diff options
Diffstat (limited to 'drivers/power')
| -rw-r--r-- | drivers/power/Kconfig | 7 | ||||
| -rw-r--r-- | drivers/power/Makefile | 1 | ||||
| -rw-r--r-- | drivers/power/ds2782_battery.c | 330 |
3 files changed, 338 insertions, 0 deletions
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig index 7eda34838bfe..bdbc4f73fcdc 100644 --- a/drivers/power/Kconfig +++ b/drivers/power/Kconfig @@ -43,6 +43,13 @@ config BATTERY_DS2760 help Say Y here to enable support for batteries with ds2760 chip. +config BATTERY_DS2782 + tristate "DS2782 standalone gas-gauge" + depends on I2C + help + Say Y here to enable support for the DS2782 standalone battery + gas-gauge. + config BATTERY_PMU tristate "Apple PMU battery" depends on PPC32 && ADB_PMU diff --git a/drivers/power/Makefile b/drivers/power/Makefile index daf3179689aa..380d17c9ae29 100644 --- a/drivers/power/Makefile +++ b/drivers/power/Makefile @@ -19,6 +19,7 @@ obj-$(CONFIG_APM_POWER) += apm_power.o obj-$(CONFIG_WM8350_POWER) += wm8350_power.o obj-$(CONFIG_BATTERY_DS2760) += ds2760_battery.o +obj-$(CONFIG_BATTERY_DS2782) += ds2782_battery.o obj-$(CONFIG_BATTERY_PMU) += pmu_battery.o obj-$(CONFIG_BATTERY_OLPC) += olpc_battery.o obj-$(CONFIG_BATTERY_TOSA) += tosa_battery.o diff --git a/drivers/power/ds2782_battery.c b/drivers/power/ds2782_battery.c new file mode 100644 index 000000000000..da14f374cb60 --- /dev/null +++ b/drivers/power/ds2782_battery.c @@ -0,0 +1,330 @@ +/* + * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC + * + * Copyright (C) 2009 Bluewater Systems Ltd + * + * Author: Ryan Mallon <ryan@bluewatersys.com> + * + * 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/idr.h> +#include <linux/power_supply.h> + +#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */ + +#define DS2782_REG_VOLT_MSB 0x0c +#define DS2782_REG_TEMP_MSB 0x0a +#define DS2782_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 to_ds2782_info(x) container_of(x, struct ds2782_info, battery) + +struct ds2782_info { + struct i2c_client *client; + struct power_supply battery; + int id; +}; + +static DEFINE_IDR(battery_id); +static DEFINE_MUTEX(battery_lock); + +static inline int ds2782_read_reg(struct ds2782_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 ds2782_read_reg16(struct ds2782_info *info, int reg_msb, + s16 *val) +{ + int ret; + + ret = swab16(i2c_smbus_read_word_data(info->client, reg_msb)); + if (ret < 0) { + dev_err(&info->client->dev, "register read failed\n"); + return ret; + } + + *val = ret; + return 0; +} + +static int ds2782_get_temp(struct ds2782_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 = ds2782_read_reg16(info, DS2782_REG_TEMP_MSB, &raw); + if (err) + return err; + *temp = ((raw / 32) * 125) / 100; + return 0; +} + +static int ds2782_get_current(struct ds2782_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 = ds2782_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 = ds2782_read_reg16(info, DS2782_REG_CURRENT_MSB, &raw); + if (err) + return err; + *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res); + return 0; +} + +static int ds2782_get_voltage(struct ds2782_info *info, int *voltage_uA) +{ + 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 = ds2782_read_reg16(info, DS2782_REG_VOLT_MSB, &raw); + if (err) + return err; + *voltage_uA = (raw / 32) * 4800; + return 0; +} + +static int ds2782_get_capacity(struct ds2782_info *info, int *capacity) +{ + int err; + u8 raw; + + err = ds2782_read_reg(info, DS2782_REG_RARC, &raw); + if (err) + return err; + *capacity = raw; + return raw; +} + +static int ds2782_get_status(struct ds2782_info *info, int *status) +{ + int err; + int current_uA; + int capacity; + + err = ds2782_get_current(info, ¤t_uA); + if (err) + return err; + + err = ds2782_get_capacity(info, &capacity); + if (err) + return err; + + 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 ds2782_battery_get_property(struct power_supply *psy, + enum power_supply_property prop, + union power_supply_propval *val) +{ + struct ds2782_info *info = to_ds2782_info(psy); + int ret; + + switch (prop) { + case POWER_SUPPLY_PROP_STATUS: + ret = ds2782_get_status(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_CAPACITY: + ret = ds2782_get_capacity(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + ret = ds2782_get_voltage(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_CURRENT_NOW: + ret = ds2782_get_current(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_TEMP: + ret = ds2782_get_temp(info, &val->intval); + break; + + default: + ret = -EINVAL; + } + + return ret; +} + +static enum power_supply_property ds2782_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 ds2782_power_supply_init(struct power_supply *battery) +{ + battery->type = POWER_SUPPLY_TYPE_BATTERY; + battery->properties = ds2782_battery_props; + battery->num_properties = ARRAY_SIZE(ds2782_battery_props); + battery->get_property = ds2782_battery_get_property; + battery->external_power_changed = NULL; +} + +static int ds2782_battery_remove(struct i2c_client *client) +{ + struct ds2782_info *info = i2c_get_clientdata(client); + + power_supply_unregister(&info->battery); + kfree(info->battery.name); + + mutex_lock(&battery_lock); + idr_remove(&battery_id, info->id); + mutex_unlock(&battery_lock); + + i2c_set_clientdata(client, info); + + kfree(info); + return 0; +} + +static int ds2782_battery_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct ds2782_info *info; + int ret; + int num; + + /* Get an ID for this battery */ + ret = idr_pre_get(&battery_id, GFP_KERNEL); + if (ret == 0) { + ret = -ENOMEM; + goto fail_id; + } + + mutex_lock(&battery_lock); + ret = idr_get_new(&battery_id, client, &num); + mutex_unlock(&battery_lock); + if (ret < 0) + goto fail_id; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) { + ret = -ENOMEM; + goto fail_info; + } + + info->battery.name = kasprintf(GFP_KERNEL, "ds2782-%d", num); + if (!info->battery.name) { + ret = -ENOMEM; + goto fail_name; + } + + i2c_set_clientdata(client, info); + info->client = client; + ds2782_power_supply_init(&info->battery); + + ret = power_supply_register(&client->dev, &info->battery); + if (ret) { + dev_err(&client->dev, "failed to register battery\n"); + goto fail_register; + } + + return 0; + +fail_register: + kfree(info->battery.name); +fail_name: + i2c_set_clientdata(client, info); + 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 ds2782_id[] = { + {"ds2782", 0}, + {}, +}; + +static struct i2c_driver ds2782_battery_driver = { + .driver = { + .name = "ds2782-battery", + }, + .probe = ds2782_battery_probe, + .remove = ds2782_battery_remove, + .id_table = ds2782_id, +}; + +static int __init ds2782_init(void) +{ + return i2c_add_driver(&ds2782_battery_driver); +} +module_init(ds2782_init); + +static void __exit ds2782_exit(void) +{ + i2c_del_driver(&ds2782_battery_driver); +} +module_exit(ds2782_exit); + +MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>"); +MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver"); +MODULE_LICENSE("GPL"); |