/*
* Driver for batteries with DS2760 chips inside.
*
* Copyright © 2007 Anton Vorontsov
* 2004-2007 Matt Reimer
* 2004 Szabolcs Gyurko
*
* Use consistent with the GNU GPL is permitted,
* provided that this copyright notice is
* preserved in its entirety in all copies and derived works.
*
* Author: Anton Vorontsov <cbou@mail.ru>
* February 2007
*
* Matt Reimer <mreimer@vpop.net>
* April 2004, 2005, 2007
*
* Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>
* September 2004
*/
#include <linux/module.h>
#include <linux/param.h>
#include <linux/jiffies.h>
#include <linux/workqueue.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include "../w1/w1.h"
#include "../w1/slaves/w1_ds2760.h"
struct ds2760_device_info {
struct device *dev;
/* DS2760 data, valid after calling ds2760_battery_read_status() */
unsigned long update_time; /* jiffies when data read */
char raw[DS2760_DATA_SIZE]; /* raw DS2760 data */
int voltage_raw; /* units of 4.88 mV */
int voltage_uV; /* units of µV */
int current_raw; /* units of 0.625 mA */
int current_uA; /* units of µA */
int accum_current_raw; /* units of 0.25 mAh */
int accum_current_uAh; /* units of µAh */
int temp_raw; /* units of 0.125 °C */
int temp_C; /* units of 0.1 °C */
int rated_capacity; /* units of µAh */
int rem_capacity; /* percentage */
int full_active_uAh; /* units of µAh */
int empty_uAh; /* units of µAh */
int life_sec; /* units of seconds */
int charge_status; /* POWER_SUPPLY_STATUS_* */
int full_counter;
struct power_supply bat;
struct device *w1_dev;
struct workqueue_struct *monitor_wqueue;
struct delayed_work monitor_work;
};
static unsigned int cache_time = 1000;
module_param(cache_time, uint, 0644);
MODULE_PARM_DESC(cache_time, "cache time in milliseconds");
/* Some batteries have their rated capacity stored a N * 10 mAh, while
* others use an index into this table. */
static int rated_capacities[] = {
0,
920, /* Samsung */
920, /* BYD */
920, /* Lishen */
920, /* NEC */
1440, /* Samsung */
1440, /* BYD */
1440, /* Lishen */
1440, /* NEC */
2880, /* Samsung */
2880, /* BYD */
2880, /* Lishen */
2880 /* NEC */
};
/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C
* temp is in Celsius */
static int battery_interpolate(int array[], int temp)
{
int index, dt;
if (temp <= 0)
return array[0];
if (temp >= 40)
return array[4];
index = temp / 10;
dt = temp % 10;
return array[index] + (((array[index + 1] - array[index]) * dt) / 10);
}
static int ds2760_battery_read_status(struct ds2760_device_info *di)
{
int ret, i, start, count, scale[5];
if (di->update_time && time_before(jiffies, di->update_time +
msecs_to_jiffies(cache_time)))
return 0;
/* The first time we read the entire contents of SRAM/EEPROM,
* but after that we just read the interesting bits that change. */
if (di->update_time == 0) {
start = 0;
count = DS2760_DATA_SIZE;
} else {
start = DS2760_VOLTAGE_MSB;
count = DS2760_TEMP_LSB - start + 1;
}
ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count);
if (ret != count) {
dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n",
di->w1_dev);
return 1;
}
di->update_time = jiffies;
/* DS2760 reports voltage in units of 4.88mV, but the battery class
* reports in units of uV, so convert by multiplying by 4880. */
di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) |
(di->raw[DS2760_VOLTAGE_LSB] >> 5);
di->voltage_uV = di->voltage_raw * 4880;
/* DS2760 reports current in signed units of 0.625mA, but the battery
* class reports in units of µA, so convert by multiplying by 625. */
di->current_raw =
(((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) |
(di->raw[DS2760_CURRENT_LSB] >> 3);
di->current_uA = di->current_raw * 625;
/* DS2760 reports accumulated current in signed units of 0.25mAh. */
di->accum_current_raw =
(((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) |
di->raw[DS2760_CURRENT_ACCUM_LSB];
di->accum_current_uAh = di->accum_current_raw * 250;
/* DS2760 reports temperature in signed units of 0.125°C, but the
