/*
* I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC
*
* Copyright (C) 2009 Bluewater Systems Ltd
*
* Author: Ryan Mallon
*
* DS2786 added by Yulia Vilensky <vilensky@compulab.co.il>
*
* UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/swab.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/idr.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/ds2782_battery.h>
#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */
#define DS278x_REG_VOLT_MSB 0x0c
#define DS278x_REG_TEMP_MSB 0x0a
#define DS278x_REG_CURRENT_MSB 0x0e
/* EEPROM Block */
#define DS2782_REG_RSNSP 0x69 /* Sense resistor value */
/* Current unit measurement in uA for a 1 milli-ohm sense resistor */
#define DS2782_CURRENT_UNITS 1563
#define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */
#define DS2786_CURRENT_UNITS 25
#define DS278x_DELAY 1000
struct ds278x_info;
struct ds278x_battery_ops {
int (*get_battery_current)(struct ds278x_info *info, int *current_uA);
int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV);
int (*get_battery_capacity)(struct ds278x_info *info, int *capacity);
};
#define to_ds278x_info(x) power_supply_get_drvdata(x)
struct ds278x_info {
struct i2c_client *client;
struct power_supply *battery;
struct power_supply_desc battery_desc;
struct ds278x_battery_ops *ops;
struct delayed_work bat_work;
int id;
int rsns;
int capacity;
int status; /* State Of Charge */
};
static DEFINE_IDR(battery_id);
static DEFINE_MUTEX(battery_lock);
static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val)
{
int ret;
ret = i2c_smbus_read_byte_data(info->client, reg);
if (ret < 0) {
dev_err(&info->client->dev, "register read failed\n");
return ret;
}
*val = ret;
return 0;
}
static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb,
s16 *val)
{
int ret;
ret = i2c_smbus_read_word_data(info->client, reg_msb);
if (ret < 0) {
dev_err(&info->client->dev, "register read failed\n");
return ret;
}
*val = swab16(ret);
return 0;
}
static int ds278x_get_temp(struct ds278x_info *info, int *temp)
{
s16 raw;
int err;
/*
* Temperature is measured in units of 0.125 degrees celcius, the
* power_supply class measures temperature in tenths of degrees
* celsius. The temperature value is stored as a 10 bit number, plus
* sign in the upper bits of a 16 bit register.
*/
err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw);
if (err)
return err;
*temp = ((raw / 32) * 125) / 100;
return 0;
}
static int ds2782_get_current(struct ds278x_info *info, int *current_uA)
{
int sense_res;
int err;
u8 sense_res_raw;
s16 raw;
/*
* The units of measurement for current are dependent on the value of
* the sense resistor.
*/
err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw);
if (err)
return err;
if (sense_res_raw == 0) {
dev_err(&info->client->dev, "sense resistor value is 0\n");
return -ENXIO;
}
sense_res = 1000 / sense_res_raw;
dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n",
sense_res);
err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
if (err)
return err;
*current_uA = raw * (DS2782_CURRENT_UNITS / sense_res);
return 0;
}
static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV)
{
s16 raw;
int err;
/*
* Voltage is measured in units of 4.88mV. The voltage is stored as
* a 10-bit number plus sign, in the upper bits of a 16-bit register
*/
err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
if (err)
return err;
*voltage_uV = (raw / 32) * 4800;
return 0;
}
static int ds2782_get_capacity(struct ds278x_info *info, int *capacity)
{
int err;
u8 raw;
err = ds278x_read_reg(info, DS2782_REG_RARC, &raw);
if (err)
return err;
*capacity = raw;
return 0;
}
static int ds2786_get_current(struct ds278x_info *info, int *current_uA)
{
int err;
s16 raw;
err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw);
if (err)
return err;
*current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns);
return 0;
}
static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV)
{
s16 raw;
int err;
/*
* Voltage is measured in units of 1.22mV. The voltage is stored as
* a 12-bit number plus sign, in the upper bits of a 16-bit register
*/
err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw);
if (err)
return err;
*voltage_uV = (raw / 8) * 1220;
return 0;
}
static int ds2786_get_capacity(struct ds278x_info *info, int *capacity)
{
int err;
u8 raw;
err = ds278x_read_reg(info, DS2786_REG_RARC, &raw);
if (err)
return err;
/* Relative capacity is displayed with resolution 0.5 % */
*capacity = raw/2 ;
return 0;
}
static int ds278x_get_status(struct ds278x_info *info, int *status)
{
int err;
int current_uA;
int capacity;
err = info->ops->get_battery_current(info, ¤t_uA);
if (err)
return err;
err = info->ops->get_battery_capacity(info, &capacity);
if (err)
return err;
info->capacity = capacity;
if (capacity == 100)
*status = POWER_SUPPLY_STATUS_FULL;
else if (current_uA == 0)
*status = POWER_SUPPLY_STATUS_NOT_CHARGING;
else if (current_uA < 0)
*status = POWER_SUPPLY_STATUS_DISCHARGING;
else
*status = POWER_SUPPLY_STATUS_CHARGING;
return 0;
}
static int ds278x_battery_get_property(struct power_supply *psy,
enum power_supply_property prop,
