1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * GPIO character device helper for reading line names. 4 * 5 * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl> 6 */ 7 8 #include <fcntl.h> 9 #include <linux/gpio.h> 10 #include <stdio.h> 11 #include <stdlib.h> 12 #include <string.h> 13 #include <sys/ioctl.h> 14 #include <sys/types.h> 15 16 static void print_usage(void) 17 { 18 printf("usage:\n"); 19 printf(" gpio-line-name <chip path> <line offset>\n"); 20 } 21 22 int main(int argc, char **argv) 23 { 24 struct gpio_v2_line_info info; 25 int fd, ret; 26 char *endp; 27 28 if (argc != 3) { 29 print_usage(); 30 return EXIT_FAILURE; 31 } 32 33 fd = open(argv[1], O_RDWR); 34 if (fd < 0) { 35 perror("unable to open the GPIO chip"); 36 return EXIT_FAILURE; 37 } 38 39 memset(&info, 0, sizeof(info)); 40 info.offset = strtoul(argv[2], &endp, 10); 41 if (*endp != '\0') { 42 print_usage(); 43 return EXIT_FAILURE; 44 } 45 46 ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &info); 47 if (ret) { 48 perror("line info ioctl failed"); 49 return EXIT_FAILURE; 50 } 51 52 printf("%s\n", info.name); 53 54 return EXIT_SUCCESS; 55 } 56