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
[] = {
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
)
111 return array
[index
] + (((array
[index
+ 1] - array
[index
]) * dt
) / 10);
114 static int ds2760_battery_read_status(struct ds2760_device_info
*di
)
116 int ret
, i
, start
, count
, scale
[5];
118 if (di
->update_time
&& time_before(jiffies
, di
->update_time
+
119 msecs_to_jiffies(cache_time
)))
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) {
126 count
= DS2760_DATA_SIZE
;
128 start
= DS2760_VOLTAGE_MSB
;
129 count
= DS2760_TEMP_LSB
- start
+ 1;
132 ret
= w1_ds2760_read(di
->w1_dev
, di
->raw
+ start
, start
, count
);
134 dev_warn(di
->dev
, "call to w1_ds2760_read failed (0x%p)\n",
139 di
->update_time
= jiffies
;
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;
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. */
150 (((signed char)di
->raw
[DS2760_CURRENT_MSB
]) << 5) |
151 (di
->raw
[DS2760_CURRENT_LSB
] >> 3);
152 di
->current_uA
= di
->current_raw
* 625;
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;
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);
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
]];
173 di
->rated_capacity
= di
->raw
[DS2760_RATED_CAPACITY
] * 10;
175 di
->rated_capacity
*= 1000; /* convert to µAh */
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];
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;
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
];
191 di
->full_active_uAh
= battery_interpolate(scale
, di
->temp_C
/ 10);
192 di
->full_active_uAh
*= 1000; /* convert to µAh */
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
];
199 di
->empty_uAh
= battery_interpolate(scale
, di
->temp_C
/ 10);
200 di
->empty_uAh
*= 1000; /* convert to µAh */
202 if (di
->full_active_uAh
== di
->empty_uAh
)
203 di
->rem_capacity
= 0;
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
);
210 if (di
->rem_capacity
< 0)
211 di
->rem_capacity
= 0;
212 if (di
->rem_capacity
> 100)
213 di
->rem_capacity
= 100;
215 if (di
->current_uA
>= 100L)
216 di
->life_sec
= -((di
->accum_current_uAh
- di
->empty_uAh
) * 36L)
217 / (di
->current_uA
/ 100L);
224 static void ds2760_battery_set_current_accum(struct ds2760_device_info
*di
,
225 unsigned int acr_val
)
227 unsigned char acr
[2];
229 /* acr is in units of 0.25 mAh */
233 acr
[0] = acr_val
>> 8;
234 acr
[1] = acr_val
& 0xff;
236 if (w1_ds2760_write(di
->w1_dev
, acr
, DS2760_CURRENT_ACCUM_MSB
, 2) < 2)
237 dev_warn(di
->dev
, "ACR write failed\n");
240 static void ds2760_battery_update_status(struct ds2760_device_info
*di
)
242 int old_charge_status
= di
->charge_status
;
244 ds2760_battery_read_status(di
);
246 if (di
->charge_status
== POWER_SUPPLY_STATUS_UNKNOWN
)
247 di
->full_counter
= 0;
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 "
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
) {
262 /* Don't consider the battery to be full unless
263 * we've seen the current < 10 mA at least two
264 * consecutive times. */
268 if (di
->full_counter
< 2) {
269 di
->charge_status
= POWER_SUPPLY_STATUS_CHARGING
;
271 di
->charge_status
= POWER_SUPPLY_STATUS_FULL
;
272 ds2760_battery_set_current_accum(di
,
273 di
->full_active_uAh
);
277 di
->charge_status
= POWER_SUPPLY_STATUS_DISCHARGING
;
278 di
->full_counter
= 0;
281 if (di
->charge_status
!= old_charge_status
)
282 power_supply_changed(&di
->bat
);
285 static void ds2760_battery_write_status(struct ds2760_device_info
