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omap: i2c: add a timeout to the busy waiting
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / power / ds2760_battery.c
blob3bf8d1f622e31319144a8077420d683231ed1195
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/slab.h>
28 #include <linux/platform_device.h>
29 #include <linux/power_supply.h>
30
31 #include "../w1/w1.h"
32 #include "../w1/slaves/w1_ds2760.h"
33
34 struct ds2760_device_info {
35 struct device *dev;
36
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_* */
54
55 int full_counter;
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;
61 };
62
63 static unsigned int cache_time = 1000;
64 module_param(cache_time, uint, 0644);
65 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
66
67 static unsigned int pmod_enabled;
68 module_param(pmod_enabled, bool, 0644);
69 MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit");
70
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");
74
75 static unsigned int current_accum;
76 module_param(current_accum, uint, 0644);
77 MODULE_PARM_DESC(current_accum, "current accumulator value");
78
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[] = {
82 0,
83 920, /* Samsung */
84 920, /* BYD */
85 920, /* Lishen */
86 920, /* NEC */
87 1440, /* Samsung */
88 1440, /* BYD */
89 1440, /* Lishen */
90 1440, /* NEC */
91 2880, /* Samsung */
92 2880, /* BYD */
93 2880, /* Lishen */
94 2880 /* NEC */
95 };
96
97 /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
98 * temp is in Celsius */
99 static int battery_interpolate(int array[], int temp)
100 {
101 int index, dt;
102
103 if (temp <= 0)
104 return array[0];
105 if (temp >= 40)
106 return array[4];
107
108 index = temp / 10;
109 dt = temp % 10;
110
111 return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
112 }
113
114 static int ds2760_battery_read_status(struct ds2760_device_info *di)
115 {
116 int ret, i, start, count, scale[5];
117
118 if (di->update_time && time_before(jiffies, di->update_time +
119 msecs_to_jiffies(cache_time)))
120 return 0;
121
122 /* The first time we read the entire contents of SRAM/EEPROM,
123 * but after that we just read the interesting bits that change. */
124 if (di->update_time == 0) {
125 start = 0;
126 count = DS2760_DATA_SIZE;
127 } else {
128 start = DS2760_VOLTAGE_MSB;
129 count = DS2760_TEMP_LSB - start + 1;
130 }
131
132 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
133 if (ret != count) {
134 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
135 di->w1_dev);
136 return 1;
137 }
138
139 di->update_time = jiffies;
140
141 /* DS2760 reports voltage in units of 4.88mV, but the battery class
142 * reports in units of uV, so convert by multiplying by 4880. */
143 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
144 (di->raw[DS2760_VOLTAGE_LSB] >> 5);
145 di->voltage_uV = di->voltage_raw * 4880;
146
147 /* DS2760 reports current in signed units of 0.625mA, but the battery
148 * class reports in units of µA, so convert by multiplying by 625. */
149 di->current_raw =
150 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
151 (di->raw[DS2760_CURRENT_LSB] >> 3);
152 di->current_uA = di->current_raw * 625;
153
154 /* DS2760 reports accumulated current in signed units of 0.25mAh. */
155 di->accum_current_raw =
156 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
157 di->raw[DS2760_CURRENT_ACCUM_LSB];
158 di->accum_current_uAh = di->accum_current_raw * 250;
159
160 /* DS2760 reports temperature in signed units of 0.125°C, but the
161 * battery class reports in units of 1/10 °C, so we convert by
162 * multiplying by .125 * 10 = 1.25. */
163 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
164 (di->raw[DS2760_TEMP_LSB] >> 5);
165 di->temp_C = di->temp_raw + (di->temp_raw / 4);
166
167 /* At least some battery monitors (e.g. HP iPAQ) store the battery's
168 * maximum rated capacity. */
169 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
170 di->rated_capacity = rated_capacities[
171 (unsigned int)di->raw[DS2760_RATED_CAPACITY]];
172 else
173 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
174
175 di->rated_capacity *= 1000; /* convert to µAh */
176
177 /* Calculate the full level at the present temperature. */
178 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
179 di->raw[DS2760_ACTIVE_FULL + 1];
180
181 /* If the full_active_uAh value is not given, fall back to the rated
182 * capacity. This is likely to happen when chips are not part of the
183 * battery pack and is therefore not bootstrapped. */
184 if (di->full_active_uAh == 0)
185 di->full_active_uAh = di->rated_capacity / 1000L;
186
187 scale[0] = di->full_active_uAh;
188 for (i = 1; i < 5; i++)
189 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
190
191 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
