在Android中加入充电指示

2020年2月6日06:19:31
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基于Andriod系统的平台在没有硬件充电指示的情况下只有进入andriod系统才能进行充电指示,而我们有时候仅仅需要充电而不需要进入系统,本文介绍了实现这种功能的方法。

具体过程如下:当内核启动后调用充电指示控制程序。充电指示程序发现如果外部供电就开始显示充电的画面,同时将设备的电源控制锁定为关闭状态(这样当拔掉电源时候系统自动关闭),如果在充电指示过程中又按了开机键,就重新开启电源按键。这个过程在单片机等简单系统上不值得一提,因为每个人都会想的比我好,这里重点介绍如何融合到andriod系统以及其中的我认为可以让别人参考的方法。

方法一  ui显示部分。显然我们不能让系统跑的太深,否则控制起来就过于麻烦,充电显示等老半天才启动别人也觉得奇怪。所以有必要仅仅使用微型系统,微型系统自然能用的功能就少,在图像显示上面只能使用c语言操作framebuff,我的方法是参考bootable/recovery/minui/里面的库,其支持png的图片也文本显示,对于充电指示足够用了。一个可能遇到的问题是andriod提供的minui显示使用驱动的双buffer机制,在有的系统上不具备该功能,你可以强制只使用一个,修改graphics.c的函数gr_flip,将gr_active_fb 赋值为0。

方法二 电池检测。 可以参考com_andriod_server_batteryService.cpp文件,基本上把里面的函数复制过来就可以使用。

完成的charge充电程序必须加入到init.rc中才能被调用,我把它当做一个只运行一次的服务运行。

service console /system/bin/busybox sh

    console

#shuaiwen added,init.c has been hacked to block to wait this process to finish

service charge  /system/bin/charge

   oneshot

在init启动服务的过程都是非阻塞型的(新开一个线程运行),这会导致虽然服务已经被加入,但是系统还会完整启动,显然不能满足要求,实际的需求为当charge运行起来不应该运行其他服务。要实现这个目的,必须对init.c进行一点修改。我的方法是让init对启动的服务名称做判断,如果为charge就等待到该程序结束才继续运行。具体修改为改动init.c的函数service_start:

if (pid == 0) {

……..

}

//shuaiwen added begin

       else{

       int status;

     if(strcmp(svc->name,"charge")==0)

       {

       wait(&status); //wait child to exist

       load_565rle_image(INIT_IMAGE_FILE);//redraw background

       }

      // else printf("shuaiwen skip process %s.",svc->name);

     }

   //shuaiwen added end

if (pid < 0) {

….}

这样系统就会被charge阻塞住。Init.rc中排在charge后面的服务就暂时不会被启动。我上面改动的init.rc把charge服务放在console服务后面是因为我还是需要控制台调试。经过这样的改动,基本的充电服务就可以实现。我这里仅仅是举了一个例子,文中的例子仅仅供参考,请酌情参考。

我写的一个简单的充电指示文件内容列在下面供大家参考。

/*

Copyright:GNU

charge monitor.

revision history:

2010/5/10 create     shuaiwen

icon path:

/res/images/%s.png

*/

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

 

#include <linux/input.h>

#include <pthread.h>

#include <stdarg.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/reboot.h>

#include <sys/time.h>

#include <time.h>

#include <unistd.h>

 

#include "minui/minui.h"

#include "minzip/Zip.h"

#define KEY_PWR 116

 

#define AC_ONLINE_PATH "/sys/class/power_supply/ac/online"

#define USB_ONLINE_PATH "/sys/class/power_supply/usb/online"

#define BATTERY_STATUS_PATH "/sys/class/power_supply/battery/status"

#define BATTERY_HEALTH_PATH "/sys/class/power_supply/battery/health"

#define BATTERY_PRESENT_PATH "/sys/class/power_supply/battery/present"

#define BATTERY_CAPACITY_PATH "/sys/class/power_supply/battery/capacity"

#define BATTERY_VOLTAGE_PATH "/sys/class/power_supply/battery/batt_vol"

#define BATTERY_TEMPERATURE_PATH "/sys/class/power_supply/battery/batt_temp"

#define BATTERY_TECHNOLOGY_PATH "/sys/class/power_supply/battery/technology"

