ds2760_battery.c revision fe0e3153acfef4864b69932cf116eb5f38f7500c 
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
65/* Some batteries have their rated capacity stored a N * 10 mAh, while
66 * others use an index into this table. */
67static int rated_capacities[] = {
68	0,
69	920,	/* Samsung */
70	920,	/* BYD */
71	920,	/* Lishen */
72	920,	/* NEC */
73	1440,	/* Samsung */
74	1440,	/* BYD */
75	1440,	/* Lishen */
76	1440,	/* NEC */
77	2880,	/* Samsung */
78	2880,	/* BYD */
79	2880,	/* Lishen */
80	2880	/* NEC */
81};
82
83/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
84 * temp is in Celsius */
85static int battery_interpolate(int array[], int temp)
86{
87	int index, dt;
88
89	if (temp <= 0)
90		return array[0];
91	if (temp >= 40)
92		return array[4];
93
94	index = temp / 10;
95	dt    = temp % 10;
96
97	return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
98}
99
100static int ds2760_battery_read_status(struct ds2760_device_info *di)
101{
102	int ret, i, start, count, scale[5];
103
104	if (di->update_time && time_before(jiffies, di->update_time +
105					   msecs_to_jiffies(cache_time)))
106		return 0;
107
108	/* The first time we read the entire contents of SRAM/EEPROM,
109	 * but after that we just read the interesting bits that change. */
110	if (di->update_time == 0) {
111		start = 0;
112		count = DS2760_DATA_SIZE;
113	} else {
114		start = DS2760_VOLTAGE_MSB;
115		count = DS2760_TEMP_LSB - start + 1;
116	}
117
118	ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
119	if (ret != count) {
120		dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
121			 di->w1_dev);
122		return 1;
123	}
124
125	di->update_time = jiffies;
126
127	/* DS2760 reports voltage in units of 4.88mV, but the battery class
128	 * reports in units of uV, so convert by multiplying by 4880. */
129	di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
130			  (di->raw[DS2760_VOLTAGE_LSB] >> 5);
131	di->voltage_uV = di->voltage_raw * 4880;
132
133	/* DS2760 reports current in signed units of 0.625mA, but the battery
134	 * class reports in units of µA, so convert by multiplying by 625. */
135	di->current_raw =
136	    (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
137			  (di->raw[DS2760_CURRENT_LSB] >> 3);
138	di->current_uA = di->current_raw * 625;
139
140	/* DS2760 reports accumulated current in signed units of 0.25mAh. */
141	di->accum_current_raw =
142	    (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
143			   di->raw[DS2760_CURRENT_ACCUM_LSB];
144	di->accum_current_uAh = di->accum_current_raw * 250;
145
146	/* DS2760 reports temperature in signed units of 0.125°C, but the
147	 * battery class reports in units of 1/10 °C, so we convert by
148	 * multiplying by .125 * 10 = 1.25. */
149	di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
150				     (di->raw[DS2760_TEMP_LSB] >> 5);
151	di->temp_C = di->temp_raw + (di->temp_raw / 4);
152
153	/* At least some battery monitors (e.g. HP iPAQ) store the battery's
154	 * maximum rated capacity. */
155	if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
156		di->rated_capacity = rated_capacities[
157			(unsigned int)di->raw[DS2760_RATED_CAPACITY]];
158	else
159		di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
160
161	di->rated_capacity *= 1000; /* convert to µAh */
162
163	/* Calculate the full level at the present temperature. */
164	di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
165			      di->raw[DS2760_ACTIVE_FULL + 1];
166
167	scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 |
168		   di->raw[DS2760_ACTIVE_FULL + 1];
169	for (i = 1; i < 5; i++)
170		scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
171
172	di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
173	di->full_active_uAh *= 1000; /* convert to µAh */
174
175	/* Calculate the empty level at the present temperature. */
176	scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
177	for (i = 3; i >= 0; i--)
178		scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
179
