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Linux 2.6.33-rc6
[cris-mirror.git] / drivers / power / ds2760_battery.c
blob6f1dba5a519dfa4c458e66a784aafadf8fee2460
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
33 struct 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 struct delayed_work set_charged_work;
60 };
61
62 static unsigned int cache_time = 1000;
63 module_param(cache_time, uint, 0644);
64 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
65
66 static unsigned int pmod_enabled;
67 module_param(pmod_enabled, bool, 0644);
68 MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
69
70 static unsigned int rated_capacity;
71 module_param(rated_capacity, uint, 0644);
72 MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index");
73
74 static unsigned int current_accum;
75 module_param(current_accum, uint, 0644);
76 MODULE_PARM_DESC(current_accum, "current accumulator value");
77
78 /* Some batteries have their rated capacity stored a N * 10 mAh, while
79 * others use an index into this table. */
80 static int rated_capacities[] = {
81 0,
82 920, /* Samsung */
83 920, /* BYD */
84 920, /* Lishen */
85 920, /* NEC */
86 1440, /* Samsung */
87 1440, /* BYD */
88 1440, /* Lishen */
89 1440, /* NEC */
90 2880, /* Samsung */
91 2880, /* BYD */
92 2880, /* Lishen */
93 2880 /* NEC */
94 };
95
96 /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
97 * temp is in Celsius */
98 static int battery_interpolate(int array[], int temp)
99 {
100 int index, dt;
101
102 if (temp <= 0)
103 return array[0];
104 if (temp >= 40)
105 return array[4];
106
107 index = temp / 10;
108 dt = temp % 10;
109
110 return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
111 }
112
113 static int ds2760_battery_read_status(struct ds2760_device_info *di)
114 {
115 int ret, i, start, count, scale[5];
116
117 if (di->update_time && time_before(jiffies, di->update_time +
118 msecs_to_jiffies(cache_time)))
119 return 0;
120
121 /* The first time we read the entire contents of SRAM/EEPROM,
122 * but after that we just read the interesting bits that change. */
123 if (di->update_time == 0) {
124 start = 0;
125 count = DS2760_DATA_SIZE;
126 } else {
127 start = DS2760_VOLTAGE_MSB;
128 count = DS2760_TEMP_LSB - start + 1;
129 }
130
131 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
132 if (ret != count) {
133 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
134 di->w1_dev);
135 return 1;
136 }
137
138 di->update_time = jiffies;
139
140 /* DS2760 reports voltage in units of 4.88mV, but the battery class
141 * reports in units of uV, so convert by multiplying by 4880. */
142 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
143 (di->raw[DS2760_VOLTAGE_LSB] >> 5);
144 di->voltage_uV = di->voltage_raw * 4880;
145
146 /* DS2760 reports current in signed units of 0.625mA, but the battery
147 * class reports in units of µA, so convert by multiplying by 625. */
148 di->current_raw =
149 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
150 (di->raw[DS2760_CURRENT_LSB] >> 3);
151 di->current_uA = di->current_raw * 625;
152
153 /* DS2760 reports accumulated current in signed units of 0.25mAh. */
154 di->accum_current_raw =
155 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
156 di->raw[DS2760_CURRENT_ACCUM_LSB];
157 di->accum_current_uAh = di->accum_current_raw * 250;
158
159 /* DS2760 reports temperature in signed units of 0.125°C, but the
160 * battery class reports in units of 1/10 °C, so we convert by
161 * multiplying by .125 * 10 = 1.25. */
162 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
163 (di->raw[DS2760_TEMP_LSB] >> 5);
164 di->temp_C = di->temp_raw + (di->temp_raw / 4);
165
166 /* At least some battery monitors (e.g. HP iPAQ) store the battery's
167 * maximum rated capacity. */
168 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
169 di->rated_capacity = rated_capacities[
170 (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
171 else
172 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
173
174 di->rated_capacity *= 1000; /* convert to µAh */
175
176 /* Calculate the full level at the present temperature. */
177 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
178 di->raw[DS2760_ACTIVE_FULL + 1];
179
180 /* If the full_active_uAh value is not given, fall back to the rated
181 * capacity. This is likely to happen when chips are not part of the
182 * battery pack and is therefore not bootstrapped. */
183 if (di->full_active_uAh == 0)
184 di->full_active_uAh = di->rated_capacity / 1000L;
185
186 scale[0] = di->full_active_uAh;
187 for (i = 1; i < 5; i++)
188 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
189
190 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
191 di->full_active_uAh *= 1000; /* convert to µAh */
