1*c66ec88fSEmmanuel Vadot* Single Byte SPI LED Device Driver. 2*c66ec88fSEmmanuel Vadot 3*c66ec88fSEmmanuel VadotThe driver can be used for controllers with a very simple SPI protocol: 4*c66ec88fSEmmanuel Vadot- one LED is controlled by a single byte on MOSI 5*c66ec88fSEmmanuel Vadot- the value of the byte gives the brightness between two values (lowest to 6*c66ec88fSEmmanuel Vadot highest) 7*c66ec88fSEmmanuel Vadot- no return value is necessary (no MISO signal) 8*c66ec88fSEmmanuel Vadot 9*c66ec88fSEmmanuel VadotThe value for lowest and highest brightness is dependent on the device and 10*c66ec88fSEmmanuel Vadottherefore on the compatible string. 11*c66ec88fSEmmanuel Vadot 12*c66ec88fSEmmanuel VadotDepending on the compatible string some special functions (like hardware 13*c66ec88fSEmmanuel Vadotaccelerated blinking) might can be supported too. 14*c66ec88fSEmmanuel Vadot 15*c66ec88fSEmmanuel VadotThe driver currently only supports one LED. The properties of the LED are 16*c66ec88fSEmmanuel Vadotconfigured in a sub-node in the device node. 17*c66ec88fSEmmanuel Vadot 18*c66ec88fSEmmanuel VadotRequired properties: 19*c66ec88fSEmmanuel Vadot- compatible: should be one of 20*c66ec88fSEmmanuel Vadot * "ubnt,acb-spi-led" microcontroller (SONiX 8F26E611LA) based device 21*c66ec88fSEmmanuel Vadot used for example in Ubiquiti airCube ISP 22*c66ec88fSEmmanuel Vadot 23*c66ec88fSEmmanuel VadotProperty rules described in Documentation/devicetree/bindings/spi/spi-bus.txt 24*c66ec88fSEmmanuel Vadotapply. 25*c66ec88fSEmmanuel Vadot 26*c66ec88fSEmmanuel VadotLED sub-node properties: 27*c66ec88fSEmmanuel Vadot- label: 28*c66ec88fSEmmanuel Vadot see Documentation/devicetree/bindings/leds/common.txt 29*c66ec88fSEmmanuel Vadot- default-state: 30*c66ec88fSEmmanuel Vadot see Documentation/devicetree/bindings/leds/common.txt 31*c66ec88fSEmmanuel Vadot Only "on" and "off" are supported. 32*c66ec88fSEmmanuel Vadot 33*c66ec88fSEmmanuel VadotExample: 34*c66ec88fSEmmanuel Vadot 35*c66ec88fSEmmanuel Vadotled-controller@0 { 36*c66ec88fSEmmanuel Vadot compatible = "ubnt,acb-spi-led"; 37*c66ec88fSEmmanuel Vadot reg = <0>; 38*c66ec88fSEmmanuel Vadot spi-max-frequency = <100000>; 39*c66ec88fSEmmanuel Vadot 40*c66ec88fSEmmanuel Vadot led { 41*c66ec88fSEmmanuel Vadot label = "white:status"; 42*c66ec88fSEmmanuel Vadot default-state = "on"; 43*c66ec88fSEmmanuel Vadot }; 44*c66ec88fSEmmanuel Vadot}; 45