一、android正常开机流程、关机充电流程
在写这篇文章之前我们先看两个流程：正常开机流程，关机充电系统启动流程
1、正常开机流程，按开机键。
可大致分成三部分
（1）、OS_level：UBOOT、kenrel、init这三步完成系统启动；
（2）、Android_level：这部分完成android部的初始化；
（3）、Home Screen：这部分就是我们看到的launcher部分。
2、关机充电系统启动流程
与前面相比，这个流程只走到init这一部分，就没有往后走了，这部分我们会在后面的代码中分析。
二、关机充电逻辑硬件逻辑
1、插入DC，charger IC从硬件上唤醒系统，相当于长按开机键开机。
下面这部分是charger IC连接系统的控制部分。
三、软件逻辑。
DC插入，其实相当于关机状态下“按开机键”开机。第一步要走UBOOT、kernel 、android init这一流程。
1、UBOOT
UBOOT启动代码我们不在这里详细分析，这里我们只要注意二个问题：
a：如何判断是DC插入；
b：设定setenv("bootargs", "androidboot.mode=charger")，androidboot.mode这个参数相当重要，这个参数决定系统是正常启动、还是关机充电状态。
Uboot/board/samsung/smdk4212/smkd4212.c
1. int board_late_init (void)
2. {
3. int keystate = 0;
4. "check start mode\n");
5. if ((*(int *)0x10020800==0x19721212) || (*(int *)0x10020804==0x19721212)
6. || (*(int *)0x10020808==0x19721212))//（1）、检查是否有DC插入；
7. {
1. int board_late_init (void)
2. {
3. int keystate = 0;
4. "check start mode\n");
5. if ((*(int *)0x10020800==0x19721212) || (*(int *)0x10020804==0x19721212)
6. || (*(int *)0x10020808==0x19721212)) //（1）、检查是否有DC插入；
7. {
8. "bootargs", "");//（2）、没有DC插入；
9. else {//DC插入
10. int tmp=*(int *)0x11000c08;
11. int *)0x10020800=*(int *)0x10020804=0x19721212;
12. int *)0x11000c08=(tmp&(~0xc000))|0xc000;
13. udelay(10000);
14. if ((*(int *)0x11000c04 & 0x80)!=0x80 && INF_REG4_REG != 0xf) {
15. "bootargs", "androidboot.mode=charger");//（3）、设定bootargs为charger状态
16. "charger mode\n");
17. else {
18. "bootargs", "");
19. }
20. int *)0x11000c08=tmp;
21. }
22. #ifdef CONFIG_CPU_EXYNOS4X12
23. int charge_status=CheckBatteryLow();//（4）、检查电池电量；
24. //（5）、检查按键状态；
25. // fuse bootloader
26. if(second_boot_info != 0) {
27. boot_symbol=1;
28. INF_REG2_REG =0x8;
29. run_command(CONFIG_BOOTCMD_FUSE_BOOTLOADER, NULL);
30. }
31. if((INF_REG4_REG == 0xd)) {
32. // reboot default
33. char buf[10];
34. "%d", CONFIG_BOOTDELAY);
35. "bootdelay", buf);
36. "reserved", NULL);
37. saveenv();
38. else if((INF_REG4_REG == 0xe) || keystate == (0x1 | 0x2)) {//（6）、按键进入fastboot模式；
39. // reboot bootloader
40. boot_symbol=1;
41. INF_REG2_REG =0x8;
42. "BOOTLOADER - FASTBOOT\n");
43. "reserved", "fastboot");
44. "bootdelay", "0");
45. else if((INF_REG4_REG == 0xf) || keystate == (0x1 | 0x2 | 0x4)) {//（7）、按键进入recovery模式；
46. // reboot recovery
47. "BOOTLOADER - RECOVERY\n");
48. boot_symbol=1;
49. INF_REG2_REG =0x8;
50. "reserved", CONFIG_BOOTCMD_RECOVERY);
51. "bootdelay", "0");
52. else
53. if(keystate == (0x1 | 0x4) || second_boot_info != 0 || partition_check()) {//（8）、按键进入卡升级模式；
54. // 2nd boot
55. "BOOTLOADER - 2ND BOOT DEVICE\n");
56. boot_symbol=1;
57. INF_REG2_REG =0x8;
58. "bootcmd", CONFIG_BOOTCOMMAND);
59. "reserved", CONFIG_BOOTCMD_FUSE_RELEASE);
60. "bootdelay", "0");
61. else {//（9）、正常启动；
62. // normal case
63. char buf[10];
