summery

chapter 1

chapter 2

chapter 3


Major number shows the driver that associated by the device by demonstrating the number of device class.

Minor number shows the number of device in the class obtained by major number.

dev_t type defined in <linux/types.h> used by kernel to obtain major and minor numbers in one object.

Macros defined in <linux/kdev_t.h> for change the dev_t type to integer minor and major numbers:
	MAJOR(dev_t dev);
	MINOR(dev_t dev);

Macro defined in <linux/kdev_t.h> for change integer minor and major numbers to dev_t object:
	MKDEV(int major, int minor);

Allocating device numbers for char device knowing the major number:
	int register_chrdev_region(dev_t first, unsigned int firstminor, unsigned int count, char* name);

Allocate device number by kernel and return it(Often we don't know what major number shall we use for our device so we use this function instead of register_chrdev_region):
	int allocate_chrdev_register(dev_t *dev, unsigned int firstminor, unsigned int count, char* name);

Free up device numbers regardless of the way that have been allocated:
	void unregister_chrdev_region(dev_t first,