tools: gpiomon: add initial-state option

index 88b5ccf..4d109c3 100644
@@ -32,6 +32,7 @@ struct config {
 	enum gpiod_line_clock event_clock;
 	int timestamp_fmt;
 	long long idle_timeout;
+	bool initial_state;
 };
 
 static void print_help(void)

@@ -69,6 +70,7 @@ static void print_help(void)
 	printf("  -p, --debounce-period <period>\n");
 	printf("\t\t\tdebounce the line(s) with the specified period\n");
 	printf("  -q, --quiet\t\tdon't generate any output\n");
+	printf("  -S, --initial-state\t\tprint initial states of the lines\n");
 	printf("  -s, --strict\t\tabort if requested line names are not unique\n");
 	printf("      --unquoted\tdon't quote line or consumer names\n");
 	printf("      --utc\t\tformat event timestamps as UTC (default for 'realtime')\n");

@@ -113,7 +115,7 @@ static int parse_event_clock_or_die(const char *option)
 
 static int parse_config(int argc, char **argv, struct config *cfg)
 {
-	static const char *const shortopts = "+b:c:C:e:E:hF:ln:p:qshv";
+	static const char *const shortopts = "+b:c:C:e:E:hF:ln:p:qshvS";
 
 	const struct option longopts[] = {
 		{ "active-low",	no_argument,	NULL,		'l' },

@@ -136,6 +138,7 @@ static int parse_config(int argc, char **argv, struct config *cfg)
 		{ "unquoted",	no_argument,	NULL,		'Q' },
 		{ "utc",	no_argument,	&cfg->timestamp_fmt,	1 },
 		{ "version",	no_argument,	NULL,		'v' },
+		{ "initial-state",	no_argument,	NULL,		'S' },
 		{ GETOPT_NULL_LONGOPT },
 	};
 

@@ -197,6 +200,9 @@ static int parse_config(int argc, char **argv, struct config *cfg)
 		case 's':
 			cfg->strict = true;
 			break;
+		case 'S':
+			cfg->initial_state = true;
+			break;
 		case 'h':
 			print_help();
 			exit(EXIT_SUCCESS);

@@ -353,6 +359,24 @@ static void event_print(struct gpiod_edge_event *event,
 		event_print_human_readable(event, resolver, chip_num, cfg);
 }
 
+static void initial_line_values_print(struct line_resolver *resolver,
+			struct config *cfg)
+{
+	printf("\nInitial line state(s): ");
+	int i;
+	const char *fmt = cfg->unquoted ? "%s=%s" : "\"%s\"=%s";
+
+	for (i = 0; i < resolver->num_lines; i++) {
+		struct resolved_line *line = &resolver->lines[i];
+
+		printf(fmt, line->id,
+		line->value ? "active" : "inactive");
+		if (i != resolver->num_lines - 1)
+			printf(" ");
+	}
+	printf("\n");
+}
+
 int main(int argc, char **argv)
 {
 	struct gpiod_edge_event_buffer *event_buffer;

@@ -363,6 +387,7 @@ int main(int argc, char **argv)
 	int num_lines, events_done = 0;
 	struct gpiod_edge_event *event;
 	struct line_resolver *resolver;
+	enum gpiod_line_value *values;
 	struct timespec idle_timeout;
 	struct gpiod_chip *chip;
 	struct pollfd *pollfds;

@@ -423,7 +448,9 @@ int main(int argc, char **argv)
 	requests = calloc(resolver->num_chips, sizeof(*requests));
 	pollfds = calloc(resolver->num_chips, sizeof(*pollfds));
 	offsets = calloc(resolver->num_lines, sizeof(*offsets));
-	if (!requests || !pollfds || !offsets)
+	values = calloc(resolver->num_lines, sizeof(*values));
+
+	if (!requests || !pollfds || !offsets || !values)
 		die("out of memory");
 
 	for (i = 0; i < resolver->num_chips; i++) {

@@ -445,6 +472,14 @@ int main(int argc, char **argv)
 			die_perror("unable to request lines on chip %s",
 				   resolver->chips[i].path);
 
+		if (cfg.initial_state) {
+			ret = gpiod_line_request_get_values(requests[i], values);
+			if (ret)
+				die_perror("unable to read GPIO line values");
+			set_line_values(resolver, i, values);
+			initial_line_values_print(resolver, &cfg);
+		}
+
 		pollfds[i].fd = gpiod_line_request_get_fd(requests[i]);
 		pollfds[i].events = POLLIN;
 		gpiod_chip_close(chip);