How to get started with writing driver in Linux?
Hi deee Ho peeps!
It has been quite a while since I did my first attempt to dig into kernel level programming. Back then I managed to write my nice "Hello World" module with printk().
After that, I've done some small attempts to get more familiar with the mysterious world of drivers, but usually I've ran out of time & skills & googling enthusiasm, before managing to accidentally overwrite non volatile memory from my network card ;)
However a few days ago I had the pleasure of participating in a one day quick course to world of device drivers... As "one day quick course" tells, it was not really anything more but an introduction of some things. However that reminded me about my present goals :D
So when I get back home, I digged through my old cabins, and managed to find MSP3880SP-W modem (with microphone socket), and
Aztec 50-0038AZ-2S-2 ISA Sound Card
So I took a new goal. I want to write my own driver, which will read voltages inputted via mic socket. I guess theres DACs there already, so if only I knew how, it should be possible :D
I've written some small things for turning on/off leds etc - but I've always had some HW guy whom to ask about memory addresses to write etc. Now I am facing a different problem. How to use ISA bridge? Is there some interface in kernel for handling ISA devices? If yes, how to detect the devices, how to find out the memory areas (or ports)? Basically, where to start from??
I tried doing some googling, but all I found was bunch of cards being sold...
I know there must be drivers for these cards in Linux, but I have no idea where to start looking for it... You know that theres ~6 000 000 lines of code in linux, and ~1000 new lines is written each day... So there's a bit too much to go through blindly :D
So, does anyone have any "wild pointers" for me ? :)