On 11/7/21 4:24 PM, Ansuel Smith wrote:
From: Marek Behún <kabel@xxxxxxxxxx>
---
Documentation/leds/leds-class.rst | 20 +++++++++++++++++++
drivers/leds/led-triggers.c | 1 +
drivers/leds/trigger/Kconfig | 10 ++++++++++
include/linux/leds.h | 33 +++++++++++++++++++++++++++++++
4 files changed, 64 insertions(+)
diff --git a/Documentation/leds/leds-class.rst b/Documentation/leds/leds-class.rst
index cd155ead8703..5bf6e5d471ce 100644
--- a/Documentation/leds/leds-class.rst
+++ b/Documentation/leds/leds-class.rst
@@ -169,6 +169,26 @@ Setting the brightness to zero with brightness_set() callback function
should completely turn off the LED and cancel the previously programmed
hardware blinking function, if any.
+Hardware offloading of LED triggers
+===================================
+
+Some LEDs can be driven by hardware triggers (for example a LED connected to
+an ethernet PHY or an ethernet switch can be configured to blink on activity on
+the network, which in software is done by the netdev trigger).
+
+To do such offloading, LED driver must support this and a deficated offload
dedicated
+trigger must be used. The LED must implement the trigger_offload() method and
+the trigger code must try to call this method (via led_trigger_offload()
+function) to set the LED to this particular mode. (and disable any software
+blinking)
+
+The implementation of the trigger_offload() method by the LED driver must return
+0 if the offload is successful and -EOPNOTSUPP if the requested trigger
+configuration is not supported.
+
+If the second argument (enable) to the trigger_offload() method is false, any
+active HW offloading must be deactivated. In this case errors are not permitted
Preferably s/HW/hardware/ and s/SW/software/ throughout documentation and Kconfig
files.
+in the trigger_offload() method and the driver will be set to the new trigger.
Known Issues
============
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index dc6816d36d06..33aba8defeab 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -9,6 +9,16 @@ menuconfig LEDS_TRIGGERS
if LEDS_TRIGGERS
+config LEDS_OFFLOAD_TRIGGERS
+ bool "LED Offload Trigger support"
+ help
+ This option enabled offload triggers support used by leds that
enables LEDs
+ can be driven in hardware by declaring some specific triggers.
+ A offload trigger will expose a sysfs dir to configure the
+ different blinking trigger and the available hardware triggers.
+
+ If unsure, say Y.
--
~Randy
