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controls.tsx
findpowermate.c 1.14 KiB
#include <linux/input.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include "findpowermate.h"
#define NUM_VALID_PREFIXES 2
static const char *valid_prefix[NUM_VALID_PREFIXES] = {
"Griffin PowerMate",
"Griffin SoundKnob"
};
#define NUM_EVENT_DEVICES 16
int open_powermate(const char *dev, int mode)
{
int fd = open(dev, mode);
int i;
char name[255];
if(fd < 0){
fprintf(stderr, "Unable to open \"%s\": %s\n", dev, strerror(errno));
return -1;
}
if(ioctl(fd, EVIOCGNAME(sizeof(name)), name) < 0){
fprintf(stderr, "\"%s\": EVIOCGNAME failed: %s\n", dev, strerror(errno));
close(fd);
return -1;
}
// it's the correct device if the prefix matches what we expect it to be:
for(i=0; i<NUM_VALID_PREFIXES; i++)
if(!strncasecmp(name, valid_prefix[i], strlen(valid_prefix[i])))
return fd;
close(fd);
return -1;
}
int find_powermate(int mode)
{
char devname[256];
int i, r;
for(i=0; i<NUM_EVENT_DEVICES; i++){
sprintf(devname, "/dev/input/event%d", i);
r = open_powermate(devname, mode);
if(r >= 0)
return r;
}
return -1;
}