64. "%d", CONFIG_BOOTDELAY);
65. "bootdelay", buf);
66. }
67. INF_REG4_REG = 0;
68. return 0;
69. }
（1）、检查是否有DC插入；
1. if ((*(int *)0x10020800==0x19721212) || (*(int *)0x10020804==0x19721212)
2. (*(int *)0x10020808==0x19721212))
1. if ((*(int *)0x10020800==0x19721212) || (*(int *)0x10020804==0x19721212)
2. int *)0x10020808==0x19721212))
这部分检查寄存器的值。
（2）、没有DC插入；
（3）、设定bootargs为charger状态
1. if ((*(int *)0x11000c04 & 0x80)!=0x80 && INF_REG4_REG != 0xf) {
2. "bootargs", "androidboot.mode=charger");
1. if ((*(int *)0x11000c04 & 0x80)!=0x80 && INF_REG4_REG != 0xf) {
2. "bootargs", "androidboot.mode=charger");
这是这部分的重点，如果能过寄存器判断是DC插入，把androidboot.mode设定为charger状态。
以下这部分根据需要加入，通过判断不同的情况进入不同的功能，如fastboot\revovery…………，这部分不做详细解释。
（4）、检查电池电量；
这个在正常开机状态下，如果检测电量太低，则不开机，这部分代码就不做分析。
（5）、检查按键状态；
我们这个平台有几种模式:fastboot\recovery\卡升级等……
（6）、按键进入fastboot模式；
（7）、按键进入recovery模式；
（8）、按键进入卡升级模式
（9）、正常启动；
2、kernel
这部分和正常启动是一样的。
3、init
前面所有的描述其实只有一点和正常启动不太一样，那就是在UBOOT中把androidboot.mode设定为charger状态，内核正常流程启动，然后到init时要对charger这种状态处理。
system\core\init\init.c
1. int main(int argc,char **argv)
2. {
3. ………………
4. "early-init", action_add_queue_tail);
5.
6. "wait_for_coldboot_done");
7. "property_init");
8. "keychord_init");
9. "console_init"); //(1)、显示initlogo.rle，也就是android第二张图片;
10. "set_init_properties");
11.
12. /* execute all the boot actions to get us started */
13. "init", action_add_queue_tail);
14.
15. /* skip mounting filesystems in charger mode */
16. if (strcmp(bootmode, "charger") != 0) {//(2)、这里就是UBOOT中设定的bootmode，如果是charger模式，跳过下面初始化；
17. "early-fs", action_add_queue_tail);
18. "fs", action_add_queue_tail);
19. "post-fs", action_add_queue_tail);
20. "post-fs-data", action_add_queue_tail);
21. }
22.
23. "property_service_init");
24. "signal_init");
25. "check_startup");
26.
27. if (!strcmp(bootmode,"charger")) {//(3)、如果为charger，则调用charger.c。
28. "charger", action_add_queue_tail);
29. else {
30. "early-boot", action_add_queue_tail);
31. "boot", action_add_queue_tail);
32. }
33. ……………………
34. }
1. int main(int argc, char **argv)
2. {
3. ………………
4. "early-init", action_add_queue_tail);
5.
6. "wait_for_coldboot_done");
7. "property_init");
8. "keychord_init");
9. "console_init"); //(1)、显示initlogo.rle，也就是android第二张图片;
10. "set_init_properties");
11.
12. /* execute all the boot actions to get us started */
13. "init", action_add_queue_tail);
14.
15. /* skip mounting filesystems in charger mode */
16. if (strcmp(bootmode, "charger") != 0) {//(2)、这里就是UBOOT中设定的bootmode，如果是charger模式，跳过下面初始化；
17. "early-fs", action_add_queue_tail);
18. "fs", action_add_queue_tail);
19. "post-fs", action_add_queue_tail);
20. "post-fs-data", action_add_queue_tail);
21. }
22.
23. "property_service_init");
24. "signal_init");
25. "check_startup");
26.
