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// SPDX-License-Identifier: GPL-2.0-only
/*
* gpio-hammer - example swiss army knife to shake GPIO lines on a system
*
* Copyright (C) 2016 Linus Walleij
*
* Usage:
* gpio-hammer -n <device-name> -o <offset1> -o <offset2>
*/
#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"
int hammer_device(const char *device_name, unsigned int *lines, int num_lines,
unsigned int loops)
{
struct gpio_v2_line_values values;
struct gpio_v2_line_config config;
char swirr[] = "-\\|/";
int fd;
int ret;
int i, j;
unsigned int iteration = 0;
memset(&config, 0, sizeof(config));
config.flags = GPIO_V2_LINE_FLAG_OUTPUT;
ret = gpiotools_request_line(device_name, lines, num_lines,
&config, "gpio-hammer");
if (ret < 0)
goto exit_error;
else
fd = ret;
values.mask = 0;
values.bits = 0;
for (i = 0; i < num_lines; i++)
gpiotools_set_bit(&values.mask, i);
ret = gpiotools_get_values(fd, &values);
if (ret < 0)
goto exit_close_error;
fprintf(stdout, "Hammer lines [");
for (i = 0; i < num_lines; i++) {
fprintf(stdout, "%u", lines[i]);
if (i != (num_lines - 1))
fprintf(stdout, ", ");
}
fprintf(stdout, "] on %s, initial states: [", device_name);
for (i = 0; i < num_lines; i++) {
fprintf(stdout, "%d", gpiotools_test_bit(values.bits, i));
if (i != (num_lines - 1))
fprintf(stdout, ", ");
}
fprintf(stdout, "]\n");
/* Hammertime! */
j = 0;
while (1) {
/* Invert all lines so we blink */
for (i = 0; i < num_lines; i++)
gpiotools_change_bit(&values.bits, i);
ret = gpiotools_set_values(fd, &values);
if (ret < 0)
goto exit_close_error;
/* Re-read values to get status */
ret = gpiotools_get_values(fd, &values);
if (ret < 0)
goto exit_close_error;
fprintf(stdout, "[%c] ", swirr[j]);
j++;
if (j == sizeof(swirr) - 1)
j = 0;
fprintf(stdout, "[");
for (i = 0; i < num_lines; i++) {
fprintf(stdout, "%u: %d", lines[i],
gpiotools_test_bit(values.bits, i));
if (i != (num_lines - 1))
fprintf(stdout, ", ");
}
fprintf(stdout, "]\r");
fflush(stdout);
sleep(1);
iteration++;
if (loops && iteration == loops)
break;
}
fprintf(stdout, "\n");
ret = 0;
exit_close_error:
gpiotools_release_line(fd);
exit_error:
return ret;
}
void print_usage(void)
{
fprintf(stderr, "Usage: gpio-hammer [options]...\n"
"Hammer GPIO lines, 0->1->0->1...\n"
" -n <name> Hammer GPIOs on a named device (must be stated)\n"
" -o <n> Offset[s] to hammer, at least one, several can be stated\n"
" [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n"
" -? This helptext\n"
"\n"
"Example:\n"
"gpio-hammer -n gpiochip0 -o 4\n"
);
}
int main(int argc, char **argv)
{
const char *device_name = NULL;
unsigned int lines[GPIOHANDLES_MAX];
unsigned int loops = 0;
int num_lines;
int c;
int i;
i = 0;
while ((c = getopt(argc, argv, "c:n:o:?")) != -1) {
switch (c) {
case 'c':
loops = strtoul(optarg, NULL, 10);
break;
case 'n':
device_name = optarg;
break;
case 'o':
/*
* Avoid overflow. Do not immediately error, we want to
* be able to accurately report on the amount of times
* '-o' was given to give an accurate error message
*/
if (i < GPIOHANDLES_MAX)
lines[i] = strtoul(optarg, NULL, 10);
i++;
break;
case '?':
print_usage();
return -1;
}
}
if (i >= GPIOHANDLES_MAX) {
fprintf(stderr,
"Only %d occurrences of '-o' are allowed, %d were found\n",
GPIOHANDLES_MAX, i + 1);
return -1;
}
num_lines = i;
if (!device_name || !num_lines) {
print_usage();
return -1;
}
return hammer_device(device_name, lines, num_lines, loops);
}
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