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1、前言
充电LED灯控制是Android设备的基本功能,主要用于提示设备的电池状态,充电状态,满电状态,低电状态,很多手机厂商还使用呼吸效果来显示,普通的低端设备会使用两个LED灯表示,红灯表示充电和低电,绿灯表示满电。
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2、kernel 层控制充电LED
代码位置主要在kernel/driver/power/power_supply_leds.c
/* Battery specific LEDs triggers. */static void power_supply_update_bat_leds(struct power_supply *psy){ union power_supply_propval status; unsigned long delay_on = 0; unsigned long delay_off = 0; if (power_supply_get_property(psy, POWER_SUPPLY_PROP_STATUS, &status)) return; dev_dbg(&psy->dev, "%s %d\n", __func__, status.intval); switch (status.intval) { case POWER_SUPPLY_STATUS_FULL: led_trigger_event(psy->charging_full_trig, LED_FULL); led_trigger_event(psy->charging_trig, LED_OFF); led_trigger_event(psy->full_trig, LED_FULL); led_trigger_event(psy->charging_blink_full_solid_trig, LED_FULL); break; case POWER_SUPPLY_STATUS_CHARGING: led_trigger_event(psy->charging_full_trig, LED_FULL); led_trigger_event(psy->charging_trig, LED_FULL); led_trigger_event(psy->full_trig, LED_OFF); led_trigger_blink(psy->charging_blink_full_solid_trig, &delay_on, &delay_off); break; default: led_trigger_event(psy->charging_full_trig, LED_OFF); led_trigger_event(psy->charging_trig, LED_OFF); led_trigger_event(psy->full_trig, LED_OFF); led_trigger_event(psy->charging_blink_full_solid_trig, LED_OFF); break; }}
如果想在kernel 层控制led灯,就需要在这里修改代码,会需要使用到trigger相关的东西,要理解什么是trigger,可以看下面的链接
trigger主要是做led灯的一些效果的东西,默认有default-on 对应打开led的trigger,还有none对应关闭LED的trigger。
被[ ]括起来的,就是当前trigger的值,然后回触发对应trigger的.activate函数。
Trigger的代码位置在 kernel/drivers/leds/trigger
3、framework控制led灯
为了统一控制led接口,Android有一个自己的框架控制led灯
Framework->Hal->kernel->hardware
设置对应的LED灯颜色主要在
Framework/base/core/res/res/values/config.xml
#ffffffff 500 2000 0xFFFF0000 0xFFFF0000 0xFF00FF00 125
充电状态灯指示状态函数调用
frameworks\base\services\core\java\com\android\server\BatteryService.java
/*** Synchronize on BatteryService.*/public void updateLightsLocked() {final int level = mBatteryProps.batteryLevel;final int status = mBatteryProps.batteryStatus;if (level < mLowBatteryWarningLevel) { if (status == BatteryManager.BATTERY_STATUS_CHARGING) { // Solid red when battery is charging mBatteryLight.setColor(mBatteryLowARGB); } else { // Flash red when battery is low and not charging mBatteryLight.setFlashing(mBatteryLowARGB, Light.LIGHT_FLASH_TIMED, mBatteryLedOn, mBatteryLedOff); }} else if (status == BatteryManager.BATTERY_STATUS_CHARGING|| status == BatteryManager.BATTERY_STATUS_FULL) { if (status == BatteryManager.BATTERY_STATUS_FULL || level >= 90) { // Solid green when full or charging and nearly full mBatteryLight.setColor(mBatteryFullARGB); } else { if (isHvdcpPresent()) { // Blinking orange if HVDCP charger mBatteryLight.setFlashing(mBatteryMediumARGB, Light.LIGHT_FLASH_TIMED, mBatteryLedOn, mBatteryLedOn); } else { // Solid orange when charging and halfway full mBatteryLight.setColor(mBatteryMediumARGB); } }} else { // No lights if not charging and not low mBatteryLight.turnOff();}}}