192
193 /* Calculate the empty level at the present temperature. */
194 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
195 for (i = 3; i >= 0; i--)
196 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
197
198 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
199 di->empty_uAh *= 1000; /* convert to µAh */
200
201 if (di->full_active_uAh == di->empty_uAh)
202 di->rem_capacity = 0;
203 else
204 /* From Maxim Application Note 131: remaining capacity =
205 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
206 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
207 (di->full_active_uAh - di->empty_uAh);
208
209 if (di->rem_capacity < 0)
210 di->rem_capacity = 0;
211 if (di->rem_capacity > 100)
212 di->rem_capacity = 100;
213
214 if (di->current_uA >= 100L)
215 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L)
216 / (di->current_uA / 100L);
217 else
218 di->life_sec = 0;
219
220 return 0;
221 }
222
223 static void ds2760_battery_set_current_accum(struct ds2760_device_info *di,
224 unsigned int acr_val)
225 {
226 unsigned char acr[2];
227
228 /* acr is in units of 0.25 mAh */
229 acr_val *= 4L;
230 acr_val /= 1000;
231
232 acr[0] = acr_val >> 8;
233 acr[1] = acr_val & 0xff;
234
235 if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2)
236 dev_warn(di->dev, "ACR write failed\n");
237 }
238
239 static void ds2760_battery_update_status(struct ds2760_device_info *di)
240 {
241 int old_charge_status = di->charge_status;
242
243 ds2760_battery_read_status(di);
244
245 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
246 di->full_counter = 0;
247
248 if (power_supply_am_i_supplied(&di->bat)) {
249 if (di->current_uA > 10000) {
250 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
251 di->full_counter = 0;
252 } else if (di->current_uA < -5000) {
253 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
254 dev_notice(di->dev, "not enough power to "
255 "charge\n");
256 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
257 di->full_counter = 0;
258 } else if (di->current_uA < 10000 &&
259 di->charge_status != POWER_SUPPLY_STATUS_FULL) {
260
261 /* Don't consider the battery to be full unless
262 * we've seen the current < 10 mA at least two
263 * consecutive times. */
264
265 di->full_counter++;
266
267 if (di->full_counter < 2) {
268 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
269 } else {
270 di->charge_status = POWER_SUPPLY_STATUS_FULL;
271 ds2760_battery_set_current_accum(di,
272 di->full_active_uAh);
273 }
274 }
275 } else {
276 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
277 di->full_counter = 0;
278 }
279
280 if (di->charge_status != old_charge_status)
281 power_supply_changed(&di->bat);
282 }
283
284 static void ds2760_battery_write_status(struct ds2760_device_info *di,
285 char status)
286 {
287 if (status == di->raw[DS2760_STATUS_REG])
288 return;
289
290 w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
291 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
292 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
293 }
294
295 static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di,
296 unsigned char rated_capacity)
297 {
298 if (rated_capacity == di->raw[DS2760_RATED_CAPACITY])
299 return;
300
301 w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1);
302 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
303 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
304 }
305
306 static void ds2760_battery_work(struct work_struct *work)
307 {
308 struct ds2760_device_info *di = container_of(work,
309 struct ds2760_device_info, monitor_work.work);
310 const int interval = HZ * 60;
311
312 dev_dbg(di->dev, "%s\n", __func__);
313
314 ds2760_battery_update_status(di);
315 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
316 }
317
318 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
319 bat);
320
321 static void ds2760_battery_external_power_changed(struct power_supply *psy)
322 {
323 struct ds2760_device_info *di = to_ds2760_device_info(psy);
324
325 dev_dbg(di->dev, "%s\n", __func__);
326
327 cancel_delayed_work(&di->monitor_work);
328 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
329 }
330
331
332 static void ds2760_battery_set_charged_work(struct work_struct *work)
333 {
334 char bias;
335 struct ds2760_device_info *di = container_of(work,
336 struct ds2760_device_info, set_charged_work.work);
337
338 dev_dbg(di->dev, "%s\n", __func__);
339
340 ds2760_battery_read_status(di);
341
342 /* When we get notified by external circuitry that the battery is
343 * considered fully charged now, we know that there is no current
344 * flow any more. However, the ds2760's internal current meter is
345 * too inaccurate to rely on - spec say something ~15% failure.
