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
 26struct gpio_flag {
 27	char *name;
 28	unsigned long long mask;
 29};
 30
 31struct 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
 74static 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[i].debounce_period_us);
 98	}
 99}
100
101int 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
161exit_close_error:
162	if (close(fd) == -1)
163		perror("Failed to close GPIO character device file");
164exit_free_name:
165	free(chrdev_name);
166	return ret;
167}
168
169void 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
178int 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	}
223error_out:
224	return ret;
225}