CODEWITHSUNDEEP
clinux-kernellinux-device-driverembedded-linuxkernel-module
Gururprasad Prusty
Gururprasad Prusty

Reputation: 5

How to add the user space headers in device driver programming?

I am trying to perform some GPIO operations through a lodable kernel module. for which, I am trying to access the file "/sys/class/leds/led1/brightness" using open() and write() system-calls, therefore I have included the following header files.

#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>

but while cross compiling the project, I got the following warning and error.

guru@guru-G40-80:~/OFC/lnx/projects/V4/source_codes/git/Device-Driver/char_dev_gsm$ make
pwd : /home/guru/OFC/lnx/projects/V4/source_codes/git/Device-Driver/char_dev_gsm 
make -C /home/guru/OFC/lnx/projects/V4/source_codes/git/linux-at91/ M=/home/guru/OFC/lnx/projects/V4/source_codes/git/Device-Driver/char_dev_gsm modules
make[1]: Entering directory '/home/guru/OFC/lnx/projects/V4/source_codes/git/linux-at91'

  WARNING: Symbol version dump ./Module.symvers
           is missing; modules will have no dependencies and modversions.

    pwd : /home/guru/OFC/lnx/projects/V4/source_codes/git/Device-Driver/char_dev_gsm 
      CC [M]  /home/guru/OFC/lnx/projects/V4/source_codes/git/Device-Driver/char_dev_gsm/src/pwr_hndl/pwr_hndl.o
    /home/guru/OFC/lnx/projects/V4/source_codes/git/Device-Driver/char_dev_gsm/src/pwr_hndl/pwr_hndl.c:5:10: fatal error: sys/stat.h: No such file or directory
     #include <sys/stat.h>
              ^~~~~~~~~~~~
    compilation terminated.

Here is a link to git-hub : https://github.com/guruprasad-92/Device-Driver.git Can you please help me with this ?

Upvotes: 0

Views: 263

Answers (1)

gby
gby

Reputation: 15218

Sorry but you are doing it wrong - don't try to access the GPIO user space interface from the kernel. Instead, use the in-kernel GPIO interface.

More info on that here: https://lwn.net/Articles/532714/

Upvotes: 1

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