diff options
Diffstat (limited to 'drivers/power/bq27x00_battery.c')
| -rw-r--r-- | drivers/power/bq27x00_battery.c | 381 |
1 files changed, 381 insertions, 0 deletions
diff --git a/drivers/power/bq27x00_battery.c b/drivers/power/bq27x00_battery.c new file mode 100644 index 000000000000..0c056fcc01ce --- /dev/null +++ b/drivers/power/bq27x00_battery.c @@ -0,0 +1,381 @@ +/* + * 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"); |