ds2760_battery.c revision 25f2bfa62ae77820a8185734c4a2ab7f3971a2fc 
1/*
2 * Driver for batteries with DS2760 chips inside.
3 *
4 * Copyright © 2007 Anton Vorontsov
5 *	       2004-2007 Matt Reimer
6 *	       2004 Szabolcs Gyurko
7 *
8 * Use consistent with the GNU GPL is permitted,
9 * provided that this copyright notice is
10 * preserved in its entirety in all copies and derived works.
11 *
12 * Author:  Anton Vorontsov <cbou@mail.ru>
13 *	    February 2007
14 *
15 *	    Matt Reimer <mreimer@vpop.net>
16 *	    April 2004, 2005, 2007
17 *
18 *	    Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
19 *	    September 2004
20 */
21
22#include <linux/module.h>
23#include <linux/param.h>
24#include <linux/jiffies.h>
25#include <linux/workqueue.h>
26#include <linux/pm.h>
27#include <linux/platform_device.h>
28#include <linux/power_supply.h>
29
30#include "../w1/w1.h"
31#include "../w1/slaves/w1_ds2760.h"
32
33struct ds2760_device_info {
34	struct device *dev;
35
36	/* DS2760 data, valid after calling ds2760_battery_read_status() */
37	unsigned long update_time;	/* jiffies when data read */
38	char raw[DS2760_DATA_SIZE];	/* raw DS2760 data */
39	int voltage_raw;		/* units of 4.88 mV */
40	int voltage_uV;			/* units of µV */
41	int current_raw;		/* units of 0.625 mA */
42	int current_uA;			/* units of µA */
43	int accum_current_raw;		/* units of 0.25 mAh */
44	int accum_current_uAh;		/* units of µAh */
45	int temp_raw;			/* units of 0.125 °C */
46	int temp_C;			/* units of 0.1 °C */
47	int rated_capacity;		/* units of µAh */
48	int rem_capacity;		/* percentage */
49	int full_active_uAh;		/* units of µAh */
50	int empty_uAh;			/* units of µAh */
51	int life_sec;			/* units of seconds */
52	int charge_status;		/* POWER_SUPPLY_STATUS_* */
53
54	int full_counter;
55	struct power_supply bat;
56	struct device *w1_dev;
57	struct workqueue_struct *monitor_wqueue;
58	struct delayed_work monitor_work;
59};
60
61static unsigned int cache_time = 1000;
62module_param(cache_time, uint, 0644);
63MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
64
65static unsigned int pmod_enabled;
66module_param(pmod_enabled, bool, 0644);
67MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
68
69static unsigned int rated_capacity;
70module_param(rated_capacity, uint, 0644);
71MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index");
72
73/* Some batteries have their rated capacity stored a N * 10 mAh, while
74 * others use an index into this table. */
75static int rated_capacities[] = {
76	0,
77	920,	/* Samsung */
78	920,	/* BYD */
79	920,	/* Lishen */
80	920,	/* NEC */
81	1440,	/* Samsung */
82	1440,	/* BYD */
83	1440,	/* Lishen */
84	1440,	/* NEC */
85	2880,	/* Samsung */
86	2880,	/* BYD */
87	2880,	/* Lishen */
88	2880	/* NEC */
89};
90
91/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
92 * temp is in Celsius */
93static int battery_interpolate(int array[], int temp)
94{
95	int index, dt;
96
97	if (temp <= 0)
98		return array[0];
99	if (temp >= 40)
100		return array[4];
101
102	index = temp / 10;
103	dt    = temp % 10;
104
105	return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
106}
107
108static int ds2760_battery_read_status(struct ds2760_device_info *di)
109{
110	int ret, i, start, count, scale[5];
111
112	if (di->update_time && time_before(jiffies, di->update_time +
113					   msecs_to_jiffies(cache_time)))
114		return 0;
115
116	/* The first time we read the entire contents of SRAM/EEPROM,
117	 * but after that we just read the interesting bits that change. */
118	if (di->update_time == 0) {
119		start = 0;
120		count = DS2760_DATA_SIZE;
121	} else {
122		start = DS2760_VOLTAGE_MSB;
123		count = DS2760_TEMP_LSB - start + 1;
124	}
125
126	ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
127	if (ret != count) {
128		dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
129			 di->w1_dev);
130		return 1;
131	}
132
133	di->update_time = jiffies;
134
135	/* DS2760 reports voltage in units of 4.88mV, but the battery class
