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Date: Tue, 18 Dec 2018 16:27:28 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Jacek Anaszewski <jacek.anaszewski@...il.com>,
Pavel Machek <pavel@....cz>, Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Raphael Teysseyre <rteysseyre@...il.com>,
Krzysztof Kozlowski <krzk@...nel.org>,
Baolin Wang <baolin.wang@...aro.org>,
linux-kernel@...r.kernel.org, linux-leds@...r.kernel.org,
devicetree@...r.kernel.org
Subject: [PATCH v4 1/5] dt-bindings: leds: Add pattern initialization from Device Tree
Document new led-pattern property for initialization of LED triggers.
The property format is trigger-specific (except being array of
integers). For pattern trigger, the explanation of pattern format was
moved to a common file shared with sysfs ABI.
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
---
.../ABI/testing/sysfs-class-led-trigger-pattern | 51 ++--------------------
Documentation/devicetree/bindings/leds/common.txt | 12 +++++
.../bindings/leds/leds-trigger-pattern.txt | 49 +++++++++++++++++++++
3 files changed, 64 insertions(+), 48 deletions(-)
create mode 100644 Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
index 1e5d172e0646..bd92ef9d6faa 100644
--- a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
+++ b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
@@ -7,55 +7,10 @@ Description:
timer. It can do gradual dimming and step change of brightness.
The pattern is given by a series of tuples, of brightness and
- duration (ms). The LED is expected to traverse the series and
- each brightness value for the specified duration. Duration of
- 0 means brightness should immediately change to new value, and
- writing malformed pattern deactivates any active one.
+ duration (ms).
- 1. For gradual dimming, the dimming interval now is set as 50
- milliseconds. So the tuple with duration less than dimming
- interval (50ms) is treated as a step change of brightness,
- i.e. the subsequent brightness will be applied without adding
- intervening dimming intervals.
-
- The gradual dimming format of the software pattern values should be:
- "brightness_1 duration_1 brightness_2 duration_2 brightness_3
- duration_3 ...". For example:
-
- echo 0 1000 255 2000 > pattern
-
- It will make the LED go gradually from zero-intensity to max (255)
- intensity in 1000 milliseconds, then back to zero intensity in 2000
- milliseconds:
-
- LED brightness
- ^
- 255-| / \ / \ /
- | / \ / \ /
- | / \ / \ /
- | / \ / \ /
- 0-| / \/ \/
- +---0----1----2----3----4----5----6------------> time (s)
-
- 2. To make the LED go instantly from one brightness value to another,
- we should use zero-time lengths (the brightness must be same as
- the previous tuple's). So the format should be:
- "brightness_1 duration_1 brightness_1 0 brightness_2 duration_2
- brightness_2 0 ...". For example:
-
- echo 0 1000 0 0 255 2000 255 0 > pattern
-
- It will make the LED stay off for one second, then stay at max brightness
- for two seconds:
-
- LED brightness
- ^
- 255-| +---------+ +---------+
- | | | | |
- | | | | |
- | | | | |
- 0-| -----+ +----+ +----
- +---0----1----2----3----4----5----6------------> time (s)
+ The exact format is described in:
+ Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
What: /sys/class/leds/<led>/hw_pattern
Date: September 2018
diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index aa1399814a2a..70876ac11367 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -37,6 +37,18 @@ Optional properties for child nodes:
"ide-disk" - LED indicates IDE disk activity (deprecated),
in new implementations use "disk-activity"
"timer" - LED flashes at a fixed, configurable rate
+ "pattern" - LED alters the brightness for the specified duration with one
+ software timer (requires "led-pattern" property)
+
+- led-pattern : Array of integers with default pattern for certain triggers.
+ Each trigger may parse this property differently:
+ - one-shot : two numbers specifying delay on and delay off (in ms),
+ - timer : two numbers specifying delay on and delay off (in ms),
+ - pattern : the pattern is given by a series of tuples, of
+ brightness and duration (in ms). The exact format is
+ described in:
+ Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
+
- led-max-microamp : Maximum LED supply current in microamperes. This property
can be made mandatory for the board configurations
diff --git a/Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt b/Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
new file mode 100644
index 000000000000..d3696680bfc8
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt
@@ -0,0 +1,49 @@
+* Pattern format for LED pattern trigger
+
+The pattern is given by a series of tuples, of brightness and duration (ms).
+The LED is expected to traverse the series and each brightness value for the
+specified duration. Duration of 0 means brightness should immediately change to
+new value, and writing malformed pattern deactivates any active one.
+
+1. For gradual dimming, the dimming interval now is set as 50 milliseconds. So
+the tuple with duration less than dimming interval (50ms) is treated as a step
+change of brightness, i.e. the subsequent brightness will be applied without
+adding intervening dimming intervals.
+
+The gradual dimming format of the software pattern values should be:
+"brightness_1 duration_1 brightness_2 duration_2 brightness_3 duration_3 ...".
+For example (using sysfs interface):
+
+echo 0 1000 255 2000 > pattern
+
+It will make the LED go gradually from zero-intensity to max (255) intensity in
+1000 milliseconds, then back to zero intensity in 2000 milliseconds:
+
+LED brightness
+ ^
+255-| / \ / \ /
+ | / \ / \ /
+ | / \ / \ /
+ | / \ / \ /
+ 0-| / \/ \/
+ +---0----1----2----3----4----5----6------------> time (s)
+
+2. To make the LED go instantly from one brightness value to another, we should
+use zero-time lengths (the brightness must be same as the previous tuple's). So
+the format should be: "brightness_1 duration_1 brightness_1 0 brightness_2
+duration_2 brightness_2 0 ...".
+For example (using sysfs interface):
+
+echo 0 1000 0 0 255 2000 255 0 > pattern
+
+It will make the LED stay off for one second, then stay at max brightness for
+two seconds:
+
+LED brightness
+ ^
+255-| +---------+ +---------+
+ | | | | |
+ | | | | |
+ | | | | |
+ 0-| -----+ +----+ +----
+ +---0----1----2----3----4----5----6------------> time (s)
--
2.7.4
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