27. if (!strcmp(bootmode, "charger")) {//(3)、如果为charger，则调用charger.c。
28. "charger", action_add_queue_tail);
29. else {
30. "early-boot", action_add_queue_tail);
31. "boot", action_add_queue_tail);
32. }
33. ……………………
34. }
(1)、显示initlogo.rle，也就是android第二张图片;
queue_builtin_action(console_init_action,"console_init");调用console_init_action
1. static int console_init_action(int nargs,char **args)
2. {
3. int fd;
4. char tmp[PROP_VALUE_MAX];
5. if (console[0]) {
6. sizeof(tmp), "/dev/%s", console);
7. console_name = strdup(tmp);
8. }
9. fd = open(console_name, O_RDWR);
10. if (fd >= 0)
11. have_console = 1;
12. close(fd);
13. if( load_565rle_image(INIT_IMAGE_FILE) ) {//这里定义rle文件的名称#define INIT_IMAGE_FILE "/initlogo.rle"
14. "/dev/tty0", O_WRONLY);
15. if (fd >= 0) {//如果没有这张图片，就显示android字样，在屏幕左上角；
16. const char *msg;
17. "\n"
18. "\n"
19. "\n" // console is 40 cols x 30 lines
20. "\n"
21. "\n"
22. "\n"
23. "\n"
24. "\n"
25. "\n"
26. "\n"
27. " A N D R O I D ";
28. write(fd, msg, strlen(msg));
29. close(fd);
30. }
31. }
32. return 0;
33. }
1. static int console_init_action(int nargs, char **args)
2. {
3. int fd;
4. char tmp[PROP_VALUE_MAX];
5. if (console[0]) {
6. sizeof(tmp), "/dev/%s", console);
7. console_name = strdup(tmp);
8. }
9. fd = open(console_name, O_RDWR);
10. if (fd >= 0)
11. have_console = 1;
12. close(fd);
13. if( load_565rle_image(INIT_IMAGE_FILE) ) {//这里定义rle文件的名称#define INIT_IMAGE_FILE "/initlogo.rle"
14. "/dev/tty0", O_WRONLY);
15. if (fd >= 0) {//如果没有这张图片，就显示android字样，在屏幕左上角；
16. const char *msg;
17. "\n"
18. "\n"
19. "\n" // console is 40 cols x 30 lines
20. "\n"
21. "\n"
22. "\n"
23. "\n"
24. "\n"
25. "\n"
26. "\n"
27. " A N D R O I D ";
28. write(fd, msg, strlen(msg));
29. close(fd);
30. }
31. }
32. return 0;
33. }
(2)、这里就是UBOOT中设定的bootmode，如果是charger模式，跳过下面初始化；
1. /* skip mounting filesystems in charger mode */
2. if (strcmp(bootmode, "charger") != 0) {
3. "early-fs", action_add_queue_tail);
4. "fs", action_add_queue_tail);
5. "post-fs", action_add_queue_tail);
6. "post-fs-data", action_add_queue_tail);
7. }
1. /* skip mounting filesystems in charger mode */
2. if (strcmp(bootmode, "charger") != 0) {
3. "early-fs", action_add_queue_tail);
4. "fs", action_add_queue_tail);
5. "post-fs", action_add_queue_tail);
6. "post-fs-data", action_add_queue_tail);
7. }
(3)、如果为charger，则调用charger.c
1. action_for_each_trigger("charger", action_add_queue_tail);
1. action_for_each_trigger("charger", action_add_queue_tail);
我们在后面细分charger这部分。
4、charger.c
这部分就是我们充电部分，充电画面显示的实现。
system\core\charger\charger.c
1. int main(int argc,char **argv)
2. {
3. ………………
4. klog_set_level(CHARGER_KLOG_LEVEL);
5. dump_last_kmsg();
6. "--------------- STARTING CHARGER MODE ---------------\n");
7.
8. gr_init();
9. //(1)、初始化graphics,包括buf大小；
10.
11. //(2)初始化按键；
12.
13. fd = uevent_open_socket(64*1024, true);
14. if (fd >= 0) {
15. fcntl(fd, F_SETFL, O_NONBLOCK);
16. ev_add_fd(fd, uevent_callback, charger);
17. }
18.
19. charger->uevent_fd = fd;
20. "/sys/class/power_supply","add");//(3)、创建/sys/class/power_supply结点，把socket信息通知应用层；
21.
