| // 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 nlines, |
| unsigned int loops) |
| { |
| struct gpiohandle_data data; |
| char swirr[] = "-\\|/"; |
| int fd; |
| int ret; |
| int i, j; |
| unsigned int iteration = 0; |
| |
| memset(&data.values, 0, sizeof(data.values)); |
| ret = gpiotools_request_linehandle(device_name, lines, nlines, |
| GPIOHANDLE_REQUEST_OUTPUT, &data, |
| "gpio-hammer"); |
| if (ret < 0) |
| goto exit_error; |
| else |
| fd = ret; |
| |
| ret = gpiotools_get_values(fd, &data); |
| if (ret < 0) |
| 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 = gpiotools_set_values(fd, &data); |
| if (ret < 0) |
| goto exit_close_error; |
| |
| /* Re-read values to get status */ |
| ret = gpiotools_get_values(fd, &data); |
| 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 < 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: |
| gpiotools_release_linehandle(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 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': |
| /* |
| * 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 occurences of '-o' are allowed, %d were found\n", |
| GPIOHANDLES_MAX, i + 1); |
| return -1; |
| } |
| |
| nlines = i; |
| |
| if (!device_name || !nlines) { |
| print_usage(); |
| return -1; |
| } |
| return hammer_device(device_name, lines, nlines, loops); |
| } |