高通電源管理函數的power_supply的調用關係

以msm8909爲例，高通的主要文件有幾個：

• qpnp-linear-charger.c(線性充電器)
• qpnp-vm-bms.c（BMS管理）
• power_supply_core.c（power_supply對外部提供對應接口）

其中，vm_bus的power_supply通常爲struct power_supply *bms_psy;
而linear-charger則是struct power_supply usb_psy;
（固然這只是一個命名方式而已了）

power_supply具體參考這篇博客：

Linux power supply class(1)_軟件架構及API彙整【轉】

struct power_supply {
    const char *name;
    enum power_supply_type type;
    enum power_supply_property *properties;
    size_t num_properties;

    char **supplied_to;
    size_t num_supplicants;

    char **supplied_from;
    size_t num_supplies;
#ifdef CONFIG_OF
    struct device_node *of_node;
#endif

    int (*get_property)(struct power_supply *psy,
                enum power_supply_property psp,
                union power_supply_propval *val);
    int (*set_property)(struct power_supply *psy,
                enum power_supply_property psp,
                const union power_supply_propval *val);
    int (*property_is_writeable)(struct power_supply *psy,
                     enum power_supply_property psp);
    void (*external_power_changed)(struct power_supply *psy);
    void (*set_charged)(struct power_supply *psy);

    /* For APM emulation, think legacy userspace. */
    int use_for_apm;

    /* private */
    struct device *dev;
    struct work_struct changed_work;
    spinlock_t changed_lock;
    bool changed;
#ifdef CONFIG_THERMAL
    struct thermal_zone_device *tzd;
    struct thermal_cooling_device *tcd;
#endif

#ifdef CONFIG_LEDS_TRIGGERS
    struct led_trigger *charging_full_trig;
    char *charging_full_trig_name;
    struct led_trigger *charging_trig;
    char *charging_trig_name;
    struct led_trigger *full_trig;
    char *full_trig_name;
    struct led_trigger *online_trig;
    char *online_trig_name;
    struct led_trigger *charging_blink_full_solid_trig;
    char *charging_blink_full_solid_trig_name;
#endif
};

獲取電量百分比改變：

在vm_bus.c中通常都有power_supply_changed()函數來改變其節點屬性；

power_supply_changed(&chip->bms_psy);(qpnp-vm-bms.c) -->
power_supply_changed()中有一個工做隊列schedule_work(&psy->changed_work);(power_supply_core.c)-->
power_supply_changed_work()工做隊列-->
class_for_each_device(power_supply_class, NULL, psy,__power_supply_changed_work);對power_supply_class下的每一個設備都進行匹配 -->
__power_supply_changed_work調用psy->external_power_changed中的函數-->
qpnp_vm_bms_ext_power_changed是bms_psy.external_power_changed註冊的回調函數;

