From: Christian Mauderer <oss@xxxxxxxxxxxxx>
This patch adds the binding documentation for a simple SPI based LED
controller which use only one byte for setting the brightness.
Signed-off-by: Christian Mauderer <oss@xxxxxxxxxxxxx>
---
Changes compared to v1:
- rename ubnt-spi to leds-spi-byte
- rename "ubnt-spi,off_bright" and "ubnt-spi,max_bright" to
"leds-spi-byte,off-value" and "leds-spi-byte,max-value" and mark them required
- rename led-controller node to "led-controller"
- extend description
- remove SPI controller
- use "white:status" for the example label
.../bindings/leds/leds-spi-byte.txt | 47 +++++++++++++++++++
1 file changed, 47 insertions(+)
create mode 100644 Documentation/devicetree/bindings/leds/leds-spi-byte.txt
diff --git a/Documentation/devicetree/bindings/leds/leds-spi-byte.txt b/Documentation/devicetree/bindings/leds/leds-spi-byte.txt
new file mode 100644
index 000000000000..1dd6ab03a56d
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-spi-byte.txt
@@ -0,0 +1,47 @@
+* Single Byte SPI LED Device Driver.
+
+The driver can be used for controllers with a very simple SPI protocol: Only one
+byte will be sent. The value of the byte can be any value between the off-value
+and max-value defined in the properties.
+
+One example where the driver can be used is the controller in Ubiquiti airCube
+ISP devices. That LED controller is based on a 8 bit microcontroller (SONiX
+8F26E611LA) that has been programmed to control the single LED of the device.
+The controller supports four modes depending on the highest two bits in a byte:
+One setting for brightness, the other three provide different blink patterns.
+With the leds-spi-byte driver a basic support for the brightness mode of that
+controller can be easily achieved by setting the minimum and maximum to the
+brightness modes minimum and maximum byte value.
+
+Required properties:
+- compatible: Should be "leds-spi-byte".
+
+Property rules described in Documentation/devicetree/bindings/spi/spi-bus.txt
+apply. In particular, "reg" and "spi-max-frequency" properties must be given.
+
+The driver currently only supports one LED. The properties of the LED are
+configured in a sub-node in the device node.
+
+LED sub-node properties:
+- label:
+ see Documentation/devicetree/bindings/leds/common.txt
+- leds-spi-byte,off-value:
+ The SPI byte value that should be sent to switch the LED off. Has to be
+ smaller than max-value. Range: 0 to 254.
+- leds-spi-byte,max-value:
+ The SPI byte value that should be sent to set the LED to the maximum
+ brightness. Has to be bigger than off-value. Range: 1 to 255.
+
+Example:
+
+led-controller@0 {
+ compatible = "leds-spi-byte";
+ reg = <0>;
+ spi-max-frequency = <100000>;
+
+ led {
+ label = "white:status";
+ leds-spi-byte,off-value = /bits/ 8 <0>;
+ leds-spi-byte,max-value = /bits/ 8 <63>;
+ };
+};
--
2.21.0
