olpc_battery.c revision 7b3d54a8c30d2c524889a05d0c1334813d516b93 
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
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
87/*********************************************************************
88 *		Battery properties
89 *********************************************************************/
90static int olpc_bat_get_property(struct power_supply *psy,
91				 enum power_supply_property psp,
92				 union power_supply_propval *val)
93{
94	int ret = 0;
95	int16_t ec_word;
96	uint8_t ec_byte;
97
98	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &ec_byte, 1);
99	if (ret)
100		return ret;
101
102	/* Theoretically there's a race here -- the battery could be
103	   removed immediately after we check whether it's present, and
104	   then we query for some other property of the now-absent battery.
105	   It doesn't matter though -- the EC will return the last-known
106	   information, and it's as if we just ran that _little_ bit faster
107	   and managed to read it out before the battery went away. */
108	if (!(ec_byte & BAT_STAT_PRESENT) && psp != POWER_SUPPLY_PROP_PRESENT)
109		return -ENODEV;
110
111	switch (psp) {
112	case POWER_SUPPLY_PROP_STATUS:
113		if (olpc_platform_info.ecver > 0x44) {
114			if (ec_byte & BAT_STAT_CHARGING)
115				val->intval = POWER_SUPPLY_STATUS_CHARGING;
116			else if (ec_byte & BAT_STAT_DISCHARGING)
117				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
118			else if (ec_byte & BAT_STAT_FULL)
119				val->intval = POWER_SUPPLY_STATUS_FULL;
120			else /* er,... */
121				val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
122		} else {
123			/* Older EC didn't report charge/discharge bits */
124			if (!(ec_byte & BAT_STAT_AC)) /* No AC means discharging */
125				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
126			else if (ec_byte & BAT_STAT_FULL)
127				val->intval = POWER_SUPPLY_STATUS_FULL;
128			else /* Not _necessarily_ true but EC doesn't tell all yet */
129				val->intval = POWER_SUPPLY_STATUS_CHARGING;
130			break;
131		}
132	case POWER_SUPPLY_PROP_PRESENT:
133		val->intval = !!(ec_byte & BAT_STAT_PRESENT);
134		break;
135
136	case POWER_SUPPLY_PROP_HEALTH:
137		if (ec_byte & BAT_STAT_DESTROY)
138			val->intval = POWER_SUPPLY_HEALTH_DEAD;
139		else {
140			ret = olpc_ec_cmd(EC_BAT_ERRCODE, NULL, 0, &ec_byte, 1);
141			if (ret)
142				return ret;
143
144			switch (ec_byte) {
145			case 0:
146				val->intval = POWER_SUPPLY_HEALTH_GOOD;
147				break;
148
149			case BAT_ERR_OVERTEMP:
150				val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
151				break;
152
153			case BAT_ERR_OVERVOLTAGE:
154				val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
155				break;
156
157			case BAT_ERR_INFOFAIL:
158			case BAT_ERR_OUT_OF_CONTROL:
159			case BAT_ERR_ID_FAIL:
160			case BAT_ERR_ACR_FAIL:
161				val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
162				break;
163
164			default:
165				/* Eep. We don't know this failure code */
166				return -EIO;
167			}
168		}
169		break;
170
171	case POWER_SUPPLY_PROP_MANUFACTURER:
172		ec_byte = BAT_ADDR_MFR_TYPE;
173		ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
174		if (ret)
175			return ret;
176
177		switch (ec_byte >> 4) {
178		case 1:
179			val->strval = "Gold Peak";
180			break;
181		case 2:
182			val->strval = "BYD";
183			break;
184		default:
185			val->strval = "Unknown";
186			break;
187		}
188		break;
189	case POWER_SUPPLY_PROP_TECHNOLOGY:
190		ec_byte = BAT_ADDR_MFR_TYPE;
191		ret = olpc_ec_cmd(EC_BAT_EEPROM, &ec_byte, 1, &ec_byte, 1);
192		if (ret)
193			return ret;
194
195		switch (ec_byte & 0xf) {
196		case 1:
197			val->intval = POWER_SUPPLY_TECHNOLOGY_NiMH;
198			break;
199		case 2:
200			val->intval = POWER_SUPPLY_TECHNOLOGY_LiFe;
201			break;
202		default:
203			val->intval = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
204			break;
205		}
206		break;
207	case POWER_SUPPLY_PROP_VOLTAGE_AVG:
208		ret = olpc_ec_cmd(EC_BAT_VOLTAGE, NULL, 0, (void *)&ec_word, 2);
209		if (ret)
210			return ret;
211
