arm64: dts: rockchip: add the pwm node info for RK3368 SoCs

The pulse-width modulator (PWM) feature is very common in
embedded systems. On the rk3368 there exist 4 built-in PWM channels.

In general, the pwm pins can via the pinctrl to
configure iomux mode except the pwm2 since the pwm2 iomux mode from
the SoC control register.

Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3368.dtsi

@@ -498,6 +498,48 @@
 		status = "disabled";
 	};
 
+	pwm0: pwm@ff680000 {
+		compatible = "rockchip,rk3368-pwm", "rockchip,rk3288-pwm";
+		reg = <0x0 0xff680000 0x0 0x10>;
+		#pwm-cells = <3>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pwm0_pin>;
+		clocks = <&cru PCLK_PWM1>;
+		clock-names = "pwm";
+		status = "disabled";
+	};
+
+	pwm1: pwm@ff680010 {
+		compatible = "rockchip,rk3368-pwm", "rockchip,rk3288-pwm";
+		reg = <0x0 0xff680010 0x0 0x10>;
+		#pwm-cells = <3>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pwm1_pin>;
+		clocks = <&cru PCLK_PWM1>;
+		clock-names = "pwm";
+		status = "disabled";
+	};
+
+	pwm2: pwm@ff680020 {
+		compatible = "rockchip,rk3368-pwm", "rockchip,rk3288-pwm";
+		reg = <0x0 0xff680020 0x0 0x10>;
+		#pwm-cells = <3>;
+		clocks = <&cru PCLK_PWM1>;
+		clock-names = "pwm";
+		status = "disabled";
+	};
+
+	pwm3: pwm@ff680030 {
+		compatible = "rockchip,rk3368-pwm", "rockchip,rk3288-pwm";
+		reg = <0x0 0xff680030 0x0 0x10>;
+		#pwm-cells = <3>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pwm3_pin>;
+		clocks = <&cru PCLK_PWM1>;
+		clock-names = "pwm";
+		status = "disabled";
+	};
+
 	uart2: serial@ff690000 {
 		compatible = "rockchip,rk3368-uart", "snps,dw-apb-uart";
 		reg = <0x0 0xff690000 0x0 0x100>;
@@ -739,6 +781,24 @@
 			};
 		};
 
+		pwm0 {
+			pwm0_pin: pwm0-pin {
+				rockchip,pins = <3 8 RK_FUNC_2 &pcfg_pull_none>;
+			};
+		};
+
+		pwm1 {
+			pwm1_pin: pwm1-pin {
+				rockchip,pins = <0 8 RK_FUNC_2 &pcfg_pull_none>;
+			};
+		};
+
+		pwm3 {
+			pwm3_pin: pwm3-pin {
+				rockchip,pins = <3 29 RK_FUNC_3 &pcfg_pull_none>;
+			};
+		};
+
 		sdio0 {
 			sdio0_bus1: sdio0-bus1 {
 				rockchip,pins = <2 28 RK_FUNC_1 &pcfg_pull_up>;