 

enum {

BACKGROUND_ICON_CHARGE0,

BACKGROUND_ICON_CHARGE1,

BACKGROUND_ICON_CHARGE2,

BACKGROUND_ICON_CHARGE3,

BACKGROUND_ICON_CHARGE4,

BACKGROUND_ICON_CHARGE5,

BACKGROUND_ICON_END,

};

 

enum {

STATUSCHARGING,

STATUSDISCHARGING,

STATUSFULL,

STATUSNOTCHARGING,

STATUSUNKNOWN

};

 

enum{

HEALTHDEAD,

HEALTHGOOD,

HEALTHOVERHEAT,

HEALTHOVERVOLTAGE,

HEALTHUNKNOWN,

HEALTHUNSPECIFIEDFAILURE,

};

 

static gr_surface gBackgroundIcon[BACKGROUND_ICON_END];

static const struct { gr_surface* surface; const char *name; } BITMAPS[] = {

    { &gBackgroundIcon[BACKGROUND_ICON_CHARGE0], "battery001" },

    { &gBackgroundIcon[BACKGROUND_ICON_CHARGE1], "battery002" },

    { &gBackgroundIcon[BACKGROUND_ICON_CHARGE2], "battery003" },

    { &gBackgroundIcon[BACKGROUND_ICON_CHARGE3], "battery004" },

    { &gBackgroundIcon[BACKGROUND_ICON_CHARGE4], "battery005" },

    { &gBackgroundIcon[BACKGROUND_ICON_CHARGE5], "battery006" },

    { NULL,                             NULL },

};

 

static int readFromFile(const char* path, char* buf, size_t size)

{

    int fd = open(path, O_RDONLY, 0);

    if (fd == -1) {

        //LOGE("Could not open '%s'", path);

        return -1;

    }

   

    size_t count = read(fd, buf, size);

    if (count > 0) {

        count = (count < size) ? count : size - 1;

        while (count > 0 && buf[count-1] == '\n') count--;

        buf[count] = '\0';

    } else {

        buf[0] = '\0';

    }

 

    close(fd);

    return count;

}

 

static int getBatteryStatus(const char* status)

{

    switch (status[0]) {

        case 'C': return STATUSCHARGING;         // Charging

        case 'D': return STATUSDISCHARGING;      // Discharging

        case 'F': return STATUSFULL;             // Not charging

        case 'N': return STATUSNOTCHARGING;      // Full

        case 'U': return STATUSUNKNOWN;          // Unknown

           

        default: {

             printf("Unknown battery status '%s'", status);

            return STATUSUNKNOWN;

        }

    }

}

 

static int getBatteryHealth(const char* status)

{

    switch (status[0]) {

        case 'D': return HEALTHDEAD;         // Dead

        case 'G': return HEALTHGOOD;         // Good

        case 'O': {

            if (strcmp(status, "Overheat") == 0) {

                return HEALTHOVERHEAT;

            } else if (strcmp(status, "Over voltage") == 0) {

                return HEALTHOVERVOLTAGE;

            }

            printf("Unknown battery health[1] '%s'", status);

            return HEALTHUNKNOWN;

        }

       

        case 'U': {

            if (strcmp(status, "Unspecified failure") == 0) {

                return HEALTHUNSPECIFIEDFAILURE;

            } else if (strcmp(status, "Unknown") == 0) {

                return HEALTHUNKNOWN;

            }

            // fall through

        }

           

        default: {

            printf("Unknown battery health[2] '%s'", status);

            return HEALTHUNKNOWN;

        }

    }

}

 

static void ui_set_background(int icon)

{

   gr_surface gIcon;

     gIcon=gBackgroundIcon[icon];

    gr_color(0, 0, 0, 255);

    gr_fill(0, 0, gr_fb_width(), gr_fb_height());

    if (gIcon) {

         //printf("set backgroupd:%s\n\r",gBackgroundIcon[icon].name);

        int iconWidth = gr_get_width(gIcon);

        int iconHeight = gr_get_height(gIcon);

        int iconX = (gr_fb_width() - iconWidth) / 2;

        int iconY = (gr_fb_height() - iconHeight) / 2;

        gr_blit(gIcon, 0, 0, iconWidth, iconHeight, iconX, iconY);

    }

   gr_flip();

}

 

static void ui_init()

{

  gr_init();

  ev_init();

  int i;

    for (i = 0; BITMAPS[i].name != NULL; ++i) {

        int result = res_create_surface(BITMAPS[i].name, BITMAPS[i].surface);

        if (result < 0) {

            printf("Missing bitmap %s\n(Code %d)\n", BITMAPS[i].name, result);

            *BITMAPS[i].surface = NULL;

               }

               //else printf("create:%s\n\r",BITMAPS[i].name);

    }

 

}

const int SIZE = 128;

 

int power_ac()

{

    char buf[SIZE];

      if (readFromFile(AC_ONLINE_PATH, buf, SIZE) > 0) {

        if (buf[0] == '1') {

            return 1;

        }

    }

return 0;

  }

 

/*

function to indicate if the battery is present.

