I am currently developing a SPI Kernel Module for my Beaglebone Black (Debian Wheezy 2015-11-12, Kernel version 3.8.13-bone79). My kernel module can access (request_mem_region() => ioremap()) registers from the AM3358 processor (read/write) to manipulate the registers, to change the settings of the SPI0. On the other side is my device tree, which can manipulate the pins of the SPI0.
Unfortunately, I´ve got Problems:
If I load my Device Tree first, and then my Kernel Module I get an message that I haven´t got permission to load my kernel module.
If I load my Module first and then my Device tree, all pinmuxes are allright, but the CLK of SPI0 is killed. Furthermore if I remove my module and free my allocated Memory (Registers, iounmap() => release_mem_region()) I get a 'Trying to free nonexistent resource' message.
You see, I am struggeling to understand the interaction between Device Tree and Kernel Module...
I would be extremely grateful, if someone could "push" me in the right direction... ;)
All the best
Flo
