/* * 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 #include #define DRIVER_VERSION "1.1.0" #define BQ27x00_REG_TEMP 0x06 #define BQ27x00_REG_VOLT 0x08 #define BQ27x00_REG_AI 0x14 #define BQ27x00_REG_FLAGS 0x0A #define BQ27x00_REG_TTE 0x16 #define BQ27x00_REG_TTF 0x18 #define BQ27x00_REG_TTECP 0x26 #define BQ27000_REG_RSOC 0x0B /* Relative State-of-Charge */ #define BQ27000_FLAG_CHGS BIT(7) #define BQ27500_REG_SOC 0x2c #define BQ27500_FLAG_DSC BIT(0) #define BQ27500_FLAG_FC BIT(9) #define BQ27000_RS 20 /* Resistor sense */ /* 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)(struct bq27x00_device_info *, u8 reg, int *rt_value, bool single); }; enum bq27x00_chip { BQ27000, BQ27500 }; struct bq27x00_device_info { struct device *dev; int id; enum bq27x00_chip chip; struct power_supply bat; struct bq27x00_access_methods bus; }; static enum power_supply_property bq27x00_battery_props[] = { POWER_SUPPLY_PROP_STATUS, POWER_SUPPLY_PROP_PRESENT, POWER_SUPPLY_PROP_VOLTAGE_NOW, POWER_SUPPLY_PROP_CURRENT_NOW, POWER_SUPPLY_PROP_CAPACITY, POWER_SUPPLY_PROP_TEMP, POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW, POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG, POWER_SUPPLY_PROP_TIME_TO_FULL_NOW, POWER_SUPPLY_PROP_TECHNOLOGY, }; /* * Common code for BQ27x00 devices */ static inline int bq27x00_read(struct bq27x00_device_info *di, u8 reg, int *rt_value, bool single) { return di->bus.read(di, reg, rt_value, single); } /* * Return the battery temperature in tenths of degree Celsius * Or < 0 if something fails. */ static int bq27x00_battery_temperature(struct bq27x00_device_info *di) { int ret; int temp = 0; ret = bq27x00_read(di, BQ27x00_REG_TEMP, &temp, false); if (ret) { dev_err(di->dev, "error reading temperature\n"); return ret; } if (di->chip == BQ27500) return temp - 2731; else return ((temp * 5) - 5463) / 2; } /* * 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(di, BQ27x00_REG_VOLT, &volt, false); if (ret) { dev_err(di->dev, "error reading voltage\n"); return ret; } return volt * 1000; } /* * 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(di, BQ27x00_REG_AI, &curr, false); if (ret) { dev_err(di->dev, "error reading current\n"); return 0; } if (di->chip == BQ27500) { /* bq27500 returns signed value */ curr = (int)((s16)curr) * 1000; } else { ret = bq27x00_read(di, BQ27x00_REG_FLAGS, &flags, false); if (ret < 0) { dev_err(di->dev, "error reading flags\n"); return 0; } if (flags & BQ27000_FLAG_CHGS) { dev_dbg(di->dev, "negative current!\n"); curr = -curr; } curr = curr * 3570 / BQ27000_RS; } 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; if (di->chip == BQ27500) ret = bq27x00_read(di, BQ27500_REG_SOC, &rsoc, false); else ret = bq27x00_read(di, BQ27000_REG_RSOC, &rsoc, true); if (ret) { dev_err(di->dev, "error reading relative State-of-Charge\n"); return ret; } return rsoc; } static int bq27x00_battery_status(struct bq27x00_device_info *di, union power_supply_propval *val) { int flags = 0; int status; int ret; ret = bq27x00_read(di, BQ27x00_REG_FLAGS, &flags, false); if (ret < 0) { dev_err(di->dev, "error reading flags\n"); return ret; } if (di->chip == BQ27500) { if (flags & BQ27500_FLAG_FC) status = POWER_SUPPLY_STATUS_FULL; else if (flags & BQ27500_FLAG_DSC) status = POWER_SUPPLY_STATUS_DISCHARGING; else status = POWER_SUPPLY_STATUS_CHARGING; } else { if (flags & BQ27000_FLAG_CHGS) status = POWER_SUPPLY_STATUS_CHARGING; else status = POWER_SUPPLY_STATUS_DISCHARGING; } val->intval = status; return 0; } /* * Read a time register. * Return < 0 if something fails. */ static int bq27x00_battery_time(struct bq27x00_device_info *di, int reg, union power_supply_propval *val) { int tval = 0; int ret; ret = bq27x00_read(di, reg, &tval, false); if (ret) { dev_err(di->dev, "error reading register %02x\n", reg); return ret; } if (tval == 65535) return -ENODATA; val->intval = tval * 60; return 0; } #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) { int ret = 0; struct bq27x00_device_info *di = to_bq27x00_device_info(psy); int voltage = bq27x00_battery_voltage(di); if (psp != POWER_SUPPLY_PROP_PRESENT && voltage <= 0) return -ENODEV; switch (psp) { case POWER_SUPPLY_PROP_STATUS: ret = bq27x00_battery_status(di, val); break; case POWER_SUPPLY_PROP_VOLTAGE_NOW: val->intval = voltage; break; case POWER_SUPPLY_PROP_PRESENT: if (psp == POWER_SUPPLY_PROP_PRESENT) val->intval = voltage <= 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; case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: ret = bq27x00_battery_time(di, BQ27x00_REG_TTE, val); break; case POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG: ret = bq27x00_battery_time(di, BQ27x00_REG_TTECP, val); break; case POWER_SUPPLY_PROP_TIME_TO_FULL_NOW: ret = bq27x00_battery_time(di, BQ27x00_REG_TTF, val); break; case POWER_SUPPLY_PROP_TECHNOLOGY: val->intval = POWER_SUPPLY_TECHNOLOGY_LION; break; default: return -EINVAL; } return ret; } static int bq27x00_powersupply_init(struct bq27x00_device_info *di) { int ret; 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; ret = power_supply_register(di->dev, &di->bat); if (ret) { dev_err(di->dev, "failed to register battery: %d\n", ret); return ret; } dev_info(di->dev, "support ver. %s enabled\n", DRIVER_VERSION); return 0; } /* * i2c specific code */ static int bq27x00_read_i2c(struct bq27x00_device_info *di, u8 reg, int *rt_value, bool single) { struct i2c_client *client = to_i2c_client(di->dev); 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 (!single) msg->len = 2; else msg->len = 1; msg->flags = I2C_M_RD; err = i2c_transfer(client->adapter, msg, 1); if (err >= 0) { if (!single) *rt_value = get_unaligned_le16(data); else *rt_value = data[0]; return 0; } } return err; } static int bq27x00_battery_probe(struct i2c_client *client, const struct i2c_device_id *id) { char *name; struct bq27x00_device_info *di; 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, "%s-%d", id->name, 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; di->dev = &client->dev; di->chip = id->driver_data; di->bat.name = name; di->bus.read = &bq27x00_read_i2c; if (bq27x00_powersupply_init(di)) goto batt_failed_3; i2c_set_clientdata(client, di); return 0; 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 bq27x00_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 bq27x00_id[] = { { "bq27200", BQ27000 }, /* bq27200 is same as bq27000, but with i2c */ { "bq27500", BQ27500 }, {}, }; static struct i2c_driver bq27x00_battery_driver = { .driver = { .name = "bq27x00-battery", }, .probe = bq27x00_battery_probe, .remove = bq27x00_battery_remove, .id_table = bq27x00_id, }; static int __init bq27x00_battery_init(void) { int ret; ret = i2c_add_driver(&bq27x00_battery_driver); if (ret) printk(KERN_ERR "Unable to register BQ27x00 driver\n"); return ret; } module_init(bq27x00_battery_init); static void __exit bq27x00_battery_exit(void) { i2c_del_driver(&bq27x00_battery_driver); } module_exit(bq27x00_battery_exit); MODULE_AUTHOR("Rodolfo Giometti "); MODULE_DESCRIPTION("BQ27x00 battery monitor driver"); MODULE_LICENSE("GPL");