Character Device Driver:
1. Generally, we use APIs that dynamically allocate device numbers:
Int alloc_chrdev_region (dev_t * Dev, unsigned int firstminor, unsigned int count, char * Name );
Dev is a function used for output. After successful call, the first number of the allocated range will be saved.
Void unregister_chrdev_region (dev_t first, unsigned int coun
How to use the platform device driver to write the driver:-------------------------------------------------------------------------1. Implement device orientation first:1) read the chip manual and obtain resources from the schematic diagram.2) construct a platform device str
The biggest feature of Linux devices is that device operations are like file operations. In the application layer, a hardware device is just a device file. Applications can operate hardware devices like operating files, such as open (), close (), read (), and write.
Below is a simple implementation of the character device
/** * Author:hasen * Reference: Linux device Driver Development Details * Introduction: Android Small rookie Linux * device Driver Development Learning Journey * Topic: device drivers that support polling operations * DATE:2014-11-07 */
In
Globalfifo's po
Linux Device Driver Programming-Linux general technology-Linux programming and kernel information-complex device driver-the following is a detailed description. The complex device drivers mentioned here involve PCI, USB, network devices, Block devices, and so on (strictly sp
I. Overview
Speaking of writing I2C drivers in Linux, there are currently two main methods: one is to treat I2C devices as a common character device, the other is to use the Linux I2C driver architecture. The two drivers are compared below.
The advantages of the first method (corresponding to the disadvantages of the second method) include:● The idea is straightforward and you don't need to take the time to
Transferred from: http://blog.csdn.net/yikai2009/article/details/8653697Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.Directory (?) [-]
Blocking
Blocking operations
Non-blocking operation
Blocking mode-read-implementation
Blocking mode-write-implementation
Non-blocking read and write operations
Implementation of instance---read blocking
Instance---key
Now, let's write our own first character device driver--light LEDs. (Imperfect, back to perfect)
Hardware platform: Exynos4412 (FS4412)
Writing the drive is divided into the following steps:
A--View the schematic, data manual, understand the equipment operation method;
B-Find a similar driver in the kernel, develop it as a template, and sometimes need to start f
Some time ago, I have been engaged in the application software of the GPS navigation system. Recently, it has come to an end. I continue to pick up the driver of the Linux device!
The last time I recorded the module initialization code, I checked the code for uninstalling the module this time.
Void scull_cleanup_module (void)
Let's take a look at scull_trim.
/*
* Empty out the scull
; cloud_device_sdi};Static void _ init smdk2410_init (void){S3c24xx_fb_set_platdata ( smdk2410_lcdcfg );Platform_add_devices (smdk2410_devices, array_size (smdk2410_devices ));......................}Platform_add_devices/* What does this function do */Bytes -----------------------------------------------------------------------------------For (I = 0; I Ret = platform_device_register (Devs [I]);
Platform_device_register/* this function is used to show how to load
I. Linux USB driver levels
1. devices, configurations, interfaces, and endpointsThe logical organization of a USB device consists of four layers: device, configuration, interface, and endpoint.
A device usually has one or more configurations:
Each USB device provides d
Access control is sometimes critical for the reliability of a device node. This part of content is only modified on the open and release methods, and some check mechanisms are added.
Exclusive Device
The most rigid access control method is to allow a device to be opened (exclusive) by a single process at a time, which is the simplest access control for a
Recently, I have been drum up the lnux character device driver. I have collected various code and comments about the linux device driver on the internet, either for 2.4 or errors, and I cannot run it successfully, I really hope that you can carefully check the correctness of the code when posting a blog. In particular,
Character Device Driver instance
With the foundation of the previous section, I will learn how to compile a character device driver and test it on the client to verify whether the character device driver has been created success
devices in the Linux kernelFor the connection on the specific bus external devices have a struct device corresponding, such as platform equipment has platform_device corresponding to it, which platform_device structure is as follows: struct Platform_device {
const char * name; Device name to match the name of the driver and, if successful, into the driven probe f
command before detaching to view the explicit address distribution of the drive in a timely manner. Detaching a drive
Execute the uninstall detection of the driver to capture the detached driver and clear the resources used (it increases the possibility of a system bug detection shortly after the driver is uninstalled ). Resources not deleted by the
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