diff options
author | Ingo Molnar <mingo@elte.hu> | 2008-10-10 13:30:08 -0400 |
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committer | Ingo Molnar <mingo@elte.hu> | 2008-10-10 13:30:08 -0400 |
commit | 3dd392a407d15250a501fa109cc1f93fee95ef85 (patch) | |
tree | c1faca3fa8bd0f7c8790b3e0887229b4a5a90e8b /Documentation/ABI/testing/sysfs-gpio | |
parent | b27a43c1e90582facad44de67d02bc9e9f900289 (diff) | |
parent | d403a6484f0341bf0624d17ece46f24f741b6a92 (diff) |
Merge branch 'linus' into x86/pat2
Conflicts:
arch/x86/mm/init_64.c
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 000000000000..8aab8092ad35 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-gpio | |||
@@ -0,0 +1,26 @@ | |||
1 | What: /sys/class/gpio/ | ||
2 | Date: July 2008 | ||
3 | KernelVersion: 2.6.27 | ||
4 | Contact: David Brownell <dbrownell@users.sourceforge.net> | ||
5 | Description: | ||
6 | |||
7 | As a Kconfig option, individual GPIO signals may be accessed from | ||
8 | userspace. GPIOs are only made available to userspace by an explicit | ||
9 | "export" operation. If a given GPIO is not claimed for use by | ||
10 | kernel code, it may be exported by userspace (and unexported later). | ||
11 | Kernel code may export it for complete or partial access. | ||
12 | |||
13 | GPIOs are identified as they are inside the kernel, using integers in | ||
14 | the range 0..INT_MAX. See Documentation/gpio.txt for more information. | ||
15 | |||
16 | /sys/class/gpio | ||
17 | /export ... asks the kernel to export a GPIO to userspace | ||
18 | /unexport ... to return a GPIO to the kernel | ||
19 | /gpioN ... for each exported GPIO #N | ||
20 | /value ... always readable, writes fail for input GPIOs | ||
21 | /direction ... r/w as: in, out (default low); write: high, low | ||
22 | /gpiochipN ... for each gpiochip; #N is its first GPIO | ||
23 | /base ... (r/o) same as N | ||
24 | /label ... (r/o) descriptive, not necessarily unique | ||
25 | /ngpio ... (r/o) number of GPIOs; numbered N to N + (ngpio - 1) | ||
26 | |||