LightsService 管理LED
frameworks\base\services\core\java\com\android\server\lights\LightsService.java
private void setLightLocked(int color, int mode, int onMS, int offMS, int brightnessMode);{//调用JNI函数设置状态setLight_native(mNativePointer, mId, color, mode, onMS, offMS, brightnessMode);}static void setLight_native(JNIEnv* /* env */, jobject /* clazz */, jlong ptr,jint light, jint colorARGB, jint flashMode, jint onMS, jint offMS, jint brightnessMode){//调用HAL层接口设置指示灯状态devices->lights[light]->set_light(devices->lights[light], &state);}
获取HAL层接口函数
static jlong init_native(JNIEnv* /* env */, jobject /* clazz */){int err;hw_module_t* module;Devices* devices;devices = (Devices*)malloc(sizeof(Devices));err = hw_get_module(LIGHTS_HARDWARE_MODULE_ID, (hw_module_t const**)&module);if (err == 0) { devices->lights[LIGHT_INDEX_BACKLIGHT] = get_device(module, LIGHT_ID_BACKLIGHT); devices->lights[LIGHT_INDEX_KEYBOARD] = get_device(module, LIGHT_ID_KEYBOARD); devices->lights[LIGHT_INDEX_BUTTONS] = get_device(module, LIGHT_ID_BUTTONS); devices->lights[LIGHT_INDEX_BATTERY] = get_device(module, LIGHT_ID_BATTERY); devices->lights[LIGHT_INDEX_NOTIFICATIONS] = get_device(module, LIGHT_ID_NOTIFICATIONS); devices->lights[LIGHT_INDEX_ATTENTION] = get_device(module, LIGHT_ID_ATTENTION); devices->lights[LIGHT_INDEX_BLUETOOTH] = get_device(module, LIGHT_ID_BLUETOOTH); devices->lights[LIGHT_INDEX_WIFI] = get_device(module, LIGHT_ID_WIFI);} else { memset(devices, 0, sizeof(Devices));}return (jlong)devices;}
中间层的代码位置主要在
Hardware/rockchip/liblight/
一个字节对应一种颜色,一共有三个颜色,想最终控制颜色就需要修改上面说的xml文件,比如0x00ffffff,表示红蓝绿三个灯同时亮。具体代码如下
int set_battery_light(struct light_device_t* dev, struct light_state_t const* state){ int err = 0; char red,blue,green; unsigned int colorRGB = state->color & 0x00ffffff; red = (colorRGB >> 16) & 0xFF; green = (colorRGB >> 8) & 0xFF; blue = colorRGB & 0xFF; pthread_mutex_lock(&g_lock); LOGI(">>>weiqifa set_battery_light 0x%x",state->color); err = write_int(RED_LED_PATH, red?1:0); err = write_int(BLUE_LED_PATH, blue?1:0); err = write_int(GREEN_LED_PATH, green?1:0); pthread_mutex_unlock(&g_lock); return 0; }
然后控制的主要是led的设备节点,led的设备节点主要是驱动层生成,代码的位置如下:kernel/driver/leds/
#define RED_LED_PATH "sys/class/leds/red/brightness" #define GREEN_LED_PATH "sys/class/leds/green/brightness" #define BLUE_LED_PATH "sys/class/leds/blue/brightness"
Led驱动对应的dts代码如下:
leds: gpio-leds { compatible = "gpio-leds"; led-green { ┊ label = "green"; gpios = <&gpio7 8 GPIO_ACTIVE_HIGH>; inux,default-trigger = "timer"; default-state = "off"; }; led-blue { ┊ label = "blue"; gpios = <&gpio7 14 GPIO_ACTIVE_HIGH>; inux,default-trigger = "timer"; default-state = "off"; }; led-red { ┊ label = "red"; gpios = <&gpio7 15 GPIO_ACTIVE_HIGH>; inux,default-trigger = "timer"; default-state = "off"; }; };
里面的linux,default-trigger 表示默认的trigger模式,如果设置为none就是表示关闭,现在我们的代码设置为timer表示用定时器的模式,实际上我们没有编译定时器模式,所以设置并没有生效。
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