/*
* BQ27x00 battery driver
*
* Copyright (C) 2008 Rodolfo Giometti <giometti@linux.it>
* Copyright (C) 2008 Eurotech S.p.A. <info@eurotech.it>
*
* Based on a previous work by Copyright (C) 2008 Texas Instruments, Inc.
*
* This package 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.
*
* THIS PACKAGE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
*/
#include <linux/module.h>
#include <linux/param.h>
#include <linux/jiffies.h>
#include <linux/workqueue.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/idr.h>
#include <linux/i2c.h>
#include <asm/unaligned.h>
#define DRIVER_VERSION "1.0.0"
#define BQ27x00_REG_TEMP 0x06
#define BQ27x00_REG_VOLT 0x08
#define BQ27x00_REG_RSOC 0x0B /* Relative State-of-Charge */
#define BQ27x00_REG_AI 0x14
#define BQ27x00_REG_FLAGS 0x0A
/* If the system has several batteries we need a different name for each
* of them...
*/
static DEFINE_IDR(battery_id);
static DEFINE_MUTEX(battery_mutex);
struct bq27x00_device_info;
struct bq27x00_access_methods {
int (*read)(u8 reg, int *rt_value, int b_single,
struct bq27x00_device_info *di);
};
struct bq27x00_device_info {
struct device *dev;
int id;
int voltage_uV;
int current_uA;
int temp_C;
int charge_rsoc;
struct bq27x00_access_methods *bus;
struct power_supply bat;
struct i2c_client *client;
};
static enum power_supply_property bq27x00_battery_props[] = {
POWER_SUPPLY_PROP_PRESENT,
POWER_SUPPLY_PROP_VOLTAGE_NOW,
POWER_SUPPLY_PROP_CURRENT_NOW,
POWER_SUPPLY_PROP_CAPACITY,
POWER_SUPPLY_PROP_TEMP,
};
/*
* Common code for BQ27x00 devices
*/
static int bq27x00_read(u8 reg, int *rt_value, int b_single,
struct bq27x00_device_info *di)
{
int ret;
ret = di->bus->read(reg, rt_value, b_single, di);
*rt_value = be16_to_cpu(*rt_value);
return ret;
}
/*
* Return the battery temperature in Celcius degrees
* Or < 0 if something fails.
*/
static int bq27x00_battery_temperature(struct bq27x00_device_info *di)
{
int ret;
int temp = 0;
ret = bq27x00_read(BQ27x00_REG_TEMP, &temp, 0, di);
if (ret) {
dev_err(di->dev, "error reading temperature\n");
return ret;
}
return (temp >> 2) - 273;
}
/*
* Return the battery Voltage in milivolts
* Or < 0 if something fails.
*/
static int bq27x00_battery_voltage(struct bq27x00_device_info *di)
{
int ret;
int volt = 0;
ret = bq27x00_read(BQ27x00_REG_VOLT, &volt, 0, di);
if (ret) {
dev_err(di->dev, "error reading voltage\n");
return ret;
}
return volt;
}
/*
* Return the battery average current
* Note that current can be negative signed as well
* Or 0 if something fails.
*/
static int bq27x00_battery_current(struct bq27x00_device_info *di)
{
int ret;
int curr = 0;
int flags = 0;
ret = bq27x00_read(BQ27x00_REG_AI, &curr, 0, di);
if (ret) {
dev_err(di->dev, "error reading current\n");
return 0;
}
ret = bq27x00_read(BQ27x00_REG_FLAGS, &flags, 0, di);
if (ret < 0) {
dev_err(di->dev, "error reading flags\n");
return 0;
}
if ((flags & (1 << 7)) != 0) {
dev_dbg(di->dev, "negative current!\n");
return -curr;
}
return curr;
}
/*
* Return the battery Relative State-of-Charge
* Or < 0 if something fails.