192 di->full_active_uAh *= 1000; /* convert to µAh */
193
194 /* Calculate the empty level at the present temperature. */
195 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
196 for (i = 3; i >= 0; i--)
197 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
198
199 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
200 di->empty_uAh *= 1000; /* convert to µAh */
201
202 if (di->full_active_uAh == di->empty_uAh)
203 di->rem_capacity = 0;
204 else
205 /* From Maxim Application Note 131: remaining capacity =
206 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
207 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
208 (di->full_active_uAh - di->empty_uAh);
209
210 if (di->rem_capacity < 0)
211 di->rem_capacity = 0;
212 if (di->rem_capacity > 100)
213 di->rem_capacity = 100;
214
215 if (di->current_uA >= 100L)
216 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 36L)
217 / (di->current_uA / 100L);
218 else
219 di->life_sec = 0;
220
221 return 0;
222 }
223
224 static void ds2760_battery_set_current_accum(struct ds2760_device_info *di,
225 unsigned int acr_val)
226 {
227 unsigned char acr[2];
228
229 /* acr is in units of 0.25 mAh */
230 acr_val *= 4L;
231 acr_val /= 1000;
232
233 acr[0] = acr_val >> 8;
234 acr[1] = acr_val & 0xff;
235
236 if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2)
237 dev_warn(di->dev, "ACR write failed\n");
238 }
239
240 static void ds2760_battery_update_status(struct ds2760_device_info *di)
241 {
242 int old_charge_status = di->charge_status;
243
244 ds2760_battery_read_status(di);
245
246 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
247 di->full_counter = 0;
248
249 if (power_supply_am_i_supplied(&di->bat)) {
250 if (di->current_uA > 10000) {
251 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
252 di->full_counter = 0;
253 } else if (di->current_uA < -5000) {
254 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
255 dev_notice(di->dev, "not enough power to "
256 "charge\n");
257 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
258 di->full_counter = 0;
259 } else if (di->current_uA < 10000 &&
260 di->charge_status != POWER_SUPPLY_STATUS_FULL) {
261
262 /* Don't consider the battery to be full unless
263 * we've seen the current < 10 mA at least two
264 * consecutive times. */
265
266 di->full_counter++;
267
268 if (di->full_counter < 2) {
269 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
270 } else {
271 di->charge_status = POWER_SUPPLY_STATUS_FULL;
272 ds2760_battery_set_current_accum(di,
273 di->full_active_uAh);
274 }
275 }
276 } else {
277 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
278 di->full_counter = 0;
279 }
280
281 if (di->charge_status != old_charge_status)
282 power_supply_changed(&di->bat);
283 }
284
285 static void ds2760_battery_write_status(struct ds2760_device_info *di,
286 char status)
287 {
288 if (status == di->raw[DS2760_STATUS_REG])
289 return;
290
291 w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1);
292 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
293 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
294 }
295
296 static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di,
297 unsigned char rated_capacity)
298 {
299 if (rated_capacity == di->raw[DS2760_RATED_CAPACITY])
300 return;
301
302 w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1);
303 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
304 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
305 }
306
307 static void ds2760_battery_work(struct work_struct *work)
308 {
309 struct ds2760_device_info *di = container_of(work,
310 struct ds2760_device_info, monitor_work.work);
311 const int interval = HZ * 60;
312
313 dev_dbg(di->dev, "%s\n", __func__);
314
315 ds2760_battery_update_status(di);
316 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
317 }
318
319 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
320 bat);
321
322 static void ds2760_battery_external_power_changed(struct power_supply *psy)
323 {
324 struct ds2760_device_info *di = to_ds2760_device_info(psy);
325
326 dev_dbg(di->dev, "%s\n", __func__);
327
328 cancel_delayed_work(&di->monitor_work);
329 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
330 }
331
332
333 static void ds2760_battery_set_charged_work(struct work_struct *work)
334 {
335 char bias;
336 struct ds2760_device_info *di = container_of(work,
337 struct ds2760_device_info, set_charged_work.work);
338
339 dev_dbg(di->dev, "%s\n", __func__);
340
341 ds2760_battery_read_status(di);
342
343 /* When we get notified by external circuitry that the battery is
344 * considered fully charged now, we know that there is no current
345 * flow any more. However, the ds2760's internal current meter is
346 * too inaccurate to rely on - spec say something ~15% failure.
