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/* The Great I2C Getter.
*
* (C)opyright 2008-2014 Matthew Kern
* Full license terms in file LICENSE
*/
#ifdef I2CBUILD
#include <stdio.h>
#include "i2c-dev.h"//use ours 'cuz it's betterer.
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
//Ideas (but not too much actual code) taken from i2c-tools. Thanks guys.
extern int quiet;
#define display(...) if (quiet == 0) { fprintf(stderr, __VA_ARGS__); }
int open_i2c_dev(int i2cbus) {
int i2cfile;
char filename[16];
unsigned long funcs;
sprintf(filename, "/dev/i2c-%d", i2cbus);
i2cfile = open(filename, O_RDWR);
if (i2cfile < 0 && errno == ENOENT) {
filename[8] = '/';
i2cfile = open(filename, O_RDWR);
}
if (errno == EACCES) {
display("Permission denied opening i2c. Run as root!\n");
i2cfile = -2;
}
if (i2cfile >=0) {
if (ioctl(i2cfile, I2C_FUNCS, &funcs) < 0) {
if (quiet==0) { perror("ioctl I2C_FUNCS"); }
i2cfile=-3;
}
if (!(funcs & (I2C_FUNC_SMBUS_READ_BYTE_DATA))) {
display("No byte reading on this bus...\n");
i2cfile=-4;
}
if (ioctl(i2cfile, I2C_SLAVE, 0x50) < 0) {
if (quiet==0) {perror("Problem requesting slave address");}
i2cfile=-5;
}
}
return i2cfile;
}
int i2cmain( int bus, int qit ) {
int i, j, ret, len, numbusses=0, tryonly=-1, i2cfile, i2cbus=0;
int goodbus[128];
unsigned char block[256];
quiet = qit;
if (bus==-1) {
for (i2cfile = open_i2c_dev(i2cbus);i2cfile >= 0 || i2cfile < -3;) {
//read a byte. This is the official way to scan
if (i2cfile < -3) //problem with a bus, not general enough. Skip and close.
goto endloop;
ret = i2c_smbus_read_byte_data(i2cfile, 0);
if (ret < 0) {
display("No EDID on bus %i\n", i2cbus);
}
else {
goodbus[numbusses] = i2cbus;
numbusses++;
}
endloop:
close(i2cfile);
i2cbus++;
i2cfile = open_i2c_dev(i2cbus);
}
if (i2cfile == -2) {
return 1;
}
if (numbusses == 0) {
display("Looks like no busses have an EDID. Sorry!\n");
return 2;
}
display("%i potential busses found:", numbusses);
for (i=0;i<numbusses;i++)
display(" %i", goodbus[i]);
display("\n");
if (numbusses > 1) {
if (bus == -1)
display("Will scan through until the first EDID is found.\nPass a bus number as an option to this program to go only for that one.\n");
}
}
else {
tryonly = bus;
numbusses=1;
display("Only trying %i as per your request.\n", tryonly);
}
ret=1;
for (i=0;i<numbusses;i++) {
i2cbus = goodbus[i];
if (tryonly >= 0) {
i2cbus = tryonly;
}
i2cfile = open_i2c_dev(i2cbus);
if (i2cfile >=0) {//no matter how many times, >=0 still looks really angry.
for (j=0;j<256;j++)
block[j] = i2c_smbus_read_byte_data(i2cfile, j);
}
close(i2cfile);
if (block[0]==0x00&&block[7]==0x00&&block[1]==0xff&&block[2]==0xff&&block[3]==0xff&&block[4]==0xff&&block[5]==0xff&&block[6]==0xff) {
ret = 0;
break;
}
else
display("Bus %i doesn't really have an EDID...\n", i2cbus);
}
if (ret==0) {
if (block[128] == 0xff)
len = 128;
else
len = 256;
display("%i-byte EDID successfully retrieved from i2c bus %i\n", len, i2cbus);
if (i2cbus < (numbusses-1))
display("If this isn't the EDID you were looking for, consider the other potential busses.\n");
for (i=0;i<len;i++) {
printf("%c", block[i]);
}
}
else {
display("Couldn't find an accessible EDID on this %s.\n", (tryonly==-1)?"computer":"bus");
return 3;
}
return 0;
}
#endif
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