This patch adds support for driving a chain of WS2812B LED chips using SPI bus. WorldSemi WS2812B is a individually addressable LED chip that can be chained together and controlled individually using a single wire. The chip recognize a long pulse as a bit of 1 and a short pulse as a bit of 0. Host sends a continuous stream of 24-bits color values, each LED chip takes the first 3 byte it receives as its color value and passes the leftover bytes to the next LED on the chain. This driver simulates this protocol using SPI bus by sending a long pulse as 3'b110 and a short pulse as 3'b100. The SPI frequency needs to be 2.105MHz~2.85MHz for the timing to be correct and the controller needs to transfer all the bytes continuously. Changes since v1: various dt binding fixes add support for default-brightness Chuanhong Guo (3): dt-bindings: vendor-prefixes: add an entry for WorldSemi dt-bindings: leds: add dt schema for worldsemi,ws2812b-spi leds: add driver for SPI driven WorldSemi WS2812B RGB LEDs .../bindings/leds/worldsemi,ws2812b.yaml | 138 ++++++++++ .../devicetree/bindings/vendor-prefixes.yaml | 2 + drivers/leds/rgb/Kconfig | 11 + drivers/leds/rgb/Makefile | 1 + drivers/leds/rgb/leds-ws2812b.c | 235 ++++++++++++++++++ 5 files changed, 387 insertions(+) create mode 100644 Documentation/devicetree/bindings/leds/worldsemi,ws2812b.yaml create mode 100644 drivers/leds/rgb/leds-ws2812b.c -- 2.38.1