*/
static int bq27x00_battery_rsoc(struct bq27x00_device_info *di)
{
int ret;
int rsoc = 0;
ret = bq27x00_read(BQ27x00_REG_RSOC, &rsoc, 1, di);
if (ret) {
dev_err(di->dev, "error reading relative State-of-Charge\n");
return ret;
}
return rsoc >> 8;
}
#define to_bq27x00_device_info(x) container_of((x), \
struct bq27x00_device_info, bat);
static int bq27x00_battery_get_property(struct power_supply *psy,
enum power_supply_property psp,
union power_supply_propval *val)
{
struct bq27x00_device_info *di = to_bq27x00_device_info(psy);
switch (psp) {
case POWER_SUPPLY_PROP_VOLTAGE_NOW:
case POWER_SUPPLY_PROP_PRESENT:
val->intval = bq27x00_battery_voltage(di);
if (psp == POWER_SUPPLY_PROP_PRESENT)
val->intval = val->intval <= 0 ? 0 : 1;
break;
case POWER_SUPPLY_PROP_CURRENT_NOW:
val->intval = bq27x00_battery_current(di);
break;
case POWER_SUPPLY_PROP_CAPACITY:
val->intval = bq27x00_battery_rsoc(di);
break;
case POWER_SUPPLY_PROP_TEMP:
val->intval = bq27x00_battery_temperature(di);
break;
default:
return -EINVAL;
}
return 0;
}
static void bq27x00_powersupply_init(struct bq27x00_device_info *di)
{
di->bat.type = POWER_SUPPLY_TYPE_BATTERY;
di->bat.properties = bq27x00_battery_props;
di->bat.num_properties = ARRAY_SIZE(bq27x00_battery_props);
di->bat.get_property = bq27x00_battery_get_property;
di->bat.external_power_changed = NULL;
}
/*
* BQ27200 specific code
*/
static int bq27200_read(u8 reg, int *rt_value, int b_single,
struct bq27x00_device_info *di)
{
struct i2c_client *client = di->client;
struct i2c_msg msg[1];
unsigned char data[2];
int err;
if (!client->adapter)
return -ENODEV;
msg->addr = client->addr;
msg->flags = 0;
msg->len = 1;
msg->buf = data;
data[0] = reg;
err = i2c_transfer(client->adapter, msg, 1);
if (err >= 0) {
if (!b_single)
msg->len = 2;
else
msg->len = 1;
msg->flags = I2C_M_RD;
err = i2c_transfer(client->adapter, msg, 1);
if (err >= 0) {
if (!b_single)
*rt_value = get_unaligned_be16(data);
else
*rt_value = data[0];
return 0;
}
}
return err;
}
static int bq27200_battery_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
char *name;
struct bq27x00_device_info *di;
struct bq27x00_access_methods *bus;
int num;
int retval = 0;
/* Get new ID for the new battery device */
retval = idr_pre_get(&battery_id, GFP_KERNEL);
if (retval == 0)
return -ENOMEM;
mutex_lock(&battery_mutex);
retval = idr_get_new(&battery_id, client, &num);
mutex_unlock(&battery_mutex);
if (retval < 0)
return retval;
name = kasprintf(GFP_KERNEL, "bq27200-%d", num);
if (!name) {
dev_err(&client->dev, "failed to allocate device name\n");
retval = -ENOMEM;
goto batt_failed_1;
}
di = kzalloc(sizeof(*di), GFP_KERNEL);
if (!di) {
dev_err(&client->dev, "failed to allocate device info data\n");
retval = -ENOMEM;
goto batt_failed_2;
}
di->id = num;
bus = kzalloc(sizeof(*bus), GFP_KERNEL);
if (!bus) {
dev_err(&client->dev, "failed to allocate access method "
"data\n");
retval = -ENOMEM;
goto batt_failed_3;
}
i2c_set_clientdata(client, di);
di->dev = &client->dev;
di->bat.name = name;
bus->read = &bq27200_read;
di->bus = bus;
di->client = client;
bq27x00_powersupply_init(di);
retval = power_supply_register(&client->dev, &di->bat);
if (retval) {
dev_err(&client->dev, "failed to register battery\n");
goto batt_failed_4;
}
dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
return 0;
batt_failed_4:
kfree(bus);
batt_failed_3:
kfree(di);
batt_failed_2:
kfree(name);
batt_failed_1:
mutex_lock(&battery_mutex);
idr_remove(&battery_id, num);
mutex_unlock(&battery_mutex);
return retval;
}
static int bq27200_battery_remove(struct i2c_client *client)
{
struct bq27x00_device_info *di = i2c_get_clientdata(client);
power_supply_unregister(&di->bat);
kfree(di->bat.name);
mutex_lock(&battery_mutex);
idr_remove(&battery_id, di->id);
mutex_unlock(&battery_mutex);
kfree(di);
return 0;
}
/*
* Module stuff
*/
static const struct i2c_device_id bq27200_id[] = {
{ "bq27200", 0 },
{},
};
static struct i2c_driver bq27200_battery_driver = {
.driver = {
.name = "bq27200-battery",
},
.probe = bq27200_battery_probe,
.remove = bq27200_battery_remove,
.id_table = bq27200_id,
};
static int __init bq27x00_battery_init(void)
{
int ret;
ret = i2c_add_driver(&bq27200_battery_driver);
if (ret)
printk(KERN_ERR "Unable to register BQ27200 driver\n");
return ret;
}
module_init(bq27x00_battery_init);
static void __exit bq27x00_battery_exit(void)
{
i2c_del_driver(&bq27200_battery_driver);
}
module_exit(bq27x00_battery_exit);
MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
MODULE_DESCRIPTION("BQ27x00 battery monitor driver");
MODULE_LICENSE("GPL");
