1*4882a593Smuzhiyun* Single Byte SPI LED Device Driver. 2*4882a593Smuzhiyun 3*4882a593SmuzhiyunThe driver can be used for controllers with a very simple SPI protocol: 4*4882a593Smuzhiyun- one LED is controlled by a single byte on MOSI 5*4882a593Smuzhiyun- the value of the byte gives the brightness between two values (lowest to 6*4882a593Smuzhiyun highest) 7*4882a593Smuzhiyun- no return value is necessary (no MISO signal) 8*4882a593Smuzhiyun 9*4882a593SmuzhiyunThe value for lowest and highest brightness is dependent on the device and 10*4882a593Smuzhiyuntherefore on the compatible string. 11*4882a593Smuzhiyun 12*4882a593SmuzhiyunDepending on the compatible string some special functions (like hardware 13*4882a593Smuzhiyunaccelerated blinking) might can be supported too. 14*4882a593Smuzhiyun 15*4882a593SmuzhiyunThe driver currently only supports one LED. The properties of the LED are 16*4882a593Smuzhiyunconfigured in a sub-node in the device node. 17*4882a593Smuzhiyun 18*4882a593SmuzhiyunRequired properties: 19*4882a593Smuzhiyun- compatible: should be one of 20*4882a593Smuzhiyun * "ubnt,acb-spi-led" microcontroller (SONiX 8F26E611LA) based device 21*4882a593Smuzhiyun used for example in Ubiquiti airCube ISP 22*4882a593Smuzhiyun 23*4882a593SmuzhiyunProperty rules described in Documentation/devicetree/bindings/spi/spi-bus.txt 24*4882a593Smuzhiyunapply. 25*4882a593Smuzhiyun 26*4882a593SmuzhiyunLED sub-node properties: 27*4882a593Smuzhiyun- label: 28*4882a593Smuzhiyun see Documentation/devicetree/bindings/leds/common.txt 29*4882a593Smuzhiyun- default-state: 30*4882a593Smuzhiyun see Documentation/devicetree/bindings/leds/common.txt 31*4882a593Smuzhiyun Only "on" and "off" are supported. 32*4882a593Smuzhiyun 33*4882a593SmuzhiyunExample: 34*4882a593Smuzhiyun 35*4882a593Smuzhiyunled-controller@0 { 36*4882a593Smuzhiyun compatible = "ubnt,acb-spi-led"; 37*4882a593Smuzhiyun reg = <0>; 38*4882a593Smuzhiyun spi-max-frequency = <100000>; 39*4882a593Smuzhiyun 40*4882a593Smuzhiyun led { 41*4882a593Smuzhiyun label = "white:status"; 42*4882a593Smuzhiyun default-state = "on"; 43*4882a593Smuzhiyun }; 44*4882a593Smuzhiyun}; 45