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298 lines
8.3 KiB
298 lines
8.3 KiB
/*
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This program is hereby placed into the public domain.
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Of course the program is provided without warranty of any kind.
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*/
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#include <sys/ioctl.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <string.h>
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#include <time.h>
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#include <linux/i2c-dev.h>
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/*
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this program can read 24C16 (and probably smaller ones, too)
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I wrote it as a quick and dirty hack because my satellite receiver
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hung again... so I had to reprogram the eeprom where is stores it's
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settings.
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*/
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#define DEFAULT_I2C_BUS "/dev/i2c-0"
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#define DEFAULT_EEPROM_ADDR 0x50 /* the 24C16 sits on i2c address 0x50 */
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#define DEFAULT_NUM_PAGES 8 /* we default to a 24C16 eeprom which has 8 pages */
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#define BYTES_PER_PAGE 256 /* one eeprom page is 256 byte */
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#define MAX_BYTES 8 /* max number of bytes to write in one chunk */
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/* ... note: 24C02 and 24C01 only allow 8 bytes to be written in one chunk. *
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* if you are going to write 24C04,8,16 you can change this to 16 */
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/* write len bytes (stored in buf) to eeprom at address addr, page-offset offset */
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/* if len=0 (buf may be NULL in this case) you can reposition the eeprom's read-pointer */
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/* return 0 on success, -1 on failure */
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int eeprom_write(int fd,
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unsigned int addr,
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unsigned int offset,
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unsigned char *buf,
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unsigned char len
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){
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struct i2c_rdwr_ioctl_data msg_rdwr;
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struct i2c_msg i2cmsg;
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int i;
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char _buf[MAX_BYTES + 1];
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if(len>MAX_BYTES){
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fprintf(stderr,"I can only write MAX_BYTES bytes at a time!\n");
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return -1;
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}
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if(len+offset >256){
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fprintf(stderr,"Sorry, len(%d)+offset(%d) > 256 (page boundary)\n",
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len,offset);
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return -1;
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}
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_buf[0]=offset; /* _buf[0] is the offset into the eeprom page! */
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for(i=0;i<len;i++) /* copy buf[0..n] -> _buf[1..n+1] */
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_buf[1+i]=buf[i];
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msg_rdwr.msgs = &i2cmsg;
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msg_rdwr.nmsgs = 1;
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i2cmsg.addr = addr;
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i2cmsg.flags = 0;
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i2cmsg.len = 1+len;
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i2cmsg.buf = _buf;
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if((i=ioctl(fd,I2C_RDWR,&msg_rdwr))<0){
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perror("ioctl()");
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fprintf(stderr,"ioctl returned %d\n",i);
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return -1;
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}
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if(len>0)
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fprintf(stderr,"Wrote %d bytes to eeprom at 0x%02x, offset %08x\n",
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len,addr,offset);
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else
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fprintf(stderr,"Positioned pointer in eeprom at 0x%02x to offset %08x\n",
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addr,offset);
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return 0;
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}
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/* read len bytes stored in eeprom at address addr, offset offset in array buf */
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/* return -1 on error, 0 on success */
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int eeprom_read(int fd,
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unsigned int addr,
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unsigned int offset,
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unsigned char *buf,
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unsigned char len
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){
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struct i2c_rdwr_ioctl_data msg_rdwr;
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struct i2c_msg i2cmsg;
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int i;
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if(len>MAX_BYTES){
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fprintf(stderr,"I can only write MAX_BYTES bytes at a time!\n");
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return -1;
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}
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if(eeprom_write(fd,addr,offset,NULL,0)<0)
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return -1;
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msg_rdwr.msgs = &i2cmsg;
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msg_rdwr.nmsgs = 1;
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i2cmsg.addr = addr;
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i2cmsg.flags = I2C_M_RD;
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i2cmsg.len = len;
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i2cmsg.buf = buf;
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if((i=ioctl(fd,I2C_RDWR,&msg_rdwr))<0){
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perror("ioctl()");
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fprintf(stderr,"ioctl returned %d\n",i);
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return -1;
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}
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fprintf(stderr,"Read %d bytes from eeprom at 0x%02x, offset %08x\n",
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len,addr,offset);
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return 0;
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}
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int main(int argc, char **argv){
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int i,j;
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/* filedescriptor and name of device */
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int d;
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char *dn=DEFAULT_I2C_BUS;
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/* filedescriptor and name of data file */
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int f=-1;
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char *fn=NULL;
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unsigned int addr=DEFAULT_EEPROM_ADDR;
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int rwmode=0;
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int pages=DEFAULT_NUM_PAGES;
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int force=0; /* suppress warning on write! */
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while((i=getopt(argc,argv,"d:a:p:wyf:h"))>=0){
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switch(i){
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case 'h':
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fprintf(stderr,"%s [-d dev] [-a adr] [-p pgs] [-w] [-y] [-f file]\n",argv[0]);
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fprintf(stderr,"\tdev: device, e.g. /dev/i2c-0 (def)\n");
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fprintf(stderr,"\tadr: base address of eeprom, eg 0xA0 (def)\n");
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fprintf(stderr,"\tpgs: number of pages to read, eg 8 (def)\n");
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fprintf(stderr,"\t-w : write to eeprom (default is reading!)\n");
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fprintf(stderr,"\t-y : suppress warning when writing (default is to warn!)\n");
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fprintf(stderr,"\t-f file: copy eeprom contents to/from file\n");
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fprintf(stderr,"\t (default for read is test only; for write is all zeros)\n");
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fprintf(stderr,"Note on pages/addresses:\n");
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fprintf(stderr,"\teeproms with more than 256 byte appear as if they\n");
