GM30代码架构

\android\kernel-4.4\drivers\power\mediatek\Makefile
内核代码已经升级到了kernel 4.4而不是原来的kernel 3.18.

电量计3.0需要定义宏CONFIG_MTK_GAUGE_VERSION为30,之后代码全部编译
battery和charger两个目录下的文件,跟原来的电量计1.0和2.0文件不一样了.
其中\android\kernel-4.4\drivers\power\mediatek\battery目录下的主要文件如下:mtk_battery.c主要是电量计相关的代码类似于之前的battery_meter.c文件

而\android\kernel-4.4\drivers\power\mediatek\charger目录下则是各种chargerIC
的driver代码.mtk_charger.c相当于之前的battery_common.c文件，mtk_switch_charging.c文件则相当于之前的switch_charging.c另外还有快充的实现代码。

充电器类型检测流程有何变化？

主要函数文件
\android\kernel-4.4\drivers\power\mediatek\charger\ mtk_chg_type_det.c
\android\kernel-4.4\drivers\power\ power_supply_core.c
\android\kernel-4.4\drivers\misc\mediatek\pmic\mt6357\v1\ pmic_chr_type_det_v2.c

harger_routine_thread该线程只在充电器插入后才执行,否则就会一直休眠等待.

while (1) {
        wait_event(info->wait_que, (info->charger_thread_timeout == true));//此处进程休眠等待,充电器插入.
}

只有条件info->charger_thread_timeout为true时才被唤醒继续执行.

void _wake_up_charger(struct charger_manager *info)
{
    unsigned long flags;

    if (info == NULL)
        return;

    spin_lock_irqsave(&info->slock, flags);
    if (wake_lock_active(&info->charger_wakelock) == 0)
        wake_lock(&info->charger_wakelock);
    spin_unlock_irqrestore(&info->slock, flags);
    info->charger_thread_timeout = true;
    wake_up(&info->wait_que);//唤醒等待队列上休眠的进程
}

void mtk_charger_int_handler(void)
{
    chr_err("mtk_charger_int_handler\n");

    if (pinfo == NULL) {
        chr_err("charger is not rdy ,skip1\n");
        return;
    }

    if (pinfo->init_done != true) {
        chr_err("charger is not rdy ,skip2\n");
        return;
    }
    chr_err("wake_up_charger\n");
    _wake_up_charger(pinfo);
}

充电器类型检测函数调用流程:

mtk_charger_probe
    init_waitqueue_head(&info->wait_que);//probe函数中初始化等待队列

void do_charger_detect(void)
{
    …
    mutex_lock(&chrdet_lock);

    if (pmic_get_register_value(PMIC_RGS_CHRDET)) {
        pr_info("charger type: charger IN\n");//检测到充电器插入
        g_chr_type = hw_charging_get_charger_type()//充电器类型检测;
        chrdet_inform_psy_changed(g_chr_type, 1);//类型通知给charger 这个power supply
    } else {
        pr_info("charger type: charger OUT\n");//检测到充电器拔出
        g_chr_type = CHARGER_UNKNOWN;
        chrdet_inform_psy_changed(g_chr_type, 0); //通知给charger 这个power supply充电器拔出，不在位
    }

    mutex_unlock(&chrdet_lock);
}

static int chrdet_inform_psy_changed(CHARGER_TYPE chg_type, bool chg_online)
{
    int ret = 0;
    union power_supply_propval propval;

    pr_info("charger type: %s: online = %d, type = %d\n", __func__, chg_online, chg_type);

