Creation of pseudo device-node under /dev

Question

Question:

• How to (where to find additional information i.e., examples) programatically create a pseudo device-node under /dev from a kernel module?

Answer 1

From your question I'm guessing your talking about Linux (since you are talking about kernel modules). In that case I'd strongly recommend reading Linux Device Driver. I'd recommend looking at chapter 14 to understand better how device work.

It should also be noted that in most current desktop and server distribution of Linux, udev is responsible for creating entries in /dev. You can configure udev with rules that allow you to create your the device node with a specific name and location. In the embedded world it might be mdev with busybox that's responsible for populating /dev or even it could simply be the deprecated devfs.

Answer 2

Linux Device Driver is certainly a must read. However, I would start with chapter 3, since it is a step by step example on how to create a char device driver.

The kernel API is a moving target. More than often, you will discover that some example that used to compile against a previous version of the kernel generates a warning or an error with a newer version. In this situation, being able to browse through the sources without getting lost is very useful.