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#include <stdio.h>
#include <getopt.h>
#include <sys/io.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <stdint.h>
#define GPIO_BASE 0x48
#define GP_LVL 0x0c
#define GP_LVL2 0x38
#define GP_LVL3 0x48
#define MAX_GPIO_NUMBER 75
#define LPC_DEV_CONFIG "/sys/bus/pci/devices/0000:00:1f.0/config"
void usage(const char *name)
{
printf("usage: %s OPTIONS\n", name);
printf("Options:\n"
" -h: Print this help\n"
" -n: GPIO pin number\n");
}
int get_gpio(int base, int num)
{
static const int gpio_reg_offsets[] = {GP_LVL, GP_LVL2, GP_LVL3};
int index, bit;
index = num / 32;
bit = num % 32;
return (inl(base + gpio_reg_offsets[index]) >> bit) & 1;
}
int main(int argc, char *argv[])
{
int c;
int num = -1;
uint16_t base;
while ((c = getopt(argc, argv, "hn:")) != -1) {
switch (c) {
case 'h':
usage(argv[0]);
return 0;
case 'n':
num = strtoul(optarg, NULL, 10);
if (num > MAX_GPIO_NUMBER) {
fprintf(stderr, "error: invalid number\n");
return 1;
}
break;
case '?':
return -1;
}
}
if (num == -1) {
usage(argv[0]);
return 0;
}
if (geteuid() != 0) {
fprintf(stderr, "error: you must be root\n");
return 1;
}
FILE *f = fopen(LPC_DEV_CONFIG, "r");
if (!f) {
fprintf(stderr, "failed to open %s: %s\n", LPC_DEV_CONFIG, strerror(errno));
return 1;
}
fseek(f, GPIO_BASE, SEEK_SET);
size_t readed = fread(&base, 2, 1, f);
fclose(f);
if (readed < 1) {
fprintf(stderr, "error: readed %lu bytes\n", readed);
return 1;
}
base &= 0xfffe;
if (ioperm(base, 0x100, 1)) {
fprintf(stderr, "ioperm: %s\n", strerror(errno));
exit(1);
}
int val = get_gpio(base, num);
printf("%d\n", val);
return 0;
}
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