union power_supply_propval *val)
{
struct ds278x_info *info = to_ds278x_info(psy);
int ret;
switch (prop) {
case POWER_SUPPLY_PROP_STATUS:
ret = ds278x_get_status(info, &val->intval);
break;
case POWER_SUPPLY_PROP_CAPACITY:
ret = info->ops->get_battery_capacity(info, &val->intval);
break;
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
ret = info->ops->get_battery_voltage(info, &val->intval);
break;
case POWER_SUPPLY_PROP_CURRENT_NOW:
ret = info->ops->get_battery_current(info, &val->intval);
break;
case POWER_SUPPLY_PROP_TEMP:
ret = ds278x_get_temp(info, &val->intval);
break;
default:
ret = -EINVAL;
}
return ret;
}
static void ds278x_bat_update(struct ds278x_info *info)
{
int old_status = info->status;
int old_capacity = info->capacity;
ds278x_get_status(info, &info->status);
if ((old_status != info->status) || (old_capacity != info->capacity))
power_supply_changed(info->battery);
}
static void ds278x_bat_work(struct work_struct *work)
{
struct ds278x_info *info;
info = container_of(work, struct ds278x_info, bat_work.work);
ds278x_bat_update(info);
schedule_delayed_work(&info->bat_work, DS278x_DELAY);
}
static enum power_supply_property ds278x_battery_props[] = {
POWER_SUPPLY_PROP_STATUS,
POWER_SUPPLY_PROP_CAPACITY,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_CURRENT_NOW,
POWER_SUPPLY_PROP_TEMP,
};
static void ds278x_power_supply_init(struct power_supply_desc *battery)
{
battery->type = POWER_SUPPLY_TYPE_BATTERY;
battery->properties = ds278x_battery_props;
battery->num_properties = ARRAY_SIZE(ds278x_battery_props);
battery->get_property = ds278x_battery_get_property;
battery->external_power_changed = NULL;
}
static int ds278x_battery_remove(struct i2c_client *client)
{
struct ds278x_info *info = i2c_get_clientdata(client);
power_supply_unregister(info->battery);
kfree(info->battery_desc.name);
mutex_lock(&battery_lock);
idr_remove(&battery_id, info->id);
mutex_unlock(&battery_lock);
cancel_delayed_work(&info->bat_work);
kfree(info);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int ds278x_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds278x_info *info = i2c_get_clientdata(client);
cancel_delayed_work(&info->bat_work);
return 0;
}
static int ds278x_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
struct ds278x_info *info = i2c_get_clientdata(client);
schedule_delayed_work(&info->bat_work, DS278x_DELAY);
return 0;
}
#endif /* CONFIG_PM_SLEEP */
static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume);
enum ds278x_num_id {
DS2782 = 0,
DS2786,
};
static struct ds278x_battery_ops ds278x_ops[] = {
[DS2782] = {
.get_battery_current = ds2782_get_current,
.get_battery_voltage = ds2782_get_voltage,
.get_battery_capacity = ds2782_get_capacity,
},
[DS2786] = {
.get_battery_current = ds2786_get_current,
.get_battery_voltage = ds2786_get_voltage,
.get_battery_capacity = ds2786_get_capacity,
}
};
static int ds278x_battery_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct ds278x_platform_data *pdata = client->dev.platform_data;
struct power_supply_config psy_cfg = {};
struct ds278x_info *info;
int ret;
int num;
/*
* ds2786 should have the sense resistor value set
* in the platform data
*/
if (id->driver_data == DS2786 && !pdata) {
dev_err(&client->dev, "missing platform data for ds2786\n");
return -EINVAL;
}
/* Get an ID for this battery */
mutex_lock(&battery_lock);
ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL);
mutex_unlock(&battery_lock);
if (ret < 0)
goto fail_id;
num = ret;
info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info) {
ret = -ENOMEM;
goto fail_info;
}
info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d",
client->name, num);
if (!info->battery_desc.name) {
ret = -ENOMEM;
goto fail_name;
}
if (id->driver_data == DS2786)
info->rsns = pdata->rsns;
i2c_set_clientdata(client, info);
info->client = client;
info->id = num;
info->ops = &ds278x_ops[id->driver_data];
ds278x_power_supply_init(&info->battery_desc);
psy_cfg.drv_data = info;
info->capacity = 100;
info->status = POWER_SUPPLY_STATUS_FULL;
INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work);
info->battery = power_supply_register(&client->dev,
&info->battery_desc, &psy_cfg);
if (IS_ERR(info->battery)) {
dev_err(&client->dev, "failed to register battery\n");
ret = PTR_ERR(info->battery);
goto fail_register;
} else {
schedule_delayed_work(&info->bat_work, DS278x_DELAY);
}
return 0;
fail_register:
kfree(info->battery_desc.name);
fail_name:
kfree(info);
fail_info:
mutex_lock(&battery_lock);
idr_remove(&battery_id, num);
mutex_unlock(&battery_lock);
fail_id:
return ret;
}
static const struct i2c_device_id ds278x_id[] = {
{"ds2782", DS2782},
{"ds2786", DS2786},
{},
};
MODULE_DEVICE_TABLE(i2c, ds278x_id);
static struct i2c_driver ds278x_battery_driver = {
.driver = {
.name = "ds2782-battery",
.pm = &ds278x_battery_pm_ops,
},
.probe = ds278x_battery_probe,
.remove = ds278x_battery_remove,
.id_table = ds278x_id,
};
module_i2c_driver(ds278x_battery_driver);
MODULE_AUTHOR("Ryan Mallon");
MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver");
MODULE_LICENSE("GPL");