hddled_tmj33 | linux module for controlling the HDD LEDs

hddled_tmj33 is a C library typically used in Internet of Things (IoT), Raspberry Pi, Arduino applications. hddled_tmj33 has no bugs, it has no vulnerabilities and it has low support. You can download it from GitHub.

Kernel module to control HDD LEDs on Terramaster NAS that run on Intel Celeron J33xx. I got the source code for module named led_drv_TMJ33 that was running on my F2-221's TOS 4.1 by emailing their support email. That module gives the ability to control the two HDD LEDs on that NAS (up to 5 on F5-221). I didn't like TOS and wanted to run any Linux distro on the NAS which is why I asked for the source code. The led_drv_TMJ33 module (the one provided by Terramaster support) creates char devices /dev/leddrv[1-10] that you can pipe into "led[1-10]on" and "led[1-10]off". However they don't do any tracking on which char device the user is writing into, meaning echo led2on > /dev/leddrv5 will actually turn on led2, so will echo led2on > /dev/leddrv3. I didn't like that interface so I wrote my own with the original one as reference on how to interface with the hardware. It finds the base address of the device that has the relevant GPIO pins that control the LEDs. This is done in function read_base. That address is stored in base in the following explanation. The module ioremaps address with hardcoded offset from base as follows. Green color of physical HDD LED[1-5] is connected to the first 5 in the list above (odd numbers in 1-9). Red color of physical HDD LED[1-5] is connected to the last 5 in the list above (even numbers in 2-10). So the green color of the physical HDD LEDs are offset of base in 0x8 intervals (starting at base+0xC505B8) and the red color are offset +0x28 from the green color of the same physical LED. This module creates char devices /dev/hddled[1-5]. Each device can only control a single LED. You can write [0-3] into them to control the LED in question.