riscv: dts: sifive unleashed: Add PWM controlled LEDs

This adds the 4 PWM controlled green LEDs to the HiFive Unleashed device
tree. The schematic doesn't specify any special function for the LEDs,
so they're added here without any default triggers and named d1, d2, d3
and d4 just like in the schematic.

Signed-off-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20221012110928.352910-1-emil.renner.berthing@canonical.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

arch/riscv/boot/dts/sifive/hifive-unleashed-a00.dts

@@ -3,6 +3,8 @@
 
 #include "fu540-c000.dtsi"
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/leds/common.h>
+#include <dt-bindings/pwm/pwm.h>
 
 /* Clock frequency (in Hz) of the PCB crystal for rtcclk */
 #define RTCCLK_FREQ		1000000
@@ -42,6 +44,42 @@
 		compatible = "gpio-restart";
 		gpios = <&gpio 10 GPIO_ACTIVE_LOW>;
 	};
+
+	led-controller {
+		compatible = "pwm-leds";
+
+		led-d1 {
+			pwms = <&pwm0 0 7812500 PWM_POLARITY_INVERTED>;
+			active-low;
+			color = <LED_COLOR_ID_GREEN>;
+			max-brightness = <255>;
+			label = "d1";
+		};
+
+		led-d2 {
+			pwms = <&pwm0 1 7812500 PWM_POLARITY_INVERTED>;
+			active-low;
+			color = <LED_COLOR_ID_GREEN>;
+			max-brightness = <255>;
+			label = "d2";
+		};
+
+		led-d3 {
+			pwms = <&pwm0 2 7812500 PWM_POLARITY_INVERTED>;
+			active-low;
+			color = <LED_COLOR_ID_GREEN>;
+			max-brightness = <255>;
+			label = "d3";
+		};
+
+		led-d4 {
+			pwms = <&pwm0 3 7812500 PWM_POLARITY_INVERTED>;
+			active-low;
+			color = <LED_COLOR_ID_GREEN>;
+			max-brightness = <255>;
+			label = "d4";
+		};
+	};
 };
 
 &uart0 {