diff options
author | Paul Mundt <lethal@linux-sh.org> | 2008-10-20 11:17:52 +0900 |
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committer | Paul Mundt <lethal@linux-sh.org> | 2008-10-20 11:17:52 +0900 |
commit | 4cb40f795af36b3deb743f6ccf6c3fd542c61c8d (patch) | |
tree | db3d7519932549bf528f5b8e4cb8350356cd544d /Documentation/ABI/testing/sysfs-gpio | |
parent | 79ed2a9216dd3cc35c4f2c5dbaddadb195af83ac (diff) | |
parent | 0cfd81031a26717fe14380d18275f8e217571615 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:
Documentation/kernel-parameters.txt
arch/sh/include/asm/elf.h
Diffstat (limited to 'Documentation/ABI/testing/sysfs-gpio')
-rw-r--r-- | Documentation/ABI/testing/sysfs-gpio | 26 |
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 00000000000..8aab8092ad3 --- /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) + |