346 * Hence, we use the current offset bias register to compensate
347 * that error.
348 */
349
350 if (!power_supply_am_i_supplied(&di->bat))
351 return;
352
353 bias = (signed char) di->current_raw +
354 (signed char) di->raw[DS2760_CURRENT_OFFSET_BIAS];
355
356 dev_dbg(di->dev, "%s: bias = %d\n", __func__, bias);
357
358 w1_ds2760_write(di->w1_dev, &bias, DS2760_CURRENT_OFFSET_BIAS, 1);
359 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
360 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
361
362 /* Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS
363 * value won't be read back by ds2760_battery_read_status() */
364 di->raw[DS2760_CURRENT_OFFSET_BIAS] = bias;
365 }
366
367 static void ds2760_battery_set_charged(struct power_supply *psy)
368 {
369 struct ds2760_device_info *di = to_ds2760_device_info(psy);
370
371 /* postpone the actual work by 20 secs. This is for debouncing GPIO
372 * signals and to let the current value settle. See AN4188. */
373 cancel_delayed_work(&di->set_charged_work);
374 queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
375 }
376
377 static int ds2760_battery_get_property(struct power_supply *psy,
378 enum power_supply_property psp,
379 union power_supply_propval *val)
380 {
381 struct ds2760_device_info *di = to_ds2760_device_info(psy);
382
383 switch (psp) {
384 case POWER_SUPPLY_PROP_STATUS:
385 val->intval = di->charge_status;
386 return 0;
387 default:
388 break;
389 }
390
391 ds2760_battery_read_status(di);
392
393 switch (psp) {
394 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
395 val->intval = di->voltage_uV;
396 break;
397 case POWER_SUPPLY_PROP_CURRENT_NOW:
398 val->intval = di->current_uA;
399 break;
400 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
401 val->intval = di->rated_capacity;
402 break;
403 case POWER_SUPPLY_PROP_CHARGE_FULL:
404 val->intval = di->full_active_uAh;
405 break;
406 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
407 val->intval = di->empty_uAh;
408 break;
409 case POWER_SUPPLY_PROP_CHARGE_NOW:
410 val->intval = di->accum_current_uAh;
411 break;
412 case POWER_SUPPLY_PROP_TEMP:
413 val->intval = di->temp_C;
414 break;
415 case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
416 val->intval = di->life_sec;
417 break;
418 case POWER_SUPPLY_PROP_CAPACITY:
419 val->intval = di->rem_capacity;
420 break;
421 default:
422 return -EINVAL;
423 }
424
425 return 0;
426 }
427
428 static enum power_supply_property ds2760_battery_props[] = {
429 POWER_SUPPLY_PROP_STATUS,
430 POWER_SUPPLY_PROP_VOLTAGE_NOW,
431 POWER_SUPPLY_PROP_CURRENT_NOW,
432 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
433 POWER_SUPPLY_PROP_CHARGE_FULL,
434 POWER_SUPPLY_PROP_CHARGE_EMPTY,
435 POWER_SUPPLY_PROP_CHARGE_NOW,
436 POWER_SUPPLY_PROP_TEMP,
437 POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
438 POWER_SUPPLY_PROP_CAPACITY,
439 };
440
441 static int ds2760_battery_probe(struct platform_device *pdev)
442 {
443 char status;
444 int retval = 0;
445 struct ds2760_device_info *di;
446
447 di = kzalloc(sizeof(*di), GFP_KERNEL);
448 if (!di) {
449 retval = -ENOMEM;
450 goto di_alloc_failed;
451 }
452
453 platform_set_drvdata(pdev, di);
454
455 di->dev = &pdev->dev;
456 di->w1_dev = pdev->dev.parent;
457 di->bat.name = dev_name(&pdev->dev);
458 di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
459 di->bat.properties = ds2760_battery_props;
460 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
461 di->bat.get_property = ds2760_battery_get_property;
462 di->bat.set_charged = ds2760_battery_set_charged;
463 di->bat.external_power_changed =
464 ds2760_battery_external_power_changed;
465
466 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
467
468 /* enable sleep mode feature */
469 ds2760_battery_read_status(di);
470 status = di->raw[DS2760_STATUS_REG];
471 if (pmod_enabled)
472 status |= DS2760_STATUS_PMOD;
473 else
474 status &= ~DS2760_STATUS_PMOD;
475
476 ds2760_battery_write_status(di, status);
477
478 /* set rated capacity from module param */
479 if (rated_capacity)
480 ds2760_battery_write_rated_capacity(di, rated_capacity);
481
482 /* set current accumulator if given as parameter.
