[ARM] Provide userspace method for controlling LEDs in ARM machines.

arch/arm/kernel/time.c

@@ -143,6 +143,54 @@ static void dummy_leds_event(led_event_t evt)
 
 void (*leds_event)(led_event_t) = dummy_leds_event;
 
+struct leds_evt_name {
+	const char	name[8];
+	int		on;
+	int		off;
+};
+
+static const struct leds_evt_name evt_names[] = {
+	{ "amber", led_amber_on, led_amber_off },
+	{ "blue",  led_blue_on,  led_blue_off  },
+	{ "green", led_green_on, led_green_off },
+	{ "red",   led_red_on,   led_red_off   },
+};
+
+static ssize_t leds_store(struct sys_device *dev, const char *buf, size_t size)
+{
+	int ret = -EINVAL, len = strcspn(buf, " ");
+
+	if (len > 0 && buf[len] == '\0')
+		len--;
+
+	if (strncmp(buf, "claim", len) == 0) {
+		leds_event(led_claim);
+		ret = size;
+	} else if (strncmp(buf, "release", len) == 0) {
+		leds_event(led_release);
+		ret = size;
+	} else {
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(evt_names); i++) {
+			if (strlen(evt_names[i].name) != len ||
+			    strncmp(buf, evt_names[i].name, len) != 0)
+				continue;
+			if (strncmp(buf+len, " on", 3) == 0) {
+				leds_event(evt_names[i].on);
+				ret = size;
+			} else if (strncmp(buf+len, " off", 4) == 0) {
+				leds_event(evt_names[i].off);
+				ret = size;
+			}
+			break;
+		}
+	}
+	return ret;
+}
+
+static SYSDEV_ATTR(event, 0200, NULL, leds_store);
+
 static int leds_suspend(struct sys_device *dev, u32 state)
 {
 	leds_event(led_stop);
@@ -179,6 +227,8 @@ static int __init leds_init(void)
 	ret = sysdev_class_register(&leds_sysclass);
 	if (ret == 0)
 		ret = sysdev_register(&leds_device);
+	if (ret == 0)
+		ret = sysdev_create_file(&leds_device, &attr_event);
 	return ret;
 }