tools: gpio: add debounce support to gpio-event-mon

Add support for debouncing monitored lines to gpio-event-mon.

Signed-off-by: Kent Gibson <[e-mail]>
Reviewed-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Bartosz Golaszewski <[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"
+		"  -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"
 		"\n"
 		"Example:\n"
-		"gpio-event-mon -n gpiochip0 -o 4 -r -f\n"
+		"gpio-event-mon -n gpiochip0 -o 4 -r -f -b 10000\n"
 	);
 }
 
···
 	unsigned int num_lines = 0;
 	unsigned int loops = 0;
 	struct gpio_v2_line_config config;
-	int c;
+	int c, attr, i;
+	unsigned long debounce_period_us = 0;
 
 	memset(&config, 0, sizeof(config));
 	config.flags = GPIO_V2_LINE_FLAG_INPUT;
-	while ((c = getopt(argc, argv, "c:n:o:dsrf?")) != -1) {
+	while ((c = getopt(argc, argv, "c:n:o:b:dsrf?")) != -1) {
 		switch (c) {
 		case 'c':
 			loops = strtoul(optarg, NULL, 10);
···
 			}
 			lines[num_lines] = strtoul(optarg, NULL, 10);
 			num_lines++;
+			break;
+		case 'b':
+			debounce_period_us = strtoul(optarg, NULL, 10);
 			break;
 		case 'd':
 			config.flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
···
 			print_usage();
 			return -1;
 		}
+	}
+
+	if (debounce_period_us) {
+		attr = config.num_attrs;
+		config.num_attrs++;
+		for (i = 0; i < num_lines; i++)
+			gpiotools_set_bit(&config.attrs[attr].mask, i);
+		config.attrs[attr].attr.id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
+		config.attrs[attr].attr.debounce_period_us = debounce_period_us;
 	}
 
 	if (!device_name || num_lines == 0) {