// SPDX-License-Identifier: GPL-2.0-or-later /* * GPIO character device helper for reading chip information. * * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl> */ #include <fcntl.h> #include <linux/gpio.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/ioctl.h> #include <sys/types.h> static void print_usage(void) { printf("usage:\n"); printf(" gpio-chip-info <chip path> [name|label|num-lines]\n"); } int main(int argc, char **argv) { struct gpiochip_info info; int fd, ret; if (argc != 3) { print_usage(); return EXIT_FAILURE; } fd = open(argv[1], O_RDWR); if (fd < 0) { perror("unable to open the GPIO chip"); return EXIT_FAILURE; } memset(&info, 0, sizeof(info)); ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &info); if (ret) { perror("chip info ioctl failed"); return EXIT_FAILURE; } if (strcmp(argv[2], "name") == 0) { printf("%s\n", info.name); } else if (strcmp(argv[2], "label") == 0) { printf("%s\n", info.label); } else if (strcmp(argv[2], "num-lines") == 0) { printf("%u\n", info.lines); } else { fprintf(stderr, "unknown command: %s\n", argv[2]); return EXIT_FAILURE; } return EXIT_SUCCESS; }