I2C总线EEPROM实现

今天实现了一下I2C总线的EEPROM。。

开发板是fl2440板子。。跑的Linux3.0内核

这里的EEPROM只是初步的实现。。并没有具体的分析函数。。以后会具体的分析。。

1.修改内核

改make menuconfig

Device Drivers --->

<*> I2C support --->

--- I2C support

[*] Enable compatibility bits for old user-space

<*> I2C device interface

< > I2C bus multiplexing support

[ ] Autoselect pertinent helper modules

<*> SMBus-specific protocols

I2C Algorithms --->

I2C Hardware Bus support --->

[ ] I2C Core debugging messages

[ ] I2C Algorithm debugging messages

[ ] I2C Bus debugging messages

[*] Misc devices --->

EEPROM support --->

<*> I2C EEPROMs from most vendors

<*> SPI EEPROMs from most vendors

<M> Old I2C EEPROM reader

< > Maxim MAX6874/5 power supply supervisor

<*> EEPROM 93CX6 support

2.改arch/arm/mach-s3c2440/mach-smdk2440.c

添加

/*add 24c02 device*/

static struct at24_platform_data at24c02 = {

.byte_len = SZ_2K / 8,

.page_size = 8,

.flags = 0,

};

static struct i2c_board_info __initdata smdk_i2c_devices[] = {

{

I2C_BOARD_INFO("24c02", 0x50),

.platform_data = &at24c02,

},

};

/* add 24c02 end */

并在smdk2440_machine_init中添加

i2c_register_board_info(0, smdk_i2c_devices, ARRAY_SIZE(smdk_i2c_devices));

这样从新编译内核就可以实现eeprom了。。该文件在/sys/devices/platform/s3c2440-i2c/i2c-0/0-0050/eeprom

下面给出一个应用程序。。

#include<stdio.h>

#include<string.h>

#include<unistd.h>

#include<sys/ioctl.h>

#include<stdlib.h>

#include<fcntl.h>

#include<sys/io.h>

int main (int argc, char **argv[])

{

int fd;

int i;

int ret;

char read_data[256];

fd = open("/sys/devices/platform/s3c2440-i2c/i2c-0/0-0050/eeprom", O_RDWR);

if(fd < 0)

{

printf ("open 24c02 fail\n");

return -1;

}

lseek(fd, 0, SEEK_SET); //point the head of eeprom

ret = read(fd, read_data, 256);

if(ret < 0)

{

printf("read error\n");

return -1;

}

else if(ret < 256)

{

perror("incomplete read\n");

printf("%d\n", ret);

return -1;

}

for(i = 0; i < 256; i++)

{

if(i % 16 == 0)

{

printf("\n");

}

printf("%03d ", read_data[i]);

}

printf("\n");

return 0;

}

这样在我们的开发板上就可以运行出来了。。