Hi,all
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?
help,plz,3Q!
Hi tony
for gpio node usage please look below links
https://community.freescale.com/docs/DOC-1459
http://falsinsoft.blogspot.com/2012/11/access-gpio-from-linux-user-space.html
for debugging purposes one can look at appnote below
http://cache.freescale.com/files/32bit/doc/app_note/AN4553.pdf
regarding debugfs please check below and post on kernel.org
https://www.kernel.org/doc/Documentation/filesystems/debugfs.txt
Best regards
igor
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Dear igor,
Now Iwant to tell you my steps for GPIO test,
Firstly, I change the high/low signal in codebase, after I measured I found it was right
Secondly, I change the high/low signal in console by echo cmd, after I measured I found it cannot change it
I also found the GPIO value after “cat /sys/kernel/debug/gpio” is not right.
So Please help me,3Q!
发件人: igorpadykov
发送时间: 2015年2月12日 8:59
收件人: Tony L Cai
主题: Re: - Issues about GPIO debug
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Issues about GPIO debug
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