How do you write a simple character driver?

chmod a+r+w /dev/mydev

this application is writing hello to device and reading same from device. save this file as test_app. c and compile this file as we compile other c file. execute this file to test the driver by following command.

How do you write a device driver?

A device driver is a kernel module that is responsible for managing the low-level I/O operations of a hardware device. Device drivers are written with standard interfaces that the kernel can call to interface with a device.