linux-kernel - [PATCH 1/2] leds: ncp5623: Add device tree binding documentation

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Message-Id: <1466494154-3786-2-git-send-email-florian.vaussard@heig-vd.ch>
Date:	Tue, 21 Jun 2016 09:29:13 +0200
From:	Florian Vaussard <florian.vaussard@...il.com>
To:	devicetree@...r.kernel.org, Richard Purdie <rpurdie@...ys.net>,
	Jacek Anaszewski <j.anaszewski@...sung.com>
Cc:	Rob Herring <robh+dt@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	linux-leds@...r.kernel.org, linux-kernel@...r.kernel.org,
	Florian Vaussard <florian.vaussard@...g-vd.ch>
Subject: [PATCH 1/2] leds: ncp5623: Add device tree binding documentation

Add device tree binding documentation for On Semiconductor NCP5623 I2C
LED driver. The driver can independently control the PWM of the 3
channels with 32 levels of intensity.

The current delivered by the current source can be controlled using the
led-max-microamp property. In order to control this value, it is also
necessary to know the current on the Iref pin, hence the
onnn,led-iref-microamp property. It is usually set using an external
bias resistor, following Iref = Vref/Rbias with Vref=0.6V.

Signed-off-by: Florian Vaussard <florian.vaussard@...g-vd.ch>
---
 .../devicetree/bindings/leds/leds-ncp5623.txt      | 44 ++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/leds-ncp5623.txt

diff --git a/Documentation/devicetree/bindings/leds/leds-ncp5623.txt b/Documentation/devicetree/bindings/leds/leds-ncp5623.txt
new file mode 100644
index 0000000..0dc8345
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-ncp5623.txt
@@ -0,0 +1,44 @@
+* ON Semiconductor - NCP5623 3-Channel LED Driver
+
+The NCP5623 is a 3-channel I2C LED driver. The brightness of each
+channel can be independently set using 32 levels. Each LED is represented
+as a sub-node of the device.
+
+Required properties:
+  - compatible: Should be "onnn,ncp5623"
+  - reg: I2C slave address (fixed to 0x38)
+  - #address-cells: must be 1
+  - #size-cells: must be 0
+  - onnn,led-iref-microamp: Current on the Iref pin in microampere
+  - led-max-microamp: Desired maximum current for each LED in microampere
+                      (maximum 30000uA)
+
+LED sub-node properties:
+  - reg : LED channel number (0..2)
+  - For other LED properties see:
+      Documentation/devicetree/bindings/leds/common.txt
+
+Example:
+
+led1: ncp5623@38 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	compatible = "onnn,ncp5623";
+	reg = <0x38>;
+
+	led1_r@0 {
+		label = "ncp:power:red";
+		reg = <0>;
+		linux,default-trigger = "default-on";
+	};
+
+	led1_b@1 {
+		label = "ncp:power:blue";
+		reg = <1>;
+	};
+
+	led1_g@2 {
+		label = "ncp:power:green";
+		reg = <2>;
+	};
+};
-- 
2.5.0