linux-kernel - [PATCH v6 1/2] dt-bindings: leds: document the "power-supply" property

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Date:   Fri, 4 Oct 2019 18:07:23 +0200
From:   Jean-Jacques Hiblot <jjhiblot@...com>
To:     <jacek.anaszewski@...il.com>, <pavel@....cz>
CC:     <linux-leds@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <dmurphy@...com>, <tomi.valkeinen@...com>,
        Jean-Jacques Hiblot <jjhiblot@...com>
Subject: [PATCH v6 1/2] dt-bindings: leds: document the "power-supply" property

Most of the LEDs are powered by a voltage/current regulator. Describing it
in the device-tree makes it possible for the LED core to enable/disable it
when needed.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@...com>
---
 Documentation/devicetree/bindings/leds/common.txt | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/Documentation/devicetree/bindings/leds/common.txt b/Documentation/devicetree/bindings/leds/common.txt
index 9fa6f9795d50..28c0cbb7c6ab 100644
--- a/Documentation/devicetree/bindings/leds/common.txt
+++ b/Documentation/devicetree/bindings/leds/common.txt
@@ -77,6 +77,19 @@ Optional properties for child nodes:
 - panic-indicator : This property specifies that the LED should be used,
 		    if at all possible, as a panic indicator.
 
+- power-supply : A voltage/current regulator used to to power the LED. When a
+		 LED is turned off, the LED core disable its regulator. The
+		 same regulator can power many LED (or other) devices. It is
+		 turned off only when all of its users disabled it.
+
+- power-off-delays-ms: This property specifies the delay between the time a LED
+                       is turned off and the time the regulator is turned off.
+                       It can be used to limit the overhead of the regulator
+                       handling if the LED is toggling fast.
+                       ex: if power-off-delays-ms is set to 500 ms, the
+                       regulator will not be turned off until the LED is turned
+                       off for more than 500ms.
+
 - trigger-sources : List of devices which should be used as a source triggering
 		    this LED activity. Some LEDs can be related to a specific
 		    device and should somehow indicate its state. E.g. USB 2.0
@@ -124,6 +137,7 @@ led-controller@0 {
 		function = LED_FUNCTION_STATUS;
 		linux,default-trigger = "heartbeat";
 		gpios = <&gpio0 0 GPIO_ACTIVE_HIGH>;
+		power-supply = <&led_regulator>;
 	};
 
 	led1 {
-- 
2.17.1