Full source code for Beagleboard X15 including device driver code

I have a feeling this is going to be a real newbie question but I was thinking that since Beagleboard OS has Linux based implementations (in my case I’m speaking specifically about BeagleBoard X15) that there would be someplace to download all of the source code thats used to build all of the devices (mostly interested in standard devices, not the graphics devices but interested in I2C, USB, SPI, etc.). I got an image from https://beagleboard.org/latest-images and I’m sure there is source code for it but I have a feeling its not public. I do see source code at //rcn-ee.com/rootfs/eewiki/minfs which was referred from https://www.digikey.com/eewiki/display/linuxonarm/BeagleBoard-X15#BeagleBoard-X15-Debian10 but I dont see any device source code, I’m basically looking for source code i.e., *.c, *.cpp file so I could build it and be able to connect a JTAG and break into the code as its running to learn more about how the device work (perhaps using an IDE like Code Composer Studio). So bottom line, is there a place (free or not) where you can get all source code for all kernel and devices (excluding graphics device code)?

Based on teh version of the OS you are using, the shipping kernel can
be found here:

https://github.com/beagleboard/linux/tree/4.14

or here:

https://github.com/beagleboard/linux/tree/4.19

For the exact version, grab the "uname -r" from your build and
checkout that version from:

https://github.com/RobertCNelson/linux-stable-rcn-ee

Regards,