*di
,
288 if (status
== di
->raw
[DS2760_STATUS_REG
])
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
);
296 static void ds2760_battery_write_rated_capacity(struct ds2760_device_info
*di
,
297 unsigned char rated_capacity
)
299 if (rated_capacity
== di
->raw
[DS2760_RATED_CAPACITY
])
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
);
307 static void ds2760_battery_write_active_full(struct ds2760_device_info
*di
,
310 unsigned char tmp
[2] = {
315 if (tmp
[0] == di
->raw
[DS2760_ACTIVE_FULL
] &&
316 tmp
[1] == di
->raw
[DS2760_ACTIVE_FULL
+ 1])
319 w1_ds2760_write(di
->w1_dev
, tmp
, DS2760_ACTIVE_FULL
, sizeof(tmp
));
320 w1_ds2760_store_eeprom(di
->w1_dev
, DS2760_EEPROM_BLOCK0
);
321 w1_ds2760_recall_eeprom(di
->w1_dev
, DS2760_EEPROM_BLOCK0
);
323 /* Write to the di->raw[] buffer directly - the DS2760_ACTIVE_FULL
324 * values won't be read back by ds2760_battery_read_status() */
325 di
->raw
[DS2760_ACTIVE_FULL
] = tmp
[0];
326 di
->raw
[DS2760_ACTIVE_FULL
+ 1] = tmp
[1];
329 static void ds2760_battery_work(struct work_struct
*work
)
331 struct ds2760_device_info
*di
= container_of(work
,
332 struct ds2760_device_info
, monitor_work
.work
);
333 const int interval
= HZ
* 60;
335 dev_dbg(di
->dev
, "%s\n", __func__
);
337 ds2760_battery_update_status(di
);
338 queue_delayed_work(di
->monitor_wqueue
, &di
->monitor_work
, interval
);
341 #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
344 static void ds2760_battery_external_power_changed(struct power_supply
*psy
)
346 struct ds2760_device_info
*di
= to_ds2760_device_info(psy
);
348 dev_dbg(di
->dev
, "%s\n", __func__
);
350 cancel_delayed_work(&di
->monitor_work
);
351 queue_delayed_work(di
->monitor_wqueue
, &di
->monitor_work
, HZ
/10);
355 static void ds2760_battery_set_charged_work(struct work_struct
*work
)
358 struct ds2760_device_info
*di
= container_of(work
,
359 struct ds2760_device_info
, set_charged_work
.work
);
361 dev_dbg(di
->dev
, "%s\n", __func__
);
363 ds2760_battery_read_status(di
);
365 /* When we get notified by external circuitry that the battery is
366 * considered fully charged now, we know that there is no current
367 * flow any more. However, the ds2760's internal current meter is
368 * too inaccurate to rely on - spec say something ~15% failure.
369 * Hence, we use the current offset bias register to compensate
373 if (!power_supply_am_i_supplied(&di
->bat
))
376 bias
= (signed char) di
->current_raw
+
377 (signed char) di
->raw
[DS2760_CURRENT_OFFSET_BIAS
];
379 dev_dbg(di
->dev
, "%s: bias = %d\n", __func__
, bias
);
381 w1_ds2760_write(di
->w1_dev
, &bias
, DS2760_CURRENT_OFFSET_BIAS
, 1);
382 w1_ds2760_store_eeprom(di
->w1_dev
, DS2760_EEPROM_BLOCK1
);
383 w1_ds2760_recall_eeprom(di
->w1_dev
, DS2760_EEPROM_BLOCK1
);
385 /* Write to the di->raw[] buffer directly - the CURRENT_OFFSET_BIAS
386 * value won't be read back by ds2760_battery_read_status() */
387 di
->raw
[DS2760_CURRENT_OFFSET_BIAS
] = bias
;
390 static void ds2760_battery_set_charged(struct power_supply
*psy
)
392 struct ds2760_device_info
*di
= to_ds2760_device_info(psy
);
394 /* postpone the actual work by 20 secs. This is for debouncing GPIO
395 * signals and to let the current value settle. See AN4188. */
396 cancel_delayed_work(&di
->set_charged_work
);
397 queue_delayed_work(di
->monitor_wqueue
, &di
->set_charged_work
, HZ
* 20);
400 static int ds2760_battery_get_property(struct power_supply
*psy
,
401 enum power_supply_property psp
