| /* |
| * 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> |
| * |
| * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il> |
| * |
| * 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> |
| #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 |
| |
| struct ds278x_info; |
| |
| struct ds278x_battery_ops { |
| int (*get_current)(struct ds278x_info *info, int *current_uA); |
| int (*get_voltage)(struct ds278x_info *info, int *voltage_uA); |
| int (*get_capacity)(struct ds278x_info *info, int *capacity_uA); |
| |
| }; |
| |
| #define to_ds278x_info(x) container_of(x, struct ds278x_info, battery) |
| |
| struct ds278x_info { |
| struct i2c_client *client; |
| struct power_supply battery; |
| struct ds278x_battery_ops *ops; |
| int id; |
| int rsns; |
| }; |
| |
| 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 = 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 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_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 = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); |
| if (err) |
| return err; |
| *voltage_uA = (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 raw; |
| } |
| |
| 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_uA) |
| { |
| s16 raw; |
| int err; |
| |
| /* |
| * Voltage is measured in units of 1.22mV. 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_uA = (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_current(info, ¤t_uA); |
| if (err) |
| return err; |
| |
| err = info->ops->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 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_capacity(info, &val->intval); |
| break; |
| |
| case POWER_SUPPLY_PROP_VOLTAGE_NOW: |
| ret = info->ops->get_voltage(info, &val->intval); |
| break; |
| |
| case POWER_SUPPLY_PROP_CURRENT_NOW: |
| ret = info->ops->get_current(info, &val->intval); |
| break; |
| |
| case POWER_SUPPLY_PROP_TEMP: |
| ret = ds278x_get_temp(info, &val->intval); |
| break; |
| |
| default: |
| ret = -EINVAL; |
| } |
| |
| return ret; |
| } |
| |
| 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 *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.name); |
| |
| mutex_lock(&battery_lock); |
| idr_remove(&battery_id, info->id); |
| mutex_unlock(&battery_lock); |
| |
| kfree(info); |
| return 0; |
| } |
| |
| static struct ds278x_battery_ops ds278x_ops[] = { |
| [0] = { |
| .get_current = ds2782_get_current, |
| .get_voltage = ds2782_get_voltage, |
| .get_capacity = ds2782_get_capacity, |
| }, |
| [1] = { |
| .get_current = ds2786_get_current, |
| .get_voltage = ds2786_get_voltage, |
| .get_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 ds278x_info *info; |
| int ret; |
| int num; |
| |
| /* |
| * ds2786 should have the sense resistor value set |
| * in the platform data |
| */ |
| if (id->driver_data == 1 && !pdata) { |
| dev_err(&client->dev, "missing platform data for ds2786\n"); |
| return -EINVAL; |
| } |
| |
| /* 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, "%s-%d", client->name, num); |
| if (!info->battery.name) { |
| ret = -ENOMEM; |
| goto fail_name; |
| } |
| |
| if (id->driver_data == 1) |
| 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); |
| |
| 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: |
| 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", 0}, |
| {"ds2786", 1}, |
| {}, |
| }; |
| |
| static struct i2c_driver ds278x_battery_driver = { |
| .driver = { |
| .name = "ds2782-battery", |
| }, |
| .probe = ds278x_battery_probe, |
| .remove = ds278x_battery_remove, |
| .id_table = ds278x_id, |
| }; |
| |
| static int __init ds278x_init(void) |
| { |
| return i2c_add_driver(&ds278x_battery_driver); |
| } |
| module_init(ds278x_init); |
| |
| static void __exit ds278x_exit(void) |
| { |
| i2c_del_driver(&ds278x_battery_driver); |
| } |
| module_exit(ds278x_exit); |
| |
| MODULE_AUTHOR("Ryan Mallon <ryan@bluewatersys.com>"); |
| MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauage IC driver"); |
| MODULE_LICENSE("GPL"); |