Overlay with custom DTS and linux-imx-rt_3.10.31.bbappend

[Igor Plyatov <plyatov@gmail.com>]

Dear all,

My Yocto is made from "poky-fido-13.0.0", "meta-fsl-arm-1.8" overlay and 
my custom "meta-geosig" overlay.

I have made my own linux-imx-rt_3.10.31.bbappend for vmx51 machine.

Then, successful build the "linux-imx-rt" with the "imx51-babbage.dtb" 
to check correctness of bbappend.
I got the "zImage--3.10.31-r0.1-imx51-babbage-20150611075900.dtb" and 
"zImage--3.10.31-r0.1-vmx51-20150611075900.bin" files.

I need to use customized Device Tree for our board, but previously I do 
not use Device Trees. So, no experience with its integration.

Please help me in some questions:
   1) Where and how should I put my custom "imx51-geosig.dts" file for 
the recipe?
     1A) As a DTS file in the recipes directory?
     1B) As a patch for kernel?
   2) How to instruct Yocto to use my "imx51-geosig.dts" during kernel 
build process?
   3) How to force kernel to use my DTB?
     3A) Does I need to instruct my Barebox to feed DTB to kernel?
     3B) Does I need to embed DTB into the zImage?
     3C) Some other way required?

Details
-------

Bootloader is the Barebox-2011.06.

Content of the "vmx51.conf" (machine config):

include conf/machine/include/imx-base.inc
include conf/machine/include/tune-cortexa8.inc
SOC_FAMILY = "mx5:mx51"
KERNEL_DEVICETREE = "imx51-babbage.dtb"
# Real DTB which should be used for vmx51 machine
#KERNEL_DEVICETREE = "imx51-geosig.dtb"
PREFERRED_PROVIDER_virtual/kernel = "linux-imx-rt"
PREFERRED_PROVIDER_virtual/bootloader = "barebox"
PREFERRED_VERSION_linux-rt = "3.10.31"
KERNEL_IMAGETYPE = "zImage"
MACHINE_FEATURES = "apm screen usbhost vfat ext2 ppp ethernet"
SERIAL_CONSOLE = "115200 ttymxc0"
ROOTFS_TYPE = "ubifs"
IMAGE_FSTYPES += "ubi tar.bz2"
# ubi fs args
UBI_VOLNAME = "rootfs"
MKUBIFS_ARGS = "-m 2KiB -e 126KiB -c 8160"
UBINIZE_ARGS = "-m 2KiB -p 128KiB -s 512"


Content of the "linux-imx-rt_3.10.31.bbappend":

FILESEXTRAPATHS_prepend := "${THISDIR}/${P}:"
PR := "${PR}.1"
COMPATIBLE_MACHINE_vmx51 = "vmx51"
SRC_URI += "file://vmx51-preempt-rt.scc \
             file://vmx51-user-config.cfg \
             file://vmx51-user-patches.scc \
             file://vmx51-user-features.scc "


Best wishes.
--
Igor Plyatov