0001 * Single Byte SPI LED Device Driver.
0002
0003 The driver can be used for controllers with a very simple SPI protocol:
0004 - one LED is controlled by a single byte on MOSI
0005 - the value of the byte gives the brightness between two values (lowest to
0006 highest)
0007 - no return value is necessary (no MISO signal)
0008
0009 The value for lowest and highest brightness is dependent on the device and
0010 therefore on the compatible string.
0011
0012 Depending on the compatible string some special functions (like hardware
0013 accelerated blinking) might can be supported too.
0014
0015 The driver currently only supports one LED. The properties of the LED are
0016 configured in a sub-node in the device node.
0017
0018 Required properties:
0019 - compatible: should be one of
0020 * "ubnt,acb-spi-led" microcontroller (SONiX 8F26E611LA) based device
0021 used for example in Ubiquiti airCube ISP
0022
0023 Property rules described in Documentation/devicetree/bindings/spi/spi-bus.txt
0024 apply.
0025
0026 LED sub-node properties:
0027 - label:
0028 see Documentation/devicetree/bindings/leds/common.txt
0029 - default-state:
0030 see Documentation/devicetree/bindings/leds/common.txt
0031 Only "on" and "off" are supported.
0032
0033 Example:
0034
0035 led-controller@0 {
0036 compatible = "ubnt,acb-spi-led";
0037 reg = <0>;
0038 spi-max-frequency = <100000>;
0039
0040 led {
0041 label = "white:status";
0042 default-state = "on";
0043 };
0044 };
