应用上i2c通过调用ioctl来读写设备

1. 简介

     在应用上通过ioctl来读写i2c设备

2. 结构体

 （1） i2c_msg结构体

/*
 * I2C Message - used for pure i2c transaction, also from /dev interface
 */
struct i2c_msg {
	__u16 addr;	/* slave address			*/
	unsigned short flags;
#define I2C_M_TEN	0x10	/* we have a ten bit chip address	*/
#define I2C_M_RD	0x01
#define I2C_M_NOSTART	0x4000
#define I2C_M_REV_DIR_ADDR	0x2000
#define I2C_M_IGNORE_NAK	0x1000
#define I2C_M_NO_RD_ACK		0x0800
	short len;		/* msg length				*/
	char *buf;		/* pointer to msg data			*/
};

（2） i2c_rdwr_ioctl_data结构体

/* This is the structure as used in the I2C_RDWR ioctl call */
struct i2c_rdwr_ioctl_data {
	struct i2c_msg *msgs;	/* pointers to i2c_msgs */
	__u32 nmsgs;			/* number of i2c_msgs */
};

3. 代码

#include<stdio.h>
#include<linux/types