,
402 union power_supply_propval
*val
)
404 struct ds2760_device_info
*di
= to_ds2760_device_info(psy
);
407 case POWER_SUPPLY_PROP_STATUS
:
408 val
->intval
= di
->charge_status
;
414 ds2760_battery_read_status(di
);
417 case POWER_SUPPLY_PROP_VOLTAGE_NOW
:
418 val
->intval
= di
->voltage_uV
;
420 case POWER_SUPPLY_PROP_CURRENT_NOW
:
421 val
->intval
= di
->current_uA
;
423 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN
:
424 val
->intval
= di
->rated_capacity
;
426 case POWER_SUPPLY_PROP_CHARGE_FULL
:
427 val
->intval
= di
->full_active_uAh
;
429 case POWER_SUPPLY_PROP_CHARGE_EMPTY
:
430 val
->intval
= di
->empty_uAh
;
432 case POWER_SUPPLY_PROP_CHARGE_NOW
:
433 val
->intval
= di
->accum_current_uAh
;
435 case POWER_SUPPLY_PROP_TEMP
:
436 val
->intval
= di
->temp_C
;
438 case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW
:
439 val
->intval
= di
->life_sec
;
441 case POWER_SUPPLY_PROP_CAPACITY
:
442 val
->intval
= di
->rem_capacity
;
451 static int ds2760_battery_set_property(struct power_supply
*psy
,
452 enum power_supply_property psp
,
453 const union power_supply_propval
*val
)
455 struct ds2760_device_info
*di
= to_ds2760_device_info(psy
);
458 case POWER_SUPPLY_PROP_CHARGE_FULL
:
459 /* the interface counts in uAh, convert the value */
460 ds2760_battery_write_active_full(di
, val
->intval
/ 1000L);
463 case POWER_SUPPLY_PROP_CHARGE_NOW
:
464 /* ds2760_battery_set_current_accum() does the conversion */
465 ds2760_battery_set_current_accum(di
, val
->intval
);
475 static int ds2760_battery_property_is_writeable(struct power_supply
*psy
,
476 enum power_supply_property psp
)
479 case POWER_SUPPLY_PROP_CHARGE_FULL
:
480 case POWER_SUPPLY_PROP_CHARGE_NOW
:
490 static enum power_supply_property ds2760_battery_props
[] = {
491 POWER_SUPPLY_PROP_STATUS
,
492 POWER_SUPPLY_PROP_VOLTAGE_NOW
,
493 POWER_SUPPLY_PROP_CURRENT_NOW
,
494 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN
,
495 POWER_SUPPLY_PROP_CHARGE_FULL
,
496 POWER_SUPPLY_PROP_CHARGE_EMPTY
,
497 POWER_SUPPLY_PROP_CHARGE_NOW
,
498 POWER_SUPPLY_PROP_TEMP
,
499 POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW
,
500 POWER_SUPPLY_PROP_CAPACITY
,
503 static int ds2760_battery_probe(struct platform_device
*pdev
)
507 struct ds2760_device_info
*di
;
509 di
= kzalloc(sizeof(*di
), GFP_KERNEL
);
512 goto di_alloc_failed
;
515 platform_set_drvdata(pdev
, di
);
517 di
->dev
= &pdev
->dev
;
518 di
->w1_dev
= pdev
->dev
.parent
;
519 di
->bat
.name
= dev_name(&pdev
->dev
);
520 di
->bat
.type
= POWER_SUPPLY_TYPE_BATTERY
;
521 di
->bat
.properties
= ds2760_battery_props
;
522 di
->bat
.num_properties
= ARRAY_SIZE(ds2760_battery_props
);
523 di
->bat
.get_property
= ds2760_battery_get_property
;
524 di
->bat
.set_property
= ds2760_battery_set_property
;
525 di
->bat
.property_is_writeable
=
526 ds2760_battery_property_is_writeable
;
527 di
->bat
.set_charged
= ds2760_battery_set_charged
;
528 di
->bat
.external_power_changed
=
529 ds2760_battery_external_power_changed
;
531 di
->charge_status
= POWER_SUPPLY_STATUS_UNKNOWN
;
533 /* enable sleep mode feature */
534 ds2760_battery_read_status(di
);
535 status
= di
->raw
[DS2760_STATUS_REG
];
537 status
|= DS2760_STATUS_PMOD
;
539 status
&= ~DS2760_STATUS_PMOD
;
541 ds2760_battery_write_status(di
, status
);
543 /* set rated capacity from module param */
545 ds2760_battery_write_rated_capacity(di
, rated_capacity
);
547 /* set current accumulator if given as parameter.
