system：Android 8.1
platform：RK3326/PX30
uboot
kernel
Android 8.1 关机充电动画（一）模式选择
Android 8.1 关机充电动画（二）Uboot模式
Android 8.1 关机充电动画（三）Android模式
前言
关机充电的动画可以在u-boot或者Android的charger模式工作，这是两个相互独立的部分，RK平台上需要在设备树进行配置。顾名思义u-boot下的charger模式，系统仍然运行在loader下，并未启动内核。
Android的charger模式下，在引导程序运行期间会传递参数给内核，则会启动内核并加载内核模块，同时安卓系统也不会启动，系统最终只工作charger模式。这里简单记录一下，在uboot中都做了哪些工作，根据什么条件选择工作的模式。
配置
设备树要增加节点charge-animation，这个rk的文档里有相应的说明，在配置下面设备树的配置中，我已经加上了注释，对照这个看就行，不过所有属性只适用u-boot下的关机充电，而不适用用Android下的关机充电，这个具体会在后面加以说明。
这里暂时把已经启动内核之后再进入charger的模式称作Android下的关机充电，可能有些不妥，但是先这样区分吧
具体的配置如下；
rockchip,uboot-charge-on = <0>; ,rockchip,android-charge-on = <1>; 这两个属性用于选择后续的程序会进入到哪一种模式工作，后面在代码中会加以区分。
charge-animation {
compatible = "rockchip,uboot-charge";
rockchip,uboot-charge-on = <0>; // 是否在U-Boot进行充电
rockchip,android-charge-on = <1>; // 是否在Android进行充电
rockchip,uboot-exit-charge-level = <5>; // U-Boot充电时，允许开机的最低电量
rockchip,uboot-exit-charge-voltage = <3600>; // U-Boot充电时，允许开机的最低电压
rockchip,screen-on-voltage = <3400>; // U-Boot充电时，允许点亮屏幕的最低电压
rockchip,uboot-low-power-voltage = <3350>; // U-Boot无条件强制进入充电模式的最低电压
rockchip,system-suspend = <0>; // 灭屏时进入trust进行低功耗待机
rockchip,auto-off-screen-interval = <10>;// 亮屏超时后自动灭屏，单位秒。(如果没有这个属性，则默认15s)
rockchip,auto-wakeup-interval = <0>; // 休眠自动唤醒时间，单位秒。(如果值为0或没有这个属性，则禁止休眠自动唤醒)
rockchip,auto-wakeup-screen-invert = <0>; // 休眠自动唤醒的时候，是否让屏幕产生亮/灭效果
status = "okay";
};
代码分析
可以定位到u-boot/drivers/power/charge_animation.c，目前只分析一下函数static int charge_animation_show(struct udevice *dev)，具体代码见最后的附录
这个函数会在启动内核之前进行一个简单的检测；
1. Extrem low power charge?
2. Preboot cmd?
3. Valid boot mode?
4. U-Boot charge enabled by dts config?
5. Screen off before charge?
6. Enter charge !
分别是1 检测低电量，2 检测启动命令，3 检测启动模式，4 检测设备树配置，这四项检测如果不符合会直接return，然后无法成功进入6 Enter charge的状态。具体的可以在代码里面慢慢看，至于第五点，不太清楚了。这里先把第四点的部分相关的代码抠出来，如下：
/* charge mode */
pdata->uboot_charge =
dev_read_u32_default(dev, "rockchip,uboot-charge-on", 0);
pdata->android_charge =
dev_read_u32_default(dev, "rockchip,android-charge-on", 0);
/* Enter android charge, set property for kernel */
if (pdata->android_charge) {
env_update("bootargs", "androidboot.mode=charger");
}
/* Not enable U-Boot charge, exit */
if (!pdata->uboot_charge) {
debug("exit charge, due to not enable uboot charge
");
return 0;
}
可以看到这里有两种情况
uboot_charge如果在设备树里配置为开启，则无法进入Android 关机充电模式了，然后最终程序会进入到while(1)不断循环显示充电动画，检测到相应事件动作之后才会退出充电进入系统，或者掉电关机;android_charge在设备树中设置开启，并且uboot_charge设置为关闭的情况下，会设置内核的启动参数env_update("bootargs", "androidboot.mode=charger")，之后uboot会启动内核，并传参数给内核，告诉他，要进入Android关机充电的模式。
总结
这里篇幅较短，主要分析了在u-boot下charge_animation_show的部分工作流程即如何选择最终充电的模式，下面会简单介绍uboot下关机充电和Android下关机充电的动画定制。
附录
代码可能已经更新请参考u-boot/drivers/power/charge_animation.c
static int charge_animation_show(struct udevice *dev)
{
struct charge_animation_pdata *pdata = dev_get_platdata(dev);
struct charge_animation_priv *priv = dev_get_priv(dev);
const struct charge_image *image = priv->image;
struct udevice *pmic = priv->pmic;
struct udevice *fg = priv->fg;
const char *preboot = env_get("preboot");
int image_num = priv->image_num;
bool ever_lowpower_screen_off = false;
bool screen_on = true;
ulong show_start = 0, charge_start = 0, debug_start = 0;
ulong delta;
ulong ms = 0, sec = 0;
int start_idx = 0, show_idx = -1, old_show_idx = IMAGE_SHOW_RESET;
int soc, voltage, current, key_state;
int i, charging = 1, ret;
int boot_mode;
int first_poll_fg = 1;
/*
* Check sequence:
*
* 1. Extrem low power charge?
