4. LED

4.1. Introduction

EC-R3588SPCThere is a three color LED light and two monochrome lights on the development board, as shown in the following table：

LED	Pin name	Pin number	remarks
Blue	GPIO1_D5	61	Tricolor Led
Red	GPIO3_B2	106	Tricolor Led
Green	GPIO3_C0	112	Tricolor Led
Ext Yellow（L2）	GPIO3_B7	111	Lower Monochrome Led work with Relay
Ext Green（L1）	GPIO3_C1	113	Upper Monochrome Led

LEDs can be controlled by using the LED device subsystem or by directly operating GPIO.

4.2. Controlling LEDs by device

Linux has its own LED subsystem for LED devices. In EC-R3588SPC, LEDs are configured as LED class devices.You can control them via /sys/class/leds/.

Tricolor led：

• Blue: Turn on after the system powers on.

• Red: defined by user.

• Green: defined by user.

Monochrome led：

• Ext Yellow : Relay work in indicator(Silk screen：L2)

• Ext Green : defined by user. (Silk screen：L1)

You can change the behavior of each LED by using the echo command to write command to its brightness property:

Tricolor led：

echo 1 > sys/class/leds/\:power/brightness //Blue led on
echo 0 > sys/class/leds/\:power/brightness //Blue led off

echo 1 > sys/class/leds/\:user/brightness //Red led on
echo 0 > sys/class/leds/\:user/brightness //Red led off

echo 1 > sys/class/leds/\:user1/brightness //Green led on
echo 0 > sys/class/leds/\:user1/brightness //Green led off

L1 Monochrome led：

echo 1 > /sys/class/leds/ext_led1/brightness //Ext Yellow led on
echo 0 > /sys/class/leds/ext_led1/brightness //Ext Yellow led off

L2 Monochrome led：

echo 1 > /sys/class/leds/ext_led2/brightness //Ext Green led on
echo 0 > /sys/class/leds/ext_led2/brightness //Ext Green led off

4.3. Using trigger control LED

Trigger contains a variety of ways to control the LED, here with two examples to illustrate.

• Simple trigger LED

• Complex trigger LED

For more information, please read the document leds-class.txt.

First of all, we need to know how many LED definition, while the corresponding property of the LED is.

Define Tricolor led node in file kernel/arch/arm64/boot/dts/rockchip/roc-rk3588s-pc.dtsi：

firefly_leds: leds {
    compatible = "gpio-leds";
    power_led: power {
        label = ":power"; //blue led
        linux,default-trigger = "ir-power-click";
        default-state = "on";
        gpios = <&gpio1 RK_PD5 GPIO_ACTIVE_HIGH>;
        pinctrl-names = "default";
        pinctrl-0 = <&led_power>;
    };

    user_led: user {
        label = ":user"; //red led
        linux,default-trigger = "ir-user-click";
        default-state = "off";
        gpios = <&gpio3 RK_PB2 GPIO_ACTIVE_HIGH>;
        pinctrl-names = "default";
        pinctrl-0 = <&led_user>;
    };

    user1_led: user1 {
        label = ":user1"; //green led
        default-state = "off";
        gpios = <&gpio3 RK_PC0 GPIO_ACTIVE_HIGH>;
        pinctrl-names = "default";
        pinctrl-0 = <&led_user1>;
    };
};

Define Monochrome led node in file kernel/arch/arm64/boot/dts/rockchip/roc-rk3588s-pc-ext.dtsi ：

&firefly_leds {
               ext_yellow_led: ext_led1 {
                       gpios = <&gpio3 RK_PB7 GPIO_ACTIVE_HIGH>;//yellow led
                       pinctrl-names = "default";
                       pinctrl-0 = <&led_user2>;
               };

               ext_green_led: ext_led2 {
                       gpios = <&gpio3 RK_PC1 GPIO_ACTIVE_HIGH>;//green led
                       pinctrl-names = "default";
                       pinctrl-0 = <&led_user3>;
               };
};

Note: The value of compatible must match the one in drivers/leds/leds-gpio.c.

4.3.1. Simple trigger LED

It is a simple trigger mode to control LEDs, as follows on the default open yellow LED. And EC-R3588SPC’s yellow LED will be turned on after boot.

(1) Defined LED trigger In the kernel/drivers/leds/trigger/led-firefly-demo.c add the following:

DEFINE_LED_TRIGGER(ledtrig_default_control);

(2) Register the trigger.

led_trigger_register_simple("ir-user-click", &ledtrig_default_control);

(3) Control the LED.

led_trigger_event(ledtrig_default_control, LED_FULL);     #yellow led on

（4）Enable LED demo.

led-firefly-demo is disabled in default,if you need to open the demo drive can use the following patch:

--- a/kernel/arch/arm64/boot/dts/rockchip/rk3588-firefly-demo.dtsi
+++ b/kernel/arch/arm64/boot/dts/rockchip/rk3588-firefly-demo.dtsi
@@ -52,7 +52,7 @@
            led_demo: led_demo {
-                status = "disabled";
+                status = "okay";
                 compatible = "firefly,rk3588-led";
                 };

4.3.2. Complex trigger LED

The following is the trigger mode control LED complex example, timer trigger is to let the LED to achieve constant light off effect.

We need to configure the timer trigger on the kernel.

In the kernel-5.10 path using make menuconfig, in accordance with the following method to chose timer trigger driver.

Device Drivers
--->LED Support
   --->LED Trigger support
      --->LED Timer Trigger

Save the configuration and compile the kernel, the kernel.img burn EC-R3588SPC board. We can use the serial input command, you can see the blue light non-stop interval flashing.

echo "timer" > /sys/class/leds/:user/trigger

The user can also use the cat command to get the available values for the trigger:

# cat /sys/class/leds/:user/trigger
none ir-power-click rfkill-any rfkill-none test_ac-online test_battery-charging-or-full 
test_battery-charging test_battery-full test_battery-charging-blink-full-solid 
test_usb-online mmc0 [timer] heartbeat backlight default-on ir-user-click mmc1 
rfkill0 tcpm-source-psy-6-0022-online rfkill1 rfkill2