tools/gpio/lsgpio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * lsgpio - example on how to list the GPIO lines on a system
   4  *
   5  * Copyright (C) 2015 Linus Walleij
   6  *
   7  * Usage:
   8  *      lsgpio <-n device-name>
   9  */
  10
  11 #include <unistd.h>
  12 #include <stdlib.h>
  13 #include <stdbool.h>
  14 #include <stdio.h>
  15 #include <dirent.h>
  16 #include <errno.h>
  17 #include <string.h>
  18 #include <poll.h>
  19 #include <fcntl.h>
  20 #include <getopt.h>
  21 #include <sys/ioctl.h>
  22 #include <linux/gpio.h>
  23
  24 #include "gpio-utils.h"
  25
  26 struct gpio_flag {
  27         char *name;
  28         unsigned long long mask;
  29 };
  30
  31 struct gpio_flag flagnames[] = {
  32         {
  33                 .name = "used",
  34                 .mask = GPIO_V2_LINE_FLAG_USED,
  35         },
  36         {
  37                 .name = "input",
  38                 .mask = GPIO_V2_LINE_FLAG_INPUT,
  39         },
  40         {
  41                 .name = "output",
  42                 .mask = GPIO_V2_LINE_FLAG_OUTPUT,
  43         },
  44         {
  45                 .name = "active-low",
  46                 .mask = GPIO_V2_LINE_FLAG_ACTIVE_LOW,
  47         },
  48         {
  49                 .name = "open-drain",
  50                 .mask = GPIO_V2_LINE_FLAG_OPEN_DRAIN,
  51         },
  52         {
  53                 .name = "open-source",
  54                 .mask = GPIO_V2_LINE_FLAG_OPEN_SOURCE,
  55         },
  56         {
  57                 .name = "pull-up",
  58                 .mask = GPIO_V2_LINE_FLAG_BIAS_PULL_UP,
  59         },
  60         {
  61                 .name = "pull-down",
  62                 .mask = GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN,
  63         },
  64         {
  65                 .name = "bias-disabled",
  66                 .mask = GPIO_V2_LINE_FLAG_BIAS_DISABLED,
  67         },
  68         {
  69                 .name = "clock-realtime",
  70                 .mask = GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME,
  71         },
  72 };
  73
  74 static void print_attributes(struct gpio_v2_line_info *info)
  75 {
  76         int i;
  77         const char *field_format = "%s";
  78
  79         for (i = 0; i < ARRAY_SIZE(flagnames); i++) {
  80                 if (info->flags & flagnames[i].mask) {
  81                         fprintf(stdout, field_format, flagnames[i].name);
  82                         field_format = ", %s";
  83                 }
  84         }
  85
  86         if ((info->flags & GPIO_V2_LINE_FLAG_EDGE_RISING) &&
  87             (info->flags & GPIO_V2_LINE_FLAG_EDGE_FALLING))
  88                 fprintf(stdout, field_format, "both-edges");
  89         else if (info->flags & GPIO_V2_LINE_FLAG_EDGE_RISING)
  90                 fprintf(stdout, field_format, "rising-edge");
  91         else if (info->flags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
  92                 fprintf(stdout, field_format, "falling-edge");
  93
  94         for (i = 0; i < info->num_attrs; i++) {
  95                 if (info->attrs[i].id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE)
  96                         fprintf(stdout, ", debounce_period=%dusec",
  97                                 info->attrs[0].debounce_period_us);
  98         }
  99 }
 100
 101 int list_device(const char *device_name)
 102 {
 103         struct gpiochip_info cinfo;
 104         char *chrdev_name;
 105         int fd;
 106         int ret;
 107         int i;
 108
 109         ret = asprintf(&chrdev_name, "/dev/%s", device_name);
 110         if (ret < 0)
 111                 return -ENOMEM;
 112
 113         fd = open(chrdev_name, 0);
 114         if (fd == -1) {
 115                 ret = -errno;
 116                 fprintf(stderr, "Failed to open %s\n", chrdev_name);
 117                 goto exit_free_name;
 118         }
 119
 120         /* Inspect this GPIO chip */
 121         ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo);
 122         if (ret == -1) {
 123                 ret = -errno;
 124                 perror("Failed to issue CHIPINFO IOCTL\n");
 125                 goto exit_close_error;
 126         }
 127         fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n",
 128                 cinfo.name, cinfo.label, cinfo.lines);
 129
 130         /* Loop over the lines and print info */
 131         for (i = 0; i < cinfo.lines; i++) {
 132                 struct gpio_v2_line_info linfo;
 133
 134                 memset(&linfo, 0, sizeof(linfo));
 135                 linfo.offset = i;
 136
 137                 ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &linfo);
 138                 if (ret == -1) {
 139                         ret = -errno;
 140                         perror("Failed to issue LINEINFO IOCTL\n");
 141                         goto exit_close_error;
 142                 }
 143                 fprintf(stdout, "\tline %2d:", linfo.offset);
 144                 if (linfo.name[0])
 145                         fprintf(stdout, " \"%s\"", linfo.name);
 146                 else
 147                         fprintf(stdout, " unnamed");
 148                 if (linfo.consumer[0])
 149                         fprintf(stdout, " \"%s\"", linfo.consumer);
 150                 else
 151                         fprintf(stdout, " unused");
 152                 if (linfo.flags) {
 153                         fprintf(stdout, " [");
 154                         print_attributes(&linfo);
 155                         fprintf(stdout, "]");
 156                 }
 157                 fprintf(stdout, "\n");
 158
 159         }
 160
 161 exit_close_error:
 162         if (close(fd) == -1)
 163                 perror("Failed to close GPIO character device file");
 164 exit_free_name:
 165         free(chrdev_name);
 166         return ret;
 167 }
 168
 169 void print_usage(void)
 170 {
 171         fprintf(stderr, "Usage: lsgpio [options]...\n"
 172                 "List GPIO chips, lines and states\n"
 173                 "  -n <name>  List GPIOs on a named device\n"
 174                 "  -?         This helptext\n"
 175         );
 176 }
 177
 178 int main(int argc, char **argv)
 179 {
 180         const char *device_name = NULL;
 181         int ret;
 182         int c;
 183
 184         while ((c = getopt(argc, argv, "n:")) != -1) {
 185                 switch (c) {
 186                 case 'n':
 187                         device_name = optarg;
 188                         break;
 189                 case '?':
 190                         print_usage();
 191                         return -1;
 192                 }
 193         }
 194
 195         if (device_name)
 196                 ret = list_device(device_name);
 197         else {
 198                 const struct dirent *ent;
 199                 DIR *dp;
 200
 201                 /* List all GPIO devices one at a time */
 202                 dp = opendir("/dev");
 203                 if (!dp) {
 204                         ret = -errno;
 205                         goto error_out;
 206                 }
 207
 208                 ret = -ENOENT;
 209                 while (ent = readdir(dp), ent) {
 210                         if (check_prefix(ent->d_name, "gpiochip")) {
 211                                 ret = list_device(ent->d_name);
 212                                 if (ret)
 213                                         break;
 214                         }
 215                 }
 216
 217                 ret = 0;
 218                 if (closedir(dp) == -1) {
 219                         perror("scanning devices: Failed to close directory");
 220                         ret = -errno;
 221                 }
 222         }
 223 error_out:
 224         return ret;
 225 }