* 2. Preboot cmd?
* 3. Valid boot mode?
* 4. U-Boot charge enabled by dts config?
* 5. Screen off before charge?
* 6. Enter charge !
*
*/
if (!fuel_gauge_bat_is_exist(fg)) {
printf("Exit charge: battery is not exist
");
return 0;
}
/* Extrem low power charge */
ret = charge_extrem_low_power(dev);
if (ret < 0) {
printf("extrem low power charge failed, ret=%d
", ret);
return ret;
}
/* If there is preboot command, exit */
if (preboot && !strstr(preboot, "dvfs")) {
printf("Exit charge: due to preboot cmd '%s'
", preboot);
return 0;
}
/* Not valid charge mode, exit */
#ifdef CONFIG_RKIMG_BOOTLOADER
boot_mode = rockchip_get_boot_mode();
if ((boot_mode != BOOT_MODE_CHARGING) &&
(boot_mode != BOOT_MODE_UNDEFINE)) {
printf("Exit charge: due to boot mode
");
return 0;
}
#endif
/* Not charger online, exit */
charging = fuel_gauge_get_chrg_online(fg);
if (charging <= 0) {
printf("Exit charge: due to charger offline
");
return 0;
}
/* Enter android charge, set property for kernel */
if (pdata->android_charge) {
env_update("bootargs", "androidboot.mode=charger");
printf("Android charge mode
");
}
/* Not enable U-Boot charge, exit */
if (!pdata->uboot_charge) {
printf("Exit charge: due to not enable uboot charge
");
return 0;
}
voltage = fuel_gauge_get_voltage(fg);
if (voltage < 0) {
printf("get voltage failed: %d
", voltage);
return -EINVAL;
}
/* If low power, turn off screen */
if (voltage <= pdata->screen_on_voltage + 50) {
screen_on = false;
ever_lowpower_screen_off = true;
charge_show_bmp(NULL);
}
/* Auto wakeup */
if (pdata->auto_wakeup_interval) {
printf("Auto wakeup: %dS
", pdata->auto_wakeup_interval);
autowakeup_timer_init(dev, pdata->auto_wakeup_interval);
}
/* Give a message warning when CONFIG_IRQ is not enabled */
#ifdef CONFIG_IRQ
printf("Enter U-Boot charging mode
");
#else
printf("Enter U-Boot charging mode(without IRQ)
");
#endif
charge_start = get_timer(0);
delta = get_timer(0);
/* Charging ! */
while (1) {
/*
* At the most time, fuel gauge is usually a i2c device, we
* should avoid read/write all the time. We had better set
* poll seconds to update fuel gauge info.
*/
if (!first_poll_fg && get_timer(delta) < FUEL_GAUGE_POLL_MS)
goto show_images;
delta = get_timer(0);
debug("step1 (%d)...
", screen_on);
/*
* Most fuel gauge is I2C interface, it shouldn't be interrupted
* during tansfer. The power key event depends on interrupt, so
* so we should disable local irq when update fuel gauge.
*/
local_irq_disable();
/* Step1: Is charging now ? */
charging = fuel_gauge_get_chrg_online(fg);
if (charging <= 0) {
printf("Not charging, online=%d. Shutdown...
",
charging);
/* wait uart flush before shutdown */
mdelay(5);
/* PMIC shutdown */
pmic_shutdown(pmic);
printf("Cpu should never reach here, shutdown failed !
");
continue;
}
debug("step2 (%d)... show_idx=%d
", screen_on, show_idx);
/* Step2: get soc and voltage */
soc = fuel_gauge_get_soc(fg);
if (soc < 0 || soc > 100) {
printf("get soc failed: %d
", soc);
continue;
}
voltage = fuel_gauge_get_voltage(fg);
if (voltage < 0) {
printf("get voltage failed: %d
", voltage);
continue;
}
current = fuel_gauge_get_current(fg);
if (current == -ENOSYS) {
printf("get current failed: %d
", current);
continue;
}
first_poll_fg = 0;
local_irq_enable();
show_images:
/*
* Just for debug, otherwise there will be nothing output which
* is not good to know what happen.
