docs: leds: convert to ReST

Rename the leds documentation files to ReST, add an
index for them and adjust in order to produce a nice html
output via the Sphinx build system.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/Documentation/leds/ledtrig-oneshot.rst b/Documentation/leds/ledtrig-oneshot.rst
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+====================
+One-shot LED Trigger
+====================
+
+This is a LED trigger useful for signaling the user of an event where there are
+no clear trap points to put standard led-on and led-off settings.  Using this
+trigger, the application needs only to signal the trigger when an event has
+happened, than the trigger turns the LED on and than keeps it off for a
+specified amount of time.
+
+This trigger is meant to be usable both for sporadic and dense events.  In the
+first case, the trigger produces a clear single controlled blink for each
+event, while in the latter it keeps blinking at constant rate, as to signal
+that the events are arriving continuously.
+
+A one-shot LED only stays in a constant state when there are no events.  An
+additional "invert" property specifies if the LED has to stay off (normal) or
+on (inverted) when not rearmed.
+
+The trigger can be activated from user space on led class devices as shown
+below::
+
+  echo oneshot > trigger
+
+This adds sysfs attributes to the LED that are documented in:
+Documentation/ABI/testing/sysfs-class-led-trigger-oneshot
+
+Example use-case: network devices, initialization::
+
+  echo oneshot > trigger # set trigger for this led
+  echo 33 > delay_on     # blink at 1 / (33 + 33) Hz on continuous traffic
+  echo 33 > delay_off
+
+interface goes up::
+
+  echo 1 > invert # set led as normally-on, turn the led on
+
+packet received/transmitted::
+
+  echo 1 > shot # led starts blinking, ignored if already blinking
+
+interface goes down::
+
+  echo 0 > invert # set led as normally-off, turn the led off