当插入/拔出电源时linux kernel如何通知android UI

Question

想了解这个机制。当充电、充电完成已经拔出电源时，android是怎么知道的？如果要访问驱动，是哪个驱动完成的工作？驱动名称？

Answer 1

android开机时会启动BatteryService电池及充电相关的服务,当充电、充电完时BatteryService会发送
Intent.ACTION_BATTERY_CHANGED的BroadcastReceiver,你注册该广播就可以收到了

Answer 2

对应于linux驱动这层，是哪个驱动在维护？

Answer 3

源码在
Android-2.3\frameworks\base\services\java\com\android\server\BatteryService.java
Android-2.3\frameworks\base\services\jni\com_android_server_BatteryService.cpp
里面定义了获取状态的方法
static jint getBatteryStatus(const char* status)
{
    switch (status[0]) {
        case 'C': return gConstants.statusCharging;         // Charging
        case 'D': return gConstants.statusDischarging;      // Discharging
        case 'F': return gConstants.statusFull;             // Not charging
        case 'N': return gConstants.statusNotCharging;      // Full
        case 'U': return gConstants.statusUnknown;          // Unknown
            
        default: {
            LOGW("Unknown battery status '%s'", status);
            return gConstants.statusUnknown;
        }
    }
}static jint getBatteryHealth(const char* status)
{
    switch (status[0]) {
        case 'D': return gConstants.healthDead;         // Dead
        case 'G': return gConstants.healthGood;         // Good
        case 'O': {
            if (strcmp(status, "Overheat") == 0) {
                return gConstants.healthOverheat;
            } else if (strcmp(status, "Over voltage") == 0) {
                return gConstants.healthOverVoltage;
            }
            LOGW("Unknown battery health[1] '%s'", status);
            return gConstants.healthUnknown;
        }
        
        case 'U': {
            if (strcmp(status, "Unspecified failure") == 0) {
                return gConstants.healthUnspecifiedFailure;
            } else if (strcmp(status, "Unknown") == 0) {
                return gConstants.healthUnknown;
            }
            // fall through
        }
            
        default: {
            LOGW("Unknown battery health[2] '%s'", status);
            return gConstants.healthUnknown;
        }
    }
}

Answer 4

电源管理驱动里找下\drivers\power\xxx_battery.c