136	 * reports in units of uV, so convert by multiplying by 4880. */
137	di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
138			  (di->raw[DS2760_VOLTAGE_LSB] >> 5);
139	di->voltage_uV = di->voltage_raw * 4880;
140
141	/* DS2760 reports current in signed units of 0.625mA, but the battery
142	 * class reports in units of µA, so convert by multiplying by 625. */
143	di->current_raw =
144	    (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
145			  (di->raw[DS2760_CURRENT_LSB] >> 3);
146	di->current_uA = di->current_raw * 625;
147
148	/* DS2760 reports accumulated current in signed units of 0.25mAh. */
149	di->accum_current_raw =
150	    (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
151			   di->raw[DS2760_CURRENT_ACCUM_LSB];
152	di->accum_current_uAh = di->accum_current_raw * 250;
153
154	/* DS2760 reports temperature in signed units of 0.125°C, but the
155	 * battery class reports in units of 1/10 °C, so we convert by
156	 * multiplying by .125 * 10 = 1.25. */
157	di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
158				     (di->raw[DS2760_TEMP_LSB] >> 5);
159	di->temp_C = di->temp_raw + (di->temp_raw / 4);
160
161	/* At least some battery monitors (e.g. HP iPAQ) store the battery's
162	 * maximum rated capacity. */
163	if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
164		di->rated_capacity = rated_capacities[
165			(unsigned int)di->raw[DS2760_RATED_CAPACITY]];
166	else
167		di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
168
169	di->rated_capacity *= 1000; /* convert to µAh */
170
171	/* Calculate the full level at the present temperature. */
172	di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
173			      di->raw[DS2760_ACTIVE_FULL + 1];
174
175	/* If the full_active_uAh value is not given, fall back to the rated
176	 * capacity. This is likely to happen when chips are not part of the
177	 * battery pack and is therefore not bootstrapped. */
178	if (di->full_active_uAh == 0)
179		di->full_active_uAh = di->rated_capacity / 1000L;
180
181	scale[0] = di->full_active_uAh;
182	for (i = 1; i < 5; i++)
183		scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
184
185	di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
186	di->full_active_uAh *= 1000; /* convert to µAh */
187
188	/* Calculate the empty level at the present temperature. */
189	scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
190	for (i = 3; i >= 0; i--)
191		scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
192
193	di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
194	di->empty_uAh *= 1000; /* convert to µAh */
195
196	if (di->full_active_uAh == di->empty_uAh)
197		di->rem_capacity = 0;
198	else
199		/* From Maxim Application Note 131: remaining capacity =
200		 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
201		di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
202				    (di->full_active_uAh - di->empty_uAh);
203
204	if (di->rem_capacity < 0)
205		di->rem_capacity = 0;
206	if (di->rem_capacity > 100)
207		di->rem_capacity = 100;
208
209	if (di->current_uA)
210		di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
211				 3600L) / di->current_uA;
212	else
213		di->life_sec = 0;
214
215	return 0;
216}
217
218static void ds2760_battery_update_status(struct ds2760_device_info *di)
219{
220	int old_charge_status = di->charge_status;
221
222	ds2760_battery_read_status(di);
223
224	if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
225		di->full_counter = 0;
226
227	if (power_supply_am_i_supplied(&di->bat)) {
228		if (di->current_uA > 10000) {
229			di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
230			di->full_counter = 0;
231		} else if (di->current_uA < -5000) {
232			if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
233				dev_notice(di->dev, "not enough power to "
234					   "charge\n");
235			di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
236			di->full_counter = 0;
237		} else if (di->current_uA < 10000 &&
238			    di->charge_status != POWER_SUPPLY_STATUS_FULL) {
