From: Ante Knezic <knezic@xxxxxxxxxxxx>
Basic description of WL-ICLED RGB LEDs from Wurth Elektronik
Signed-off-by: Ante Knezic <knezic@xxxxxxxxxxxx>
---
Documentation/leds/index.rst | 1 +
Documentation/leds/leds-wl-icled.rst | 69 ++++++++++++++++++++++++++++
2 files changed, 70 insertions(+)
create mode 100644 Documentation/leds/leds-wl-icled.rst
diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
index 76fae171039c..b9a4db72cc26 100644
--- a/Documentation/leds/index.rst
+++ b/Documentation/leds/index.rst
@@ -30,3 +30,4 @@ LEDs
leds-sc27xx
leds-st1202
leds-qcom-lpg
+ leds-wl-icled
diff --git a/Documentation/leds/leds-wl-icled.rst b/Documentation/leds/leds-wl-icled.rst
new file mode 100644
index 000000000000..0e55683e9468
--- /dev/null
+++ b/Documentation/leds/leds-wl-icled.rst
@@ -0,0 +1,69 @@
+=================================================
+Kernel driver for WL-ICLED from Wurth Elektronik
+=================================================
+
+Description
+-----------
+The WL-ICLEDs are RGB LEDs with integrated controller that can be
+daisy-chained to a arbitrary number of units. The MCU communicates
+with the first LED in chain via SPI interface and can be single or
+two wire connection, depending on the model.
+
+Single wire models like 1315050930002, 1313210530000, 1312020030000 and
+1312121320437 are controlled with specific signal pattern on the
+input line. The MCU is connected to input line only via SPI MOSI signal.
+For example WE-1312121320437 uses following signal pattern per one LED:
+
+| RED | GREEN | BLUE |
+| GAIN:4bits | PWM:12bits | GAIN:4bits | PWM:12bits | GAIN:4bits | PWM:12bits |
+
+ where logical 1 is represented as:
+ (V)^
+ | T
+ |<-------1.2us------->
+ |
+ +================+
+ | <---0.9us----> |
+ | |
+ +----------------+===|------> t
+
+ and logical 0 is represented as:
+ (V)^
+ | T
+ |<-------1.2us------->
+ |
+ +=====+
+ |0.3us|
+ | |
+ +-----+==============|------> t
+
+To generate the required pattern with exact timings SPI clock is selected
+so that it devides T in 8 equal parts such that a logical true symbol can be
+represented as 1111 1100 and a logical false can be represented as 1100 0000.
+Single wire LEDs require the MOSI line to be set to low at idle and this should
+be provided by the chip driver if possible or by external HW circuit.
+
+Models 1313210530000, 1312020030000 and 1315050930002 require a slightly
+different signaling scheme where each color of the LED is encoded in
+8 bits.
+
+Two wire LED types do not require specific encoding of the input line as
+both clock and data are provided to each LED.
+
+Additionally, models differ by available controls:
+- WE 1312121320437 provide PWM and GAIN control per each RGB element.
+ Both GAIN and PWM values are calculated by normalising particular
+ multi_intensity value to 4 and 12 bits.
+
+- WE 1315050930246 and 1311610030140 provide PWM control per each
+ RGB element and one global GAIN control.
+ Global GAIN value is calculated by normalising global led brightness
+ value to 5 bits while PWM values are set by particular
+ multi_intensity values.
+
+- WE 1315050930002, 1313210530000 and 1312020030000 provide only PWM
+ control per each RGB element.
+ PWM values are set by particular multi_intensity value.
+
+For more product information please see the link below:
+https://www.we-online.com/en/components/products/WL-ICLED
--
2.48.1
