gpiomon: new tool

Implement a simple GPIO event monitor.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/.gitignore b/.gitignore
index 060ee04c559443174f8e6af6bd888523ef9f53aa..2879c594bcb3d92571957772fc1bd0aa6555c1f5 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -4,6 +4,7 @@ gpiodetect
 gpioinfo
 gpioget
 gpioset
+gpiomon
 *.o
 *.lo
 doc

diff --git a/Makefile.am b/Makefile.am
index 585dac47e8fbd4277c507840aa1a7be28856bf79..d47b230cd966ac55a260349d73e0a4ed159a180b 100644 (file)
--- a/Makefile.am
+++ b/Makefile.am
@@ -37,6 +37,10 @@ gpioset_SOURCES = gpioset.c
 gpioset_LDFLAGS = -lgpiod
 gpioset_DEPENDENCIES = libgpiod.la
 
+gpiomon_SOURCES = gpiomon.c
+gpiomon_LDFLAGS = -lgpiod
+gpiomon_DEPENDENCIES = libgpiod.la
+
 doc:
        doxygen
 .PHONY: doc

diff --git a/gpiomon.c b/gpiomon.c
new file mode 100644 (file)
index 0000000..1550e25
--- /dev/null
+++ b/gpiomon.c
@@ -0,0 +1,101 @@
+/*
+ * Monitor events on a GPIO line.
+ *
+ * Copyright (C) 2017 Bartosz Golaszewski <bartekgola@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 3 as
+ * published by the Free Software Foundation.
+ */
+
+#include <gpiod.h>
+
+#include <stdio.h>
+#include <string.h>
+
+int main(int argc, char **argv)
+{
+       struct gpiod_line_evreq_config config;
+       struct gpiod_line_event event;
+       struct timespec timeout;
+       struct gpiod_chip *chip;
+       struct gpiod_line *line;
+       unsigned int offset;
+       char *device, *end;
+       int status;
+
+       if (argc < 2) {
+               fprintf(stderr, "%s: gpiochip must be specified\n", argv[0]);
+               return EXIT_FAILURE;
+       }
+
+       if (argc < 3) {
+               fprintf(stderr,
+                       "%s: gpio line offset must be specified\n", argv[0]);
+               return EXIT_FAILURE;
+       }
+
+       device = argv[1];
+       /* FIXME Handle negative numbers. */
+       offset = strtoul(argv[2], &end, 10);
+       if (*end != '\0') {
+               fprintf(stderr,
+                       "%s: invalid GPIO offset: %s\n", argv[0], argv[2]);
+               return EXIT_FAILURE;
+       }
+
+       chip = gpiod_chip_open_lookup(device);
+       if (!chip) {
+               fprintf(stderr,
+                       "%s: error accessing gpiochip %s: %s\n",
+                       argv[0], device, gpiod_strerror(gpiod_errno()));
+               return EXIT_FAILURE;
+       }
+
+       line = gpiod_chip_get_line(chip, offset);
+       if (!line) {
+               fprintf(stderr,
+                       "%s: error accessing line %u: %s\n",
+                       argv[0], offset, gpiod_strerror(gpiod_errno()));
+               return EXIT_FAILURE;
+       }
+
+       memset(&config, 0, sizeof(config));
+       config.consumer = "gpiomon";
+       config.event_type = GPIOD_EVENT_BOTH_EDGES;
+
+       status = gpiod_line_event_request(line, &config);
+       if (status < 0) {
+               fprintf(stderr,
+                       "%s: error requesting line event: %s\n",
+                       argv[0], gpiod_strerror(gpiod_errno()));
+               return EXIT_FAILURE;
+       }
+
+       for (;;) {
+               timeout.tv_sec = 1;
+               timeout.tv_nsec = 0;
+
+               status = gpiod_line_event_wait(line, &timeout, &event);
+               if (status < 0) {
+                       fprintf(stderr,
+                               "%s: error waiting for line event: %s\n",
+                               argv[0], gpiod_strerror(gpiod_errno()));
+                       return EXIT_FAILURE;
+               } else if (status == 0) {
+                       continue;
+               }
+
+               printf("GPIO EVENT: %s [%ld.%ld]\n",
+                      event.event_type == GPIOD_EVENT_FALLING_EDGE
+                                                       ? "FALLING EDGE"
+                                                       : "RAISING EDGE",
+                      event.ts.tv_sec, event.ts.tv_nsec);
+       }
+
+       gpiod_line_event_release(line);
+       gpiod_line_release(line);
+       gpiod_chip_close(chip);
+
+       return EXIT_SUCCESS;
+}