[Country EMBED strategy] [155] [I²c user-driven design]

User Mode Driver Model

The user-driven model is first an application, followed by a kernel call in the user program to drive the device.

IIC Universal Driver Code

The code for the IIC generic driver is in/DRIVERS/I2C/I2C-DEV.C. One read operation or one write operation is a message.

EEPROM User State Driver

IIC generic equipment corresponds to/dev/i2c-0 equipment files.

1. Turn on universal device driver

2. Construct a message that writes data to the EEPROM

3. Writing data using the IOCTL

4. Constructs a message that reads data from the EEPROM

5. Read data using the IOCTL

6. Turn off the device

Configuring the IIC Drive

Make Menuconfig Arch=arm

Device DRVIERS-><*>I2C SOUPPORT-><*>I2C Device interface

Device drviers-><*>i2c SOUPPORT->I2C Hardware bus support-><*>s3c2410 i²c driver

I2capp.c

/********************************************************************* Header File ************************************ *********************************/#include<stdio.h>#include<stdlib.h>#include<sys/types.h>#include<sys/stat.h>#include<fcntl.h>#include<unistd.h>#include<sys/ioctl.h>/********************************************************************* Macro Definition ************************************ *********************************/#defineI2c_rdwr 0x0707//I²c Read and write commands/********************************************************************* type definition *********************************** **********************************/typedefstructi2c_msg{unsigned ShortAddr//Device AddressUnsigned ShortFlags//read/write FlagsUnsigned ShortLen//Message LengthUnsignedChar*buf;//Message Content}iic_msg;typedefstructi2c_rdwr_ioctl_data{structI2c_msg *msgs;//Message PointersUnsignedintNMSGS;//Number of messages}iic_data;/********************************************************************* Name: main* parameter: * none* return: * none* function: main function ****** ***************************************************************/intMain () {//Open the device file    intFD; FD= Open ("/dev/i2c-0", O_RDWR); //Construct Write MessageIic_data Wrdata; Wrdata.msgs= (IIC_MSG *) malloc (1*sizeof(iic_msg)); wrdata.msgs[0].ADDR =0x50;//Note that the device address is 0b01010000, but the chip manual address is 0b10100000wrdata.msgs[0].flags =0; wrdata.msgs[0].len =2; wrdata.msgs[0].buf = (unsignedChar*) malloc (2*sizeof(unsignedChar)); wrdata.msgs[0].buf[0] =0; wrdata.msgs[0].buf[1] =123; Wrdata.nmsgs=1; //Write message dataIOCTL (FD, I2C_RDWR, (unsignedLong) (&wrdata)); printf ("Wrdata is%d\n", wrdata.msgs[0].buf[1]); //Release Write MessageFree (wrdata.msgs[0].buf);        Free (WRDATA.MSGS); //construct Read MessageIic_data Rddata; Rddata.msgs= (IIC_MSG *) malloc (2*sizeof(iic_msg)); rddata.msgs[0].ADDR =0x50; rddata.msgs[0].flags =0; rddata.msgs[0].len =1; rddata.msgs[0].buf = (unsignedChar*) malloc (1*sizeof(unsignedChar)); rddata.msgs[0].buf[0] =0; rddata.msgs[1].ADDR =0x50; rddata.msgs[1].flags =1; rddata.msgs[1].len =1; rddata.msgs[1].buf = (unsignedChar*) malloc (1*sizeof(unsignedChar)); rddata.msgs[1].buf[0] =0; Rddata.nmsgs=2; //Reading message DataIOCTL (FD, I2C_RDWR, (unsignedLong) (&rddata)); printf ("Rddata is%d\n", rddata.msgs[1].buf[0]); //releasing read messagesFree (rddata.msgs[0].buf); Free (rddata.msgs[1].buf);        Free (RDDATA.MSGS); //Close Device FilesClose (FD);}

[Country EMBED strategy] [155] [I²c user-driven design]