Spell "LED" consistently with uppercase.
We do not want people to use LED subsystem for vibrations; there's
already support for that in input subsystem. Remove notes about
vibrations not to confuse people.
Signed-off-by: Pavel Machek <pavel@xxxxxx>
diff --git a/Documentation/leds/ledtrig-transient.txt b/Documentation/leds/ledtrig-transient.txt
index 3bd38b4..f412603 100644
--- a/Documentation/leds/ledtrig-transient.txt
+++ b/Documentation/leds/ledtrig-transient.txt
@@ -1,7 +1,7 @@
LED Transient Trigger
=====================
-The leds timer trigger does not currently have an interface to activate
+The LED timer trigger does not currently have an interface to activate
a one shot timer. The current support allows for setting two timers, one for
specifying how long a state to be on, and the second for how long the state
to be off. The delay_on value specifies the time period an LED should stay
@@ -16,17 +16,11 @@ set a timer to hold a state, however when user space application crashes or
goes away without deactivating the timer, the hardware will be left in that
state permanently.
-As a specific example of this use-case, let's look at vibrate feature on
-phones. Vibrate function on phones is implemented using PWM pins on SoC or
-PMIC. There is a need to activate one shot timer to control the vibrate
-feature, to prevent user space crashes leaving the phone in vibrate mode
-permanently causing the battery to drain.
-
Transient trigger addresses the need for one shot timer activation. The
-transient trigger can be enabled and disabled just like the other leds
+transient trigger can be enabled and disabled just like the other LED
triggers.
-When an led class device driver registers itself, it can specify all leds
+When an LED class device driver registers itself, it can specify all LED
triggers it supports and a default trigger. During registration, activation
routine for the default trigger gets called. During registration of an led
class device, the LED state does not change.
@@ -42,12 +36,12 @@ that are active at the time driver gets suspended, continue to run, without
being able to actually change the LED state. Once driver is resumed, triggers
start functioning again.
-LED state changes are controlled using brightness which is a common led
+LED state changes are controlled using brightness which is a common LED
class device property. When brightness is set to 0 from user space via
echo 0 > brightness, it will result in deactivating the current trigger.
Transient trigger uses standard register and unregister interfaces. During
-trigger registration, for each led class device that specifies this trigger
+trigger registration, for each LED class device that specifies this trigger
as its default trigger, trigger activation routine will get called. During
registration, the LED state does not change, unless there is another trigger
active, in which case LED state changes to LED_OFF.
@@ -56,12 +50,12 @@ During trigger unregistration, LED state gets changed to LED_OFF.
Transient trigger activation routine doesn't change the LED state. It
creates its properties and does its initialization. Transient trigger
-deactivation routine, will cancel any timer that is active before it cleans
+deactivation routine will cancel any timer that is active before it cleans
up and removes the properties it created. It will restore the LED state to
non-transient state. When driver gets suspended, irrespective of the transient
state, the LED state changes to LED_OFF.
-Transient trigger can be enabled and disabled from user space on led class
+Transient trigger can be enabled and disabled from user space on LED class
devices, that support this trigger as shown below:
echo transient > trigger
@@ -144,7 +138,6 @@ repeat the following step as needed:
echo none > trigger
This trigger is intended to be used for for the following example use cases:
- - Control of vibrate (phones, tablets etc.) hardware by user space app.
- Use of LED by user space app as activity indicator.
- Use of LED by user space app as a kind of watchdog indicator -- as
long as the app is alive, it can keep the LED illuminated, if it dies
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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