22. ret = res_create_surface("charger/battery_fail", &charger->surf_unknown);
23. if (ret < 0) {
24. "Cannot load image\n");
25. charger->surf_unknown = NULL;
26. }
27. for (i = 0; i < charger->batt_anim->num_frames; i++) {//(4)、这里是显示charger logo，res_create_surface显示图片函数；
28. struct frame *frame = &charger->batt_anim->frames[i];
29. ret = res_create_surface(frame->name, &frame->surface);
30. if (ret < 0) {
31. "Cannot load image %s\n", frame->name);
32. /* TODO: free the already allocated surfaces... */
33. charger->batt_anim->num_frames = 0;
34. charger->batt_anim->num_cycles = 1;
35. break;
36. }
37. }
38. ev_sync_key_state(set_key_callback, charger);
39. true);
40.
41. charger->next_screen_transition = now - 1;
42. charger->next_key_check = -1;
43. charger->next_pwr_check = -1;
44. reset_animation(charger->batt_anim);
45. kick_animation(charger->batt_anim);
46. //（5）、event_loop循环，电池状态，检测按键是否按下；
47. return 0;
48.
49. }
1. int main(int argc, char **argv)
2. {
3. ………………
4. klog_set_level(CHARGER_KLOG_LEVEL);
5. dump_last_kmsg();
6. "--------------- STARTING CHARGER MODE ---------------\n");
7.
8. gr_init();
9. //(1)、初始化graphics,包括buf大小；
10.
11. //(2)初始化按键；
12.
13. fd = uevent_open_socket(64*1024, true);
14. if (fd >= 0) {
15. fcntl(fd, F_SETFL, O_NONBLOCK);
16. ev_add_fd(fd, uevent_callback, charger);
17. }
18.
19. charger->uevent_fd = fd;
20. "/sys/class/power_supply", "add");//(3)、创建/sys/class/power_supply结点，把socket信息通知应用层；
21.
22. ret = res_create_surface("charger/battery_fail", &charger->surf_unknown);
23. if (ret < 0) {
24. "Cannot load image\n");
25. charger->surf_unknown = NULL;
26. }
27. for (i = 0; i < charger->batt_anim->num_frames; i++) {//(4)、这里是显示charger logo，res_create_surface显示图片函数；
28. struct frame *frame = &charger->batt_anim->frames[i];
29. ret = res_create_surface(frame->name, &frame->surface);
30. if (ret < 0) {
31. "Cannot load image %s\n", frame->name);
32. /* TODO: free the already allocated surfaces... */
33. charger->batt_anim->num_frames = 0;
34. charger->batt_anim->num_cycles = 1;
35. break;
36. }
37. }
38. ev_sync_key_state(set_key_callback, charger);
39. true);
40.
41. charger->next_screen_transition = now - 1;
42. charger->next_key_check = -1;
43. charger->next_pwr_check = -1;
44. reset_animation(charger->batt_anim);
45. kick_animation(charger->batt_anim);
46. //（5）、event_loop循环，电池状态，检测按键是否按下；
47. return 0;
48.
49. }
(1)、初始化graphics,包括buf大小
android/bootable/recovery/minui/graphics.c
gr_init():minui/graphics.c［settty0 to graphic mode, open fb0]，设制tty0为图形模式，打开fb0;
1. int gr_init(void)
2. {
3. gglInit(&gr_context);
4. GGLContext *gl = gr_context;
5. gr_init_font();
6. "/dev/tty0", O_RDWR | O_SYNC);
7. if (gr_vt_fd < 0) {
8. // This is non-fatal; post-Cupcake kernels don't have tty0.
9. "can't open /dev/tty0");
10.
11. else if (ioctl(gr_vt_fd, KDSETMODE, (void*) KD_GRAPHICS)) {
12. // However, if we do open tty0, we expect the ioctl to work.
13. "failed KDSETMODE to KD_GRAPHICS on tty0");
14. gr_exit();
15. return -1;
16. }
17. gr_fb_fd = get_framebuffer(gr_framebuffer);
18. if (gr_fb_fd < 0) {
19. gr_exit();
20. return -1;
21. }
22. get_memory_surface(&gr_mem_surface);
23. "framebuffer: fd %d (%d x %d)\n",
24. gr_fb_fd, gr_framebuffer[0].width, gr_framebuffer[0].height);
25. /* start with 0 as front (displayed) and 1 as back (drawing) */
26. gr_active_fb = 0;
27. set_active_framebuffer(0);
28. gl->colorBuffer(gl, &gr_mem_surface);
29. gl->activeTexture(gl, 0);
30. gl->enable(gl, GGL_BLEND);
31. gl->blendFunc(gl, GGL_SRC_ALPHA, GGL_ONE_MINUS_SRC_ALPHA);
32. true);
33. false);
34. return 0;
35.
