| 1 | /* |
| 2 | * lsgpio - example on how to list the GPIO lines on a system |
| 3 | * |
| 4 | * Copyright (C) 2015 Linus Walleij |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify it |
| 7 | * under the terms of the GNU General Public License version 2 as published by |
| 8 | * the Free Software Foundation. |
| 9 | * |
| 10 | * Usage: |
| 11 | * lsgpio <-n device-name> |
| 12 | */ |
| 13 | |
| 14 | #include <unistd.h> |
| 15 | #include <stdlib.h> |
| 16 | #include <stdbool.h> |
| 17 | #include <stdio.h> |
| 18 | #include <dirent.h> |
| 19 | #include <errno.h> |
| 20 | #include <string.h> |
| 21 | #include <poll.h> |
| 22 | #include <fcntl.h> |
| 23 | #include <getopt.h> |
| 24 | #include <sys/ioctl.h> |
| 25 | #include <linux/gpio.h> |
| 26 | |
| 27 | #include "gpio-utils.h" |
| 28 | |
| 29 | int list_device(const char *device_name) |
| 30 | { |
| 31 | struct gpiochip_info cinfo; |
| 32 | char *chrdev_name; |
| 33 | int fd; |
| 34 | int ret; |
| 35 | |
| 36 | ret = asprintf(&chrdev_name, "/dev/%s", device_name); |
| 37 | if (ret < 0) |
| 38 | return -ENOMEM; |
| 39 | |
| 40 | fd = open(chrdev_name, 0); |
| 41 | if (fd == -1) { |
| 42 | ret = -errno; |
| 43 | fprintf(stderr, "Failed to open %s\n", chrdev_name); |
| 44 | goto free_chrdev_name; |
| 45 | } |
| 46 | |
| 47 | /* Inspect this GPIO chip */ |
| 48 | ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo); |
| 49 | if (ret == -1) { |
| 50 | ret = -errno; |
| 51 | fprintf(stderr, "Failed to retrieve GPIO fd\n"); |
| 52 | if (close(fd) == -1) |
| 53 | perror("Failed to close GPIO character device file"); |
| 54 | |
| 55 | goto free_chrdev_name; |
| 56 | } |
| 57 | fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n", |
| 58 | cinfo.name, cinfo.label, cinfo.lines); |
| 59 | |
| 60 | if (close(fd) == -1) { |
| 61 | ret = -errno; |
| 62 | goto free_chrdev_name; |
| 63 | } |
| 64 | |
| 65 | free_chrdev_name: |
| 66 | free(chrdev_name); |
| 67 | |
| 68 | return ret; |
| 69 | |
| 70 | } |
| 71 | |
| 72 | void print_usage(void) |
| 73 | { |
| 74 | fprintf(stderr, "Usage: lsgpio [options]...\n" |
| 75 | "List GPIO chips, lines and states\n" |
| 76 | " -n <name> List GPIOs on a named device\n" |
| 77 | " -? This helptext\n" |
| 78 | ); |
| 79 | } |
| 80 | |
| 81 | int main(int argc, char **argv) |
| 82 | { |
| 83 | const char *device_name; |
| 84 | int ret; |
| 85 | int c; |
| 86 | |
| 87 | while ((c = getopt(argc, argv, "n:")) != -1) { |
| 88 | switch (c) { |
| 89 | case 'n': |
| 90 | device_name = optarg; |
| 91 | break; |
| 92 | case '?': |
| 93 | print_usage(); |
| 94 | return -1; |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | if (device_name) |
| 99 | ret = list_device(device_name); |
| 100 | else { |
| 101 | const struct dirent *ent; |
| 102 | DIR *dp; |
| 103 | |
| 104 | /* List all GPIO devices one at a time */ |
| 105 | dp = opendir("/dev"); |
| 106 | if (!dp) { |
| 107 | ret = -errno; |
| 108 | goto error_out; |
| 109 | } |
| 110 | |
| 111 | ret = -ENOENT; |
| 112 | while (ent = readdir(dp), ent) { |
| 113 | if (check_prefix(ent->d_name, "gpiochip")) { |
| 114 | ret = list_device(ent->d_name); |
| 115 | if (ret) |
| 116 | break; |
| 117 | } |
| 118 | } |
| 119 | |
| 120 | ret = 0; |
| 121 | if (closedir(dp) == -1) { |
| 122 | perror("scanning devices: Failed to close directory"); |
| 123 | ret = -errno; |
| 124 | } |
| 125 | } |
| 126 | error_out: |
| 127 | return ret; |
| 128 | } |