LXR linux/tools/gpio/gpio-hammer.c

   1/*
   2 * gpio-hammer - example swiss army knife to shake GPIO lines on a system
   3 *
   4 * Copyright (C) 2016 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 *      gpio-hammer -n <device-name> -o <offset1> -o <offset2>
  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#include "gpio-utils.h"
  27
  28int hammer_device(const char *device_name, unsigned int *lines, int nlines,
  29                  unsigned int loops)
  30{
  31        struct gpiohandle_data data;
  32        char swirr[] = "-\\|/";
  33        int fd;
  34        int ret;
  35        int i, j;
  36        unsigned int iteration = 0;
  37
  38        memset(&data.values, 0, sizeof(data.values));
  39        ret = gpiotools_request_linehandle(device_name, lines, nlines,
  40                                           GPIOHANDLE_REQUEST_OUTPUT, &data,
  41                                           "gpio-hammer");
  42        if (ret < 0)
  43                goto exit_error;
  44        else
  45                fd = ret;
  46
  47        ret = gpiotools_get_values(fd, &data);
  48        if (ret < 0)
  49                goto exit_close_error;
  50
  51        fprintf(stdout, "Hammer lines [");
  52        for (i = 0; i < nlines; i++) {
  53                fprintf(stdout, "%d", lines[i]);
  54                if (i != (nlines - 1))
  55                        fprintf(stdout, ", ");
  56        }
  57        fprintf(stdout, "] on %s, initial states: [", device_name);
  58        for (i = 0; i < nlines; i++) {
  59                fprintf(stdout, "%d", data.values[i]);
  60                if (i != (nlines - 1))
  61                        fprintf(stdout, ", ");
  62        }
  63        fprintf(stdout, "]\n");
  64
  65        /* Hammertime! */
  66        j = 0;
  67        while (1) {
  68                /* Invert all lines so we blink */
  69                for (i = 0; i < nlines; i++)
  70                        data.values[i] = !data.values[i];
  71
  72                ret = gpiotools_set_values(fd, &data);
  73                if (ret < 0)
  74                        goto exit_close_error;
  75
  76                /* Re-read values to get status */
  77                ret = gpiotools_get_values(fd, &data);
  78                if (ret < 0)
  79                        goto exit_close_error;
  80
  81                fprintf(stdout, "[%c] ", swirr[j]);
  82                j++;
  83                if (j == sizeof(swirr)-1)
  84                        j = 0;
  85
  86                fprintf(stdout, "[");
  87                for (i = 0; i < nlines; i++) {
  88                        fprintf(stdout, "%d: %d", lines[i], data.values[i]);
  89                        if (i != (nlines - 1))
  90                                fprintf(stdout, ", ");
  91                }
  92                fprintf(stdout, "]\r");
  93                fflush(stdout);
  94                sleep(1);
  95                iteration++;
  96                if (loops && iteration == loops)
  97                        break;
  98        }
  99        fprintf(stdout, "\n");
 100        ret = 0;
 101
 102exit_close_error:
 103        gpiotools_release_linehandle(fd);
 104exit_error:
 105        return ret;
 106}
 107
 108void print_usage(void)
 109{
 110        fprintf(stderr, "Usage: gpio-hammer [options]...\n"
 111                "Hammer GPIO lines, 0->1->0->1...\n"
 112                "  -n <name>  Hammer GPIOs on a named device (must be stated)\n"
 113                "  -o <n>     Offset[s] to hammer, at least one, several can be stated\n"
 114                " [-c <n>]    Do <n> loops (optional, infinite loop if not stated)\n"
 115                "  -?         This helptext\n"
 116                "\n"
 117                "Example:\n"
 118                "gpio-hammer -n gpiochip0 -o 4\n"
 119        );
 120}
 121
 122int main(int argc, char **argv)
 123{
 124        const char *device_name = NULL;
 125        unsigned int lines[GPIOHANDLES_MAX];
 126        unsigned int loops = 0;
 127        int nlines;
 128        int c;
 129        int i;
 130
 131        i = 0;
 132        while ((c = getopt(argc, argv, "c:n:o:?")) != -1) {
 133                switch (c) {
 134                case 'c':
 135                        loops = strtoul(optarg, NULL, 10);
 136                        break;
 137                case 'n':
 138                        device_name = optarg;
 139                        break;
 140                case 'o':
 141                        lines[i] = strtoul(optarg, NULL, 10);
 142                        i++;
 143                        break;
 144                case '?':
 145                        print_usage();
 146                        return -1;
 147                }
 148        }
 149        nlines = i;
 150
 151        if (!device_name || !nlines) {
 152                print_usage();
 153                return -1;
 154        }
 155        return hammer_device(device_name, lines, nlines, loops);
 156}
 157