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tools/gpio: add the gpio-hammer tool
The gpio-hammer is used from userspace as an example of how to retrieve a GPIO handle for one or several GPIO lines and hammer the outputs from low to high and back again. It will pulse the selected lines once per second for a specified number of times or indefinitely if no loop count is supplied. Example output: $ gpio-hammer -n gpiochip0 -o5 -o6 -o7 Hammer lines [5, 6, 7] on gpiochip0, initial states: [1, 1, 1] [-] [5: 0, 6: 0, 7: 0] Tested-by: Michael Welling <mwelling@ieee.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij
parent
d7c51b47ac
commit
2a144dd091
@ -1,12 +1,13 @@
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CC = $(CROSS_COMPILE)gcc
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CFLAGS += -O2 -Wall -g -D_GNU_SOURCE
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all: lsgpio
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all: lsgpio gpio-hammer
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lsgpio: lsgpio.o gpio-utils.o
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gpio-hammer: gpio-hammer.o gpio-utils.o
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%.o: %.c gpio-utils.h
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.PHONY: clean
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clean:
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rm -f *.o lsgpio
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rm -f *.o lsgpio gpio-hammer
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189
tools/gpio/gpio-hammer.c
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189
tools/gpio/gpio-hammer.c
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/*
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* gpio-hammer - example swiss army knife to shake GPIO lines on a system
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*
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* Copyright (C) 2016 Linus Walleij
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*
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* Usage:
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* gpio-hammer -n <device-name> -o <offset1> -o <offset2>
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*/
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <dirent.h>
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#include <errno.h>
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#include <string.h>
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#include <poll.h>
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#include <fcntl.h>
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#include <getopt.h>
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#include <sys/ioctl.h>
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#include <linux/gpio.h>
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int hammer_device(const char *device_name, unsigned int *lines, int nlines,
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unsigned int loops)
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{
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struct gpiohandle_request req;
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struct gpiohandle_data data;
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char *chrdev_name;
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char swirr[] = "-\\|/";
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int fd;
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int ret;
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int i, j;
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unsigned int iteration = 0;
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ret = asprintf(&chrdev_name, "/dev/%s", device_name);
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if (ret < 0)
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return -ENOMEM;
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fd = open(chrdev_name, 0);
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if (fd == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to open %s\n", chrdev_name);
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goto exit_close_error;
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}
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/* Request lines as output */
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for (i = 0; i < nlines; i++)
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req.lineoffsets[i] = lines[i];
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req.flags = GPIOHANDLE_REQUEST_OUTPUT; /* Request as output */
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strcpy(req.consumer_label, "gpio-hammer");
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req.lines = nlines;
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ret = ioctl(fd, GPIO_GET_LINEHANDLE_IOCTL, &req);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GET LINEHANDLE "
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"IOCTL (%d)\n",
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ret);
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goto exit_close_error;
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}
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/* Read initial states */
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ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE "
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"VALUES IOCTL (%d)\n",
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ret);
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goto exit_close_error;
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}
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fprintf(stdout, "Hammer lines [");
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for (i = 0; i < nlines; i++) {
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fprintf(stdout, "%d", lines[i]);
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if (i != (nlines - 1))
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fprintf(stdout, ", ");
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}
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fprintf(stdout, "] on %s, initial states: [", device_name);
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for (i = 0; i < nlines; i++) {
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fprintf(stdout, "%d", data.values[i]);
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if (i != (nlines - 1))
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fprintf(stdout, ", ");
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}
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fprintf(stdout, "]\n");
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/* Hammertime! */
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j = 0;
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while (1) {
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/* Invert all lines so we blink */
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for (i = 0; i < nlines; i++)
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data.values[i] = !data.values[i];
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ret = ioctl(req.fd, GPIOHANDLE_SET_LINE_VALUES_IOCTL, &data);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GPIOHANDLE SET LINE "
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"VALUES IOCTL (%d)\n",
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ret);
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goto exit_close_error;
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}
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/* Re-read values to get status */
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ret = ioctl(req.fd, GPIOHANDLE_GET_LINE_VALUES_IOCTL, &data);
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if (ret == -1) {
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ret = -errno;
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fprintf(stderr, "Failed to issue GPIOHANDLE GET LINE "
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"VALUES IOCTL (%d)\n",
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ret);
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goto exit_close_error;
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}
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fprintf(stdout, "[%c] ", swirr[j]);
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j++;
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if (j == sizeof(swirr)-1)
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j = 0;
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fprintf(stdout, "[");
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for (i = 0; i < nlines; i++) {
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fprintf(stdout, "%d: %d", lines[i], data.values[i]);
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if (i != (nlines - 1))
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fprintf(stdout, ", ");
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}
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fprintf(stdout, "]\r");
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fflush(stdout);
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sleep(1);
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iteration++;
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if (loops && iteration == loops)
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break;
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}
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fprintf(stdout, "\n");
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ret = 0;
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exit_close_error:
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if (close(fd) == -1)
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perror("Failed to close GPIO character device file");
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free(chrdev_name);
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return ret;
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}
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void print_usage(void)
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{
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fprintf(stderr, "Usage: gpio-hammer [options]...\n"
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"Hammer GPIO lines, 0->1->0->1...\n"
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" -n <name> Hammer GPIOs on a named device (must be stated)\n"
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" -o <n> Offset[s] to hammer, at least one, several can be stated\n"
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" [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n"
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" -? This helptext\n"
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"\n"
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"Example:\n"
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"gpio-hammer -n gpiochip0 -o 4\n"
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);
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}
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int main(int argc, char **argv)
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{
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const char *device_name = NULL;
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unsigned int lines[GPIOHANDLES_MAX];
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unsigned int loops = 0;
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int nlines;
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int c;
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int i;
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i = 0;
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while ((c = getopt(argc, argv, "c:n:o:?")) != -1) {
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switch (c) {
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case 'c':
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loops = strtoul(optarg, NULL, 10);
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break;
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case 'n':
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device_name = optarg;
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break;
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case 'o':
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lines[i] = strtoul(optarg, NULL, 10);
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i++;
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break;
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case '?':
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print_usage();
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return -1;
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}
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}
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nlines = i;
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if (!device_name || !nlines) {
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print_usage();
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return -1;
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}
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return hammer_device(device_name, lines, nlines, loops);
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}
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