diff options
Diffstat (limited to 'tools/gpio/gpio-event-mon.c')
| -rw-r--r-- | tools/gpio/gpio-event-mon.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/tools/gpio/gpio-event-mon.c b/tools/gpio/gpio-event-mon.c new file mode 100644 index 000000000..c864544ef --- /dev/null +++ b/tools/gpio/gpio-event-mon.c @@ -0,0 +1,194 @@ +/* + * gpio-event-mon - monitor GPIO line events from userspace + * + * 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-event-mon -n <device-name> -o <offset> + */ + +#include <unistd.h> +#include <stdlib.h> +#include <stdbool.h> +#include <stdint.h> +#include <stdio.h> +#include <dirent.h> +#include <errno.h> +#include <string.h> +#include <poll.h> +#include <fcntl.h> +#include <getopt.h> +#include <inttypes.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <linux/gpio.h> + +int monitor_device(const char *device_name, + unsigned int line, + uint32_t handleflags, + uint32_t eventflags, + unsigned int loops) +{ + struct gpioevent_request req; + struct gpiohandle_data data; + char *chrdev_name; + int fd; + int ret; + int i = 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; + } + + req.lineoffset = line; + req.handleflags = handleflags; + req.eventflags = eventflags; + strcpy(req.consumer_label, "gpio-event-mon"); + + ret = ioctl(fd, GPIO_GET_LINEEVENT_IOCTL, &req); + if (ret == -1) { + ret = -errno; + fprintf(stderr, "Failed to issue GET EVENT " + "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, "Monitoring line %d on %s\n", line, device_name); + fprintf(stdout, "Initial line value: %d\n", data.values[0]); + + while (1) { + struct gpioevent_data event; + + ret = read(req.fd, &event, sizeof(event)); + if (ret == -1) { + if (errno == -EAGAIN) { + fprintf(stderr, "nothing available\n"); + continue; + } else { + ret = -errno; + fprintf(stderr, "Failed to read event (%d)\n", + ret); + break; + } + } + + if (ret != sizeof(event)) { + fprintf(stderr, "Reading event failed\n"); + ret = -EIO; + break; + } + fprintf(stdout, "GPIO EVENT %llu: ", event.timestamp); + switch (event.id) { + case GPIOEVENT_EVENT_RISING_EDGE: + fprintf(stdout, "rising edge"); + break; + case GPIOEVENT_EVENT_FALLING_EDGE: + fprintf(stdout, "falling edge"); + break; + default: + fprintf(stdout, "unknown event"); + } + fprintf(stdout, "\n"); + + i++; + if (i == loops) + break; + } + +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-event-mon [options]...\n" + "Listen to events on GPIO lines, 0->1 1->0\n" + " -n <name> Listen on GPIOs on a named device (must be stated)\n" + " -o <n> Offset to monitor\n" + " -d Set line as open drain\n" + " -s Set line as open source\n" + " -r Listen for rising edges\n" + " -f Listen for falling edges\n" + " [-c <n>] Do <n> loops (optional, infinite loop if not stated)\n" + " -? This helptext\n" + "\n" + "Example:\n" + "gpio-event-mon -n gpiochip0 -o 4 -r -f\n" + ); +} + +int main(int argc, char **argv) +{ + const char *device_name = NULL; + unsigned int line = -1; + unsigned int loops = 0; + uint32_t handleflags = GPIOHANDLE_REQUEST_INPUT; + uint32_t eventflags = 0; + int c; + + while ((c = getopt(argc, argv, "c:n:o:dsrf?")) != -1) { + switch (c) { + case 'c': + loops = strtoul(optarg, NULL, 10); + break; + case 'n': + device_name = optarg; + break; + case 'o': + line = strtoul(optarg, NULL, 10); + break; + case 'd': + handleflags |= GPIOHANDLE_REQUEST_OPEN_DRAIN; + break; + case 's': + handleflags |= GPIOHANDLE_REQUEST_OPEN_SOURCE; + break; + case 'r': + eventflags |= GPIOEVENT_REQUEST_RISING_EDGE; + break; + case 'f': + eventflags |= GPIOEVENT_REQUEST_FALLING_EDGE; + break; + case '?': + print_usage(); + return -1; + } + } + + if (!device_name || line == -1) { + print_usage(); + return -1; + } + if (!eventflags) { + printf("No flags specified, listening on both rising and " + "falling edges\n"); + eventflags = GPIOEVENT_REQUEST_BOTH_EDGES; + } + return monitor_device(device_name, line, handleflags, + eventflags, loops); +} |