dsendcomm/testplan/programrst.dts

// Configure reset on GPIO-26(Pin-37)
// Unknown if pullup works on output?
// Note: Until its know how to set a
//       inital output value (to HIGH)
//       then we must initalise for input
//
/dts-v1/;
/plugin/;

// /* brcm,function property */
// #define BCM2835_FSEL_GPIO_IN  0
// #define BCM2835_FSEL_GPIO_OUT 1
// #define BCM2835_FSEL_ALT5     2
// #define BCM2835_FSEL_ALT4     3
// #define BCM2835_FSEL_ALT0     4
// #define BCM2835_FSEL_ALT1     5
// #define BCM2835_FSEL_ALT2     6
// #define BCM2835_FSEL_ALT3     7
//
// /* brcm,pull property */
// #define BCM2835_PUD_OFF       0
// #define BCM2835_PUD_DOWN      1
// #define BCM2835_PUD_UP        2

/ {
    //compatible = "brcm,bcm2835";
    //compatible = "brcm,bcm2708,bcm2835";

    fragment@0 {
        target = <&gpio>;
        __overlay__ {
            status = "okay";
            gpclk2_gpio26: gpclk2_gpio26 {
                brcm,pins = <26>;
                //brcm,function = <1>;  // BCM2835_FSEL_GPIO_OUT 1
                brcm,function = <0>;  // BCM2835_FSEL_GPIO_IN 0
                //brcm,value = <1>;     // This may not work?
                //brcm,state = <1>;     // This may not work?
                //brcm,pull = <0>;      // Pullup not possible out?
                brcm,pull = <2>;      // BCM2835_PUD_UP 2
            };
        };
    };
};