android power key 长按8s 关机

来源：互联网发布：comfortable zone 知乎编辑：程序博客网时间：2024/04/27 19:45

该功能是系统启动后，在任何情况下，长按power key 8s都能做到直接关机。因此在kernel中实现。

所有修改都在keypad driver中，如下文件。

mediatek\platform\mt6573\kernel\drivers\keypad\kpd.c:

#define FORCE_POWERKEY_SECONDS   8   //定义power key按键持续时间

struct timer_list timer;

//定时器timer初始化

static int timer_init()  {     init_timer(&timer);     timer.data= 5;     timer.expires = jiffies + (FORCE_POWERKEY_SECONDS*HZ);      timer.function = timer_function;     add_timer(&timer);     printk("<0>ziheng add_timer\n");     return 0;  }

//定时器timer退出

static void timer_exit()

{

   del_timer(&timer);

}

//定时器到时事件处理函数

static void timer_function(int para)  {     timer_exit();    arch_reset(0, "charger");  //kernel强制关机接口}

按键时间在kpd_pwrkey_handler中处理，kpd_pwrkey_handler是一个tasklet，用于power key的按键中断下半部处理。

static void kpd_pwrkey_handler(unsigned long data){

bool pressed; u8 old_state = kpd_pwrkey_state; kpd_pwrkey_state = !kpd_pwrkey_state; pressed = (kpd_pwrkey_state == !!KPD_PWRKEY_POLARITY); if (kpd_show_hw_keycode) { printk(KPD_SAY "(%s) HW keycode = using EINT\n", pressed ? "pressed" : "released");

    #ifdef  FORCE_POWERKEY     if(pressed == 1)   {   printk("<0> kpd_pwr_handler press 1\n");           timer_init();    }     else if(pressed == 0)   {   printk("<0> kpd_pwr_handler press 0\n");           timer_exit();

}

    #endif

kpd_backlight_handler(pressed, KPD_PWRKEY_MAP); input_report_key(kpd_input_dev, KPD_PWRKEY_MAP, pressed); kpd_print("report Linux keycode = %u\n", KPD_PWRKEY_MAP); /* for detecting the return to old_state */ mt65xx_eint_set_polarity(KPD_PWRKEY_EINT, old_state); mt65xx_eint_unmask(KPD_PWRKEY_EINT);