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

/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）PWM 控制背光

2）PMIC 控制背光

4、背光灯客制化

1）lk 部分客制化

2）Kernel 部分客制化

修改设备树参数： 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@0 {
compatible = "mediatek,red";
led_mode = <0>;
data = <1>;
pwm_config = <0 0 0 0 0>;
};
led1:led@1 {
compatible = "mediatek,green";
led_mode = <0>; ---------------------LED 模式需要设置对
data = <1>;
pwm_config = <0 0 0 0 0>;
};
led2:led@2 {
compatible = "mediatek,blue";
led_mode = <0>;
data = <1>;
pwm_config = <0 0 0 0 0>;
};
led3:led@3 {
compatible = "mediatek,jogball-backlight";
led_mode = <0>;
data = <1>;
pwm_config = <0 0 0 0 0>;
};
led4:led@4 {
compatible = "mediatek,keyboard-backlight";
led_mode = <0>;
data = <1>;
pwm_config = <0 0 0 0 0>;
};
led5:led@5 {
compatible = "mediatek,button-backlight";
led_mode = <0>;
data = <1>;
pwm_config = <0 0 0 0 0>;
};
led6:led@6 {
compatible = "mediatek,lcd-backlight";
led_mode = <5>;
data = <1>;
pwm_config = <0 0 0 0 0>;

};

3）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，如果参数为0，就是使用系统定义的默认的参数，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，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