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111 lines
2.0 KiB
C
111 lines
2.0 KiB
C
// Gerardo Marx 24/09/2026
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// gpio command tool
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// eg. ./gpio 17 out 1
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// ./gpio 17 in
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// ./gpio 17 blink 500(ms)
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <string.h>
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// prototype functions
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int gpio_export(const char *gpio);
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int gpio_direction(const char *gpio, const char *direction); // this function
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int gpio_write(int gpio, int value);
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int main(int argc, char *argv[]){
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int fd;
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const char *pin = argv[1]; // get gpio number from argument
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const char *dir = argv[2]; // get gpio direction from arguments
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//
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gpio_export(pin);
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gpio_direction(pin, dir);
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// pin value to 1
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fd = open("/sys/class/gpio/chip0/gpio17/value", O_WRONLY);
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if(fd<0)
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{
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perror("Error opening the GPIO path");
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return -1;
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}
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write(fd,"1",1);
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close(fd);
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sleep(1);
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// pin valu to 0
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fd = open("/sys/class/gpio/chip0/gpio17/value", O_WRONLY);
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if(fd<0)
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{
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perror("Error opening the GPIO path");
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return -1;
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}
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write(fd,"0",1);
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close(fd);
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sleep(1);
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// unexport
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fd = open("/sys/class/gpio/chip0/unexport", O_WRONLY);
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if(fd<0)
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{
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perror("Error opening the GPIO path");
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return -1;
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}
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write(fd,"17",2);
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close(fd);
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printf("Hello from Raspberry Pi!\n");
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printf("Number of arguments: %d\n", argc);
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printf("Program is reciving: %s\n", argv[0]);
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if(argc > 1 )
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printf("Argument: %s\n", argv[1]);
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return 0;
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}
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// comple functions
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//
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// gpio_export
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int gpio_export(const char *gpio){
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int fd;
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fd = open("/sys/class/gpio/chip0/export", O_WRONLY);
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if(fd<0){
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perror("Error opening the GPIO path");
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return -1;
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}
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write(fd,gpio,strlen(gpio));
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close(fd);
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return 0;
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}
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// gpio direction
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int gpio_direction(const char *gpio, const char *direction){
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// pin direction - convert into functions
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int fd;
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char path[64];
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snprintf(path, sizeof(path),
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"/sys/class/gpio/chip0/gpio%s/direction", gpio);
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fd = open(path, O_WRONLY); //gpio number
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if(fd<0)
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{
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perror("Error opening the GPIO path");
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return -1;
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}
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write(fd,direction,strlen(direction));
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close(fd);
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return 0;
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}
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