Pasted

// UPDATE: sufficiently recent versions of dtc support syntax similar to that used by overlay-utils, except you do still need the two directives at the top, and manually add the file identification fragment.
 // normal overlay syntax:                                |  // dtsi-style syntax, converted to overlay syntax using
                                                         |  // bin/dtsi-to-overlay perl script from overlay-utils
                                                         |
/dts-v1/;                                                |
/plugin/;                                                |
                                                         |
#include <dt-bindings/board/am335x-bbw-bbb-base.h>       |  #include <dt-bindings/board/am335x-bbw-bbb-base.h>
#include <dt-bindings/pinctrl/am33xx.h>                  |  #include <dt-bindings/pinctrl/am33xx.h>
                                                         |
/ {                                                      |
    fragment@0 {                                         |
        target-path= " /chosen";                         |
        __overlay__ {                                    |
            overlays {                                   |
                BB-UART1-00A0 = __TIMESTAMP__;           |  // file identification is added automatically
            };                                           |  // by dtsi-to-overlay
        };                                               |
    };                                                   |
                                                         |
    fragment@1 {                                         |
        target = <&ocp>;                                 |
        __overlay__ {                                    |  &ocp {
            P9_24_pinmux { status = "disabled"; };       |      P9_24_pinmux { status = "disabled"; };
            P9_26_pinmux { status = "disabled"; };       |      P9_26_pinmux { status = "disabled"; };
        };                                               |  };
    };                                                   |
                                                         |
    fragment@2 {                                         |
        target = <&am33xx_pinmux>;                       |
        __overlay__ {                                    |  &am33xx_pinmux {
            uart1_pins: uart1 {                          |      uart1_pins: uart1 {
                pinctrl-single,pins = <                  |          pinctrl-single,pins = <
                    BONE_P9_24 (PIN_OUTPUT | MUX_MODE0)  |              BONE_P9_24 (PIN_OUTPUT | MUX_MODE0)
                    BONE_P9_26 (PIN_INPUT  | MUX_MODE0)  |              BONE_P9_26 (PIN_INPUT  | MUX_MODE0)
                >;                                       |          >;
            };                                           |      };
        };                                               |  };
    };                                                   |
                                                         |
    fragment@3 {                                         |
        target = <&uart1>;                               |
        __overlay__ {                                    |  &uart1 {
            status = "okay";                             |      status = "okay";
            pinctrl-names = "default";                   |      pinctrl-names = "default";
            pinctrl-0 = <&uart1_pins>;                   |      pinctrl-0 = <&uart1_pins>;
        };                                               |  };
    };                                                   |
};                                                       |