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}