    /* Inform chg det power supply */
    if (chg_online) {
        propval.intval = chg_online;
        ret = power_supply_set_property(chrdet_psy, POWER_SUPPLY_PROP_ONLINE, &propval);//调用power supply core函数设置online属性
        if (ret < 0)
            pr_err("%s: psy online failed, ret = %d\n", __func__, ret);

        propval.intval = chg_type;
        ret = power_supply_set_property(chrdet_psy, POWER_SUPPLY_PROP_CHARGE_TYPE, &propval); //调用power supply core函数设置类型属性

        if (ret < 0)
            pr_err("%s: psy type failed, ret = %d\n", __func__, ret);

        return ret;
    }

    propval.intval = chg_type;
    ret = power_supply_set_property(chrdet_psy, POWER_SUPPLY_PROP_CHARGE_TYPE, &propval);
    if (ret < 0)
        pr_err("%s: psy type failed, ret(%d)\n", __func__, ret);

    propval.intval = chg_online;
    ret = power_supply_set_property(chrdet_psy, POWER_SUPPLY_PROP_ONLINE,
        &propval);
    if (ret < 0)
        pr_err("%s: psy online failed, ret(%d)\n", __func__, ret);
    return ret;
}

通过调用power supply core的核心函数power_supply_set_property后，就会最终调用到如下的mt_charger_set_property函数

static int mt_charger_set_property(struct power_supply *psy,
    enum power_supply_property psp, const union power_supply_propval *val)
{
    switch (psp) {
    case POWER_SUPPLY_PROP_ONLINE:
        mtk_chg->chg_online = val->intval;
        mt_charger_online(mtk_chg);
        return 0;
    case POWER_SUPPLY_PROP_CHARGE_TYPE:
        mtk_chg->chg_type = val->intval;
        g_chr_type = val->intval;
        break;
    default:
        return -EINVAL;
    }

    dump_charger_name(mtk_chg->chg_type);

    /* usb */
    if ((mtk_chg->chg_type == STANDARD_HOST) ||
        (mtk_chg->chg_type == CHARGING_HOST))
        mt_usb_connect();
    else
        mt_usb_disconnect();

    mtk_charger_int_handler();//启动10s的thread
    fg_charger_in_handler();//唤醒电量计

    power_supply_changed(mtk_chg->ac_psy);
    power_supply_changed(mtk_chg->usb_psy);
}

charger_class.c文件是个什么东东？

charger_class.c文件封装了底层操作chargeric的一些函数，并向linux内核注册一个类文件，名称为switch_charging的类。每一个驱动ic在加载时只需要在该类文件下向内核注册名为primary_chg的设备文件即可。

static int __init charger_class_init(void)
{
    charger_class = class_create(THIS_MODULE, "switching_charger");//创建switching_charger这个class
    if (IS_ERR(charger_class)) {
        pr_err("Unable to create charger class; errno = %ld\n",
            PTR_ERR(charger_class));
        return PTR_ERR(charger_class);
    }
    charger_class->dev_groups = charger_groups;
    charger_class->suspend = charger_suspend;
    charger_class->resume = charger_resume;
    return 0;
}

struct charger_device *charger_device_register(const char *name,
        struct device *parent, void *devdata,
        const struct charger_ops *ops,
        const struct charger_properties *props)
{
    struct charger_device *charger_dev;
    int rc;

    pr_debug("charger_device_register: name=%s\n", name);
    charger_dev = kzalloc(sizeof(*charger_dev), GFP_KERNEL);
    if (!charger_dev)
        return ERR_PTR(-ENOMEM);

    mutex_init(&charger_dev->ops_lock);
    charger_dev->dev.class = charger_class;
    charger_dev->dev.parent = parent;
    charger_dev->dev.release = charger_device_release;
    dev_set_name(&charger_dev->dev, name);
    dev_set_drvdata(&charger_dev->dev, devdata);
    srcu_init_notifier_head(&charger_dev->evt_nh);

    /* Copy properties */
    if (props) {
        memcpy(&charger_dev->props, props,
               sizeof(struct charger_properties));
    }
    rc = device_register(&charger_dev->dev);
    if (rc) {
        kfree(charger_dev);
        return ERR_PTR(rc);
    }
    charger_dev->ops = ops;
    return charger_dev;
}