36. }
1. int gr_init(void)
2. {
3. gglInit(&gr_context);
4. GGLContext *gl = gr_context;
5. gr_init_font();
6. "/dev/tty0", O_RDWR | O_SYNC);
7. if (gr_vt_fd < 0) {
8. // This is non-fatal; post-Cupcake kernels don't have tty0.
9. "can't open /dev/tty0");
10.
11. else if (ioctl(gr_vt_fd, KDSETMODE, (void*) KD_GRAPHICS)) {
12. // However, if we do open tty0, we expect the ioctl to work.
13. "failed KDSETMODE to KD_GRAPHICS on tty0");
14. gr_exit();
15. return -1;
16. }
17. gr_fb_fd = get_framebuffer(gr_framebuffer);
18. if (gr_fb_fd < 0) {
19. gr_exit();
20. return -1;
21. }
22. get_memory_surface(&gr_mem_surface);
23. "framebuffer: fd %d (%d x %d)\n",
24. gr_fb_fd, gr_framebuffer[0].width, gr_framebuffer[0].height);
25. /* start with 0 as front (displayed) and 1 as back (drawing) */
26. gr_active_fb = 0;
27. set_active_framebuffer(0);
28. gl->colorBuffer(gl, &gr_mem_surface);
29. gl->activeTexture(gl, 0);
30. gl->enable(gl, GGL_BLEND);
31. gl->blendFunc(gl, GGL_SRC_ALPHA, GGL_ONE_MINUS_SRC_ALPHA);
32. true);
33. false);
34. return 0;
35.
36. }
(2)android/bootable/recovery/minui/events.c
ev_init():minui/events.c[open /dev/input/event*]打开 /dev/input/event*
这部分是在，充电状态下，按键操作的初始化，比如：短按显示充电logo，长按开机，初始化代码如下。
1. int ev_init(ev_callback input_cb,void *data)
2. {
3. DIR *dir;
4. struct dirent *de;
5. int fd;
6. "/dev/input");//打开驱动结点；
7. if(dir != 0) {
8. while((de = readdir(dir))) {
9. long ev_bits[BITS_TO_LONGS(EV_MAX)];
10. // fprintf(stderr,"/dev/input/%s\n", de->d_name);
11. if(strncmp(de->d_name,"event",5))continue;
12. fd = openat(dirfd(dir), de->d_name, O_RDONLY);
13. if(fd < 0) continue;
14. /* read the evbits of the input device */
15. if (ioctl(fd, EVIOCGBIT(0,sizeof(ev_bits)), ev_bits) < 0) {
16. close(fd);
17. continue;
18. }
19. /* TODO: add ability to specify event masks. For now, just assume
20. * that only EV_KEY and EV_REL event types are ever needed. */
21. if (!test_bit(EV_KEY, ev_bits) && !test_bit(EV_REL, ev_bits)) {
22. close(fd);
23. continue;
24. }
25. ev_fds[ev_count].fd = fd;
26. ev_fds[ev_count].events = POLLIN;
27. ev_fdinfo[ev_count].cb = input_cb;
28. ev_fdinfo[ev_count].data = data;
29. ev_count++;
30. ev_dev_count++;
31. if(ev_dev_count == MAX_DEVICES)break;
32. }
33. }
34. return 0;
35. }
1. int ev_init(ev_callback input_cb, void *data)
2. {
3. DIR *dir;
4. struct dirent *de;
5. int fd;
6. "/dev/input");//打开驱动结点；
7. if(dir != 0) {
8. while((de = readdir(dir))) {
9. long ev_bits[BITS_TO_LONGS(EV_MAX)];
10. // fprintf(stderr,"/dev/input/%s\n", de->d_name);
11. if(strncmp(de->d_name,"event",5)) continue;
12. fd = openat(dirfd(dir), de->d_name, O_RDONLY);
13. if(fd < 0) continue;
14. /* read the evbits of the input device */
15. if (ioctl(fd, EVIOCGBIT(0, sizeof(ev_bits)), ev_bits) < 0) {
16. close(fd);
17. continue;
18. }
19. /* TODO: add ability to specify event masks. For now, just assume
20. * that only EV_KEY and EV_REL event types are ever needed. */
21. if (!test_bit(EV_KEY, ev_bits) && !test_bit(EV_REL, ev_bits)) {