* battery class reports in units of 1/10 °C, so we convert by
* multiplying by .125 * 10 = 1.25. */
di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) |
(di->raw[DS2760_TEMP_LSB] >> 5);
di->temp_C = di->temp_raw + (di->temp_raw / 4);
/* At least some battery monitors (e.g. HP iPAQ) store the battery's
* maximum rated capacity. */
if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities))
di->rated_capacity = rated_capacities[
(unsigned int)di->raw[DS2760_RATED_CAPACITY]];
else
di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10;
di->rated_capacity *= 1000; /* convert to µAh */
/* Calculate the full level at the present temperature. */
di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 |
di->raw[DS2760_ACTIVE_FULL + 1];
scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 |
di->raw[DS2760_ACTIVE_FULL + 1];
for (i = 1; i < 5; i++)
scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i];
di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10);
di->full_active_uAh *= 1000; /* convert to µAh */
/* Calculate the empty level at the present temperature. */
scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4];
for (i = 3; i >= 0; i--)
scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i];
di->empty_uAh = battery_interpolate(scale, di->temp_C / 10);
di->empty_uAh *= 1000; /* convert to µAh */
/* From Maxim Application Note 131: remaining capacity =
* ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */
di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) /
(di->full_active_uAh - di->empty_uAh);
if (di->rem_capacity < 0)
di->rem_capacity = 0;
if (di->rem_capacity > 100)
di->rem_capacity = 100;
if (di->current_uA)
di->life_sec = -((di->accum_current_uAh - di->empty_uAh) *
3600L) / di->current_uA;
else
di->life_sec = 0;
return 0;
}
static void ds2760_battery_update_status(struct ds2760_device_info *di)
{
int old_charge_status = di->charge_status;
ds2760_battery_read_status(di);
if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN)
di->full_counter = 0;
if (power_supply_am_i_supplied(&di->bat)) {
if (di->current_uA > 10000) {
di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
di->full_counter = 0;
} else if (di->current_uA < -5000) {
if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING)
dev_notice(di->dev, "not enough power to "
"charge\n");
di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING;
di->full_counter = 0;
} else if (di->current_uA < 10000 &&
di->charge_status != POWER_SUPPLY_STATUS_FULL) {
/* Don't consider the battery to be full unless
* we've seen the current < 10 mA at least two
* consecutive times. */
di->full_counter++;
if (di->full_counter < 2) {
di->charge_status = POWER_SUPPLY_STATUS_CHARGING;
} else {
unsigned char acr[2];
int acr_val;
/* acr is in units of 0.25 mAh */
acr_val = di->full_active_uAh * 4L / 1000;
acr[0] = acr_val >> 8;
acr[1] = acr_val & 0xff;
if (w1_ds2760_write(di->w1_dev, acr,
DS2760_CURRENT_ACCUM_MSB, 2) < 2)
dev_warn(di->dev,
"ACR reset failed\n");
di->charge_status = POWER_SUPPLY_STATUS_FULL;
}
}
} else {
di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING;
di->full_counter = 0;
}
if (di->charge_status != old_charge_status)
power_supply_changed(&di->bat);
}
static void ds2760_battery_work(struct work_struct *work)
{
struct ds2760_device_info *di = container_of(work,
struct ds2760_device_info, monitor_work.work);
const int interval = HZ * 60;
dev_dbg(di->dev, "%s\n", __func__);
ds2760_battery_update_status(di);
queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval);
}
#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \
bat);
static void ds2760_battery_external_power_changed(struct power_supply *psy)
{
struct ds2760_device_info *di = to_ds2760_device_info(psy);
dev_dbg(di->dev, "%s\n", __func__);
cancel_delayed_work(&di->monitor_work);
queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10);
}
static int ds2760_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct ds2760_device_info *di = to_ds2760_device_info(psy);
