impletement ControlValueAccessor in generic component "CustomComponent" and its methods:

writeValue(obj: any): void;
registerOnChange(fn: any): void;
registerOnTouched(fn: any): void;
optional setDisabledState(isDisabled: boolean): void;

add

providers:[{
    provide: NG_VALUE_ACCESSOR,
    useExisting:CustomComponent ,
    multi: true
  }]

in @Component decorator