*/

int battery_present()

{

char buf[SIZE];

      if (readFromFile(BATTERY_PRESENT_PATH, buf, SIZE) > 0) {

        if (buf[0] == '1') {

            return 1;

        }

    }

return 0;

}

 

int battery_capacity()

{

char buf[SIZE];

   

    if (readFromFile(BATTERY_CAPACITY_PATH, buf, SIZE) > 0) {

        return atoi(buf);

    }

  return 0;

}

 

int battery_voltage()

{

char buf[SIZE];

   

    if (readFromFile(BATTERY_VOLTAGE_PATH, buf, SIZE) > 0) {

        return atoi(buf);

    }

  return 0;

}

 

 

int battery_temperature()

{

char buf[SIZE];

   

    if (readFromFile(BATTERY_TEMPERATURE_PATH, buf, SIZE) > 0) {

        return atoi(buf);

    }

  return 0;

}

 

int capacity_full()

{

  char buf[SIZE];

 if (readFromFile(BATTERY_STATUS_PATH, buf, SIZE) > 0)

    {

       return getBatteryStatus(buf);

    }

 

}

 

void do_nothing()    //don't commnet it before fix zip error.  shuaiwen

{

 ZipArchive zip;

  mzOpenZipArchive(NULL, &zip);

 

}

int main(int argc, char **argv)

{

   int index=0;

#define CIRCLE   100   //1000x1000 microsecond

    int circle=0;//interval to update battery status.

struct input_event ev;

 

//is AC power charging?

if(!power_ac())

{

printf("battery supply,don't enter charge mode.\n\r");

return 0; //continue runing.

}

printf("entern charge mode\n\r");

//powerio_low();  //fixme,set power io low to shutdown system when unplug the power.

   ui_init();

   while(1)

     {

       circle=0;

     ui_set_background(capacity_full()==STATUSCHARGING?index++%BACKGROUND_ICON_END:BACKGROUND_ICON_END-1);//todo:more condition must be considered.

     // ui_set_background(index++%BACKGROUND_ICON_END);

        while(circle++<CIRCLE)

        {

          usleep(1000);

         ev_get(&ev, 10);

         if((ev.type == EV_KEY)&&(ev.code==62))

             {

                 //  powerio_high();  //fixme

                 ev_exit();

                 gr_exit();

              return 0;//the system will continue running

               }

         //debug

            if(ev.type==EV_KEY)printf("key:%d pressed\n",ev.code);

           //

        }

 

    }

ev_exit();

gr_exit();

return 0;

}

 

 

对应的andriod.mk文件如下:

LOCAL_PATH :=$(call my-dir)

 

include $(CLEAR_VARS)

 

charge_local_path := $(LOCAL_PATH)

LOCAL_SRC_FILES :=main.c

LOCAL_MODULE := charge

LOCAL_FORCE_STATIC_EXECUTABLE := true

# This binary is in the recovery ramdisk, which is otherwise a copy of root.

# It gets copied there in config/Makefile.  LOCAL_MODULE_TAGS suppresses

# a (redundant) copy of the binary in /system/bin for user builds.

# TODO: Build the ramdisk image in a more principled way.

 

LOCAL_MODULE_TAGS := eng

 

LOCAL_STATIC_LIBRARIES := libminzip libunz libminui libpixelflinger_static libpng libcutils libstdc++ libc

 

include $(BUILD_EXECUTABLE)

 

include $(charge_local_path)/minui/Android.mk

include $(charge_local_path)/minzip/Android.mk

 

PRODUCT_COPY_FILES += \

       $(charge_local_path)/res/images/battery001.PNG:system/res/images/battery001.png \

       $(charge_local_path)/res/images/battery002.PNG:system/res/images/battery002.png \

       $(charge_local_path)/res/images/battery003.PNG:system/res/images/battery003.png \

       $(charge_local_path)/res/images/battery004.PNG:system/res/images/battery004.png \

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