Now I want to "cat /sys/kernel/debug/gpio", but I found "debugfs_create_file" was called but didnt reate the path "sys/kernel/debug/gpio",and both the CONFIG_DEBUG_FS and CONFIG_DEBUG_FS are open. but when debugfs_create_file was to create the gpio node, it failed to create the node. and I want to use the dump_stack to trace, and the dump_stack cannot be used, in another word, it cannot dump the log.
So, I have the 2 questions: 1. how to create the GPIO node? Can I use mount the debugfs before entering to kernel? where to add the cmd?
2. how to use dump_stack? why cant I dump the log?