olpc_bat_props,
390	.num_properties = ARRAY_SIZE(olpc_bat_props),
391	.get_property = olpc_bat_get_property,
392	.use_for_apm = 1,
393};
394
395void olpc_battery_trigger_uevent(unsigned long cause)
396{
397	if (cause & EC_SCI_SRC_ACPWR)
398		kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
399	if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
400		kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
401}
402
403static int __init olpc_bat_init(void)
404{
405	int ret = 0;
406	uint8_t status;
407
408	if (!olpc_platform_info.ecver)
409		return -ENXIO;
410
411	/*
412	 * We've seen a number of EC protocol changes; this driver requires
413	 * the latest EC protocol, supported by 0x44 and above.
414	 */
415	if (olpc_platform_info.ecver < 0x44) {
416		printk(KERN_NOTICE "OLPC EC version 0x%02x too old for "
417			"battery driver.\n", olpc_platform_info.ecver);
418		return -ENXIO;
419	}
420
421	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
422	if (ret)
423		return ret;
424
425	/* Ignore the status. It doesn't actually matter */
426
427	bat_pdev = platform_device_register_simple("olpc-battery", 0, NULL, 0);
428	if (IS_ERR(bat_pdev))
429		return PTR_ERR(bat_pdev);
430
431	ret = power_supply_register(&bat_pdev->dev, &olpc_ac);
432	if (ret)
433		goto ac_failed;
434
435	olpc_bat.name = bat_pdev->name;
436
437	ret = power_supply_register(&bat_pdev->dev, &olpc_bat);
438	if (ret)
439		goto battery_failed;
440
441	ret = device_create_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
442	if (ret)
443		goto eeprom_failed;
444
445	goto success;
446
447eeprom_failed:
448	power_supply_unregister(&olpc_bat);
449battery_failed:
450	power_supply_unregister(&olpc_ac);
451ac_failed:
452	platform_device_unregister(bat_pdev);
453success:
454	return ret;
455}
456
457static void __exit olpc_bat_exit(void)
458{
459	device_remove_bin_file(olpc_bat.dev, &olpc_bat_eeprom);
460	power_supply_unregister(&olpc_bat);
461	power_supply_unregister(&olpc_ac);
462	platform_device_unregister(bat_pdev);
463}
464
465module_init(olpc_bat_init);
466module_exit(olpc_bat_exit);
467
468MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
469MODULE_LICENSE("GPL");
470MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");
471