[PATCH v7 5/5] iio: Documentation: Add IIO configfs documentation

[Daniel Baluta <daniel.baluta@intel.com>]

Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
---
 Documentation/ABI/testing/configfs-iio | 20 ++++++++++++
 Documentation/iio/iio_configfs.txt     | 57 ++++++++++++++++++++++++++++++++++
 2 files changed, 77 insertions(+)
 create mode 100644 Documentation/ABI/testing/configfs-iio
 create mode 100644 Documentation/iio/iio_configfs.txt

diff --git a/Documentation/ABI/testing/configfs-iio b/Documentation/ABI/testing/configfs-iio
new file mode 100644
index 0000000..1fd7cf4
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-iio
@@ -0,0 +1,20 @@
+What:		/config/iio
+Date:		May 2015
+KernelVersion:	4.2
+Contact:	linux-iio@vger.kernel.org
+Description:
+		This represents Industrial IO configuration entry point
+		directory. It contains sub-groups corresponding to IIO
+		objects.
+
+What:		/config/iio/triggers
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Industrial IO software triggers directory.
+
+What:		/config/iio/triggers/hrtimer
+Date:		August 2015
+KernelVersion:	4.2
+Description:
+		Industrial IO hrtimer based software triggers directory.
diff --git a/Documentation/iio/iio_configfs.txt b/Documentation/iio/iio_configfs.txt
new file mode 100644
index 0000000..7c56997
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+++ b/Documentation/iio/iio_configfs.txt
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+Industrial IIO configfs support
+
+1. Overview
+
+Configfs is a filesystem-based manager of kernel objects. IIO uses some
+objects that could be easily configured using configfs (e.g.: devices,
+triggers).
+
+See Documentation/filesystems/configfs/configfs.txt for more information
+about how configfs works.
+
+2. Usage
+
+In order to use configfs support in IIO we need to select it at compile
+time via CONFIG_IIO_CONFIGFS config option.
+
+Then, mount the configfs filesystem (usually under /config directory):
+
+$ mkdir /config
+$ mount -t configfs none /config
+
+At this point, all default IIO groups will be created and can be accessed
+under /config/iio. Next chapters will describe available IIO configuration
+objects.
+
+3. Software triggers
+
+One of the IIO default configfs groups is the "triggers" groups. It is
+automagically accessible when the configfs is mounted and can be found
+under /config/iio/triggers.
+
+Software triggers are created under /config/iio/triggers directory. There
+must exist an associated kernel module that implements a software trigger type.
+
+We support now the following software trigger types:
+	* hrtimer, uses high resolution timers as interrupt source implemened
+	by the iio-trig-hrtimer.c module.
+
+3.1 Software triggers creation and destruction
+
+As simply as:
+
+$ insmod iio-trig-hrtimer.ko
+$ ls /config/triggers
+hrtimer
+$ mkdir /config/triggers/hrtimer/trig1
+
+$ rmdir /config/triggers/hrtimer/trig1
+$ rmmod iio-trig-hrtimer
+
+Each trigger can have one or more attributes specific to the trigger type.
+
+3.2 "hrtimer" trigger types attributes
+
+"hrtimer" trigger type doesn't have any configurable attribute from /config dir,
+but hrtimer triggers have the sampling_frequency attribute under /sys/bus/iio/devices/triggerX
+directory.
-- 
2.1.4