tools: gpio: add option to report wall-clock time to gpio-event-mon

Add support for selecting the realtime clock for events.

Signed-off-by: Kent Gibson <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

tools/gpio/gpio-event-mon.c

···
 		"  -s         Set line as open source\n"
 		"  -r         Listen for rising edges\n"
 		"  -f         Listen for falling edges\n"
+		"  -w         Report the wall-clock time for events\n"
 		"  -b <n>     Debounce the line with period n microseconds\n"
 		" [-c <n>]    Do <n> loops (optional, infinite loop if not stated)\n"
 		"  -?         This helptext\n"
···
 
 	memset(&config, 0, sizeof(config));
 	config.flags = GPIO_V2_LINE_FLAG_INPUT;
-	while ((c = getopt(argc, argv, "c:n:o:b:dsrf?")) != -1) {
+	while ((c = getopt(argc, argv, "c:n:o:b:dsrfw?")) != -1) {
 		switch (c) {
 		case 'c':
 			loops = strtoul(optarg, NULL, 10);
···
 			break;
 		case 'f':
 			config.flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
+			break;
+		case 'w':
+			config.flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
 			break;
 		case '?':
 			print_usage();