MTK驱动开发（26）背光灯

1、light系统框架

2、驱动相关的文件

1)Hal      

     /vendor/mediatek/proprietary/hardware/liblights/lights.c

2)Kernel 

    /kernel-3.18/drivers/leds/led-class.c

    /kernel-3.18/drivers/leds/led-core.c

    /kernel-3.18/drivers/leds/led-triggers.c

    /kernel-3.18/drivers/leds/led-trigger/ledtring-timer.c

3)Driver

    Kernel 

   /kernel-3.18/drivers/misc/mediatek/leds/$(platform)/leds.c

   /kernel-3.18/drivers/misc/mediatek/leds/leds_drv.c

   lk

   /vendor/mediatek/proprietary/bootable/bootloader/lk/platform/$(platform)/mt_leds.c

  4)客制化

 ---  Kernel(DTS):  

  /kernel-3.18/arch/arm64/boot/dts/$(project).dts

---LK

   /vendor/mediatek/proprietary/bootable/bootloader/lk/target/$(project)/cust_leds.c

3、背光灯模式

 1&＃xff09;PWM 控制背光

2&＃xff09;PMIC 控制背光

4、背光灯客制化

1&＃xff09;lk 部分客制化

2&＃xff09;Kernel  部分客制化

  修改设备树参数&＃xff1a; led_mode 和data [参数的具体定义参考上图]

   /kernel-3.18/arch/arm64/boot/dts/$(project).dts

led0:led&＃64;0 {
compatible &＃61; "mediatek,red";
led_mode &＃61; <0>;
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;
};
led1:led&＃64;1 {
compatible &＃61; "mediatek,green";
led_mode &＃61; <0>;   ---------------------LED 模式需要设置对
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;
};
led2:led&＃64;2 {
compatible &＃61; "mediatek,blue";
led_mode &＃61; <0>;
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;
};
led3:led&＃64;3 {
compatible &＃61; "mediatek,jogball-backlight";
led_mode &＃61; <0>;
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;
};
led4:led&＃64;4 {
compatible &＃61; "mediatek,keyboard-backlight";
led_mode &＃61; <0>;
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;
};
led5:led&＃64;5 {
compatible &＃61; "mediatek,button-backlight";
led_mode &＃61; <0>;
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;
};
led6:led&＃64;6 {
compatible &＃61; "mediatek,lcd-backlight";
led_mode &＃61; <5>;
data &＃61; <1>;
pwm_config &＃61; <0 0 0 0 0>;

};

 3&＃xff09;BB_PWM的波形周期和波形持续时间决定背光灯的亮度。

       需要配置的参数在PWM_config定义&＃xff0c;如果参数为0&＃xff0c;就是使用系统定义的默认的参数&＃xff0c;参数的具体定义参考硬件手册。

5 、调试方法 
       看背光灯的亮度和是否亮      

---/sys/class/leds/xxx/brightness   xxx---green,blue,red  light的名字

---如果背光灯工作不正常&＃xff0c;可以检查驱动。

    echo brightness_level>brightness     检查设置的背光值是否正确

  ---背光灯的blank

   echo timer>trigger

  echo on_timer>delay_on

  echo off_timer>delay_off