diff options
Diffstat (limited to 'drivers/power/supply/ds2782_battery.c')
| -rw-r--r-- | drivers/power/supply/ds2782_battery.c | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/drivers/power/supply/ds2782_battery.c b/drivers/power/supply/ds2782_battery.c new file mode 100644 index 000000000..a1b7e0592 --- /dev/null +++ b/drivers/power/supply/ds2782_battery.c @@ -0,0 +1,475 @@ +/* + * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC + * + * Copyright (C) 2009 Bluewater Systems Ltd + * + * Author: Ryan Mallon + * + * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il> + * + * UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru> + * + * 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/delay.h> +#include <linux/idr.h> +#include <linux/power_supply.h> +#include <linux/slab.h> +#include <linux/ds2782_battery.h> + +#define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */ + +#define DS278x_REG_VOLT_MSB 0x0c +#define DS278x_REG_TEMP_MSB 0x0a +#define DS278x_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 DS2786_REG_RARC 0x02 /* Remaining active relative capacity */ + +#define DS2786_CURRENT_UNITS 25 + +#define DS278x_DELAY 1000 + +struct ds278x_info; + +struct ds278x_battery_ops { + int (*get_battery_current)(struct ds278x_info *info, int *current_uA); + int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV); + int (*get_battery_capacity)(struct ds278x_info *info, int *capacity); +}; + +#define to_ds278x_info(x) power_supply_get_drvdata(x) + +struct ds278x_info { + struct i2c_client *client; + struct power_supply *battery; + struct power_supply_desc battery_desc; + const struct ds278x_battery_ops *ops; + struct delayed_work bat_work; + int id; + int rsns; + int capacity; + int status; /* State Of Charge */ +}; + +static DEFINE_IDR(battery_id); +static DEFINE_MUTEX(battery_lock); + +static inline int ds278x_read_reg(struct ds278x_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 ds278x_read_reg16(struct ds278x_info *info, int reg_msb, + s16 *val) +{ + int ret; + + ret = i2c_smbus_read_word_data(info->client, reg_msb); + if (ret < 0) { + dev_err(&info->client->dev, "register read failed\n"); + return ret; + } + + *val = swab16(ret); + return 0; +} + +static int ds278x_get_temp(struct ds278x_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 = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw); + if (err) + return err; + *temp = ((raw / 32) * 125) / 100; + return 0; +} + +static int ds2782_get_current(struct ds278x_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 = ds278x_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 = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw); + if (err) + return err; + *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res); + return 0; +} + +static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV) +{ + 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 = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); + if (err) + return err; + *voltage_uV = (raw / 32) * 4800; + return 0; +} + +static int ds2782_get_capacity(struct ds278x_info *info, int *capacity) +{ + int err; + u8 raw; + + err = ds278x_read_reg(info, DS2782_REG_RARC, &raw); + if (err) + return err; + *capacity = raw; + return 0; +} + +static int ds2786_get_current(struct ds278x_info *info, int *current_uA) +{ + int err; + s16 raw; + + err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw); + if (err) + return err; + *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns); + return 0; +} + +static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV) +{ + s16 raw; + int err; + + /* + * Voltage is measured in units of 1.22mV. The voltage is stored as + * a 12-bit number plus sign, in the upper bits of a 16-bit register + */ + err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); + if (err) + return err; + *voltage_uV = (raw / 8) * 1220; + return 0; +} + +static int ds2786_get_capacity(struct ds278x_info *info, int *capacity) +{ + int err; + u8 raw; + + err = ds278x_read_reg(info, DS2786_REG_RARC, &raw); + if (err) + return err; + /* Relative capacity is displayed with resolution 0.5 % */ + *capacity = raw/2 ; + return 0; +} + +static int ds278x_get_status(struct ds278x_info *info, int *status) +{ + int err; + int current_uA; + int capacity; + + err = info->ops->get_battery_current(info, ¤t_uA); + if (err) + return err; + + err = info->ops->get_battery_capacity(info, &capacity); + if (err) + return err; + + info->capacity = capacity; + + 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 ds278x_battery_get_property(struct power_supply *psy, + enum power_supply_property prop, + union power_supply_propval *val) +{ + struct ds278x_info *info = to_ds278x_info(psy); + int ret; + + switch (prop) { + case POWER_SUPPLY_PROP_STATUS: + ret = ds278x_get_status(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_CAPACITY: + ret = info->ops->get_battery_capacity(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_VOLTAGE_NOW: + ret = info->ops->get_battery_voltage(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_CURRENT_NOW: + ret = info->ops->get_battery_current(info, &val->intval); + break; + + case POWER_SUPPLY_PROP_TEMP: + ret = ds278x_get_temp(info, &val->intval); + break; + + default: + ret = -EINVAL; + } + + return ret; +} + +static void ds278x_bat_update(struct ds278x_info *info) +{ + int old_status = info->status; + int old_capacity = info->capacity; + + ds278x_get_status(info, &info->status); + + if ((old_status != info->status) || (old_capacity != info->capacity)) + power_supply_changed(info->battery); +} + +static void ds278x_bat_work(struct work_struct *work) +{ + struct ds278x_info *info; + + info = container_of(work, struct ds278x_info, bat_work.work); + ds278x_bat_update(info); + + schedule_delayed_work(&info->bat_work, DS278x_DELAY); +} + +static enum power_supply_property ds278x_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 ds278x_power_supply_init(struct power_supply_desc *battery) +{ + battery->type = POWER_SUPPLY_TYPE_BATTERY; + battery->properties = ds278x_battery_props; + battery->num_properties = ARRAY_SIZE(ds278x_battery_props); + battery->get_property = ds278x_battery_get_property; + battery->external_power_changed = NULL; +} + +static int ds278x_battery_remove(struct i2c_client *client) +{ + struct ds278x_info *info = i2c_get_clientdata(client); + + power_supply_unregister(info->battery); + kfree(info->battery_desc.name); + + mutex_lock(&battery_lock); + idr_remove(&battery_id, info->id); + mutex_unlock(&battery_lock); + + cancel_delayed_work(&info->bat_work); + + kfree(info); + return 0; +} + +#ifdef CONFIG_PM_SLEEP + +static int ds278x_suspend(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct ds278x_info *info = i2c_get_clientdata(client); + + cancel_delayed_work(&info->bat_work); + return 0; +} + +static int ds278x_resume(struct device *dev) +{ + struct i2c_client *client = to_i2c_client(dev); + struct ds278x_info *info = i2c_get_clientdata(client); + + schedule_delayed_work(&info->bat_work, DS278x_DELAY); + return 0; +} +#endif /* CONFIG_PM_SLEEP */ + +static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume); + +enum ds278x_num_id { + DS2782 = 0, + DS2786, +}; + +static const struct ds278x_battery_ops ds278x_ops[] = { + [DS2782] = { + .get_battery_current = ds2782_get_current, + .get_battery_voltage = ds2782_get_voltage, + .get_battery_capacity = ds2782_get_capacity, + }, + [DS2786] = { + .get_battery_current = ds2786_get_current, + .get_battery_voltage = ds2786_get_voltage, + .get_battery_capacity = ds2786_get_capacity, + } +}; + +static int ds278x_battery_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct ds278x_platform_data *pdata = client->dev.platform_data; + struct power_supply_config psy_cfg = {}; + struct ds278x_info *info; + int ret; + int num; + + /* + * ds2786 should have the sense resistor value set + * in the platform data + */ + if (id->driver_data == DS2786 && !pdata) { + dev_err(&client->dev, "missing platform data for ds2786\n"); + return -EINVAL; + } + + /* Get an ID for this battery */ + mutex_lock(&battery_lock); + ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL); + mutex_unlock(&battery_lock); + if (ret < 0) + goto fail_id; + num = ret; + + info = kzalloc(sizeof(*info), GFP_KERNEL); + if (!info) { + ret = -ENOMEM; + goto fail_info; + } + + info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d", + client->name, num); + if (!info->battery_desc.name) { + ret = -ENOMEM; + goto fail_name; + } + + if (id->driver_data == DS2786) + info->rsns = pdata->rsns; + + i2c_set_clientdata(client, info); + info->client = client; + info->id = num; + info->ops = &ds278x_ops[id->driver_data]; + ds278x_power_supply_init(&info->battery_desc); + psy_cfg.drv_data = info; + + info->capacity = 100; + info->status = POWER_SUPPLY_STATUS_FULL; + + INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work); + + info->battery = power_supply_register(&client->dev, + &info->battery_desc, &psy_cfg); + if (IS_ERR(info->battery)) { + dev_err(&client->dev, "failed to register battery\n"); + ret = PTR_ERR(info->battery); + goto fail_register; + } else { + schedule_delayed_work(&info->bat_work, DS278x_DELAY); + } + + return 0; + +fail_register: + kfree(info->battery_desc.name); +fail_name: + 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 ds278x_id[] = { + {"ds2782", DS2782}, + {"ds2786", DS2786}, + {}, +}; +MODULE_DEVICE_TABLE(i2c, ds278x_id); + +static struct i2c_driver ds278x_battery_driver = { + .driver = { + .name = "ds2782-battery", + .pm = &ds278x_battery_pm_ops, + }, + .probe = ds278x_battery_probe, + .remove = ds278x_battery_remove, + .id_table = ds278x_id, +}; +module_i2c_driver(ds278x_battery_driver); + +MODULE_AUTHOR("Ryan Mallon"); +MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver"); +MODULE_LICENSE("GPL"); |