Hi Heinz,
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After searching a while I found that it could be that not all clocks are enabled. Can someone please point me how I can enable the CAN module clocks. What are the clocks I have to enable and how?
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You can find all the module clock definitions & declarations at arch/arm/mach-omap2/clock3xxx_data.c
Please refer the following TI wiki links for enabling D_CAN driver in linux kernel with debugging.
http://processors.wiki.ti.com/index.php/AM335X_DCAN_Driver_Guide