Kernel Driver API Reference¶

This section collects Linux kernel APIs used by the character driver, blocking I/O, pollable driver, fasync/SIGIO, GPIO, and IRQ labs.

Driver Core¶

API	Purpose
Driver Core APIs	Register buses, devices, and drivers and understand matching and probe lifecycle

API	Purpose
file_operations	Define VFS callbacks for a character device
alloc_chrdev_region	Allocate a dynamic device number range
cdev_add	Register a character device with the VFS
class_create	Create a sysfs class for device nodes
device_create	Create a device object and `/dev` node
misc_register	Register a simple misc character device

API	Purpose
copy_to_user	Copy data from kernel to user space
copy_from_user	Copy data from user space to kernel
ioctl	Implement command-based control plane
sysfs attributes	Expose simple device attributes

API	Purpose
wait queues	Sleep until a condition becomes true
poll_wait	Integrate driver readiness with poll/epoll
non-blocking I/O	Implement `O_NONBLOCK` behavior
fasync_helper	Register or unregister asynchronous listeners for `SIGIO`

API	Purpose
spinlock	Protect shared state accessed from Process Context and IRQ Context using an interrupt-safe spinlock.
mutex	Protect shared state in sleepable contexts such as Process Context, workqueues, and kernel threads.
rw_semaphore	Reader-writer synchronization allowing multiple concurrent readers.
devm_gpiod_get	Get GPIO descriptors from Device Tree
devm_request_threaded_irq	Register threaded IRQ handlers

API	Purpose
workqueue	Execute deferred work in process context using kernel worker threads
kthread	Create and manage long-lived kernel execution threads