*/
if (!debug_start)
debug_start = get_timer(0);
if (get_timer(debug_start) > 20000) {
debug_start = get_timer(0);
printf("[%8ld]: soc=%d%%, vol=%dmv, c=%dma, online=%d, screen_on=%d
",
get_timer(0)/1000, soc, voltage,
current, charging, screen_on);
}
/*
* If ever lowpower screen off, force screen_on=false, which
* means key event can't modify screen_on, only voltage higher
* then threshold can update screen_on=true;
*/
if (ever_lowpower_screen_off)
screen_on = false;
/*
* Auto turn on screen when voltage higher than Vol screen on.
* 'ever_lowpower_screen_off' means enter while loop with
* screen off.
*/
if ((ever_lowpower_screen_off) &&
(voltage > pdata->screen_on_voltage)) {
ever_lowpower_screen_off = false;
screen_on = true;
show_idx = IMAGE_SHOW_RESET;
}
/*
* IMAGE_SHOW_RESET means show_idx show be update by start_idx.
* When short key pressed event trigged, we will set show_idx
* as IMAGE_SHOW_RESET which updates images index from start_idx
* that calculate by current soc.
*/
if (show_idx == IMAGE_SHOW_RESET) {
for (i = 0; i < image_num - 2; i++) {
/* Find out which image we start to show */
if ((soc >= image[i].soc) &&
(soc < image[i + 1].soc)) {
start_idx = i;
break;
}
if (soc >= 100) {
start_idx = image_num - 2;
break;
}
}
debug("%s: show_idx=%d, screen_on=%d
",
__func__, show_idx, screen_on);
/* Mark start index and start time */
show_idx = start_idx;
show_start = get_timer(0);
}
debug("step3 (%d)... show_idx=%d
", screen_on, show_idx);
/* Step3: show images */
if (screen_on) {
/* Don't call 'charge_show_bmp' unless image changed */
if (old_show_idx != show_idx) {
old_show_idx = show_idx;
debug("SHOW: %s
", image[show_idx].name);
charge_show_bmp(image[show_idx].name);
}
/* Re calculate timeout to off screen */
if (priv->auto_screen_off_timeout == 0)
priv->auto_screen_off_timeout = get_timer(0);
} else {
priv->auto_screen_off_timeout = 0;
system_suspend_enter(pdata);
}
mdelay(5);
/* Every image shows period */
if (get_timer(show_start) > image[show_idx].period) {
show_start = get_timer(0);
/* Update to next image */
show_idx++;
if (show_idx > (image_num - 2))
show_idx = IMAGE_SHOW_RESET;
}
debug("step4 (%d)...
", screen_on);
/*
* Step4: check key event.
*
* Short key event: turn on/off screen;
* Long key event: show logo and boot system or still charging.
*/
key_state = check_key_press(dev);
if (key_state == KEY_PRESS_DOWN) {
old_show_idx = IMAGE_SHOW_RESET;
/* NULL means show nothing, ie. turn off screen */
if (screen_on)
charge_show_bmp(NULL);
/*
* Clear current image index, and show image
* from start_idx
*/
show_idx = IMAGE_SHOW_RESET;
/*
* We turn off screen by charge_show_bmp(NULL), so we
* should tell while loop to stop show images any more.
*
* If screen_on=false, means this short key pressed
* event turn on the screen and we need show images.
*
* If screen_on=true, means this short key pressed
* event turn off the screen and we never show images.
*/
if (screen_on)
screen_on = false;
else
screen_on = true;
} else if (key_state == KEY_PRESS_LONG_DOWN) {
/* Only long pressed while screen off needs screen_on true */
if (!screen_on)
screen_on = true;
/* Is able to boot now ? */
if (soc < pdata->exit_charge_level) {
printf("soc=%d%%, threshold soc=%d%%
",
soc, pdata->exit_charge_level);
printf("Low power, unable to boot, charging...
");
show_idx = image_num - 1;
continue;
}
if (voltage < pdata->exit_charge_voltage) {
printf("voltage=%dmv, threshold voltage=%dmv
",
voltage, pdata->exit_charge_voltage);
printf("Low power, unable to boot, charging...
");
show_idx = image_num - 1;
continue;
}
/* Success exit charging */
printf("Exit charge animation...
");
charge_show_logo();
break;
} else {
/* Do nothing */
}
debug("step5 (%d)...
", screen_on);
/* Step5: Exit by ctrl+c */
if (ctrlc()) {
if (voltage >= pdata->screen_on_voltage)
charge_show_logo();
printf("Exit charge, due to ctrl+c
");
break;
}
}
if (pdata->auto_wakeup_interval)
autowakeup_timer_uninit();
ms = get_timer(charge_start);
if (ms >= 1000) {
sec = ms / 1000;
ms = ms % 1000;
}
printf("charging time total: %lu.%lus, soc=%d%%, vol=%dmv
",
sec, ms, soc, voltage);
return 0;
}