[yocto] Deploy new driver

[binhancntt]

Hi all,
I'm deploying a customized usb gadget as following ways:
1. create a new recipes and specify MACHINE_ESSENTIAL_EXTRA_RDEPEND += 
"mygadget". I expect it is loaded with kernel but the .KO is included 
only to /lib/modules/3.14.28-1.0.0_ga+g91cf351/extra. I tried with 
KERNEL_MODULE_AUTOLOAD += "mygadget" but it does not help.

2. Kernel source code is extracted to 
build/tmp/work-shared/<MACHINE>/kernel-source. I intended to add my 
driver to drivers/usb/gadget/ but whenever I tried 'bitbake linux-imx -c 
menuconfig', this source is removed completely.

Can you please show me what wrong I have made and what direction should 
I follow to add a new driver to kernel?
Thank you!!!