347 * Hence, we use the current offset bias register to compensate
348 * that error.
349 */
350
351 if (!power_supply_am_i_supplied(&di->bat))
352 return;
353
354 bias = (signed char) di->current_raw +
355 (signed char) di->raw[DS2760_CURRENT_OFFSET_BIAS];
356
357 dev_dbg(di->dev, "%s: bias = %d\n", __func__, bias);
358
359 w1_ds2760_write(di->w1_dev, &bias, DS2760_CURRENT_OFFSET_BIAS, 1);
360 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
361 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1);
362
363 /* Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS
364 * value won't be read back by ds2760_battery_read_status() */
365 di->raw[DS2760_CURRENT_OFFSET_BIAS] = bias;
366 }
367
368 static void ds2760_battery_set_charged(struct power_supply *psy)
369 {
370 struct ds2760_device_info *di = to_ds2760_device_info(psy);
371
372 /* postpone the actual work by 20 secs. This is for debouncing GPIO
373 * signals and to let the current value settle. See AN4188. */
374 cancel_delayed_work(&di->set_charged_work);
375 queue_delayed_work(di->monitor_wqueue, &di->set_charged_work, HZ * 20);
376 }
377
378 static int ds2760_battery_get_property(struct power_supply *psy,
379 enum power_supply_property psp,
380 union power_supply_propval *val)
381 {
382 struct ds2760_device_info *di = to_ds2760_device_info(psy);
383
384 switch (psp) {
385 case POWER_SUPPLY_PROP_STATUS:
386 val->intval = di->charge_status;
387 return 0;
388 default:
389 break;
390 }
391
392 ds2760_battery_read_status(di);
393
394 switch (psp) {
395 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
396 val->intval = di->voltage_uV;
397 break;
398 case POWER_SUPPLY_PROP_CURRENT_NOW:
399 val->intval = di->current_uA;
400 break;
401 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
402 val->intval = di->rated_capacity;
403 break;
404 case POWER_SUPPLY_PROP_CHARGE_FULL:
405 val->intval = di->full_active_uAh;
406 break;
407 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
408 val->intval = di->empty_uAh;
409 break;
410 case POWER_SUPPLY_PROP_CHARGE_NOW:
411 val->intval = di->accum_current_uAh;
412 break;
413 case POWER_SUPPLY_PROP_TEMP:
414 val->intval = di->temp_C;
415 break;
416 case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW:
417 val->intval = di->life_sec;
418 break;
419 case POWER_SUPPLY_PROP_CAPACITY:
420 val->intval = di->rem_capacity;
421 break;
422 default:
423 return -EINVAL;
424 }
425
426 return 0;
427 }
428
429 static enum power_supply_property ds2760_battery_props[] = {
430 POWER_SUPPLY_PROP_STATUS,
431 POWER_SUPPLY_PROP_VOLTAGE_NOW,
432 POWER_SUPPLY_PROP_CURRENT_NOW,
433 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
434 POWER_SUPPLY_PROP_CHARGE_FULL,
435 POWER_SUPPLY_PROP_CHARGE_EMPTY,
436 POWER_SUPPLY_PROP_CHARGE_NOW,
437 POWER_SUPPLY_PROP_TEMP,
438 POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
439 POWER_SUPPLY_PROP_CAPACITY,
440 };
441
442 static int ds2760_battery_probe(struct platform_device *pdev)
443 {
444 char status;
445 int retval = 0;
446 struct ds2760_device_info *di;
447
448 di = kzalloc(sizeof(*di), GFP_KERNEL);
449 if (!di) {
450 retval = -ENOMEM;
451 goto di_alloc_failed;
452 }
453
454 platform_set_drvdata(pdev, di);
455
456 di->dev = &pdev->dev;
457 di->w1_dev = pdev->dev.parent;
458 di->bat.name = dev_name(&pdev->dev);
459 di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
460 di->bat.properties = ds2760_battery_props;
461 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
462 di->bat.get_property = ds2760_battery_get_property;
463 di->bat.set_charged = ds2760_battery_set_charged;
464 di->bat.external_power_changed =
465 ds2760_battery_external_power_changed;
466
467 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
468
469 /* enable sleep mode feature */
470 ds2760_battery_read_status(di);
471 status = di->raw[DS2760_STATUS_REG];
472 if (pmod_enabled)
473 status |= DS2760_STATUS_PMOD;
474 else
475 status &= ~DS2760_STATUS_PMOD;
476
477 ds2760_battery_write_status(di, status);
478
479 /* set rated capacity from module param */
480 if (rated_capacity)
481 ds2760_battery_write_rated_capacity(di, rated_capacity);
482
483 /* set current accumulator if given as parameter.