22. close(fd);
23. continue;
24. }
25. ev_fds[ev_count].fd = fd;
26. ev_fds[ev_count].events = POLLIN;
27. ev_fdinfo[ev_count].cb = input_cb;
28. ev_fdinfo[ev_count].data = data;
29. ev_count++;
30. ev_dev_count++;
31. if(ev_dev_count == MAX_DEVICES) break;
32. }
33. }
34. return 0;
35. }
(3)、创建/sys/class/power_supply结点，把socket信息通知应用层
uevent_open_socket这个函数是通过kobject_uevent的方式通知的应用层，就是往一个socket广播一个消息，只需要在应用层打开socket监听NETLINK_KOBJECT_UEVENT组的消息，就可以收到了,主要是创建了socket接口获得uevent的文件描述符，然后触发/sys/class/power_supply目录及其子目录下的uevent，然后接受并创建设备节点，至此设备节点才算创建。
(4)、这里显示charger logo，res_create_surface显示图片函数；
res_create_surface:minui/resource.c[create surfaces for all bitmaps used later, include icons, bmps]
创建surface为所以的位图，包括图标、位图。 这些图片的位置为：system\core\charger\images
（5）、event_loop循环，电池状态，检测按键是否按下；
5、event_loop
这个函数判断按键状态，DC是否插拔。如果长按开机：执行android_reboot(ANDROID_RB_RESTART,0, 0);如果拔出DC:执行android_reboot(ANDROID_RB_POWEROFF,0, 0);
1. static void event_loop(struct charger *charger)
2. {
3. int ret;
4. while (true) {
5. //（1）、获得当前时间；
6. "[%lld] event_loop()\n", now);
7. //（2）、检查按键状态；
8. // (3)、检查DC是否拔出；
9. /* do screen update last in case any of the above want to start
10. * screen transitions (animations, etc)
11. */
12. //(4)、对按键时间状态标志位的判断，显示不同电量的充电logo;
13. wait_next_event(charger, now);
14. }
15. }
1. static void event_loop(struct charger *charger)
2. {
3. int ret;
4. while (true) {
5. //（1）、获得当前时间；
6. "[%lld] event_loop()\n", now);
7. //（2）、检查按键状态；
8. // (3)、检查DC是否拔出；
9. /* do screen update last in case any of the above want to start
10. * screen transitions (animations, etc)
11. */
12. //(4)、对按键时间状态标志位的判断，显示不同电量的充电logo;
13. wait_next_event(charger, now);
14. }
15. }
（1）、获得当前时间；
int64_t now = curr_time_ms();
这个时间来判断，有没有屏幕超时，如果超时关闭屏幕充电logo显示。
（2）、检查按键状态；
1. static void handle_input_state(struct charger *charger, int64_t now)
2. {
3. process_key(charger, KEY_POWER, now);
4. if (charger->next_key_check != -1 && now > charger->next_key_check)
5. charger->next_key_check = -1;
6. }
7. 我们再看下：process_key(charger, KEY_POWER, now);
8. static void process_key(struct charger *charger,int code, int64_t now)
9. {
10. ………………
11. if (code == KEY_POWER) {
12. if (key->down) {
13. int64_t reboot_timeout = key->timestamp + POWER_ON_KEY_TIME;
14. if (now >= reboot_timeout) {//如果长按power键，就重新启动，也就是重启开机；
15. "[%lld] rebooting\n", now);
16. //重启命令；
17. }
18. ………………
19. }
20.
21. false;
22. }
1. static void handle_input_state(struct charger *charger, int64_t now)
2. {
3. process_key(charger, KEY_POWER, now);
4. if (charger->next_key_check != -1 && now > charger->next_key_check)
5. charger->next_key_check = -1;
6. }
7. 我们再看下：process_key(charger, KEY_POWER, now);
8. static void process_key(struct charger *charger, int code, int64_t now)
9. {
10. ………………
11. if (code == KEY_POWER) {
12. if (key->down) {
13. int64_t reboot_timeout = key->timestamp + POWER_ON_KEY_TIME;
14. if (now >= reboot_timeout) {//如果长按power键，就重新启动，也就是重启开机；
15. "[%lld] rebooting\n", now);
16. //重启命令；
17. }
18. ………………
19. }
20.
