This WS2812 driver package was extracted from a subdir of the ws2812_sprites project, which in turn contained a fork of the carambola2_ws2812_driver.

I extracted the driver to get WS2812 support on the Onion Omega1 (also a AR9331 based module), and modified it to support the SK6812 RGBW LEDs as well. vdcd and messagetorch are two of my project that make use of this driver.

While the driver works fine as such, it is not a good Linux kernel space citizen, as it needs to block IRQs for extended time periods (this is unfortunately unavoidable to generate the WS2812 timing on the AR9331 which lacks DMA-controlled PWM/timer outputs). So please be aware that writing to /dev/ws2812 will probably delay or otherwise mess up any other tightly timed operations.

after compiling/installing the ws2812-draiveris kernel module package, activate the driver as follows:

# example module load for 20 WS2812 LEDs:
insmod ws2812-draiveris gpio_number=20 inverted=1
# test - should turn on the first LED in blue color
# (each LED has 3 bytes: R,G,B)
echo -en '\x00\x00\x40' > /dev/ws2812

# example module load for 20 SK6812 LEDs:
insmod ws2812-draiveris gpio_number=20 inverted=1 rgbw=1
# test - should turn on the first LED in blueish white color
# (each LED has 4 bytes: R,G,B,W)
echo -en '\x00\x00\x40\x40' > /dev/ws2812