max17040_battery.c

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/*
 *  max17040_battery.c
 *  fuel-gauge systems for lithium-ion (Li+) batteries
 *
 *  Copyright (C) 2009 Samsung Electronics
 *  Minkyu Kang <[email protected]>
 *
 * 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/module.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/power_supply.h>
#include <linux/max17040_battery.h>
#include <linux/slab.h>

#define MAX17040_VCELL_MSB  0x02
#define MAX17040_VCELL_LSB  0x03
#define MAX17040_SOC_MSB    0x04
#define MAX17040_SOC_LSB    0x05
#define MAX17040_MODE_MSB   0x06
#define MAX17040_MODE_LSB   0x07
#define MAX17040_VER_MSB    0x08
#define MAX17040_VER_LSB    0x09
#define MAX17040_RCOMP_MSB  0x0C
#define MAX17040_RCOMP_LSB  0x0D
#define MAX17040_CMD_MSB    0xFE
#define MAX17040_CMD_LSB    0xFF

#define MAX17040_DELAY      1000
#define MAX17040_BATTERY_FULL   95

struct max17040_chip {
    struct i2c_client       *client;
    struct delayed_work     work;
    struct power_supply     battery;
    struct max17040_platform_data   *pdata;

    /* State Of Connect */
    int online;
    /* battery voltage */
    int vcell;
    /* battery capacity */
    int soc;
    /* State Of Charge */
    int status;
};

static int max17040_get_property(struct power_supply *psy,
                enum power_supply_property psp,
                union power_supply_propval *val)
{
    struct max17040_chip *chip = container_of(psy,
                struct max17040_chip, battery);

    switch (psp) {
    case POWER_SUPPLY_PROP_STATUS:
        val->intval = chip->status;
        break;
    case POWER_SUPPLY_PROP_ONLINE:
        val->intval = chip->online;
        break;
    case POWER_SUPPLY_PROP_VOLTAGE_NOW:
        val->intval = chip->vcell;
        break;
    case POWER_SUPPLY_PROP_CAPACITY:
        val->intval = chip->soc;
        break;
    default:
        return -EINVAL;
    }
    return 0;
}

static int max17040_write_reg(struct i2c_client *client, int reg, u8 value)
{
    int ret;

    ret = i2c_smbus_write_byte_data(client, reg, value);

    if (ret < 0)
        dev_err(&client->dev, "%s: err %d\n", __func__, ret);

    return ret;
}

static int max17040_read_reg(struct i2c_client *client, int reg)
{
    int ret;

    ret = i2c_smbus_read_byte_data(client, reg);

    if (ret < 0)
        dev_err(&client->dev, "%s: err %d\n", __func__, ret);

    return ret;
}

static void max17040_reset(struct i2c_client *client)
{
    max17040_write_reg(client, MAX17040_CMD_MSB, 0x54);
    max17040_write_reg(client, MAX17040_CMD_LSB, 0x00);
}

static void max17040_get_vcell(struct i2c_client *client)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);
    u8 msb;
    u8 lsb;

    msb = max17040_read_reg(client, MAX17040_VCELL_MSB);
    lsb = max17040_read_reg(client, MAX17040_VCELL_LSB);

    chip->vcell = (msb << 4) + (lsb >> 4);
}

static void max17040_get_soc(struct i2c_client *client)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);
    u8 msb;
    u8 lsb;

    msb = max17040_read_reg(client, MAX17040_SOC_MSB);
    lsb = max17040_read_reg(client, MAX17040_SOC_LSB);

    chip->soc = msb;
}

static void max17040_get_version(struct i2c_client *client)
{
    u8 msb;
    u8 lsb;

    msb = max17040_read_reg(client, MAX17040_VER_MSB);
    lsb = max17040_read_reg(client, MAX17040_VER_LSB);

    dev_info(&client->dev, "MAX17040 Fuel-Gauge Ver %d%d\n", msb, lsb);
}

static void max17040_get_online(struct i2c_client *client)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);

    if (chip->pdata->battery_online)
        chip->online = chip->pdata->battery_online();
    else
        chip->online = 1;
}

