Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

1 files changed, 26 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-gpio b/Documentation/ABI/testing/sysfs-gpio
new file mode 100644
index 0000000..8aab809
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-gpio
@@ -0,0 +1,26 @@
+What:		/sys/class/gpio/
+Date:		July 2008
+KernelVersion:	2.6.27
+Contact:	David Brownell <dbrownell@users.sourceforge.net>
+Description:
+
+  As a Kconfig option, individual GPIO signals may be accessed from
+  userspace.  GPIOs are only made available to userspace by an explicit
+  "export" operation.  If a given GPIO is not claimed for use by
+  kernel code, it may be exported by userspace (and unexported later).
+  Kernel code may export it for complete or partial access.
+
+  GPIOs are identified as they are inside the kernel, using integers in
+  the range 0..INT_MAX.  See Documentation/gpio.txt for more information.
+
+    /sys/class/gpio
+	/export ... asks the kernel to export a GPIO to userspace
+	/unexport ... to return a GPIO to the kernel
+	/gpioN ... for each exported GPIO #N
+	    /value ... always readable, writes fail for input GPIOs
+	    /direction ... r/w as: in, out (default low); write: high, low
+	/gpiochipN ... for each gpiochip; #N is its first GPIO
+	    /base ... (r/o) same as N
+	    /label ... (r/o) descriptive, not necessarily unique
+	    /ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1)
+