/* * BQ27x00 battery driver * * Copyright (C) 2008 Rodolfo Giometti * Copyright (C) 2008 Eurotech S.p.A. * * 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 #include #include #include #include #include #include #include #include #include #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; 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) { return di->bus->read(reg, rt_value, b_single, di); } /* * Return the battery temperature in Celsius 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; } #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_le16(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 "); MODULE_DESCRIPTION("BQ27x00 battery monitor driver"); MODULE_LICENSE("GPL");