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| author | Greg Kroah-Hartman <gregkh@google.com> | 2015-04-13 19:48:37 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@google.com> | 2015-04-17 16:12:49 +0200 |
| commit | 75052a5504705aded68e544967fdd1d296470bcc (patch) | |
| tree | 82f1f81a84cc473440ea22a89072fffc420c170f /drivers/staging/greybus/Documentation | |
| parent | 1ffc12be5549085faac2d6116f666cb9cbcb2930 (diff) | |
| download | op-kernel-dev-75052a5504705aded68e544967fdd1d296470bcc.zip op-kernel-dev-75052a5504705aded68e544967fdd1d296470bcc.tar.gz | |
greybus: bundle: add state sysfs file
A bundle has a state file, that is managed by the endo userspace
process. This file can be written to and any process that is polling on
the file will be woken up and can read the new value. It's a "cheap"
IPC for programs that are not allowed to do anything other than
read/write to kernel sysfs files.
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Diffstat (limited to 'drivers/staging/greybus/Documentation')
| -rw-r--r-- | drivers/staging/greybus/Documentation/sysfs-bus-greybus | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/staging/greybus/Documentation/sysfs-bus-greybus b/drivers/staging/greybus/Documentation/sysfs-bus-greybus index 4b511db..ab728a4 100644 --- a/drivers/staging/greybus/Documentation/sysfs-bus-greybus +++ b/drivers/staging/greybus/Documentation/sysfs-bus-greybus @@ -113,3 +113,16 @@ KernelVersion: 4.XX Contact: Greg Kroah-Hartman <greg@kroah.com> Description: The device id of a Greybus bundle. + +What: /sys/bus/greybus/device/.../state +Date: October 2015 +KernelVersion: 4.XX +Contact: Greg Kroah-Hartman <greg@kroah.com> +Description: + A bundle has a state that is managed by the userspace + Endo process. This file allows that Endo to signal + other Android HALs that the state of the bundle has + changed to a specific value. When written to, any + process watching the file will be woken up, and the new + value can be read. It's a "poor-man's IPC", yes, but + simplifies the Android userspace code immensely. |
