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", __func__
);
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", __func__
);
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\n");
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");