21. false;
22. }
（3）、检查DC是否拔出；
handle_power_supply_state(charger, now);
1. static void handle_power_supply_state(struct charger *charger, int64_t now)
2. {
3. if (charger->num_supplies_online == 0) {
4. if (charger->next_pwr_check == -1) {
5. charger->next_pwr_check = now + UNPLUGGED_SHUTDOWN_TIME;
6. "[%lld] device unplugged: shutting down in %lld (@ %lld)\n",
7. now, UNPLUGGED_SHUTDOWN_TIME, charger->next_pwr_check);
8. else if (now >= charger->next_pwr_check) {
9. "[%lld] shutting down\n", now);
10. //如果DC拔出，则关机；
11. }
12. ………………
13. }
1. static void handle_power_supply_state(struct charger *charger, int64_t now)
2. {
3. if (charger->num_supplies_online == 0) {
4. if (charger->next_pwr_check == -1) {
5. charger->next_pwr_check = now + UNPLUGGED_SHUTDOWN_TIME;
6. "[%lld] device unplugged: shutting down in %lld (@ %lld)\n",
7. now, UNPLUGGED_SHUTDOWN_TIME, charger->next_pwr_check);
8. else if (now >= charger->next_pwr_check) {
9. "[%lld] shutting down\n", now);
10. //如果DC拔出，则关机；
11. }
12. ………………
13. }
(4)、对按键时间状态标志位的判断，显示不同电量的充电logo;
update_screen_state(charger, now);
这个函数比较长了，其实做用就是：我们在状态的过程中,充电logo的电量是要增加的，比如电量是20%时，要从第一格开始闪烁；如果是80%时，则要从第三格开始闪烁，电量显示就是通过这个函数来计算实现的。
1. static void update_screen_state(struct charger *charger, int64_t now)
2. {
3. struct animation *batt_anim = charger->batt_anim;
4. int cur_frame;
5. int disp_time;
6.
7. if (!batt_anim->run || now < charger->next_screen_transition)
8. return;
9.
10. /* animation is over, blank screen and leave */
11. if (batt_anim->cur_cycle == batt_anim->num_cycles) {
12. reset_animation(batt_anim);
13. charger->next_screen_transition = -1;
14. true);
15. "[%lld] animation done\n", now);
16. return;
17. }
18.
19. disp_time = batt_anim->frames[batt_anim->cur_frame].disp_time;
20.
21. /* animation starting, set up the animation */
22. if (batt_anim->cur_frame == 0) {
23. int batt_cap;
24. int ret;
25.
26. "[%lld] animation starting\n", now);
27. batt_cap = get_battery_capacity(charger);
28. if (batt_cap >= 0 && batt_anim->num_frames != 0) {
29. int i;
30.
31. /* find first frame given current capacity */
32. for (i = 1; i < batt_anim->num_frames; i++) {
33. if (batt_cap < batt_anim->frames[i].min_capacity)
34. break;
35. }
36. batt_anim->cur_frame = i - 1;
37.
38. /* show the first frame for twice as long */
39. disp_time = batt_anim->frames[batt_anim->cur_frame].disp_time * 2;
40. }
41.
42. batt_anim->capacity = batt_cap;
43. }
44.
45. /* unblank the screen on first cycle */
46. if (batt_anim->cur_cycle == 0)
47. false);
48.
49. /* draw the new frame (@ cur_frame) */
50. redraw_screen(charger);
51.
52. /* if we don't have anim frames, we only have one image, so just bump
53. * the cycle counter and exit
54. */
55. if (batt_anim->num_frames == 0 || batt_anim->capacity < 0) {
56. "[%lld] animation missing or unknown battery status\n", now);
57. charger->next_screen_transition = now + BATTERY_UNKNOWN_TIME;
58. batt_anim->cur_cycle++;
59. return;
60. }
61.
62. /* schedule next screen transition */
63. charger->next_screen_transition = now + disp_time;
64.
65. /* advance frame cntr to the next valid frame
66. * if necessary, advance cycle cntr, and reset frame cntr
67. */
68. batt_anim->cur_frame++;
69.
