| Tom Rini | 53633a8 | 2024-02-29 12:33:36 -0500 | [diff] [blame] | 1 | * Single Byte SPI LED Device Driver. |
| 2 | |
| 3 | The driver can be used for controllers with a very simple SPI protocol: |
| 4 | - one LED is controlled by a single byte on MOSI |
| 5 | - the value of the byte gives the brightness between two values (lowest to |
| 6 | highest) |
| 7 | - no return value is necessary (no MISO signal) |
| 8 | |
| 9 | The value for lowest and highest brightness is dependent on the device and |
| 10 | therefore on the compatible string. |
| 11 | |
| 12 | Depending on the compatible string some special functions (like hardware |
| 13 | accelerated blinking) might can be supported too. |
| 14 | |
| 15 | The driver currently only supports one LED. The properties of the LED are |
| 16 | configured in a sub-node in the device node. |
| 17 | |
| 18 | Required properties: |
| 19 | - compatible: should be one of |
| 20 | * "ubnt,acb-spi-led" microcontroller (SONiX 8F26E611LA) based device |
| 21 | used for example in Ubiquiti airCube ISP |
| 22 | |
| 23 | Property rules described in Documentation/devicetree/bindings/spi/spi-bus.txt |
| 24 | apply. |
| 25 | |
| 26 | LED sub-node properties: |
| 27 | - label: |
| 28 | see Documentation/devicetree/bindings/leds/common.txt |
| 29 | - default-state: |
| 30 | see Documentation/devicetree/bindings/leds/common.txt |
| 31 | Only "on" and "off" are supported. |
| 32 | |
| 33 | Example: |
| 34 | |
| 35 | led-controller@0 { |
| 36 | compatible = "ubnt,acb-spi-led"; |
| 37 | reg = <0>; |
| 38 | spi-max-frequency = <100000>; |
| 39 | |
| 40 | led { |
| 41 | label = "white:status"; |
| 42 | default-state = "on"; |
| 43 | }; |
| 44 | }; |