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/platform_device.h>
28 #include <linux/power_supply.h>
31 #include "../w1/slaves/w1_ds2760.h"
33 struct ds2760_device_info {
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_* */
55 struct power_supply bat;
56 struct device *w1_dev;
57 struct workqueue_struct *monitor_wqueue;
58 struct delayed_work monitor_work;
61 static unsigned int cache_time = 1000;
62 module_param(cache_time, uint, 0644);
63 MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
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[] = {
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)
97 return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
100 static int ds2760_battery_read_status(struct ds2760_device_info *di)
102 int ret, i, start, count, scale[5];
104 if (di->update_time && time_before(jiffies, di->update_time +
105 msecs_to_jiffies(cache_time)))
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) {
112 count = DS2760_DATA_SIZE;
114 start = DS2760_VOLTAGE_MSB;
115 count = DS2760_TEMP_LSB - start + 1;
118 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
120 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
125 di->update_time = jiffies;
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;
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. */
136 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
137 (di->raw[DS2760_CURRENT_LSB] >> 3);
138 di->current_uA = di->current_raw * 625;
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;
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);
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]];
159 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
161 di->rated_capacity *= 1000; /* convert to µAh */
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];
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];
172 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
173 di->full_active_uAh *= 1000; /* convert to µAh */
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];
180 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
181 di->empty_uAh *= 1000; /* convert to µAh */
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);
188 if (di->rem_capacity < 0)
189 di->rem_capacity = 0;
190 if (di->rem_capacity > 100)
191 di->rem_capacity = 100;
194 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
195 3600L) / di->current_uA;
202 static void ds2760_battery_update_status(struct ds2760_device_info *di)
204 int old_charge_status = di->charge_status;
206 ds2760_battery_read_status(di);
208 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
209 di->full_counter = 0;
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 "
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) {
224 /* Don't consider the battery to be full unless
225 * we've seen the current < 10 mA at least two
226 * consecutive times. */
230 if (di->full_counter < 2) {
231 di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
233 unsigned char acr[2];
236 /* acr is in units of 0.25 mAh */
237 acr_val = di->full_active_uAh * 4L / 1000;
239 acr[0] = acr_val >> 8;
240 acr[1] = acr_val & 0xff;
242 if (w1_ds2760_write(di->w1_dev, acr,
243 DS2760_CURRENT_ACCUM_MSB, 2) < 2)
245 "ACR reset failed\n");
247 di->charge_status = POWER_SUPPLY_STATUS_FULL;
251 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
252 di->full_counter = 0;
255 if (di->charge_status != old_charge_status)
256 power_supply_changed(&di->bat);
259 static void ds2760_battery_work(struct work_struct *work)
261 struct ds2760_device_info *di = container_of(work,
262 struct ds2760_device_info, monitor_work.work);
263 const int interval = HZ * 60;
265 dev_dbg(di->dev, "%s\n", __FUNCTION__);
267 ds2760_battery_update_status(di);
268 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
271 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
274 static void ds2760_battery_external_power_changed(struct power_supply *psy)
276 struct ds2760_device_info *di = to_ds2760_device_info(psy);
278 dev_dbg(di->dev, "%s\n", __FUNCTION__);
280 cancel_delayed_work(&di->monitor_work);
281 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
284 static int ds2760_battery_get_property(struct power_supply *psy,
285 enum power_supply_property psp,
286 union power_supply_propval *val)
288 struct ds2760_device_info *di = to_ds2760_device_info(psy);
291 case POWER_SUPPLY_PROP_STATUS:
292 val->intval = di->charge_status;
298 ds2760_battery_read_status(di);
301 case POWER_SUPPLY_PROP_VOLTAGE_NOW:
302 val->intval = di->voltage_uV;
304 case POWER_SUPPLY_PROP_CURRENT_NOW:
305 val->intval = di->current_uA;
307 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
308 val->intval = di->rated_capacity;
310 case POWER_SUPPLY_PROP_CHARGE_FULL:
311 val->intval = di->full_active_uAh;
313 case POWER_SUPPLY_PROP_CHARGE_EMPTY:
314 val->intval = di->empty_uAh;
316 case POWER_SUPPLY_PROP_CHARGE_NOW:
317 val->intval = di->accum_current_uAh;
319 case POWER_SUPPLY_PROP_TEMP:
320 val->intval = di->temp_C;
329 static enum power_supply_property ds2760_battery_props[] = {
330 POWER_SUPPLY_PROP_STATUS,
331 POWER_SUPPLY_PROP_VOLTAGE_NOW,
332 POWER_SUPPLY_PROP_CURRENT_NOW,
333 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
334 POWER_SUPPLY_PROP_CHARGE_FULL,
335 POWER_SUPPLY_PROP_CHARGE_EMPTY,
336 POWER_SUPPLY_PROP_CHARGE_NOW,
337 POWER_SUPPLY_PROP_TEMP,
340 static int ds2760_battery_probe(struct platform_device *pdev)
343 struct ds2760_device_info *di;
344 struct ds2760_platform_data *pdata;
346 di = kzalloc(sizeof(*di), GFP_KERNEL);
349 goto di_alloc_failed;
352 platform_set_drvdata(pdev, di);
354 pdata = pdev->dev.platform_data;
355 di->dev = &pdev->dev;
356 di->w1_dev = pdev->dev.parent;
357 di->bat.name = pdev->dev.bus_id;
358 di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
359 di->bat.properties = ds2760_battery_props;
360 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
361 di->bat.get_property = ds2760_battery_get_property;
362 di->bat.external_power_changed =
363 ds2760_battery_external_power_changed;
365 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
367 retval = power_supply_register(&pdev->dev, &di->bat);
369 dev_err(di->dev, "failed to register battery");
373 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
374 di->monitor_wqueue = create_singlethread_workqueue(pdev->dev.bus_id);
375 if (!di->monitor_wqueue) {
377 goto workqueue_failed;
379 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
384 power_supply_unregister(&di->bat);
392 static int ds2760_battery_remove(struct platform_device *pdev)
394 struct ds2760_device_info *di = platform_get_drvdata(pdev);
396 cancel_rearming_delayed_workqueue(di->monitor_wqueue,
398 destroy_workqueue(di->monitor_wqueue);
399 power_supply_unregister(&di->bat);
406 static int ds2760_battery_suspend(struct platform_device *pdev,
409 struct ds2760_device_info *di = platform_get_drvdata(pdev);
411 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
416 static int ds2760_battery_resume(struct platform_device *pdev)
418 struct ds2760_device_info *di = platform_get_drvdata(pdev);
420 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
421 power_supply_changed(&di->bat);
423 cancel_delayed_work(&di->monitor_work);
424 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
431 #define ds2760_battery_suspend NULL
432 #define ds2760_battery_resume NULL
434 #endif /* CONFIG_PM */
436 static struct platform_driver ds2760_battery_driver = {
438 .name = "ds2760-battery",
440 .probe = ds2760_battery_probe,
441 .remove = ds2760_battery_remove,
442 .suspend = ds2760_battery_suspend,
443 .resume = ds2760_battery_resume,
446 static int __init ds2760_battery_init(void)
448 return platform_driver_register(&ds2760_battery_driver);
451 static void __exit ds2760_battery_exit(void)
453 platform_driver_unregister(&ds2760_battery_driver);
456 module_init(ds2760_battery_init);
457 module_exit(ds2760_battery_exit);
459 MODULE_LICENSE("GPL");
460 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
461 "Matt Reimer <mreimer@vpop.net>, "
462 "Anton Vorontsov <cbou@mail.ru>");
463 MODULE_DESCRIPTION("ds2760 battery driver");