239
240			/* Don't consider the battery to be full unless
241			 * we've seen the current < 10 mA at least two
242			 * consecutive times. */
243
244			di->full_counter++;
245
246			if (di->full_counter < 2) {
247				di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
248			} else {
249				unsigned char acr[2];
250				int acr_val;
251
252				/* acr is in units of 0.25 mAh */
253				acr_val = di->full_active_uAh * 4L / 1000;
254
255				acr[0] = acr_val >> 8;
256				acr[1] = acr_val & 0xff;
257
258				if (w1_ds2760_write(di->w1_dev, acr,
259				    DS2760_CURRENT_ACCUM_MSB, 2) < 2)
260					dev_warn(di->dev,
261						 "ACR reset failed\n");
262
263				di->charge_status = POWER_SUPPLY_STATUS_FULL;
264			}
265		}
266	} else {
267		di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
268		di->full_counter = 0;
269	}
270
271	if (di->charge_status != old_charge_status)
272		power_supply_changed(&di->bat);
273}
274
275static void ds2760_battery_write_status(struct ds2760_device_info *di,
276					char status)
277{
278	if (status == di->raw[DS2760_STATUS_REG])
279		return;
280
281	w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
282	w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
283	w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
284}
285
286static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di,
287						unsigned char rated_capacity)
288{
289	if (rated_capacity == di->raw[DS2760_RATED_CAPACITY])
290		return;
291
292	w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1);
293	w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
294	w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
295}
296
297static void ds2760_battery_work(struct work_struct *work)
298{
299	struct ds2760_device_info *di = container_of(work,
300		struct ds2760_device_info, monitor_work.work);
301	const int interval = HZ * 60;
302
303	dev_dbg(di->dev, "%s\n", __func__);
304
305	ds2760_battery_update_status(di);
306	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
307}
308
309#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
310					      bat);
311
312static void ds2760_battery_external_power_changed(struct power_supply *psy)
313{
314	struct ds2760_device_info *di = to_ds2760_device_info(psy);
315
316	dev_dbg(di->dev, "%s\n", __func__);
317
318	cancel_delayed_work(&di->monitor_work);
319	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
320}
321
322static int ds2760_battery_get_property(struct power_supply *psy,
323				       enum power_supply_property psp,
324				       union power_supply_propval *val)
325{
326	struct ds2760_device_info *di = to_ds2760_device_info(psy);
327
328	switch (psp) {
329	case POWER_SUPPLY_PROP_STATUS:
330		val->intval = di->charge_status;
331		return 0;
332	default:
333		break;
334	}
335
336	ds2760_battery_read_status(di);
337
338	switch (psp) {
339	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
340		val->intval = di->voltage_uV;
341		break;
342	case POWER_SUPPLY_PROP_CURRENT_NOW:
343		val->intval = di->current_uA;
344		break;
345	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
346		val->intval = di->rated_capacity;
347		break;
348	case POWER_SUPPLY_PROP_CHARGE_FULL:
349		val->intval = di->full_active_uAh;
350		break;
351	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
352		val->intval = di->empty_uAh;
353		break;
354	case POWER_SUPPLY_PROP_CHARGE_NOW:
355		val->intval = di->accum_current_uAh;
356		break;
357	case POWER_SUPPLY_PROP_TEMP:
358		val->intval = di->temp_C;
359		break;
360	case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
361		val->intval = di->life_sec;
362		break;
363	case POWER_SUPPLY_PROP_CAPACITY:
364		val->intval = di->rem_capacity;
365		break;
366	default:
367		return -EINVAL;
368	}
369
370	return 0;
371}
372
373static enum power_supply_property ds2760_battery_props[] = {
374	POWER_SUPPLY_PROP_STATUS,
375	POWER_SUPPLY_PROP_VOLTAGE_NOW,
376	POWER_SUPPLY_PROP_CURRENT_NOW,
377	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
