Enabling SPI on J3A1 Expansion Headers

I need to control an external DAC but I am having trouble figuring out how to use the SPI bus on the Jetson TK1. I found the tutorial on elinux using the Grinch kernel however I do not want to use this kernel because I do not want to run into driver errors with my USB3 camera. I imagine if NVIDIA claims they offer SPI support then it must be doable on thier L4T kernel. I am currently running L4T 3.10.40 and Ubuntu 14.04. The first thing I did right out of the box was download and install Jetpack which also included the kernel image. I have searched for .dts and .dtsi files everywhere but there are none. All I found were .dtb files in my /boot directory. I have a spidev.h file under /usr/include/kernel but that’s it and it doesn’t look like much. Are there any tutorials on using SPI on the TK1 or at least some documentation on how to enable it? Just an FYI, I was able to control the GPIO after following a “simpleGPIO” example in nSight and tried to bitbang the spi but I got a clock rate of 20kHz which is doesn’t work for my project.

The dts files are in the kernel source. For ARMv7 look for dts/dtsi in subdirectory “arch/arm/boot/dts/”. I don’t know about SPI.

Sorry, I already looked there. The only file inside that directory is a makefile.

Where was the source downloaded from? The files I’m looking at are from the L4T R21.4 download page…there are a lot of files there…hundreds.