548 * this should only be done for bootstrapping the value */
550 ds2760_battery_set_current_accum(di
, current_accum
);
552 retval
= power_supply_register(&pdev
->dev
, &di
->bat
);
554 dev_err(di
->dev
, "failed to register battery\n");
558 INIT_DELAYED_WORK(&di
->monitor_work
, ds2760_battery_work
);
559 INIT_DELAYED_WORK(&di
->set_charged_work
,
560 ds2760_battery_set_charged_work
);
561 di
->monitor_wqueue
= create_singlethread_workqueue(dev_name(&pdev
->dev
));
562 if (!di
->monitor_wqueue
) {
564 goto workqueue_failed
;
566 queue_delayed_work(di
->monitor_wqueue
, &di
->monitor_work
, HZ
* 1);
571 power_supply_unregister(&di
->bat
);
579 static int ds2760_battery_remove(struct platform_device
*pdev
)
581 struct ds2760_device_info
*di
= platform_get_drvdata(pdev
);
583 cancel_rearming_delayed_workqueue(di
->monitor_wqueue
,
585 cancel_rearming_delayed_workqueue(di
->monitor_wqueue
,
586 &di
->set_charged_work
);
587 destroy_workqueue(di
->monitor_wqueue
);
588 power_supply_unregister(&di
->bat
);
595 static int ds2760_battery_suspend(struct platform_device
*pdev
,
598 struct ds2760_device_info
*di
= platform_get_drvdata(pdev
);
600 di
->charge_status
= POWER_SUPPLY_STATUS_UNKNOWN
;
605 static int ds2760_battery_resume(struct platform_device
*pdev
)
607 struct ds2760_device_info
*di
= platform_get_drvdata(pdev
);
609 di
->charge_status
= POWER_SUPPLY_STATUS_UNKNOWN
;
610 power_supply_changed(&di
->bat
);
612 cancel_delayed_work(&di
->monitor_work
);
613 queue_delayed_work(di
->monitor_wqueue
, &di
->monitor_work
, HZ
);
620 #define ds2760_battery_suspend NULL
621 #define ds2760_battery_resume NULL
623 #endif /* CONFIG_PM */
625 MODULE_ALIAS("platform:ds2760-battery");
627 static struct platform_driver ds2760_battery_driver
= {
629 .name
= "ds2760-battery",
631 .probe
= ds2760_battery_probe
,
632 .remove
= ds2760_battery_remove
,
633 .suspend
= ds2760_battery_suspend
,
634 .resume
= ds2760_battery_resume
,
637 static int __init
ds2760_battery_init(void)
639 return platform_driver_register(&ds2760_battery_driver
);
642 static void __exit
ds2760_battery_exit(void)
644 platform_driver_unregister(&ds2760_battery_driver
);
647 module_init(ds2760_battery_init
);
648 module_exit(ds2760_battery_exit
);
650 MODULE_LICENSE("GPL");
651 MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
652 "Matt Reimer <mreimer@vpop.net>, "
653 "Anton Vorontsov <cbou@mail.ru>");
654 MODULE_DESCRIPTION("ds2760 battery driver");