linux-kernel - [PATCH 11/13] Documentation: leds: document pattern behavior of Samsung S2M series PMIC RGB LEDs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251114-s2mu005-pmic-v1-11-9e3184d3a0c9@disroot.org>
Date: Fri, 14 Nov 2025 00:35:12 +0530
From: Kaustabh Chakraborty <kauschluss@...root.org>
To: Lee Jones <lee@...nel.org>, Pavel Machek <pavel@...nel.org>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, MyungJoo Ham <myungjoo.ham@...sung.com>, 
 Chanwoo Choi <cw00.choi@...sung.com>, Sebastian Reichel <sre@...nel.org>, 
 Krzysztof Kozlowski <krzk@...nel.org>, 
 André Draszik <andre.draszik@...aro.org>, 
 Alexandre Belloni <alexandre.belloni@...tlin.com>, 
 Jonathan Corbet <corbet@....net>
Cc: linux-leds@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
 linux-samsung-soc@...r.kernel.org, linux-rtc@...r.kernel.org, 
 linux-doc@...r.kernel.org, Kaustabh Chakraborty <kauschluss@...root.org>
Subject: [PATCH 11/13] Documentation: leds: document pattern behavior of
 Samsung S2M series PMIC RGB LEDs

Add documentation to describe how hardware patterns (as defined by the
documentation of led-class-multicolor) are parsed and implemented by the
Samsung S2M series PMIC RGB LED driver.

Signed-off-by: Kaustabh Chakraborty <kauschluss@...root.org>
---
 Documentation/leds/index.rst        |  1 +
 Documentation/leds/leds-s2m-rgb.rst | 60 +++++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst
index 76fae171039c..05d8e8517a80 100644
--- a/Documentation/leds/index.rst
+++ b/Documentation/leds/index.rst
@@ -27,6 +27,7 @@ LEDs
    leds-lp55xx
    leds-mlxcpld
    leds-mt6370-rgb
+   leds-s2m-rgb
    leds-sc27xx
    leds-st1202
    leds-qcom-lpg
diff --git a/Documentation/leds/leds-s2m-rgb.rst b/Documentation/leds/leds-s2m-rgb.rst
new file mode 100644
index 000000000000..cf91f0238093
--- /dev/null
+++ b/Documentation/leds/leds-s2m-rgb.rst
@@ -0,0 +1,60 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+======================================
+Samsung S2M Series PMIC RGB LED Driver
+======================================
+
+Description
+-----------
+
+The RGB LED on the S2M series PMIC hardware features a three-channel LED that is
+grouped together as a single device. Furthermore, the it supports 8-bit
+brightness control for each channel. This LED is typically used as a status
+indicator in mobile devices. It also supports various parameters for hardware
+patterns.
+
+The hardware pattern can be programmed using the "pattern" trigger, using the
+hw_pattern attribute.
+
+/sys/class/leds/<led>/repeat
+----------------------------
+
+The hardware supports only indefinitely repeating patterns. The repeat
+attribute must be set to -1 for hardware patterns to function.
+
+/sys/class/leds/<led>/hw_pattern
+--------------------------------
+
+Specify a hardware pattern for the RGB LEDs.
+
+The pattern is a series of brightness levels and durations in milliseconds.
+There should be only one non-zero brightness level. Unlike the results
+described in leds-trigger-pattern, the transitions between on and off states
+are smoothed out by the hardware.
+
+Simple pattern::
+
+    "255 3000 0 1000"
+
+    255 -+ ''''''-.                     .-'''''''-.
+         |         '.                 .'           '.
+         |           \               /               \
+         |            '.           .'                 '.
+         |              '-.......-'                     '-
+      0 -+-------+-------+-------+-------+-------+-------+--> time (s)
+         0       1       2       3       4       5       6
+
+As described in leds-trigger-pattern, it is also possible to use zero-length
+entries to disable the ramping mechanism.
+
+On-Off pattern::
+
+    "255 1000 255 0 0 1000 0 0"
+
+    255 -+ ------+       +-------+       +-------+
+         |       |       |       |       |       |
+         |       |       |       |       |       |
+         |       |       |       |       |       |
+         |       +-------+       +-------+       +-------
+      0 -+-------+-------+-------+-------+-------+-------+--> time (s)
+         0       1       2       3       4       5       6

-- 
2.51.2