[PATCH 3/3] Documentation: leds: document ledtrig-device trigger

From: Maciek Borzecki
Date: Mon Sep 28 2015 - 16:44:26 EST


This patch adds documentation for ledtrig-device trigger.

Signed-off-by: Maciek Borzecki <maciek.borzecki@xxxxxxxxx>
---
Documentation/leds/00-INDEX | 3 +++
Documentation/leds/ledtrig-device.txt | 32 ++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
create mode 100644 Documentation/leds/ledtrig-device.txt

diff --git a/Documentation/leds/00-INDEX b/Documentation/leds/00-INDEX
index b4ef1f34e25faafe544971f619019d748538e4de..7f18adaadc04756a6b52157a71f86bd131dd915c 100644
--- a/Documentation/leds/00-INDEX
+++ b/Documentation/leds/00-INDEX
@@ -20,3 +20,6 @@ ledtrig-oneshot.txt
- One-shot LED trigger for both sporadic and dense events.
ledtrig-transient.txt
- LED Transient Trigger, one shot timer activation.
+ledtrig-device.txt
+ - LED Device Activity Trigger for indicating an activity
+ on a device
\ No newline at end of file
diff --git a/Documentation/leds/ledtrig-device.txt b/Documentation/leds/ledtrig-device.txt
new file mode 100644
index 0000000000000000000000000000000000000000..b319d5da9df513a15b5c8094c6a5923682ff4579
--- /dev/null
+++ b/Documentation/leds/ledtrig-device.txt
@@ -0,0 +1,32 @@
+Device Activity LED Trigger
+==========================
+
+This is a LED trigger useful for signaling an activity on a given
+device identified by it's MKDEV(major, minor). A typical use case
+would be debugging of a device or a driver on an embedded board,
+patching up trivial electronic hardware design deficiencies in
+software or just plain desire to indicate activity on a certain
+device.
+
+Internally, a instance of a trigger is created and registered with LED
+triggers for every device added via ledtrig_dev_add() call. The
+triggers are named in the following manner:
+
+ `dev-<major>:<minor>`
+
+And can be selected from under /sys/class/leds/*/trigger. A device
+activity is explicitly indicated by calling ledtrig_dev_activity() for
+a registered device.
+
+The driver also creates a set of debugfs entries under
+/sys/kernel/debug/ledtrig-dev, these are:
+
+ devices - cat'ing will produce a list of currently registered
+ devices
+
+ register - echo'ing <major>:<minor> will create a trigger for this
+ device (note, you still need to add at least
+ ledtrig_dev_activity() hook)
+
+ trigger - echo'ing <major>:<minor> will fire the trigger for this
+ device
--
2.5.3

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