Android LED Implementation

1. 在config裡勾選
   

   CONFIG_NEW_LEDS=y
   CONFIG_LEDS_CLASS=y
   CONFIG_LEDS_GPIO=y
   CONFIG_LEDS_TRIGGERS=y
   CONFIG_LEDS_TRIGGER_TIMER=y 



2. 在board-*.c 裡面建立platform_device 
   

   static struct gpio_led gpio_leds[] = {
    {
    .name = "WHITE_LED",//should change to your own
    .gpio = _GPIO_1,    //should change to your own
    .active_low = 1,
    .default_trigger = "timer", 
    },
   };
   
   static struct gpio_led_platform_data gpio_led_info = {
    .leds = gpio_leds,
    .num_leds = ARRAY_SIZE(gpio_leds),
   };
   
   static struct platform_device leds_gpio = {
    .name = "leds-gpio",
    .id = -1,
    .dev = {
    .platform_data = &gpio_led_info,
    },
   };
   //記得要在類似init加入-->
   platform_device_register(&leds_gpio);
   



3. 實做platform_driver

   基本上依我的板子為例，platform_driver的實做已經在driver/leds/leds-gpio.c裡面做好了 不需要更改



4. 修改LED HAL

   以我的版為例，修改的是libleds.c
   在
   static int open_lights(const struct hw_module_t *module, char const *name,
            struct hw_device_t **device)
   裡面新增了
   }else if(0 == strcmp(LIGHT_ID_BATTERY, name)){
       set_light = set_light_battery;
   }
   
   
   然後因為我的led是gpio led, 只支援on/off ,沒有brightness level, Android定義了不同的level會有不同的顏色或閃爍
   因此我的實做為
   
   
   static int set_light_battery(struct light_device_t *dev,
             struct light_state_t const *state)
   {
    int err = 0;
    int flashmode=state->flashMode;
    
    pthread_mutex_lock(&g_lock);
           
           //set flash
    if(flashmode==1){
     err = write_str("/sys/class/leds/PMU_LED/trigger","timer");
     err = write_int("/sys/class/leds/PMU_LED/delay_on",250);
     err = write_int("/sys/class/leds/PMU_LED/delay_off",150);
    
           }else if(state->color ==0xffffff00||state->color ==0xffff0000||state->color ==-256){
     err = write_str("/sys/class/leds/PMU_LED/trigger","none");
     err = write_int("/sys/class/leds/PMU_LED/brightness",0);
    }else if(state->color ==0xff00ff00||state->color ==0x0){
     err = write_str("/sys/class/leds/PMU_LED/trigger","none");
     err = write_int("/sys/class/leds/PMU_LED/brightness",255);
    }
    pthread_mutex_unlock(&g_lock);
   
    return err;
   }