180	di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
181	di->empty_uAh *= 1000; /* convert to µAh */
182
183	/* From Maxim Application Note 131: remaining capacity =
184	 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
185	di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
186			    (di->full_active_uAh - di->empty_uAh);
187
188	if (di->rem_capacity < 0)
189		di->rem_capacity = 0;
190	if (di->rem_capacity > 100)
191		di->rem_capacity = 100;
192
193	if (di->current_uA)
194		di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
195				 3600L) / di->current_uA;
196	else
197		di->life_sec = 0;
198
199	return 0;
200}
201
202static void ds2760_battery_update_status(struct ds2760_device_info *di)
203{
204	int old_charge_status = di->charge_status;
205
206	ds2760_battery_read_status(di);
207
208	if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
209		di->full_counter = 0;
210
211	if (power_supply_am_i_supplied(&di->bat)) {
212		if (di->current_uA > 10000) {
213			di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
214			di->full_counter = 0;
215		} else if (di->current_uA < -5000) {
216			if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
217				dev_notice(di->dev, "not enough power to "
218					   "charge\n");
219			di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
220			di->full_counter = 0;
221		} else if (di->current_uA < 10000 &&
222			    di->charge_status != POWER_SUPPLY_STATUS_FULL) {
223
224			/* Don't consider the battery to be full unless
225			 * we've seen the current < 10 mA at least two
226			 * consecutive times. */
227
228			di->full_counter++;
229
230			if (di->full_counter < 2) {
231				di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
232			} else {
233				unsigned char acr[2];
234				int acr_val;
235
236				/* acr is in units of 0.25 mAh */
237				acr_val = di->full_active_uAh * 4L / 1000;
238
239				acr[0] = acr_val >> 8;
240				acr[1] = acr_val & 0xff;
241
242				if (w1_ds2760_write(di->w1_dev, acr,
243				    DS2760_CURRENT_ACCUM_MSB, 2) < 2)
244					dev_warn(di->dev,
245						 "ACR reset failed\n");
246
247				di->charge_status = POWER_SUPPLY_STATUS_FULL;
248			}
249		}
250	} else {
251		di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
252		di->full_counter = 0;
253	}
254
255	if (di->charge_status != old_charge_status)
256		power_supply_changed(&di->bat);
257
258	return;
259}
260
261static void ds2760_battery_work(struct work_struct *work)
262{
263	struct ds2760_device_info *di = container_of(work,
264		struct ds2760_device_info, monitor_work.work);
265	const int interval = HZ * 60;
266
267	dev_dbg(di->dev, "%s\n", __FUNCTION__);
268
269	ds2760_battery_update_status(di);
270	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
271
272	return;
273}
274
275#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
276					      bat);
277
278static void ds2760_battery_external_power_changed(struct power_supply *psy)
279{
280	struct ds2760_device_info *di = to_ds2760_device_info(psy);
281
282	dev_dbg(di->dev, "%s\n", __FUNCTION__);
283
284	cancel_delayed_work(&di->monitor_work);
285	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
286
287	return;
288}
289
290static int ds2760_battery_get_property(struct power_supply *psy,
291				       enum power_supply_property psp,
292				       union power_supply_propval *val)
293{
294	struct ds2760_device_info *di = to_ds2760_device_info(psy);
295
296	switch (psp) {
297	case POWER_SUPPLY_PROP_STATUS:
298		val->intval = di->charge_status;
299		return 0;
300	default:
301		break;
302	}
303
304	ds2760_battery_read_status(di);
305
306	switch (psp) {
307	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
308		val->intval = di->voltage_uV;
309		break;
310	case POWER_SUPPLY_PROP_CURRENT_NOW:
311		val->intval = di->current_uA;
312		break;
313	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
314		val->intval = di->rated_capacity;
315		break;
316	case POWER_SUPPLY_PROP_CHARGE_FULL:
317		val->intval = di->full_active_uAh;
318		break;
319	case POWER_SUPPLY_PROP_CHARGE_EMPTY:
320		val->intval = di->empty_uAh;
321		break;
322	case POWER_SUPPLY_PROP_CHARGE_NOW:
323		val->intval = di->accum_current_uAh;
324		break;
325	case POWER_SUPPLY_PROP_TEMP:
326		val->intval = di->temp_C;
327		break;
328	default:
329		return -EINVAL;
330	}
331
332	return 0;
333}
334
335static enum power_supply_property ds2760_battery_props[] = {
336	POWER_SUPPLY_PROP_STATUS,
337	POWER_SUPPLY_PROP_VOLTAGE_NOW,
338	POWER_SUPPLY_PROP_CURRENT_NOW,
339	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
340	POWER_SUPPLY_PROP_CHARGE_FULL,
341	POWER_SUPPLY_PROP_CHARGE_EMPTY,
342	POWER_SUPPLY_PROP_CHARGE_NOW,
343	POWER_SUPPLY_PROP_TEMP,
344};
345
346static int ds2760_battery_probe(struct platform_device *pdev)
347{
348	int retval = 0;
349	struct ds2760_device_info *di;
350	struct ds2760_platform_data *pdata;
351
352	di = kzalloc(sizeof(*di), GFP_KERNEL);
353	if (!di) {
354		retval = -ENOMEM;
355		goto di_alloc_failed;
356	}
357
358	platform_set_drvdata(pdev, di);
359
360	pdata = pdev->dev.platform_data;
361	di->dev		= &pdev->dev;
362	di->w1_dev	     = pdev->dev.parent;
363	di->bat.name	   = pdev->dev.bus_id;
364	di->bat.type	   = POWER_SUPPLY_TYPE_BATTERY;
365	di->bat.properties     = ds2760_battery_props;
366	di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
367	di->bat.get_property   = ds2760_battery_get_property;
368	di->bat.external_power_changed =
369				  ds2760_battery_external_power_changed;
370
371	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
372
373	retval = power_supply_register(&pdev->dev, &di->bat);
374	if (retval) {
375		dev_err(di->dev, "failed to register battery");
376		goto batt_failed;
377	}
378
379	INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
380	di->monitor_wqueue = create_singlethread_workqueue(pdev->dev.bus_id);
381	if (!di->monitor_wqueue) {
382		retval = -ESRCH;
383		goto workqueue_failed;
384	}
385	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
386
387	goto success;
388
389workqueue_failed:
390	power_supply_unregister(&di->bat);
391batt_failed:
392	kfree(di);
393di_alloc_failed:
394success:
395	return retval;
396}
397
398static int ds2760_battery_remove(struct platform_device *pdev)
399{
400	struct ds2760_device_info *di = platform_get_drvdata(pdev);
401
402	cancel_rearming_delayed_workqueue(di->monitor_wqueue,
403					  &di->monitor_work);
404	destroy_workqueue(di->monitor_wqueue);
405	power_supply_unregister(&di->bat);
406
407	return 0;
408}
409
410#ifdef CONFIG_PM
411
412static int ds2760_battery_suspend(struct platform_device *pdev,
413				  pm_message_t state)
414{
415	struct ds2760_device_info *di = platform_get_drvdata(pdev);
416
417	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
418
419	return 0;
420}
421
422static int ds2760_battery_resume(struct platform_device *pdev)
423{
424	struct ds2760_device_info *di = platform_get_drvdata(pdev);
425
426	di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
427	power_supply_changed(&di->bat);
428
429	cancel_delayed_work(&di->monitor_work);
430	queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
431
432	return 0;
433}
434
435#else
436
437#define ds2760_battery_suspend NULL
438#define ds2760_battery_resume NULL
439
440#endif /* CONFIG_PM */
441
442static struct platform_driver ds2760_battery_driver = {
443	.driver = {
444		.name = "ds2760-battery",
445	},
446	.probe	  = ds2760_battery_probe,
447	.remove   = ds2760_battery_remove,
448	.suspend  = ds2760_battery_suspend,
449	.resume	  = ds2760_battery_resume,
450};
451
452static int __init ds2760_battery_init(void)
453{
454	return platform_driver_register(&ds2760_battery_driver);
455}
456
457static void __exit ds2760_battery_exit(void)
458{
459	platform_driver_unregister(&ds2760_battery_driver);
460	return;
461}
462
463module_init(ds2760_battery_init);
464module_exit(ds2760_battery_exit);
465
466MODULE_LICENSE("GPL");
467MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
468	      "Matt Reimer <mreimer@vpop.net>, "
469	      "Anton Vorontsov <cbou@mail.ru>");
470MODULE_DESCRIPTION("ds2760 battery driver");
471