qpnp_vm_bms_ext_power_changed則是獲取電池的狀態，根據各個函數來判斷；

獲取電量值：

power supply class將全部可能PSY屬性，以枚舉型變量形式抽象出來，PSY driver能夠根據設備的實際狀況，從中選取一些。

enum power_supply_property {
    /* Properties of type `int' */
    POWER_SUPPLY_PROP_STATUS = 0, //該PSY的status，主要是充電狀態，包括：unknown,charging,discharging,not charging full,
    POWER_SUPPLY_PROP_CHARGE_TYPE,//充電類型
    POWER_SUPPLY_PROP_HEALTH, //健康情況，包括：good dead  over voltage等
    POWER_SUPPLY_PROP_PRESENT, //電量百分比
    POWER_SUPPLY_PROP_ONLINE,  //是否在線
    POWER_SUPPLY_PROP_AUTHENTIC,
    POWER_SUPPLY_PROP_TECHNOLOGY, //採用的技術
    POWER_SUPPLY_PROP_CYCLE_COUNT,
    POWER_SUPPLY_PROP_VOLTAGE_MAX,
    POWER_SUPPLY_PROP_VOLTAGE_MIN,
    POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
    POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
    POWER_SUPPLY_PROP_VOLTAGE_NOW,
    POWER_SUPPLY_PROP_VOLTAGE_AVG,
    POWER_SUPPLY_PROP_VOLTAGE_OCV,
    POWER_SUPPLY_PROP_CURRENT_MAX,
    POWER_SUPPLY_PROP_CURRENT_NOW,
    POWER_SUPPLY_PROP_CURRENT_AVG,
    POWER_SUPPLY_PROP_POWER_NOW,
    POWER_SUPPLY_PROP_POWER_AVG,
    POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
    POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN,
    POWER_SUPPLY_PROP_CHARGE_FULL,
    POWER_SUPPLY_PROP_CHARGE_EMPTY,
    POWER_SUPPLY_PROP_CHARGE_NOW,
    POWER_SUPPLY_PROP_CHARGE_AVG,
    POWER_SUPPLY_PROP_CHARGE_COUNTER,
    POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
    POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
    POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
    POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
    POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT,
    POWER_SUPPLY_PROP_CHARGE_CONTROL_LIMIT_MAX,
    POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
    POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN,
    POWER_SUPPLY_PROP_ENERGY_FULL,
    POWER_SUPPLY_PROP_ENERGY_EMPTY,
    POWER_SUPPLY_PROP_ENERGY_NOW,
    POWER_SUPPLY_PROP_ENERGY_AVG,
    POWER_SUPPLY_PROP_CAPACITY, /* in percents! */
    POWER_SUPPLY_PROP_CAPACITY_ALERT_MIN, /* in percents! */
    POWER_SUPPLY_PROP_CAPACITY_ALERT_MAX, /* in percents! */
    POWER_SUPPLY_PROP_CAPACITY_LEVEL, //容量
    POWER_SUPPLY_PROP_TEMP,
    POWER_SUPPLY_PROP_TEMP_ALERT_MIN,
    POWER_SUPPLY_PROP_TEMP_ALERT_MAX,
    POWER_SUPPLY_PROP_TEMP_AMBIENT,
    POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MIN,
    POWER_SUPPLY_PROP_TEMP_AMBIENT_ALERT_MAX,
    POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
    POWER_SUPPLY_PROP_TIME_TO_EMPTY_AVG,
    POWER_SUPPLY_PROP_TIME_TO_FULL_NOW,
    POWER_SUPPLY_PROP_TIME_TO_FULL_AVG,
    POWER_SUPPLY_PROP_TYPE, /* use power_supply.type instead */
    POWER_SUPPLY_PROP_SCOPE,
    /* Local extensions */
    POWER_SUPPLY_PROP_USB_HC,
    POWER_SUPPLY_PROP_USB_OTG,
    POWER_SUPPLY_PROP_CHARGE_ENABLED,
    /* Local extensions of type int64_t */
    POWER_SUPPLY_PROP_CHARGE_COUNTER_EXT,
    /* Properties of type `const char *' */
    POWER_SUPPLY_PROP_MODEL_NAME,
    POWER_SUPPLY_PROP_MANUFACTURER,
    POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

根據屬性來判斷：

qpnp-linear-charger.c中的chip->bms_psy->get_property(qpnp-linear-charger.c)————>
qpnp_vm_bms_power_get_property————>
get_prop_bms_capacity

設置電量：

以設置充電狀態爲例，POWER_SUPPLY_STATUS_CHARGING爲其power_supply須要設置的狀態，而且使用POWER_SUPPLY_PROP_STATUS來肯定設置的東西：

vm_bus只有在復充的時候會會設置充電，其餘狀況都只有linear-charge充電器中使用：

ret.intval = POWER_SUPPLY_STATUS_CHARGING;
rc = chip->batt_psy->set_property(chip->batt_psy,
        POWER_SUPPLY_PROP_STATUS, &ret);