1e7c787cbSChristian Mauderer* Single Byte SPI LED Device Driver. 2e7c787cbSChristian Mauderer 3e7c787cbSChristian MaudererThe driver can be used for controllers with a very simple SPI protocol: 4e7c787cbSChristian Mauderer- one LED is controlled by a single byte on MOSI 5e7c787cbSChristian Mauderer- the value of the byte gives the brightness between two values (lowest to 6e7c787cbSChristian Mauderer highest) 7e7c787cbSChristian Mauderer- no return value is necessary (no MISO signal) 8e7c787cbSChristian Mauderer 9e7c787cbSChristian MaudererThe value for lowest and highest brightness is dependent on the device and 10e7c787cbSChristian Mauderertherefore on the compatible string. 11e7c787cbSChristian Mauderer 12e7c787cbSChristian MaudererDepending on the compatible string some special functions (like hardware 13e7c787cbSChristian Maudereraccelerated blinking) might can be supported too. 14e7c787cbSChristian Mauderer 15e7c787cbSChristian MaudererThe driver currently only supports one LED. The properties of the LED are 16e7c787cbSChristian Maudererconfigured in a sub-node in the device node. 17e7c787cbSChristian Mauderer 18e7c787cbSChristian MaudererRequired properties: 19e7c787cbSChristian Mauderer- compatible: should be one of 20e7c787cbSChristian Mauderer * "ubnt,acb-spi-led" microcontroller (SONiX 8F26E611LA) based device 21e7c787cbSChristian Mauderer used for example in Ubiquiti airCube ISP 22e7c787cbSChristian Mauderer 23e7c787cbSChristian MaudererProperty rules described in Documentation/devicetree/bindings/spi/spi-bus.txt 24e7c787cbSChristian Maudererapply. 25e7c787cbSChristian Mauderer 26e7c787cbSChristian MaudererLED sub-node properties: 27e7c787cbSChristian Mauderer- label: 28e7c787cbSChristian Mauderer see Documentation/devicetree/bindings/leds/common.txt 29e7c787cbSChristian Mauderer- default-state: 30e7c787cbSChristian Mauderer see Documentation/devicetree/bindings/leds/common.txt 31e7c787cbSChristian Mauderer Only "on" and "off" are supported. 32e7c787cbSChristian Mauderer 33e7c787cbSChristian MaudererExample: 34e7c787cbSChristian Mauderer 35e7c787cbSChristian Maudererled-controller@0 { 36e7c787cbSChristian Mauderer compatible = "ubnt,acb-spi-led"; 37e7c787cbSChristian Mauderer reg = <0>; 38e7c787cbSChristian Mauderer spi-max-frequency = <100000>; 39e7c787cbSChristian Mauderer 40e7c787cbSChristian Mauderer led { 41e7c787cbSChristian Mauderer label = "white:status"; 42e7c787cbSChristian Mauderer default-state = "on"; 43e7c787cbSChristian Mauderer }; 44e7c787cbSChristian Mauderer}; 45