2 * Driver for batteries with DS2760 chips inside.
4 * Copyright © 2007 Anton Vorontsov
5 * 2004-2007 Matt Reimer
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.
12 * Author: Anton Vorontsov <cbou@mail.ru>
15 * Matt Reimer <mreimer@vpop.net>
16 * April 2004, 2005, 2007
18 * Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
22 #include <linux/module.h>
23 #include <linux/param.h>
24 #include <linux/jiffies.h>
25 #include <linux/workqueue.h>
27 #include <linux/slab.h>
28 #include <linux/platform_device.h>
29 #include <linux/power_supply.h>
32 #include "../w1/slaves/w1_ds2760.h"
34 struct ds2760_device_info {
37 /* DS2760 data, valid after calling ds2760_battery_read_status() */
38 unsigned long update_time; /* jiffies when data read */
39 char raw[DS2760_DATA_SIZE]; /* raw DS2760 data */
40 int voltage_raw; /* units of 4.88 mV */
41 int voltage_uV; /* units of µV */
42 int current_raw; /* units of 0.625 mA */
43 int current_uA; /* units of µA */
44 int accum_current_raw; /* units of 0.25 mAh */
45 int accum_current_uAh; /* units of µAh */
46 int temp_raw; /* units of 0.125 °C */
47 int temp_C; /* units of 0.1 °C */
48 int rated_capacity; /* units of µAh */
49 int rem_capacity; /* percentage */
50 int full_active_uAh; /* units of µAh */
51 int empty_uAh; /* units of µAh */
52 int life_sec; /* units of seconds */
53 int charge_status; /* POWER_SUPPLY_STATUS_* */
56 struct power_supply bat;
57 struct device *w1_dev;
58 struct workqueue_struct *monitor_wqueue;
59 struct delayed_work monitor_work;
60 struct delayed_work set_charged_work;
63 static unsigned int cache_time = 1000;
64 module_param(cache_time, uint, 0644);
65 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
67 static unsigned int pmod_enabled;
68 module_param(pmod_enabled, bool, 0644);
69 MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
71 static unsigned int rated_capacity;
72 module_param(rated_capacity, uint, 0644);
73 MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index");
75 static unsigned int current_accum;
76 module_param(current_accum, uint, 0644);
77 MODULE_PARM_DESC(current_accum, "current accumulator value");
79 /* Some batteries have their rated capacity stored a N * 10 mAh, while
80 * others use an index into this table. */
81 static int rated_capacities[] = {
89 #ifdef CONFIG_MACH_H4700
90 1800, /* HP iPAQ hx4700 3.7V 1800mAh (359113-001) */
101 /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
102 * temp is in Celsius */
103 static int battery_interpolate(int array[], int temp)
115 return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
118 static int ds2760_battery_read_status(struct ds2760_device_info *di)
120 int ret, i, start, count, scale[5];
122 if (di->update_time && time_before(jiffies, di->update_time +
123 msecs_to_jiffies(cache_time)))
126 /* The first time we read the entire contents of SRAM/EEPROM,
127 * but after that we just read the interesting bits that change. */
128 if (di->update_time == 0) {
130 count = DS2760_DATA_SIZE;
132 start = DS2760_VOLTAGE_MSB;
133 count = DS2760_TEMP_LSB - start + 1;
136 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
138 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
143 di->update_time = jiffies;
145 /* DS2760 reports voltage in units of 4.88mV, but the battery class
146 * reports in units of uV, so convert by multiplying by 4880. */
147 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
148 (di->raw[DS2760_VOLTAGE_LSB] >> 5);
149 di->voltage_uV = di->voltage_raw * 4880;
151 /* DS2760 reports current in signed units of 0.625mA, but the battery
152 * class reports in units of µA, so convert by multiplying by 625. */
154 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
155 (di->raw[DS2760_CURRENT_LSB] >> 3);
156 di->current_uA = di->current_raw * 625;
158 /* DS2760 reports accumulated current in signed units of 0.25mAh. */
159 di->accum_current_raw =
160 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
161 di->raw[DS2760_CURRENT_ACCUM_LSB];
162 di->accum_current_uAh = di->accum_current_raw * 250;
164 /* DS2760 reports temperature in signed units of 0.125°C, but the
165 * battery class reports in units of 1/10 °C, so we convert by
166 * multiplying by .125 * 10 = 1.25. */
167 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
168 (di->raw[DS2760_TEMP_LSB] >> 5);
169 di->temp_C = di->temp_raw + (di->temp_raw / 4);
171 /* At least some battery monitors (e.g. HP iPAQ) store the battery's
172 * maximum rated capacity. */
173 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
174 di->rated_capacity = rated_capacities[
175 (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
177 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
179 di->rated_capacity *= 1000; /* convert to µAh */
181 /* Calculate the full level at the present temperature. */
182 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
183 di->raw[DS2760_ACTIVE_FULL + 1];
185 /* If the full_active_uAh value is not given, fall back to the rated
186 * capacity. This is likely to happen when chips are not part of the
187 * battery pack and is therefore not bootstrapped. */
188 if (di->full_active_uAh == 0)
