How to use "reflect" to set interface value inside a struct of struct

Had a rough time trying to set the interface value by using "reflect" package. The interface value is actually inside a struct of a struct. See my code in Go Playground

Basically, inside initProc, I want to assign dummyAFunc function to DummyA field in Box struct

package main 

import (
    "fmt"
    "reflect"
)

type Box struct {
    Name               string
    DummyA             interface{}
}

type SmartBox struct {
    Box
}

func dummyAFunc(i int) {
    fmt.Println("dummyAFunc() is here!")
}

func initProc(inout interface{}) {
    // Using "inout interface{}", I can take any struct that contains Box struct
    // And my goal is assign dummyAFunc to dummyA in Box struct

    iType:=reflect.TypeOf(inout)
    iValue:=reflect.ValueOf(inout)
    
    fmt.Println("Type & value:", iType.Elem(), iValue.Elem()) // Type & value: *main.SmartBox &

    e := reflect.ValueOf(inout).Elem()
    
    fmt.Println("Can set?", e.CanSet()).      // true
    fmt.Println("NumField", e.NumField())     // panic: reflect: call of reflect.Value.NumField on ptr Value ?????
    fmt.Println("NumMethod", e.NumMethod())   // NumMethod = 0
        
}

func main() {
    smartbox := new (SmartBox)
    initProc(&smartbox)
}

I'm new to Go and I've read the The laws of Reflection but still can't figure it out. Please help. Thanks!