Linux Kernel Device Driver Development (Part 2) | driver.c |

🚀 Linux Kernel Device Driver Development | Part 2 | driver.c



🧠 In this video, we move one level deeper into Linux Kernel Development.
This part focuses on writing the actual kernel driver (driver.c) that registers
a character device, creates a /dev entry, and prepares an IOCTL interface
for communication between user space and kernel space.


🔧 What is covered in this video?

📌 Writing a Linux Kernel Module (LKM)
📌 Registering a Character Device using `register_chrdev()`
📌 Understanding major numbers and kernel device registration
📌 Creating a device node automatically using
    → `class_create()`
    → `device_create()`
📌 Defining and handling *IOCTL commands*
📌 Understanding *file_operations structure*
📌 Kernel ↔ User Space interaction basics
📌 Proper resource cleanup using module exit



🧩 Core Concepts Explained

🔹 What happens when a kernel module is inserted using `insmod`
🔹 Why `module_init()` and `module_exit()` are critical
🔹 How `/dev/aditya` is created automatically
🔹 Difference between:


Kernel IOCTL handler vs User-space ioctl()
```

🔹 How the kernel decides which function to call on an ioctl request



📂 Code implemented in this video

✔ `driver.c` (Kernel module source file)
✔ IOCTL command definition using `_IOW()`
✔ `file_operations` rulebook
✔ Kernel logging using `printk()`
✔ Proper driver cleanup on module removal



🖥️ Result of this video

After loading the module:

/dev/aditya

✔ Device is successfully created
✔ Kernel is ready to receive ioctl commands
✔ Foundation is set for user-space programs



🔜 What’s coming next? (Part 3)

➡️ Writing a User Space Application
➡️ Calling `ioctl()` from user space
➡️ Triggering kernel code from terminal
➡️ Verifying kernel execution using `dmesg`



🎯 Who is this video for?

✅ Students learning *Linux Kernel Development*
✅ Beginners in *Device Driver Programming*
✅ Internship / Interview preparation
✅ Anyone curious about how Linux talks to hardware



⚠️ Important Notes

🔸 This video focuses only on driver setup & registration
🔸 Queue logic, blocking behavior, and data handling will be added later
🔸 All code is written step-by-step and explained in depth



📌 Tools & Environment

🖥️ Ubuntu Linux
🧠 Linux Kernel Modules
⚙️ GCC + Makefile
📦 Character Device Drivers



⭐ Support the series

👍 Like the video if it helped
💬 Comment your doubts or suggestions
📌 Subscribe for upcoming kernel driver parts



🔗 Part 1: Makefile for Kernel Module
🔗 Part 2: Driver Skeleton (this video)
🔗 Part 3: User Space IOCTL Program (coming next)



🔥 This video builds the backbone of the entire driver.
Master this part, and everything ahead becomes easy