LED 使用

前言

Face-RK3399 开发板上有 2 个 LED 灯：Blue（GPIO2_D3）和Yellow（GPIO2_D2）。

LED可通过使用 LED 设备子系统或者直接操作 GPIO 控制该 LED。

标准的 Linux 专门为 LED 设备定义了 LED 子系统。 在 Face-RK3399 开发板中的两个 LED 均以设备的形式被定义。

用户可以通过 /sys/class/leds/ 目录控制这两个 LED。

开发板上的 LED 的默认状态为：

• Blue: 系统上电时打开

• Yellow：用户自定义

用户可以通过 echo 向其 brightness属性输入命令控制每一个 LED：

root@rk3399_firefly_face:~ # echo 0 >/sys/class/leds/firefly:blue:power/brightness  //蓝灯灭
root@rk3399_firefly_face:~ # echo 1 >/sys/class/leds/firefly:blue:power/brightness  //蓝灯亮

在 kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-port.dts 文件中定义LED节点，具体定义如下：

leds {   
    compatible = "gpio-leds";   
    power{
        label = "firefly:blue:power";   
        linux,default-trigger = "ir-power-click";   
        default-state = "on";   
        gpios = <&gpio2 27 GPIO_ACTIVE_HIGH>;   
        pinctrl-names = "default";   
        pinctrl-0 = <&led_power>;
    };   
    user{   
        label = "firefly:yellow:user";   
        linux,default-trigger = "ir-user-click";   
        default-state = "off";   
        gpios = <&gpio2 26 GPIO_ACTIVE_HIGH>;   
        pinctrl-names = "default";   
        pinctrl-0 = <&led_user>;   
    };
};

若客户购买的是Face-X1人脸识别一体机,则控制补光灯板上面三个控制灯对应如下：

/sys/class/leds/face:green:user/brightness //绿灯
/sys/class/leds/face:red:user/brightness //红灯
/sys/class/leds/face:white:user/brightness //白灯

在 kernel/arch/arm64/boot/dts/rockchip/rk3399-firefly-face.dtsi 文件中定义LED节点，具体定义如下：

face_leds {
    compatible = "gpio-leds";
        face_green_led: face_green {
            label = "face:green:user";
            linux,default-trigger = "ir-user-click";
            default-state = "off";
            gpios = <&gpio3 0 GPIO_ACTIVE_HIGH>;
            pinctrl-names = "default";
            pinctrl-0 = <&led_user>;
        };
        face_red_led: face_red {
            label = "face:red:user";
            linux,default-trigger = "ir-user-click";
            default-state = "off";
            gpios = <&gpio3 1 GPIO_ACTIVE_HIGH>;
            pinctrl-names = "default";
            pinctrl-0 = <&led_user>;
        };
        face_white_led: face_white {
            label = "face:white:user";
            linux,default-trigger = "ir-user-click";
            default-state = "on";
            gpios = <&gpio4 27 GPIO_ACTIVE_HIGH>;
            pinctrl-names = "default";
            pinctrl-0 = <&led_user>;
        };
};

若客户购买的是Face-X2人脸识别一体机,则控制补光灯板上面三个控制灯对应如下：

/sys/class/leds/face:green:user/brightness //绿灯
/sys/class/leds/face:red:user/brightness //红灯
/sys/pwm/face_white_led //白灯

其中白灯亮度是可调的

echo x > /sys/pwm/face_white_led

x范围0-8