189 di->full_active_uAh = di->rated_capacity / 1000L;
191 scale[0] = di->full_active_uAh;
192 for (i = 1; i < 5; i++)
193 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 1 + i];
195 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
196 di->full_active_uAh *= 1000; /* convert to µAh */
198 /* Calculate the empty level at the present temperature. */
199 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
200 for (i = 3; i >= 0; i--)
201 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
203 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
204 di->empty_uAh *= 1000; /* convert to µAh */
206 if (di->full_active_uAh == di->empty_uAh)
207 di->rem_capacity = 0;
209 /* From Maxim Application Note 131: remaining capacity =
210 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
211 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
212 (di->full_active_uAh - di->empty_uAh);
214 if (di->rem_capacity < 0)
215 di->rem_capacity = 0;
216 if (di->rem_capacity > 100)
217 di->rem_capacity = 100;
219 if (di->current_uA < -100L)
220 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L)
221 / (di->current_uA / 100L);
228 static void ds2760_battery_set_current_accum(struct ds2760_device_info *di,
229 unsigned int acr_val)
231 unsigned char acr[2];
233 /* acr is in units of 0.25 mAh */
237 acr[0] = acr_val >> 8;
238 acr[1] = acr_val & 0xff;
240 if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2)
241 dev_warn(di->dev, "ACR write failed\n");
244 static void ds2760_battery_update_status(struct ds2760_device_info *di)
246 int old_charge_status = di->charge_status;
248 ds2760_battery_read_status(di);
250 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
251 di->full_counter = 0;
253 if (power_supply_am_i_supplied(&di->bat)) {
254 if (di->current_uA > 10000) {
255 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
256 di->full_counter = 0;
257 } else if (di->current_uA < -5000) {
258 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
259 dev_notice(di->dev, "not enough power to "
261 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
262 di->full_counter = 0;
263 } else if (di->current_uA < 10000 &&
264 di->charge_status != POWER_SUPPLY_STATUS_FULL) {
266 /* Don't consider the battery to be full unless
267 * we've seen the current < 10 mA at least two
268 * consecutive times. */
272 if (di->full_counter < 2) {
273 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
275 di->charge_status = POWER_SUPPLY_STATUS_FULL;
276 ds2760_battery_set_current_accum(di,
277 di->full_active_uAh);
281 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
282 di->full_counter = 0;
285 if (di->charge_status != old_charge_status)
286 power_supply_changed(&di->bat);
289 static void ds2760_battery_write_status(struct ds2760_device_info *di,
292 if (status == di->raw[DS2760_STATUS_REG])
295 w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
296 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
297 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
300 static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di,
301 unsigned char rated_capacity)
303 if (rated_capacity == di->raw[DS2760_RATED_CAPACITY])
306 w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1);
307 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
308 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
311 static void ds2760_battery_write_active_full(struct ds2760_device_info *di,
314 unsigned char tmp[2] = {
319 if (tmp[0] == di->raw[DS2760_ACTIVE_FULL] &&
320 tmp[1] == di->raw[DS2760_ACTIVE_FULL + 1])
323 w1_ds2760_write(di->w1_dev, tmp, DS2760_ACTIVE_FULL, sizeof(tmp));
324 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK0);
325 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK0);
327 /* Write to the di->raw[] buffer directly - the DS2760_ACTIVE_FULL
328 * values won't be read back by ds2760_battery_read_status() */
329 di->raw[DS2760_ACTIVE_FULL] = tmp[0];
330 di->raw[DS2760_ACTIVE_FULL + 1] = tmp[1];
333 static void ds2760_battery_work(struct work_struct *work)
335 struct ds2760_device_info *di = container_of(work,
336 struct ds2760_device_info, monitor_work.work);
337 const int interval = HZ * 60;
339 dev_dbg(di->dev, "%s\n", __func__);
341 ds2760_battery_update_status(di);
342 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
345 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
348 static void ds2760_battery_external_power_changed(struct power_supply *psy)
350 struct ds2760_device_info *di = to_ds2760_device_info(psy);
352 dev_dbg(di->dev, "%s\n", __func__);
354 cancel_delayed_work(&di->monitor_work);
355 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
359 static void ds2760_battery_set_charged_work(struct work_struct *work)
362 struct ds2760_device_info *di = container_of(work,
363 struct ds2760_device_info, set_charged_work.work);
365 dev_dbg(di->dev, "%s\n", __func__);
367 ds2760_battery_read_status(di);
369 /* When we get notified by external circuitry that the battery is
370 * considered fully charged now, we know that there is no current
371 * flow any more. However, the ds2760's internal current meter is
372 * too inaccurate to rely on - spec say something ~15% failure.
