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Date: Wed, 11 Mar 2015 10:34:26 +0100
From: Pavel Machek <pavel@ucw.cz>
To: Bryan Wu <cooloney@gmail.com>
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Subject: Documentation: leds: clarify what 50% brightness means
Message-ID: <20150311093425.GA8866@amd>
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I played with RGB LED a bit, and we have quite a gap in
documentation: what 50% brightness means is non-trivial and very
important in case we want to do smooth blinking and color
transitions.
    
Signed-off-by: Pavel Machek <pavel@ucw.cz>

diff --git a/Documentation/ABI/testing/sysfs-class-led b/Documentation/ABI/testing/sysfs-class-led
index 3646ec8..649d7a6 100644
--- a/Documentation/ABI/testing/sysfs-class-led
+++ b/Documentation/ABI/testing/sysfs-class-led
@@ -8,6 +8,11 @@ Description:
 		non-zero brightness settings. The value is between 0 and
 		/sys/class/leds/<led>/max_brightness.
 
+		If LED supports continuous brightness settings, 50% brightness
+		should correspond to 50% brightness perceived by human, in a similar
+		manner pixel brightness on monitor does (not 50% PWM).
+
+
 What:		/sys/class/leds/<led>/max_brightness
 Date:		March 2006
 KernelVersion:	2.6.17