00e1ea6f1de22927790caeb833c5f11fe4f7871c
[linux-2.6.git] / drivers / power / ds2760_battery.c
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 };
60
61 static unsigned int cache_time = 1000;
62 module_param(cache_time, uint, 0644);
63 MODULE_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. */
67 static 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 */
85 static 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
100 static 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
202 static 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
261 static 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
278 static 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
290 static 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
335 static 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
346 static 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
389 workqueue_failed:
390         power_supply_unregister(&di->bat);
391 batt_failed:
392         kfree(di);
393 di_alloc_failed:
394 success:
395         return retval;
396 }
397
398 static 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
412 static 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
422 static 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
442 static 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
452 static int __init ds2760_battery_init(void)
453 {
454         return platform_driver_register(&ds2760_battery_driver);
455 }
456
457 static void __exit ds2760_battery_exit(void)
458 {
459         platform_driver_unregister(&ds2760_battery_driver);
460         return;
461 }
462
463 module_init(ds2760_battery_init);
464 module_exit(ds2760_battery_exit);
465
466 MODULE_LICENSE("GPL");
467 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
468               "Matt Reimer <mreimer@vpop.net>, "
469               "Anton Vorontsov <cbou@mail.ru>");
470 MODULE_DESCRIPTION("ds2760 battery driver");