373 * Hence, we use the current offset bias register to compensate
377 if (!power_supply_am_i_supplied(&di->bat))
380 bias = (signed char) di->current_raw +
381 (signed char) di->raw[DS2760_CURRENT_OFFSET_BIAS];
383 dev_dbg(di->dev, "%s: bias = %d\n", __func__, bias);
385 w1_ds2760_write(di->w1_dev, &bias, DS2760_CURRENT_OFFSET_BIAS, 1);
386 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
387 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
389 /* Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS
390 * value won't be read back by ds2760_battery_read_status() */
391 di->raw[DS2760_CURRENT_OFFSET_BIAS] = bias;
394 static void ds2760_battery_set_charged(struct power_supply *psy)
396 struct ds2760_device_info *di = to_ds2760_device_info(psy);
398 /* postpone the actual work by 20 secs. This is for debouncing GPIO
399 * signals and to let the current value settle. See AN4188. */
400 cancel_delayed_work(&di->set_charged_work);
401 queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
404 static int ds2760_battery_get_property(struct power_supply *psy,
405 enum power_supply_property psp,
406 union power_supply_propval *val)
408 struct ds2760_device_info *di = to_ds2760_device_info(psy);
411 case POWER_SUPPLY_PROP_STATUS:
412 val->intval = di->charge_status;
418 ds2760_battery_read_status(di);
421 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
422 val->intval = di->voltage_uV;
424 case POWER_SUPPLY_PROP_CURRENT_NOW:
425 val->intval = di->current_uA;
427 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
428 val->intval = di->rated_capacity;
430 case POWER_SUPPLY_PROP_CHARGE_FULL:
431 val->intval = di->full_active_uAh;
433 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
434 val->intval = di->empty_uAh;
436 case POWER_SUPPLY_PROP_CHARGE_NOW:
437 val->intval = di->accum_current_uAh;
439 case POWER_SUPPLY_PROP_TEMP:
440 val->intval = di->temp_C;
442 case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
443 val->intval = di->life_sec;
445 case POWER_SUPPLY_PROP_CAPACITY:
446 val->intval = di->rem_capacity;
455 static int ds2760_battery_set_property(struct power_supply *psy,
456 enum power_supply_property psp,
457 const union power_supply_propval *val)
459 struct ds2760_device_info *di = to_ds2760_device_info(psy);
462 case POWER_SUPPLY_PROP_CHARGE_FULL:
463 /* the interface counts in uAh, convert the value */
464 ds2760_battery_write_active_full(di, val->intval / 1000L);
467 case POWER_SUPPLY_PROP_CHARGE_NOW:
468 /* ds2760_battery_set_current_accum() does the conversion */
469 ds2760_battery_set_current_accum(di, val->intval);
479 static int ds2760_battery_property_is_writeable(struct power_supply *psy,
480 enum power_supply_property psp)
483 case POWER_SUPPLY_PROP_CHARGE_FULL:
484 case POWER_SUPPLY_PROP_CHARGE_NOW:
494 static enum power_supply_property ds2760_battery_props[] = {
495 POWER_SUPPLY_PROP_STATUS,
496 POWER_SUPPLY_PROP_VOLTAGE_NOW,
497 POWER_SUPPLY_PROP_CURRENT_NOW,
498 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
499 POWER_SUPPLY_PROP_CHARGE_FULL,
500 POWER_SUPPLY_PROP_CHARGE_EMPTY,
501 POWER_SUPPLY_PROP_CHARGE_NOW,
502 POWER_SUPPLY_PROP_TEMP,
503 POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
504 POWER_SUPPLY_PROP_CAPACITY,
507 static int ds2760_battery_probe(struct platform_device *pdev)
511 struct ds2760_device_info *di;
513 di = kzalloc(sizeof(*di), GFP_KERNEL);
