NXP LPC32xx SoC GPIO controller Required properties: - compatible: must be "nxp,lpc3220-gpio" - reg: Physical base address and length of the controller's registers. - gpio-controller: Marks the device node as a GPIO controller. - #gpio-cells: Should be 3: 1) bank: 0: GPIO P0 1: GPIO P1 2: GPIO P2 3: GPIO P3 4: GPI P3 5: GPO P3 2) pin number 3) optional parameters: - bit 0 specifies polarity (0 for normal, 1 for inverted) - reg: Index of the GPIO group Example: gpio: gpio@40028000 { compatible = "nxp,lpc3220-gpio"; reg = <0x40028000 0x1000>; gpio-controller; #gpio-cells = <3>; /* bank, pin, flags */ }; leds { compatible = "gpio-leds"; led0 { gpios = <&gpio 5 1 1>; /* GPO_P3 1, active low */ linux,default-trigger = "heartbeat"; default-state = "off"; }; led1 { gpios = <&gpio 5 14 1>; /* GPO_P3 14, active low */ linux,default-trigger = "timer"; default-state = "off"; }; };