How to view an I2C device through a device node

Look at the datasheet of the chip, and then look at the hardware circuit diagram or ask the hardware designer the address pin configuration of the chip, because the address of the I2C device is fixed and some can be configured.

The I2C (Inter Integrated Circuit) bus is a two-wire serial bus developed by Philips to connect microcontrollers and their peripherals. The I2C bus was created in the 80's and was originally developed for audio and ** devices, and today it is mainly used in server management, which includes the communication of the state of individual components. For example, administrators can query individual components to manage the configuration of the system or to grasp the functional status of components, such as power supplies and system fans.

Multiple parameters such as memory, hard disk, network, and system temperature can be monitored at any time, which increases the security of the system and facilitates management.

Consult the data sheet for this device.

Each I2C device will solidify its own I2C address when it leaves the factory, and there is also a file search to select the I2C address through hardware guidance; Moreover, the I2C device has an MCU inside, which can identify the signal on the bus and make corresponding lead removal according to the signal; After receiving the address bit on the bus, it will compare it with its own address, and once it is the same, it will send a response signal;

In short, the MCU inside the I2C device knows its own address, which is the I2C specification.

Everyone may know this problem, but the understanding may not be very profound, and I only understood it after I wrote a driver myself. The driver is shielded to the details of the underlying device, for example, the keyboard driver, when QT opens the device node of the keyboard, it doesn't know what the keyboard of the system is, it is GPIO connected, it is connected to the I2C bus, it doesn't know the ,..

Suppose I have a development board bought from **, and I want to add a slave device (such as AT24C08) to the I2C bus of the development board, so how do I write this "I2C Device Driver" so that the application can access AT24C08? Let's start with the simplest I2C device driver: static struct i2c board info at24cxx info = .

Normally, it should be done by the driver.

The dev directory has an I2C device, which can be read through interface functions such as read write, which is equivalent to manipulating a file.