516 goto di_alloc_failed;
519 platform_set_drvdata(pdev, di);
521 di->dev = &pdev->dev;
522 di->w1_dev = pdev->dev.parent;
523 di->bat.name = dev_name(&pdev->dev);
524 di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
525 di->bat.properties = ds2760_battery_props;
526 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
527 di->bat.get_property = ds2760_battery_get_property;
528 di->bat.set_property = ds2760_battery_set_property;
529 di->bat.property_is_writeable =
530 ds2760_battery_property_is_writeable;
531 di->bat.set_charged = ds2760_battery_set_charged;
532 di->bat.external_power_changed =
533 ds2760_battery_external_power_changed;
535 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
537 /* enable sleep mode feature */
538 ds2760_battery_read_status(di);
539 status = di->raw[DS2760_STATUS_REG];
541 status |= DS2760_STATUS_PMOD;
543 status &= ~DS2760_STATUS_PMOD;
545 ds2760_battery_write_status(di, status);
547 /* set rated capacity from module param */
549 ds2760_battery_write_rated_capacity(di, rated_capacity);
551 /* set current accumulator if given as parameter.
552 * this should only be done for bootstrapping the value */
554 ds2760_battery_set_current_accum(di, current_accum);
556 retval = power_supply_register(&pdev->dev, &di->bat);
558 dev_err(di->dev, "failed to register battery\n");
562 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
563 INIT_DELAYED_WORK(&di->set_charged_work,
564 ds2760_battery_set_charged_work);
565 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
566 if (!di->monitor_wqueue) {
568 goto workqueue_failed;
570 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
575 power_supply_unregister(&di->bat);
583 static int ds2760_battery_remove(struct platform_device *pdev)
585 struct ds2760_device_info *di = platform_get_drvdata(pdev);
587 cancel_delayed_work_sync(&di->monitor_work);
588 cancel_delayed_work_sync(&di->set_charged_work);
589 destroy_workqueue(di->monitor_wqueue);
590 power_supply_unregister(&di->bat);
598 static int ds2760_battery_suspend(struct platform_device *pdev,
601 struct ds2760_device_info *di = platform_get_drvdata(pdev);
603 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
608 static int ds2760_battery_resume(struct platform_device *pdev)
610 struct ds2760_device_info *di = platform_get_drvdata(pdev);
612 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
613 power_supply_changed(&di->bat);
615 cancel_delayed_work(&di->monitor_work);
616 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
623 #define ds2760_battery_suspend NULL
624 #define ds2760_battery_resume NULL
626 #endif /* CONFIG_PM */
628 MODULE_ALIAS("platform:ds2760-battery");
630 static struct platform_driver ds2760_battery_driver = {
632 .name = "ds2760-battery",
634 .probe = ds2760_battery_probe,
635 .remove = ds2760_battery_remove,
636 .suspend = ds2760_battery_suspend,
637 .resume = ds2760_battery_resume,
640 static int __init ds2760_battery_init(void)
642 return platform_driver_register(&ds2760_battery_driver);
645 static void __exit ds2760_battery_exit(void)
647 platform_driver_unregister(&ds2760_battery_driver);
650 module_init(ds2760_battery_init);
651 module_exit(ds2760_battery_exit);
653 MODULE_LICENSE("GPL");
654 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
655 "Matt Reimer <mreimer@vpop.net>, "
656 "Anton Vorontsov <cbou@mail.ru>");
657 MODULE_DESCRIPTION("ds2760 battery driver");