该函数charger_device_register实现了在switching_charger这个class下注册设备文件。之后在charger ic的probe函数中只需要调用该函数来创建设备文件即可，对charger ic的任意操作都可以通过操作该设备文件即可。
具体封装的函数有如下：

int charger_dev_is_enabled(struct charger_device *charger_dev, bool *en)
int charger_dev_plug_in(struct charger_device *charger_dev)
int charger_dev_plug_out(struct charger_device *charger_dev)
int charger_dev_set_charging_current(struct charger_device *charger_dev, u32 uA)
int charger_dev_get_charging_current(struct charger_device *charger_dev, u32 *uA)
int charger_dev_get_min_charging_current(struct charger_device *charger_dev, u32 *uA)
int charger_dev_enable_chip(struct charger_device *charger_dev, bool en)
int charger_dev_is_chip_enabled(struct charger_device *charger_dev, bool *en)
int charger_dev_enable_direct_charging(struct charger_device *charger_dev, bool en)
int charger_dev_kick_direct_charging_wdt(struct charger_device *charger_dev)
int charger_dev_get_ibus(struct charger_device *charger_dev, u32 *ibus)
int charger_dev_get_temperature(struct charger_device *charger_dev, int *tchg_min,int *tchg_max)
int charger_dev_set_input_current(struct charger_device *charger_dev, u32 uA)
int charger_dev_get_input_current(struct charger_device *charger_dev, u32 *uA)
int charger_dev_get_min_input_current(struct charger_device *charger_dev, u32 *uA)
int charger_dev_get_eoc_current(struct charger_device *charger_dev, u32 *uA)
int charger_dev_kick_wdt(struct charger_device *charger_dev)
int charger_dev_set_constant_voltage(struct charger_device *charger_dev, u32 uV)
int charger_dev_dump_registers(struct charger_device *charger_dev)
int charger_dev_is_charging_done(struct charger_device *charger_dev, bool *done)
int charger_dev_enable_vbus_ovp(struct charger_device *charger_dev, bool en)
int charger_dev_set_mivr(struct charger_device *charger_dev, u32 uV)
int charger_dev_is_powerpath_enabled(struct charger_device *charger_dev, bool *en)
int charger_dev_enable_safety_timer(struct charger_device *charger_dev, bool en)
int charger_dev_enable_termination(struct charger_device *charger_dev, bool en)
。。。。

因此具体的charger id driver代码在注册时需要根据具体需要实现以上函数即可。
具体来看bct24157.c文件如下

static int bct24157_i2c_probe(struct i2c_client *i2c,
                const struct i2c_device_id *id)
{
    ….
    ri->chg_dev = charger_device_register(pdata->chg_name, ri->dev, ri,
                          &bct24157_chg_ops,
                          &bct24157_chg_props);
}

static const struct charger_ops bct24157_chg_ops = {
    /* enable */
    .enable = bct24157_charger_enable,
    .is_enabled = bct24157_charger_is_enabled,
    /* charging current */
    .get_charging_current = bct24157_charger_get_ichg,
    .set_charging_current = bct24157_charger_set_ichg,
    .get_min_charging_current = bct24157_charger_get_min_ichg,
    /* charging voltage */
    .set_constant_voltage = bct24157_charger_set_cv,
    .get_constant_voltage = bct24157_charger_get_cv,
    /* charging input current */
    .get_input_current = bct24157_charger_get_aicr,
    .set_input_current = bct24157_charger_set_aicr,
    .get_min_input_current = bct24157_charger_get_min_aicr,
    /* charging mivr */
    .set_mivr = bct24157_charger_set_mivr,
    /* safety timer */
    .is_safety_timer_enabled = bct24157_charger_is_timer_enabled,
    .enable_safety_timer = bct24157_charger_enable_timer,
    /* OTG */
    .enable_otg = bct24157_charger_enable_otg,
    /* misc */
    .is_charging_done = bct24157_charger_is_charging_done,
    .dump_registers = bct24157_charger_dump_registers,
    /* event */
    .event = bct24157_charger_do_event,
};

static const struct charger_properties bct24157_chg_props = {
    .alias_name = "bct24157",
};

同样的新的代码中还增加了mtk_gauge_class.c文件，向上封装了不同的PMIC芯片电量计部分代码接口.