"default-on" LED Trigger

The current LED subsystem always initialises LEDs in the OFF state. This is fine for most LEDs but some should be on right from boot (e.g. POWER LED). Following some discussion with the LED subsystem maintainers, a trigger was recommended as the best way to implement this functionality.

Here is a patch to add a new trigger "default-on" which will initialise an LED in the ON state. It is not compiled by default.

Particular thanks to Rod Whitby for all his help with this.

Signed-off-by: Nick Forbes <nick.forbes@incepta.com>

SVN-Revision: 10348

1 files changed, 45 insertions, 0 deletions

diff --git a/target/linux/generic-2.6/files/drivers/leds/ledtrig-default-on.c b/target/linux/generic-2.6/files/drivers/leds/ledtrig-default-on.c
new file mode 100644
index 0000000..92995e4
--- /dev/null
+++ b/target/linux/generic-2.6/files/drivers/leds/ledtrig-default-on.c
@@ -0,0 +1,45 @@
+/*
+ * LED Kernel Default ON Trigger
+ *
+ * Copyright 2008 Nick Forbes <nick.forbes@incepta.com>
+ *
+ * Based on Richard Purdie's ledtrig-timer.c.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+static void defon_trig_activate(struct led_classdev *led_cdev)
+{
+	led_set_brightness(led_cdev, LED_FULL);
+}
+
+static struct led_trigger defon_led_trigger = {
+	.name     = "default-on",
+	.activate = defon_trig_activate,
+};
+
+static int __init defon_trig_init(void)
+{
+	return led_trigger_register(&defon_led_trigger);
+}
+
+static void __exit defon_trig_exit(void)
+{
+	led_trigger_unregister(&defon_led_trigger);
+}
+
+module_init(defon_trig_init);
+module_exit(defon_trig_exit);
+
+MODULE_AUTHOR("Nick Forbes <nick.forbes@incepta.com>");
+MODULE_DESCRIPTION("Default-ON LED trigger");
+MODULE_LICENSE("GPL");