378	POWER_SUPPLY_PROP_CHARGE_FULL,
379	POWER_SUPPLY_PROP_CHARGE_EMPTY,
380	POWER_SUPPLY_PROP_CHARGE_NOW,
381	POWER_SUPPLY_PROP_TEMP,
382	POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
383	POWER_SUPPLY_PROP_CAPACITY,
384};
385
386static int ds2760_battery_probe(struct platform_device *pdev)
387{
388	char status;
389	int retval = 0;
390	struct ds2760_device_info *di;
391
392	di = kzalloc(sizeof(*di), GFP_KERNEL);
393	if (!di) {
394		retval = -ENOMEM;
395		goto di_alloc_failed;
396	}
397
398	platform_set_drvdata(pdev, di);
399
400	di->dev			= &pdev->dev;
401	di->w1_dev		= pdev->dev.parent;
402	di->bat.name		= dev_name(&pdev->dev);
403	di->bat.type		= POWER_SUPPLY_TYPE_BATTERY;
404	di->bat.properties	= ds2760_battery_props;
405	di->bat.num_properties	= ARRAY_SIZE(ds2760_battery_props);
406	di->bat.get_property	= ds2760_battery_get_property;
407	di->bat.external_power_changed =
408				  ds2760_battery_external_power_changed;
409
410	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
411
412	/* enable sleep mode feature */
413	ds2760_battery_read_status(di);
414	status = di->raw[DS2760_STATUS_REG];
415	if (pmod_enabled)
416		status |= DS2760_STATUS_PMOD;
417	else
418		status &= ~DS2760_STATUS_PMOD;
419
420	ds2760_battery_write_status(di, status);
421
422	/* set rated capacity from module param */
423	if (rated_capacity)
424		ds2760_battery_write_rated_capacity(di, rated_capacity);
425
426	retval = power_supply_register(&pdev->dev, &di->bat);
427	if (retval) {
428		dev_err(di->dev, "failed to register battery\n");
429		goto batt_failed;
430	}
431
432	INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
433	di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
434	if (!di->monitor_wqueue) {
435		retval = -ESRCH;
436		goto workqueue_failed;
437	}
438	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
439
440	goto success;
441
442workqueue_failed:
443	power_supply_unregister(&di->bat);
444batt_failed:
445	kfree(di);
446di_alloc_failed:
447success:
448	return retval;
449}
450
451static int ds2760_battery_remove(struct platform_device *pdev)
452{
453	struct ds2760_device_info *di = platform_get_drvdata(pdev);
454
455	cancel_rearming_delayed_workqueue(di->monitor_wqueue,
456					  &di->monitor_work);
457	destroy_workqueue(di->monitor_wqueue);
458	power_supply_unregister(&di->bat);
459
460	return 0;
461}
462
463#ifdef CONFIG_PM
464
465static int ds2760_battery_suspend(struct platform_device *pdev,
466				  pm_message_t state)
467{
468	struct ds2760_device_info *di = platform_get_drvdata(pdev);
469
470	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
471
472	return 0;
473}
474
475static int ds2760_battery_resume(struct platform_device *pdev)
476{
477	struct ds2760_device_info *di = platform_get_drvdata(pdev);
478
479	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
480	power_supply_changed(&di->bat);
481
482	cancel_delayed_work(&di->monitor_work);
483	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
484
485	return 0;
486}
487
488#else
489
490#define ds2760_battery_suspend NULL
491#define ds2760_battery_resume NULL
492
493#endif /* CONFIG_PM */
494
495MODULE_ALIAS("platform:ds2760-battery");
496
497static struct platform_driver ds2760_battery_driver = {
498	.driver = {
499		.name = "ds2760-battery",
500	},
501	.probe	  = ds2760_battery_probe,
502	.remove   = ds2760_battery_remove,
503	.suspend  = ds2760_battery_suspend,
504	.resume	  = ds2760_battery_resume,
505};
506
507static int __init ds2760_battery_init(void)
508{
509	return platform_driver_register(&ds2760_battery_driver);
510}
511
512static void __exit ds2760_battery_exit(void)
513{
514	platform_driver_unregister(&ds2760_battery_driver);
515}
516
517module_init(ds2760_battery_init);
518module_exit(ds2760_battery_exit);
519
520MODULE_LICENSE("GPL");
521MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
522	      "Matt Reimer <mreimer@vpop.net>, "
523	      "Anton Vorontsov <cbou@mail.ru>");
524MODULE_DESCRIPTION("ds2760 battery driver");
525