tools/gpio: add the gpio-hammer tool

CC = $(CROSS_COMPILE)gcc

CFLAGS += -O2 -Wall -g -D_GNU_SOURCE

all: lsgpio

all: lsgpio gpio-hammer

lsgpio: lsgpio.o gpio-utils.o

gpio-hammer: gpio-hammer.o gpio-utils.o

%.o: %.c gpio-utils.h

.PHONY: clean

clean:

	rm -f *.o lsgpio

	rm -f *.o lsgpio gpio-hammer

/*

 * gpio-hammer - example swiss army knife to shake GPIO lines on a system

 *

 * Copyright (C) 2016 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:

 *	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>

int hammer_device(const char *device_name, unsigned int *lines, int nlines,

		  unsigned int loops)

{

	struct gpiohandle_request req;

	struct gpiohandle_data data;

	char *chrdev_name;

	char swirr[] = "-\\|/";

	int fd;

	int ret;

	int i, j;

	unsigned int iteration = 0;

	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;

	}

	/* Request lines as output */

	for (i = 0; i < nlines; i++)

		req.lineoffsets[i] = lines[i];

	req.flags = GPIOHANDLE_REQUEST_OUTPUT; /* Request as output */

	strcpy(req.consumer_label, "gpio-hammer");

	req.lines = nlines;

	ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req);

	if (ret == -1) {

		ret = -errno;

		fprintf(stderr, "Failed to issue GET LINEHANDLE "

			"IOCTL (%d)\n",

			ret);

		goto exit_close_error;

	}

	/* Read initial states */

	ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);

	if (ret == -1) {

		ret = -errno;

		fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE "

			"VALUES IOCTL (%d)\n",

			ret);

		goto exit_close_error;

	}

	fprintf(stdout, "Hammer lines [");

	for (i = 0; i < nlines; i++) {

		fprintf(stdout, "%d", lines[i]);

		if (i != (nlines - 1))

			fprintf(stdout, ", ");

	}

	fprintf(stdout, "] on %s, initial states: [", device_name);

	for (i = 0; i < nlines; i++) {

		fprintf(stdout, "%d", data.values[i]);

		if (i != (nlines - 1))

			fprintf(stdout, ", ");

	}

	fprintf(stdout, "]\n");

	/* Hammertime! */

	j = 0;

	while (1) {

		/* Invert all lines so we blink */

		for (i = 0; i < nlines; i++)

			data.values[i] = !data.values[i];

		ret = ioctl(req.fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data);

		if (ret == -1) {

			ret = -errno;

			fprintf(stderr, "Failed to issue GPIOHANDLE SET LINE "

				"VALUES IOCTL (%d)\n",

				ret);

			goto exit_close_error;

		}

		/* Re-read values to get status */

		ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);

		if (ret == -1) {

			ret = -errno;

			fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE "

				"VALUES IOCTL (%d)\n",

				ret);

			goto exit_close_error;

		}

		fprintf(stdout, "[%c] ", swirr[j]);

		j++;

		if (j == sizeof(swirr)-1)

			j = 0;

		fprintf(stdout, "[");

		for (i = 0; i < nlines; i++) {

			fprintf(stdout, "%d: %d", lines[i], data.values[i]);

			if (i != (nlines - 1))

				fprintf(stdout, ", ");

		}

		fprintf(stdout, "]\r");

		fflush(stdout);

		sleep(1);

		iteration++;

		if (loops && iteration == loops)

			break;

	}

	fprintf(stdout, "\n");

	ret = 0;

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: 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 nlines;

	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':

			lines[i] = strtoul(optarg, NULL, 10);

			i++;

			break;

		case '?':

			print_usage();

			return -1;

		}

	}

	nlines = i;

	if (!device_name || !nlines) {

		print_usage();

		return -1;

	}

	return hammer_device(device_name, lines, nlines, loops);

}