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fprintf(stderr,"\twere several eeproms with consecutive addresses on the bus\n");
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fprintf(stderr,"\tso we might as well address several separate eeproms with\n");
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fprintf(stderr,"\tincreasing addresses....\n\n");
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exit(1);
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break;
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case 'd':
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dn=optarg;
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break;
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case 'a':
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if(sscanf(optarg,"0x%x",&addr)!=1){
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fprintf(stderr,"Cannot parse '%s' as addrs., example: 0xa0\n",
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optarg);
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exit(1);
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}
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break;
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case 'p':
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if(sscanf(optarg,"%d",&pages)!=1){
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fprintf(stderr,"Cannot parse '%s' as number of pages, example: 8\n",
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optarg);
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exit(1);
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}
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break;
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case 'w':
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rwmode++;
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break;
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case 'f':
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fn=optarg;
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break;
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case 'y':
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force++;
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break;
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}
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}
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fprintf(stderr,"base-address of eeproms : 0x%02x\n",addr);
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fprintf(stderr,"number of pages to read : %d (0x%02x .. 0x%02x)\n",
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pages,addr,addr+pages-1);
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if(fn){
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if(!rwmode) /* if we are reading, *WRITE* to file */
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f=open(fn,O_WRONLY|O_CREAT,0666);
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else /* if we are writing to eeprom, *READ* from file */
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f=open(fn,O_RDONLY);
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if(f<0){
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fprintf(stderr,"Could not open data-file %s for reading or writing\n",fn);
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perror(fn);
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exit(1);
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}
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fprintf(stderr,"file opened for %7s : %s\n",rwmode?"reading":"writing",fn);
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fprintf(stderr," on filedescriptor : %d\n",f);
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}
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if((d=open(dn,O_RDWR))<0){
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fprintf(stderr,"Could not open i2c at %s\n",dn);
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perror(dn);
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exit(1);
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}
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fprintf(stderr,"i2c-devicenode is : %s\n",dn);
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fprintf(stderr," on filedescriptor : %d\n\n",d);
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/***
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*** I'm not the one to blame of you screw your computer!
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***/
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if(rwmode && ! force){
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unsigned char warnbuf[4];
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fprintf(stderr,"**WARNING**\n");
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fprintf(stderr," - \tYou have chosen to WRITE to this eeprom.\n");
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fprintf(stderr,"\tMake sure that this tiny chip is *NOT* vital to the\n");
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fprintf(stderr,"\toperation of your computer as you can easily corrupt\n");
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fprintf(stderr,"\tthe configuration memory of your SDRAM-memory-module,\n");
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fprintf(stderr,"\tyour IBM ThinkPad or whatnot...! Fixing these errors can be\n");
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fprintf(stderr,"\ta time-consuming and very costly process!\n\n");
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fprintf(stderr,"Things to consider:\n");
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fprintf(stderr," - \tYou can have more than one i2c-bus, check in /proc/bus/i2c\n");
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fprintf(stderr,"\tand specify the correct one with -d\n");
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fprintf(stderr,"\tright now you have chosen to use '%s'\n",dn);
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fprintf(stderr," - \tA eeprom can occupy several i2c-addresses (one per page)\n");
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fprintf(stderr,"\tso please make sure that there is no vital eeprom in your computer\n");
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fprintf(stderr,"\tsitting at addresses between 0x%02x and 0x%02x\n",addr,addr+pages-1);
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fprintf(stderr,"Enter 'yes' to continue:");
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fflush(stderr);
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if(!fgets(warnbuf,sizeof(warnbuf),stdin)){
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fprintf(stderr,"\nCould not read confirmation from stdin!\n");
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exit(1);
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}
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if(strncmp(warnbuf,"yes",3)){
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fprintf(stderr,"\n** ABORTING WRITE! **, you did not answer 'yes'\n");
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exit(1);
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}
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}
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for(i=0;i<pages;i++){
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unsigned char buf[BYTES_PER_PAGE];
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if(rwmode){
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if(f>=0){
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j=read(f,buf,sizeof(buf));
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if(j<0){
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fprintf(stderr,"Cannot read from file '%s'\n",fn);
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perror(fn);
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exit(1);
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}
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if(j!=sizeof(buf)){
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fprintf(stderr,"File '%s' is too small, padding eeprom with zeroes\n",fn);
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while(j<sizeof(buf))
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buf[j++]=0;
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}
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} else {
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for(j=0;j<sizeof(buf);j++)
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buf[j]=0;
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}
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for(j=0;j<(BYTES_PER_PAGE/MAX_BYTES);j++)
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if(eeprom_write(d,addr+i,j*MAX_BYTES,buf+(j*MAX_BYTES),MAX_BYTES)<0)
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exit(1);
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} else {
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for(j=0;j<(BYTES_PER_PAGE/MAX_BYTES);j++)
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if(eeprom_read(d,addr+i,j*MAX_BYTES,buf+(j*MAX_BYTES),MAX_BYTES)<0)
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exit(1);
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}
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if(!rwmode && f>=0){
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j=write(f,buf,sizeof(buf));
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if(j!=sizeof(buf)){
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fprintf(stderr,"Cannot write to file '%s'\n",fn);
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perror(fn);
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exit(1);
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}
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}
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}
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if(f>=0)
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close(f);
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close(d);
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exit(0);
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}
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