linux-kernel - [PATCH 1/3] Documentation: leds: Add docs for Wurth Elektronik WL-ICLED

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Message-Id: <7f324a9a25ad1ac3a622aa1201cbd91ead80f8f9.1744636666.git.knezic@helmholz.com>
Date: Mon, 14 Apr 2025 15:28:49 +0200
From: Ante Knezic <ante.knezic@...mholz.de>
To: linux-leds@...r.kernel.org
Cc: lee@...nel.org,
	pavel@...nel.org,
	robh@...nel.org,
	krzk+dt@...nel.org,
	conor+dt@...nel.org,
	corbet@....net,
	knezic@...mholz.com,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-doc@...r.kernel.org
Subject: [PATCH 1/3] Documentation: leds: Add docs for Wurth Elektronik WL-ICLED

From: Ante Knezic <knezic@...mholz.com>

Basic description of WL-ICLED RGB LEDs from Wurth Elektronik

Signed-off-by: Ante Knezic <knezic@...mholz.com>
---
 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