tools: gpio: add multi-line monitoring to gpio-event-mon

Extend gpio-event-mon to support monitoring multiple lines.
This would require multiple lineevent requests to implement using uAPI v1,
but can be performed with a single line request using uAPI v2.

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

···
 #include "gpio-utils.h"
 
 int monitor_device(const char *device_name,
-		   unsigned int line,
+		   unsigned int *lines,
+		   unsigned int num_lines,
 		   struct gpio_v2_line_config *config,
 		   unsigned int loops)
 {
···
 		goto exit_free_name;
 	}
 
-	ret = gpiotools_request_line(device_name, &line, 1, config,
+	ret = gpiotools_request_line(device_name, lines, num_lines, config,
 				     "gpio-event-mon");
 	if (ret < 0)
 		goto exit_device_close;
···
 		lfd = ret;
 
 	/* Read initial states */
-	values.mask = 1;
+	values.mask = 0;
 	values.bits = 0;
+	for (i = 0; i < num_lines; i++)
+		gpiotools_set_bit(&values.mask, i);
 	ret = gpiotools_get_values(lfd, &values);
 	if (ret < 0) {
 		fprintf(stderr,
···
 		goto exit_line_close;
 	}
 
-	fprintf(stdout, "Monitoring line %d on %s\n", line, device_name);
-	fprintf(stdout, "Initial line value: %d\n",
-		gpiotools_test_bit(values.bits, 0));
+	if (num_lines == 1) {
+		fprintf(stdout, "Monitoring line %d on %s\n", lines[0], device_name);
+		fprintf(stdout, "Initial line value: %d\n",
+			gpiotools_test_bit(values.bits, 0));
+	} else {
+		fprintf(stdout, "Monitoring lines %d", lines[0]);
+		for (i = 1; i < num_lines - 1; i++)
+			fprintf(stdout, ", %d", lines[i]);
+		fprintf(stdout, " and %d on %s\n", lines[i], device_name);
+		fprintf(stdout, "Initial line values: %d",
+			gpiotools_test_bit(values.bits, 0));
+		for (i = 1; i < num_lines - 1; i++)
+			fprintf(stdout, ", %d",
+				gpiotools_test_bit(values.bits, i));
+		fprintf(stdout, " and %d\n",
+			gpiotools_test_bit(values.bits, i));
+	}
 
 	while (1) {
 		struct gpio_v2_line_event event;
···
 	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"
+		"  -o <n>     Offset of line to monitor (may be repeated)\n"
 		"  -d         Set line as open drain\n"
 		"  -s         Set line as open source\n"
 		"  -r         Listen for rising edges\n"
···
 int main(int argc, char **argv)
 {
 	const char *device_name = NULL;
-	unsigned int line = -1;
+	unsigned int lines[GPIO_V2_LINES_MAX];
+	unsigned int num_lines = 0;
 	unsigned int loops = 0;
 	struct gpio_v2_line_config config;
 	int c;
···
 			device_name = optarg;
 			break;
 		case 'o':
-			line = strtoul(optarg, NULL, 10);
+			if (num_lines >= GPIO_V2_LINES_MAX) {
+				print_usage();
+				return -1;
+			}
+			lines[num_lines] = strtoul(optarg, NULL, 10);
+			num_lines++;
 			break;
 		case 'd':
 			config.flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
···
 		}
 	}
 
-	if (!device_name || line == -1) {
+	if (!device_name || num_lines == 0) {
 		print_usage();
 		return -1;
 	}
···
 		       "falling edges\n");
 		config.flags |= EDGE_FLAGS;
 	}
-	return monitor_device(device_name, line, &config, loops);
+	return monitor_device(device_name, lines, num_lines, &config, loops);
 }