RK3568-pinctrl子系统和gpio子系统

pinctrl子系统

pinctrl子系统主要用于配置引脚复用，驱动强度，上下拉配置等。

驱动程序：/kernel/drivers/pinctrl/pinctrl-rockchip.c
	
rk3568.dtsi设备树配置：
	pinctrl: pinctrl {
	compatible = "rockchip,rk3568-pinctrl";
	rockchip,grf = <&grf>;
	rockchip,pmu = <&pmugrf>;
	#address-cells = <2>;
	#size-cells = <2>;
	ranges;

		gpio0: gpio@fdd60000 {
			compatible = "rockchip,gpio-bank";
			reg = <0x0 0xfdd60000 0x0 0x100>;
			interrupts = ;
			clocks = <&pmucru PCLK_GPIO0>, <&pmucru DBCLK_GPIO0>;

			gpio-controller;
			#gpio-cells = <2>;
			gpio-ranges = <&pinctrl 0 0 32>;
			interrupt-controller;
			#interrupt-cells = <2>;
		};
	};
	
板级文件设备树配置：
	&pinctrl {
		key {
	 		key_gpio: key-gpio {
	 			rockchip,pins =
					<3 RK_PB6 RK_FUNC_GPIO &