70. /* if the frame is used for level-only, that is only show it when it's
71. * the current level, skip it during the animation.
72. */
73. while (batt_anim->cur_frame < batt_anim->num_frames &&
74. batt_anim->frames[batt_anim->cur_frame].level_only)
75. batt_anim->cur_frame++;
76. if (batt_anim->cur_frame >= batt_anim->num_frames) {
77. batt_anim->cur_cycle++;
78. batt_anim->cur_frame = 0;
79.
80. /* don't reset the cycle counter, since we use that as a signal
81. * in a test above to check if animation is over
82. */
83. }
84. }
1. static void update_screen_state(struct charger *charger, int64_t now)
2. {
3. struct animation *batt_anim = charger->batt_anim;
4. int cur_frame;
5. int disp_time;
6.
7. if (!batt_anim->run || now < charger->next_screen_transition)
8. return;
9.
10. /* animation is over, blank screen and leave */
11. if (batt_anim->cur_cycle == batt_anim->num_cycles) {
12. reset_animation(batt_anim);
13. charger->next_screen_transition = -1;
14. true);
15. "[%lld] animation done\n", now);
16. return;
17. }
18.
19. disp_time = batt_anim->frames[batt_anim->cur_frame].disp_time;
20.
21. /* animation starting, set up the animation */
22. if (batt_anim->cur_frame == 0) {
23. int batt_cap;
24. int ret;
25.
26. "[%lld] animation starting\n", now);
27. batt_cap = get_battery_capacity(charger);
28. if (batt_cap >= 0 && batt_anim->num_frames != 0) {
29. int i;
30.
31. /* find first frame given current capacity */
32. for (i = 1; i < batt_anim->num_frames; i++) {
33. if (batt_cap < batt_anim->frames[i].min_capacity)
34. break;
35. }
36. batt_anim->cur_frame = i - 1;
37.
38. /* show the first frame for twice as long */
39. disp_time = batt_anim->frames[batt_anim->cur_frame].disp_time * 2;
40. }
41.
42. batt_anim->capacity = batt_cap;
43. }
44.
45. /* unblank the screen on first cycle */
46. if (batt_anim->cur_cycle == 0)
47. false);
48.
49. /* draw the new frame (@ cur_frame) */
50. redraw_screen(charger);
51.
52. /* if we don't have anim frames, we only have one image, so just bump
53. * the cycle counter and exit
54. */
55. if (batt_anim->num_frames == 0 || batt_anim->capacity < 0) {
56. "[%lld] animation missing or unknown battery status\n", now);
57. charger->next_screen_transition = now + BATTERY_UNKNOWN_TIME;
58. batt_anim->cur_cycle++;
59. return;
60. }
61.
62. /* schedule next screen transition */
63. charger->next_screen_transition = now + disp_time;
64.
65. /* advance frame cntr to the next valid frame
66. * if necessary, advance cycle cntr, and reset frame cntr
67. */
68. batt_anim->cur_frame++;
69.
70. /* if the frame is used for level-only, that is only show it when it's
71. * the current level, skip it during the animation.
72. */
73. while (batt_anim->cur_frame < batt_anim->num_frames &&
74. batt_anim->frames[batt_anim->cur_frame].level_only)
75. batt_anim->cur_frame++;
76. if (batt_anim->cur_frame >= batt_anim->num_frames) {
77. batt_anim->cur_cycle++;
78. batt_anim->cur_frame = 0;
79.
80. /* don't reset the cycle counter, since we use that as a signal
81. * in a test above to check if animation is over
82. */
83. }
84. }
下面是不能容量时显示logo的函数：
1. static struct frame batt_anim_frames[] = {
2. {
3. "charger/battery_0",
4. .disp_time = 750,
5. .min_capacity = 0,
6. },
7. {
8. "charger/battery_1",
9. .disp_time = 750,
10. .min_capacity = 20,
11. },
12. {
13. "charger/battery_2",
14. .disp_time = 750,
15. .min_capacity = 40,
16. },
17. {
18. "charger/battery_3",
19. .disp_time = 750,
20. .min_capacity = 60,
21. },
22. {
23. "charger/battery_4",
24. .disp_time = 750,
25. .min_capacity = 80,
26. true,
27. },
28. {
29. "charger/battery_5",
30. .disp_time = 750,
31. .min_capacity = BATTERY_FULL_THRESH,
32. },
33. };
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