212		ec_word = be16_to_cpu(ec_word);
213		val->intval = ec_word * 9760L / 32;
214		break;
215	case POWER_SUPPLY_PROP_CURRENT_AVG:
216		ret = olpc_ec_cmd(EC_BAT_CURRENT, NULL, 0, (void *)&ec_word, 2);
217		if (ret)
218			return ret;
219
220		ec_word = be16_to_cpu(ec_word);
221		val->intval = ec_word * 15625L / 120;
222		break;
223	case POWER_SUPPLY_PROP_CAPACITY:
224		ret = olpc_ec_cmd(EC_BAT_SOC, NULL, 0, &ec_byte, 1);
225		if (ret)
226			return ret;
227		val->intval = ec_byte;
228		break;
229	case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
230		if (ec_byte & BAT_STAT_FULL)
231			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
232		else if (ec_byte & BAT_STAT_LOW)
233			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
234		else
235			val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
236		break;
237	case POWER_SUPPLY_PROP_TEMP:
238		ret = olpc_ec_cmd(EC_BAT_TEMP, NULL, 0, (void *)&ec_word, 2);
239		if (ret)
240			return ret;
241		ec_word = be16_to_cpu(ec_word);
242		val->intval = ec_word * 100 / 256;
243		break;
244	case POWER_SUPPLY_PROP_TEMP_AMBIENT:
245		ret = olpc_ec_cmd(EC_AMB_TEMP, NULL, 0, (void *)&ec_word, 2);
246		if (ret)
247			return ret;
248
249		ec_word = be16_to_cpu(ec_word);
250		val->intval = ec_word * 100 / 256;
251		break;
252	default:
253		ret = -EINVAL;
254		break;
255	}
256
257	return ret;
258}
259
260static enum power_supply_property olpc_bat_props[] = {
261	POWER_SUPPLY_PROP_STATUS,
262	POWER_SUPPLY_PROP_PRESENT,
263	POWER_SUPPLY_PROP_HEALTH,
264	POWER_SUPPLY_PROP_TECHNOLOGY,
265	POWER_SUPPLY_PROP_VOLTAGE_AVG,
266	POWER_SUPPLY_PROP_CURRENT_AVG,
267	POWER_SUPPLY_PROP_CAPACITY,
268	POWER_SUPPLY_PROP_CAPACITY_LEVEL,
269	POWER_SUPPLY_PROP_TEMP,
270	POWER_SUPPLY_PROP_TEMP_AMBIENT,
271	POWER_SUPPLY_PROP_MANUFACTURER,
272};
273
274/*********************************************************************
275 *		Initialisation
276 *********************************************************************/
277
278static struct platform_device *bat_pdev;
279
280static struct power_supply olpc_bat = {
281	.properties = olpc_bat_props,
282	.num_properties = ARRAY_SIZE(olpc_bat_props),
283	.get_property = olpc_bat_get_property,
284	.use_for_apm = 1,
285};
286
287void olpc_battery_trigger_uevent(unsigned long cause)
288{
289	if (cause & EC_SCI_SRC_ACPWR)
290		kobject_uevent(&olpc_ac.dev->kobj, KOBJ_CHANGE);
291	if (cause & (EC_SCI_SRC_BATERR|EC_SCI_SRC_BATSOC|EC_SCI_SRC_BATTERY))
292		kobject_uevent(&olpc_bat.dev->kobj, KOBJ_CHANGE);
293}
294
295static int __init olpc_bat_init(void)
296{
297	int ret = 0;
298	uint8_t status;
299
300	if (!olpc_platform_info.ecver)
301		return -ENXIO;
302	if (olpc_platform_info.ecver < 0x43) {
303		printk(KERN_NOTICE "OLPC EC version 0x%02x too old for battery driver.\n", olpc_platform_info.ecver);
304		return -ENXIO;
305	}
306
307	ret = olpc_ec_cmd(EC_BAT_STATUS, NULL, 0, &status, 1);
308	if (ret)
309		return ret;
310
311	/* Ignore the status. It doesn't actually matter */
312
313	bat_pdev = platform_device_register_simple("olpc-battery", 0, NULL, 0);
314	if (IS_ERR(bat_pdev))
315		return PTR_ERR(bat_pdev);
316
317	ret = power_supply_register(&bat_pdev->dev, &olpc_ac);
318	if (ret)
319		goto ac_failed;
320
321	olpc_bat.name = bat_pdev->name;
322
323	ret = power_supply_register(&bat_pdev->dev, &olpc_bat);
324	if (ret)
325		goto battery_failed;
326
327	olpc_register_battery_callback(&olpc_battery_trigger_uevent);
328	goto success;
329
330battery_failed:
331	power_supply_unregister(&olpc_ac);
332ac_failed:
333	platform_device_unregister(bat_pdev);
334success:
335	return ret;
336}
337
338static void __exit olpc_bat_exit(void)
339{
340	olpc_deregister_battery_callback();
341	power_supply_unregister(&olpc_bat);
342	power_supply_unregister(&olpc_ac);
343	platform_device_unregister(bat_pdev);
344}
345
346module_init(olpc_bat_init);
347module_exit(olpc_bat_exit);
348
349MODULE_AUTHOR("David Woodhouse <dwmw2@infradead.org>");
350MODULE_LICENSE("GPL");
351MODULE_DESCRIPTION("Battery driver for One Laptop Per Child 'XO' machine");
352