external representation in the Code, the Code does not need to be changed even if the internal data type changes again in the future.
Common macros are:
The official registry cannot statically allocate these additional available device numbers, which can only be used when handling special requirements for device numbers. In fact, for assigning device numbers and creating device files, it is more likely to process device files in a highly dynamic manner.
3.2 dynamically allocat
Document directory
A quick tour of the hardware
The various modules and their interrelations
How URBS keep it all together
Input Handling
Even though UNIX traditionally considers a device as either a "char device" or a "Block device" (as outlined by the 'C' or 'B' in their/DevEntry points), new classes of device are being introduced as technology advances. One of such classes is that of ''usb devices ''.
An USB device is still, at its lowest levels, a ''char devic'' or a ''block devic''
of the LCD controller.
Specifically:
Fill in a fbinfo Structure
Use reigster_framebuffer (fbinfo *) to register the fbinfo structure to the kernel
For the fbinfo structure, the most important thing is its fs_ops member. You need to implement interfaces in fs_ops for specific devices.
Whether to use interrupt handling
Memory Access
If the video card does not have its own video memory, the system memory is allocated as the video memory.
The graphics card comes with a vide
Under Linux, the drive device has character device driver, block device driver and network device drive three kinds, before learning the character device driver, now began to learn block device driver. First of all to compare the two device drivers why not pass, why to split into different types of drivers. Take an example to illustrate the need to introduce block device drivers:If you construct the drive i
);
The filter function is called when the kernel is about to generate an event for the specified Kobject, and if 0 is returned, no event is generated
Bus, device, and driver
Bus
A bus is a channel between a processor and one or more devices
struct BUS_TYPE
Char *name;
struct subsystem Subsys;
struct Kset drivers;
struct Kse
The complex device drivers mentioned here involve PCI, USB, network devices, block devices, and so on (strictly speaking, these devices are conceptually not parallel, for example, a character device is tied to a block device, and a PCI, USB device, etc. may be part of a character device). Some of the more complex data structures and program structures associated with specific device types are also involved in the
The audio system in Android is using the ALSA system architecture. Asoc--alsa System on Chip, is built on the standard ALSA drive layer, in order to better supportA software system for audio codec in embedded processors and mobile devices, ASOC is divided into three parts: machine, platform and codec in audio device drivers.Codec part: Responsible for audio decoding, this part of the code is completely non-platform-independent (the device is provided by the original), it contains some audio cont
To understand the Linux PCI device driver, first understand that the so-called Linux PCI device driver actually includesLinux PCI device drivers and Device Drivers. I do not know whether the reader understands this sentence. I think this sentence is very important. For drivers like PCI and USB, we must understand this concept, in order to understand how to look a
How to compile a Linux Device Driver
2006-12-10 16:52:36
LinuxIs a variant of the UNIX operating system. The principle and idea of writing a driver in Linux is similar to that in other UNIX systems, however, the drivers in the DoS or window environment differ greatly. In a Linux environment, the driver is designed with simple ideas, convenient operations, and powerful functions. However, it only supports a small number of functions and can only rely o
Development of uClinux drivers
Basic knowledge:
Kernel space ------- user space (memory application data exchange, etc)
Device ---- Device Driver ----- device No.
Driver category: character device block device network device
Interrupt handling
Driver development for uClinux and Linux is the same, but the debugging method is different. Learning driver development for uClinux is the process of learning the driver development for Linux. Linux driver debu
I have been learning device-driven programming for some time and have written several drivers. So I have a new understanding and understanding of the device driver. I have been learning device-driven programming for some time and have written several drivers. So I have a new understanding and understanding of the device driver.★What is a driver?
When I first started learning the device driver, there were a
Linux device driversOne, the role of device-drivenThe most popular explanation for device drivers is " Drive hardware Device Actions ". Drive and the underlying hardware directly to deal with, according to the specific work of the hardware device, read and write device registers, the completion of the device polling (polling (Polling) is a CPU decision how to provide peripheral equipment services, also known as "programmed output in" (programmed I/O).
The function of counting the number of words is encapsulated in the Linux driver. The Linux system maps each driver into a single file. These files are called device files or drive files and are stored in the/dev directory. The steps for writing a Linux driver are as follows:1. Build Linux drive skeleton (load and unload Linux drivers);2, registration and cancellation of equipment documents;3, specify the information related to the drive;4, specify th
Brief introduction
The name of the TTY device is abbreviated from the previous telex, originally referred to as a physical or virtual terminal connected to a UNIX system
The core of the Linux TTY driver is immediately below the standard character device driver layer and provides a range of functions that are used as interfaces by terminal type devices
There are three types of TTY drivers: console, serial, and Pty
/proc/tty
Hardware vendors usually update the device's drivers regularly, to modify bugs in older drivers, improve driver compatibility, and so on, in general, newer drivers often mean better performance and more reliable stability, which is what many friends see when a vendor publishes a new driver The main reason for the system driver to be updated immediately within the
Reprint! Adding drivers to the Android kernel is actually adding drivers to the Linux kernel. Mainly in two files add point information, one is the Kconfig file, and the other is a makefile file. For example, you add the driver of your code into the drivers directory under the XXX directory, then repair in the directory of Kconfig files and makefile files.Specifi
How do I practice writing drivers and developing BSP after I buy a development board? (Author: wogoyixikexie @ gliet)
How do I practice writing drivers and developing BSP after I buy a development board? (Author: wogoyixikexie @ gliet)
---------- A newcomer asked questions at the csdn Forum
Recently I want to buy a 2440 Development Board. To learn about embedded development of wince, I still have a few ques
car, why are they all crowded at the door?"A driver said that if he saw a suspicious person on the bus, he would shout out "Ask the passengers behind him to give a seat to the elderly or pregnant women" or "do not litter the passengers behind him ". If there are elderly people, pregnant women, or people who litter on the car, the passengers still feel quite normal. If there is no such situation, the passengers may still feel "this driver is faulty" when looking around ".In addition to these whi
Recently, I have been reading books and learning about Linux device drivers. I am getting started with the simplest character device drivers and can have a macro understanding of the driver framework and functions of various elements. The following is a detailed analysis of the device driver with the first character I have written. I will sort out some basic driver knowledge to deepen my impression. First,
1.1 In object-oriented programming, the device driver core layer and examples can define a base class for a class of similar things, and specific things can inherit the functions in this base class. If the implementation of a function of the inherited object is the same as that of the base class, it can directly inherit the functions of the base class. On the contrary, it can be overloaded. This object-oriented design method greatly improves the code reusable ability and is a good display of the
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