diff options
Diffstat (limited to 'tools/gpio/lsgpio.c')
| -rw-r--r-- | tools/gpio/lsgpio.c | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/tools/gpio/lsgpio.c b/tools/gpio/lsgpio.c new file mode 100644 index 000000000000..1124da375942 --- /dev/null +++ b/tools/gpio/lsgpio.c @@ -0,0 +1,195 @@ +/* + * lsgpio - example on how to list the GPIO lines on a system + * + * Copyright (C) 2015 Linus Walleij + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * Usage: + * lsgpio <-n device-name> + */ + +#include <unistd.h> +#include <stdlib.h> +#include <stdbool.h> +#include <stdio.h> +#include <dirent.h> +#include <errno.h> +#include <string.h> +#include <poll.h> +#include <fcntl.h> +#include <getopt.h> +#include <sys/ioctl.h> +#include <linux/gpio.h> + +#include "gpio-utils.h" + +struct gpio_flag { + char *name; + unsigned long mask; +}; + +struct gpio_flag flagnames[] = { + { + .name = "kernel", + .mask = GPIOLINE_FLAG_KERNEL, + }, + { + .name = "output", + .mask = GPIOLINE_FLAG_IS_OUT, + }, + { + .name = "active-low", + .mask = GPIOLINE_FLAG_ACTIVE_LOW, + }, + { + .name = "open-drain", + .mask = GPIOLINE_FLAG_OPEN_DRAIN, + }, + { + .name = "open-source", + .mask = GPIOLINE_FLAG_OPEN_SOURCE, + }, +}; + +void print_flags(unsigned long flags) +{ + int i; + int printed = 0; + + for (i = 0; i < ARRAY_SIZE(flagnames); i++) { + if (flags & flagnames[i].mask) { + if (printed) + fprintf(stdout, " "); + fprintf(stdout, "%s", flagnames[i].name); + printed++; + } + } +} + +int list_device(const char *device_name) +{ + struct gpiochip_info cinfo; + char *chrdev_name; + int fd; + int ret; + int i; + + ret = asprintf(&chrdev_name, "/dev/%s", device_name); + if (ret < 0) + return -ENOMEM; + + fd = open(chrdev_name, 0); + if (fd == -1) { + ret = -errno; + fprintf(stderr, "Failed to open %s\n", chrdev_name); + goto exit_close_error; + } + + /* Inspect this GPIO chip */ + ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo); + if (ret == -1) { + ret = -errno; + perror("Failed to issue CHIPINFO IOCTL\n"); + goto exit_close_error; + } + fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n", + cinfo.name, cinfo.label, cinfo.lines); + + /* Loop over the lines and print info */ + for (i = 0; i < cinfo.lines; i++) { + struct gpioline_info linfo; + + memset(&linfo, 0, sizeof(linfo)); + linfo.line_offset = i; + + ret = ioctl(fd, GPIO_GET_LINEINFO_IOCTL, &linfo); + if (ret == -1) { + ret = -errno; + perror("Failed to issue LINEINFO IOCTL\n"); + goto exit_close_error; + } + fprintf(stdout, "\tline %2d:", linfo.line_offset); + if (linfo.name[0]) + fprintf(stdout, " \"%s\"", linfo.name); + else + fprintf(stdout, " unnamed"); + if (linfo.consumer[0]) + fprintf(stdout, " \"%s\"", linfo.consumer); + else + fprintf(stdout, " unused"); + if (linfo.flags) { + fprintf(stdout, " ["); + print_flags(linfo.flags); + fprintf(stdout, "]"); + } + fprintf(stdout, "\n"); + + } + +exit_close_error: + if (close(fd) == -1) + perror("Failed to close GPIO character device file"); + free(chrdev_name); + return ret; +} + +void print_usage(void) +{ + fprintf(stderr, "Usage: lsgpio [options]...\n" + "List GPIO chips, lines and states\n" + " -n <name> List GPIOs on a named device\n" + " -? This helptext\n" + ); +} + +int main(int argc, char **argv) +{ + const char *device_name; + int ret; + int c; + + while ((c = getopt(argc, argv, "n:")) != -1) { + switch (c) { + case 'n': + device_name = optarg; + break; + case '?': + print_usage(); + return -1; + } + } + + if (device_name) + ret = list_device(device_name); + else { + const struct dirent *ent; + DIR *dp; + + /* List all GPIO devices one at a time */ + dp = opendir("/dev"); + if (!dp) { + ret = -errno; + goto error_out; + } + + ret = -ENOENT; + while (ent = readdir(dp), ent) { + if (check_prefix(ent->d_name, "gpiochip")) { + ret = list_device(ent->d_name); + if (ret) + break; + } + } + + ret = 0; + if (closedir(dp) == -1) { + perror("scanning devices: Failed to close directory"); + ret = -errno; + } + } +error_out: + return ret; +} |