I need some help to maintain gpio on my bf537 stamp board.
I'm trying to enable/ access to gpio and I followed the instruction on http://docs.blackfin.uclinux.org/doku.php?id=linux-kernel:drivers:gpio-sysfs&s=gpio&s=sys
root:~> echo 23 > /sys/class/gpio/export
/sys/class/gpio/export: cannot create
so I thought may be the kernel is not compiled in a way to support gpio. i checked the flags in the kernel settings:
[*] GPIO Support --->
--- GPIO Support │ │
│ │ [ ] Debug GPIO calls │ │
│ │ [*] /sys/class/gpio/... (sysfs interface)
compiled it and loaded it to the stamp board, however still the same result.
the contend of the /sys/class directory is:
root:~> cd /sys/class
root:/sys/class> ls -la
drwxr-xr-x 11 root root 0 Jan 1 2007 .
drwxr-xr-x 11 root root 0 Jan 1 2007 ..
drwxr-xr-x 2 root root 0 Jan 1 2007 hwmon
drwxr-xr-x 2 root root 0 Jan 1 2007 input
drwxr-xr-x 11 root root 0 Jan 1 2007 mem
drwxr-xr-x 3 root root 0 Jan 1 2007 misc
drwxr-xr-x 4 root root 0 Jan 1 2007 net
drwxr-xr-x 3 root root 0 Jan 1 2007 rtc
drwxr-xr-x 3 root root 0 Jan 1 2007 rtc-dev
drwxr-xr-x 3 root root 0 Jan 1 2007 spi_master
drwxr-xr-x 6 root root 0 Jan 1 2007 tty
even with the new kernel uImage no gpio directory
root:/sys/class> touch foo
touch: foo: Permission denied
-->error message no access
2nd question: after new compilation, i would expect a directory /sys/class/gpio at least. what goes wrong (any jumper on my board?)
might be due to the fact that the directory is busy...? since i'm root anyway, i should have write-access everywhere.
can somebody tell me what I'm missed.
getting an answer would be nice
thanks in advance