static void max17040_get_status(struct i2c_client *client)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);

    if (!chip->pdata->charger_online || !chip->pdata->charger_enable) {
        chip->status = POWER_SUPPLY_STATUS_UNKNOWN;
        return;
    }

    if (chip->pdata->charger_online()) {
        if (chip->pdata->charger_enable())
            chip->status = POWER_SUPPLY_STATUS_CHARGING;
        else
            chip->status = POWER_SUPPLY_STATUS_NOT_CHARGING;
    } else {
        chip->status = POWER_SUPPLY_STATUS_DISCHARGING;
    }

    if (chip->soc > MAX17040_BATTERY_FULL)
        chip->status = POWER_SUPPLY_STATUS_FULL;
}

static void max17040_work(struct work_struct *work)
{
    struct max17040_chip *chip;

    chip = container_of(work, struct max17040_chip, work.work);

    max17040_get_vcell(chip->client);
    max17040_get_soc(chip->client);
    max17040_get_online(chip->client);
    max17040_get_status(chip->client);

    schedule_delayed_work(&chip->work, MAX17040_DELAY);
}

static enum power_supply_property max17040_battery_props[] = {
    POWER_SUPPLY_PROP_STATUS,
    POWER_SUPPLY_PROP_ONLINE,
    POWER_SUPPLY_PROP_VOLTAGE_NOW,
    POWER_SUPPLY_PROP_CAPACITY,
};

static int __devinit max17040_probe(struct i2c_client *client,
            const struct i2c_device_id *id)
{
    struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
    struct max17040_chip *chip;
    int ret;

    if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE))
        return -EIO;

    chip = kzalloc(sizeof(*chip), GFP_KERNEL);
    if (!chip)
        return -ENOMEM;

    chip->client = client;
    chip->pdata = client->dev.platform_data;

    i2c_set_clientdata(client, chip);

    chip->battery.name      = "battery";
    chip->battery.type      = POWER_SUPPLY_TYPE_BATTERY;
    chip->battery.get_property  = max17040_get_property;
    chip->battery.properties    = max17040_battery_props;
    chip->battery.num_properties    = ARRAY_SIZE(max17040_battery_props);

    ret = power_supply_register(&client->dev, &chip->battery);
    if (ret) {
        dev_err(&client->dev, "failed: power supply register\n");
        kfree(chip);
        return ret;
    }

    max17040_reset(client);
    max17040_get_version(client);

    INIT_DEFERRABLE_WORK(&chip->work, max17040_work);
    schedule_delayed_work(&chip->work, MAX17040_DELAY);

    return 0;
}

static int __devexit max17040_remove(struct i2c_client *client)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);

    power_supply_unregister(&chip->battery);
    cancel_delayed_work(&chip->work);
    kfree(chip);
    return 0;
}

#ifdef CONFIG_PM

static int max17040_suspend(struct i2c_client *client,
        pm_message_t state)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);

    cancel_delayed_work(&chip->work);
    return 0;
}

static int max17040_resume(struct i2c_client *client)
{
    struct max17040_chip *chip = i2c_get_clientdata(client);

    schedule_delayed_work(&chip->work, MAX17040_DELAY);
    return 0;
}

#else

#define max17040_suspend NULL
#define max17040_resume NULL

#endif /* CONFIG_PM */

static const struct i2c_device_id max17040_id[] = {
    { "max17040", 0 },
    { }
};
MODULE_DEVICE_TABLE(i2c, max17040_id);

static struct i2c_driver max17040_i2c_driver = {
    .driver = {
        .name   = "max17040",
    },
    .probe      = max17040_probe,
    .remove     = __devexit_p(max17040_remove),
    .suspend    = max17040_suspend,
    .resume     = max17040_resume,
    .id_table   = max17040_id,
};
module_i2c_driver(max17040_i2c_driver);

MODULE_AUTHOR("Minkyu Kang <[email protected]>");
MODULE_DESCRIPTION("MAX17040 Fuel Gauge");
MODULE_LICENSE("GPL");