483 * this should only be done for bootstrapping the value */
484 if (current_accum)
485 ds2760_battery_set_current_accum(di, current_accum);
486
487 retval = power_supply_register(&pdev->dev, &di->bat);
488 if (retval) {
489 dev_err(di->dev, "failed to register battery\n");
490 goto batt_failed;
491 }
492
493 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
494 INIT_DELAYED_WORK(&di->set_charged_work,
495 ds2760_battery_set_charged_work);
496 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
497 if (!di->monitor_wqueue) {
498 retval = -ESRCH;
499 goto workqueue_failed;
500 }
501 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
502
503 goto success;
504
505 workqueue_failed:
506 power_supply_unregister(&di->bat);
507 batt_failed:
508 kfree(di);
509 di_alloc_failed:
510 success:
511 return retval;
512 }
513
514 static int ds2760_battery_remove(struct platform_device *pdev)
515 {
516 struct ds2760_device_info *di = platform_get_drvdata(pdev);
517
518 cancel_rearming_delayed_workqueue(di->monitor_wqueue,
519 &di->monitor_work);
520 cancel_rearming_delayed_workqueue(di->monitor_wqueue,
521 &di->set_charged_work);
522 destroy_workqueue(di->monitor_wqueue);
523 power_supply_unregister(&di->bat);
524
525 return 0;
526 }
527
528 #ifdef CONFIG_PM
529
530 static int ds2760_battery_suspend(struct platform_device *pdev,
531 pm_message_t state)
532 {
533 struct ds2760_device_info *di = platform_get_drvdata(pdev);
534
535 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
536
537 return 0;
538 }
539
540 static int ds2760_battery_resume(struct platform_device *pdev)
541 {
542 struct ds2760_device_info *di = platform_get_drvdata(pdev);
543
544 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
545 power_supply_changed(&di->bat);
546
547 cancel_delayed_work(&di->monitor_work);
548 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
549
550 return 0;
551 }
552
553 #else
554
555 #define ds2760_battery_suspend NULL
556 #define ds2760_battery_resume NULL
557
558 #endif /* CONFIG_PM */
559
560 MODULE_ALIAS("platform:ds2760-battery");
561
562 static struct platform_driver ds2760_battery_driver = {
563 .driver = {
564 .name = "ds2760-battery",
565 },
566 .probe = ds2760_battery_probe,
567 .remove = ds2760_battery_remove,
568 .suspend = ds2760_battery_suspend,
569 .resume = ds2760_battery_resume,
570 };
571
572 static int __init ds2760_battery_init(void)
573 {
574 return platform_driver_register(&ds2760_battery_driver);
575 }
576
577 static void __exit ds2760_battery_exit(void)
578 {
579 platform_driver_unregister(&ds2760_battery_driver);
580 }
581
582 module_init(ds2760_battery_init);
583 module_exit(ds2760_battery_exit);
584
585 MODULE_LICENSE("GPL");
586 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
587 "Matt Reimer <mreimer@vpop.net>, "
588 "Anton Vorontsov <cbou@mail.ru>");
589 MODULE_DESCRIPTION("ds2760 battery driver");
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