Android light系统分析
光线系统包括：背光，闪光，led指示灯
一.内核层
Led-class.c (kernel-3.10\drivers\leds) 这个文件给HAL层提供接口
led_brightness_store是sysfs文件，在"/sys/class/leds/lcd-backlight/brightness"
__led_set_brightness(led_cdev, i);
led_cdev->brightness_set(led_cdev, value); （Leds.h (kernel-3.10\drivers\leds)）
led_cdev->brightness_set在Leds_drv.c (kernel-3.10\drivers\misc\mediatek\leds)中的probe函数中被赋值
g_leds_data[i]->cdev.brightness_set = mt65xx_led_set;
mt65xx_led_set
mt_mt65xx_led_set(led_cdev, level);
mt_mt65xx_led_set_cust(&led_data->cust, led_data->level); 在Leds.c (kernel-3.10\drivers\misc\mediatek\leds\mt6735) 中
mt_mt65xx_led_set_cust //因为我们是GPIO模式，所以就会进入这个分支
case MT65XX_LED_MODE_GPIO:
LEDS_DEBUG("brightness_set_cust:go GPIO mode!!!!!\n");
return ((cust_set_brightness)(cust->data))(level);
cust->data这个函数指针在Cust_leds.c (kernel-3.10\drivers\misc\mediatek\mach\mt6735\lentek6735_65c_l\leds\mt65xx)被赋值
static struct cust_mt65xx_led cust_led_list[MT65XX_LED_TYPE_TOTAL] = {
{"red", MT65XX_LED_MODE_PMIC, MT65XX_LED_PMIC_NLED_ISINK0,{0}},{"blue", MT65XX_LED_MODE_NONE, -1,{0}},{"green", MT65XX_LED_MODE_PMIC, MT65XX_LED_PMIC_NLED_ISINK1,{0}},{"jogball-backlight", MT65XX_LED_MODE_NONE, -1,{0}},{"keyboard-backlight",MT65XX_LED_MODE_NONE, -1,{0}},{"button-backlight", MT65XX_LED_MODE_NONE, -1,{0}},{"lcd-backlight", MT65XX_LED_MODE_GPIO, (long)Cust_Tintele_SetBacklight,{0}},{"flashlight", MT65XX_LED_MODE_GPIO, (long)Cust_Tintele_SetFlashlight,{0}},
};
因为是16节的控制芯片，就是只有16级亮度，用io模拟这种进行控制
for (; i<=16-level; i++) {
mt_set_gpio_out(GPIO_LCD_BACKLIGHT_EN | 0x80000000, 0);
udelay(2);
mt_set_gpio_out(GPIO_LCD_BACKLIGHT_EN | 0x80000000, 1);
udelay(2);
}
GPIO_LCD_BACKLIGHT_EN | 0x80000000 //是为了让这个执行更快
二.hal层
Lights.c (vendor\mediatek\proprietary\hardware\liblights)
set_light_backlight
write_int(LCD_FILE, brightness); //LCD_FILE就是/sys/class/leds/lcd-backlight/brightness
提供接口给中间层
struct hw_module_t HAL_MODULE_INFO_SYM = {
.tag = HARDWARE_MODULE_TAG,
//.version_major = 1,
//.version_minor = 0,
.id = LIGHTS_HARDWARE_MODULE_ID,
.name = "MTK lights Module",
.author = "MediaTek",
.methods = &lights_module_methods,
};
打开函数
static struct hw_module_methods_t lights_module_methods = {
.open = open_lights,
};
open_lights
if (0 == strcmp(LIGHT_ID_BACKLIGHT, name)) {
set_light = set_light_backlight;
}
三.jni层
init_native
hw_get_module(LIGHTS_HARDWARE_MODULE_ID, (hw_module_t const**)&module); //获得hal层的接口
get_device(module, LIGHT_ID_BACKLIGHT);
module->methods->open(module, name, &device); //调用hal层的open函数
finalize_native 和 setLight_native上层可以调用、
static JNINativeMethod method_table[] = {
{ "init_native", "()J", (void*)init_native },
{ "finalize_native", "(J)V", (void*)finalize_native },
{ "setLight_native", "(JIIIIII)V", (void*)setLight_native },
};
int register_android_server_LightsService(JNIEnv *env)
{
return jniRegisterNativeMethods(env, "com/android/server/lights/LightsService",
method_table, NELEM(method_table));
}
四.framework层
DisplayPowerController.java (frameworks\base\services\core\java\com\android\server\display)
我要改变拉动背光条，中间过滤一些数值// Brightness animation ramp rate in brightness units per second.private static final int BRIGHTNESS_RAMP_RATE_FAST = 20000;private static final int BRIGHTNESS_RAMP_RATE_SLOW = 2000;