484 * this should only be done for bootstrapping the value */
485 if (current_accum)
486 ds2760_battery_set_current_accum(di, current_accum);
487
488 retval = power_supply_register(&pdev->dev, &di->bat);
489 if (retval) {
490 dev_err(di->dev, "failed to register battery\n");
491 goto batt_failed;
492 }
493
494 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
495 INIT_DELAYED_WORK(&di->set_charged_work,
496 ds2760_battery_set_charged_work);
497 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev));
498 if (!di->monitor_wqueue) {
499 retval = -ESRCH;
500 goto workqueue_failed;
501 }
502 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
503
504 goto success;
505
506 workqueue_failed:
507 power_supply_unregister(&di->bat);
508 batt_failed:
509 kfree(di);
510 di_alloc_failed:
511 success:
512 return retval;
513 }
514
515 static int ds2760_battery_remove(struct platform_device *pdev)
516 {
517 struct ds2760_device_info *di = platform_get_drvdata(pdev);
518
519 cancel_rearming_delayed_workqueue(di->monitor_wqueue,
520 &di->monitor_work);
521 cancel_rearming_delayed_workqueue(di->monitor_wqueue,
522 &di->set_charged_work);
523 destroy_workqueue(di->monitor_wqueue);
524 power_supply_unregister(&di->bat);
525
526 return 0;
527 }
528
529 #ifdef CONFIG_PM
530
531 static int ds2760_battery_suspend(struct platform_device *pdev,
532 pm_message_t state)
533 {
534 struct ds2760_device_info *di = platform_get_drvdata(pdev);
535
536 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
537
538 return 0;
539 }
540
541 static int ds2760_battery_resume(struct platform_device *pdev)
542 {
543 struct ds2760_device_info *di = platform_get_drvdata(pdev);
544
545 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
546 power_supply_changed(&di->bat);
547
548 cancel_delayed_work(&di->monitor_work);
549 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
550
551 return 0;
552 }
553
554 #else
555
556 #define ds2760_battery_suspend NULL
557 #define ds2760_battery_resume NULL
558
559 #endif /* CONFIG_PM */
560
561 MODULE_ALIAS("platform:ds2760-battery");
562
563 static struct platform_driver ds2760_battery_driver = {
564 .driver = {
565 .name = "ds2760-battery",
566 },
567 .probe = ds2760_battery_probe,
568 .remove = ds2760_battery_remove,
569 .suspend = ds2760_battery_suspend,
570 .resume = ds2760_battery_resume,
571 };
572
573 static int __init ds2760_battery_init(void)
574 {
575 return platform_driver_register(&ds2760_battery_driver);
576 }
577
578 static void __exit ds2760_battery_exit(void)
579 {
580 platform_driver_unregister(&ds2760_battery_driver);
581 }
582
583 module_init(ds2760_battery_init);
584 module_exit(ds2760_battery_exit);
585
586 MODULE_LICENSE("GPL");
587 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
588 "Matt Reimer <mreimer@vpop.net>, "
589 "Anton Vorontsov <cbou@mail.ru>");
590 MODULE_DESCRIPTION("ds2760 battery driver");
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