switch (psp) {
case POWER_SUPPLY_PROP_STATUS:
val->intval = di->charge_status;
return 0;
default:
break;
}
ds2760_battery_read_status(di);
switch (psp) {
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
val->intval = di->voltage_uV;
break;
case POWER_SUPPLY_PROP_CURRENT_NOW:
val->intval = di->current_uA;
break;
case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
val->intval = di->rated_capacity;
break;
case POWER_SUPPLY_PROP_CHARGE_FULL:
val->intval = di->full_active_uAh;
break;
case POWER_SUPPLY_PROP_CHARGE_EMPTY:
val->intval = di->empty_uAh;
break;
case POWER_SUPPLY_PROP_CHARGE_NOW:
val->intval = di->accum_current_uAh;
break;
case POWER_SUPPLY_PROP_TEMP:
val->intval = di->temp_C;
break;
default:
return -EINVAL;
}
return 0;
}
static enum power_supply_property ds2760_battery_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_CURRENT_NOW,
POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
POWER_SUPPLY_PROP_CHARGE_FULL,
POWER_SUPPLY_PROP_CHARGE_EMPTY,
POWER_SUPPLY_PROP_CHARGE_NOW,
POWER_SUPPLY_PROP_TEMP,
};
static int ds2760_battery_probe(struct platform_device *pdev)
{
int retval = 0;
struct ds2760_device_info *di;
struct ds2760_platform_data *pdata;
di = kzalloc(sizeof(*di), GFP_KERNEL);
if (!di) {
retval = -ENOMEM;
goto di_alloc_failed;
}
platform_set_drvdata(pdev, di);
pdata = pdev->dev.platform_data;
di->dev = &pdev->dev;
di->w1_dev = pdev->dev.parent;
di->bat.name = pdev->dev.bus_id;
di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
di->bat.properties = ds2760_battery_props;
di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props);
di->bat.get_property = ds2760_battery_get_property;
di->bat.external_power_changed =
ds2760_battery_external_power_changed;
di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
retval = power_supply_register(&pdev->dev, &di->bat);
if (retval) {
dev_err(di->dev, "failed to register battery\n");
goto batt_failed;
}
INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work);
di->monitor_wqueue = create_singlethread_workqueue(pdev->dev.bus_id);
if (!di->monitor_wqueue) {
retval = -ESRCH;
goto workqueue_failed;
}
queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1);
goto success;
workqueue_failed:
power_supply_unregister(&di->bat);
batt_failed:
kfree(di);
di_alloc_failed:
success:
return retval;
}
static int ds2760_battery_remove(struct platform_device *pdev)
{
struct ds2760_device_info *di = platform_get_drvdata(pdev);
cancel_rearming_delayed_workqueue(di->monitor_wqueue,
&di->monitor_work);
destroy_workqueue(di->monitor_wqueue);
power_supply_unregister(&di->bat);
return 0;
}
#ifdef CONFIG_PM
static int ds2760_battery_suspend(struct platform_device *pdev,
pm_message_t state)
{
struct ds2760_device_info *di = platform_get_drvdata(pdev);
di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
return 0;
}
static int ds2760_battery_resume(struct platform_device *pdev)
{
struct ds2760_device_info *di = platform_get_drvdata(pdev);
di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN;
power_supply_changed(&di->bat);
cancel_delayed_work(&di->monitor_work);
queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ);
return 0;
}
#else
#define ds2760_battery_suspend NULL
#define ds2760_battery_resume NULL
#endif /* CONFIG_PM */
static struct platform_driver ds2760_battery_driver = {
.driver = {
.name = "ds2760-battery",
},
.probe = ds2760_battery_probe,
.remove = ds2760_battery_remove,
.suspend = ds2760_battery_suspend,
.resume = ds2760_battery_resume,
};
static int __init ds2760_battery_init(void)
{
return platform_driver_register(&ds2760_battery_driver);
}
static void __exit ds2760_battery_exit(void)
{
platform_driver_unregister(&ds2760_battery_driver);
}
module_init(ds2760_battery_init);
module_exit(ds2760_battery_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, "
"Matt Reimer <mreimer@vpop.net>, "
"Anton Vorontsov <cbou@mail.ru>");
MODULE_DESCRIPTION("ds2760 battery driver");
