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authorLinus Walleij <linus.walleij@linaro.org>2016-06-02 11:38:33 +0200
committerLinus Walleij <linus.walleij@linaro.org>2016-06-15 09:29:29 +0200
commit97f69747d8b11c76df321894344beeae6bafc301 (patch)
tree5058310cc8675829b3cfb28561926b0c717244f1 /tools/gpio
parent61f922db72216b00386581c851db9c9095961522 (diff)
downloadlinux-linaro-stable-97f69747d8b11c76df321894344beeae6bafc301.tar.gz
tools/gpio: add the gpio-event-mon tool
The gpio-event-mon is used from userspace as an example of how to monitor GPIO line events. It will latch on to a certain GPIO line on a certain gpiochip and print timestamped events as they arrive. Example output: $ gpio-event-mon -n gpiochip2 -o 0 -r -f Monitoring line 0 on gpiochip2 Initial line value: 1 GPIO EVENT 946685798487609863: falling edge GPIO EVENT 946685798732482910: rising edge GPIO EVENT 946685799115997314: falling edge GPIO EVENT 946685799381469726: rising edge Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'tools/gpio')
-rw-r--r--tools/gpio/Makefile5
-rw-r--r--tools/gpio/gpio-event-mon.c192
2 files changed, 195 insertions, 2 deletions
diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
index aea23949054e..619314ff9bd6 100644
--- a/tools/gpio/Makefile
+++ b/tools/gpio/Makefile
@@ -1,13 +1,14 @@
CC = $(CROSS_COMPILE)gcc
CFLAGS += -O2 -Wall -g -D_GNU_SOURCE
-all: lsgpio gpio-hammer
+all: lsgpio gpio-hammer gpio-event-mon
lsgpio: lsgpio.o gpio-utils.o
gpio-hammer: gpio-hammer.o gpio-utils.o
+gpio-event-mon: gpio-event-mon.o gpio-utils.o
%.o: %.c gpio-utils.h
.PHONY: clean
clean:
- rm -f *.o lsgpio gpio-hammer
+ rm -f *.o lsgpio gpio-hammer gpio-event-mon
diff --git a/tools/gpio/gpio-event-mon.c b/tools/gpio/gpio-event-mon.c
new file mode 100644
index 000000000000..448ed96b3b4f
--- /dev/null
+++ b/tools/gpio/gpio-event-mon.c
@@ -0,0 +1,192 @@
+/*
+ * 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-event-mon -n <device-name> -o <offset>
+ */
+
+#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 <inttypes.h>
+#include <sys/ioctl.h>
+#include <linux/gpio.h>
+
+int monitor_device(const char *device_name,
+ unsigned int line,
+ u_int32_t handleflags,
+ u_int32_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 %" PRIu64 ": ", 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;
+ u_int32_t handleflags = GPIOHANDLE_REQUEST_INPUT;
+ u_int32_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);
+}