3 files changed, 120 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 14bb57b16593..2a72ce5c6d1f 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -200,6 +200,15 @@ config LEDS_TRIGGER_HEARTBEAT
           load average.
           If unsure, say Y.
 
+config LEDS_TRIGGER_BACKLIGHT
+        tristate "LED backlight Trigger"
+        depends on LEDS_TRIGGERS
+        help
+          This allows LEDs to be controlled as a backlight device: they
+          turn off and on when the display is blanked and unblanked.
+
+          If unsure, say N.
+
 config LEDS_TRIGGER_DEFAULT_ON
         tristate "LED Default ON Trigger"
         depends on LEDS_TRIGGERS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index e8714ad3ffff..07d937f4651d 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -28,4 +28,5 @@ obj-$(CONFIG_LEDS_DA903X)		+= leds-da903x.o
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)        += ledtrig-timer.o
 obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK)     += ledtrig-ide-disk.o
 obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT)    += ledtrig-heartbeat.o
+obj-$(CONFIG_LEDS_TRIGGER_BACKLIGHT)    += ledtrig-backlight.o
 obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)   += ledtrig-default-on.o
diff --git a/drivers/leds/ledtrig-backlight.c b/drivers/leds/ledtrig-backlight.c
new file mode 100644
index 000000000000..d3dfcfb417b8
--- /dev/null
+++ b/drivers/leds/ledtrig-backlight.c
@@ -0,0 +1,110 @@
+/*
+ * Backlight emulation LED trigger
+ *
+ * Copyright 2008 (C) Rodolfo Giometti <giometti@linux.it>
+ * Copyright 2008 (C) Eurotech S.p.A. <info@eurotech.it>
+ *
+ * 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/fb.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+#define BLANK           1
+#define UNBLANK         0
+
+struct bl_trig_notifier {
+        struct led_classdev *led;
+        int brightness;
+        int old_status;
+        struct notifier_block notifier;
+};
+
+static int fb_notifier_callback(struct notifier_block *p,
+                                unsigned long event, void *data)
+{
+        struct bl_trig_notifier *n = container_of(p,
+                                        struct bl_trig_notifier, notifier);
+        struct led_classdev *led = n->led;
+        struct fb_event *fb_event = data;
+        int *blank = fb_event->data;
+
+        switch (event) {
+        case FB_EVENT_BLANK :
+                if (*blank && n->old_status == UNBLANK) {
+                        n->brightness = led->brightness;
+                        led_set_brightness(led, LED_OFF);
+                        n->old_status = BLANK;
+                } else if (!*blank && n->old_status == BLANK) {
+                        led_set_brightness(led, n->brightness);
+                        n->old_status = UNBLANK;
+                }
+                break;
+        }
+
+        return 0;
+}
+
+static void bl_trig_activate(struct led_classdev *led)
+{
+        int ret;
+
+        struct bl_trig_notifier *n;
+
+        n = kzalloc(sizeof(struct bl_trig_notifier), GFP_KERNEL);
+        led->trigger_data = n;
+        if (!n) {
+                dev_err(led->dev, "unable to allocate backlight trigger\n");
+                return;
+        }
+
+        n->led = led;
+        n->brightness = led->brightness;
+        n->old_status = UNBLANK;
+        n->notifier.notifier_call = fb_notifier_callback;
+
+        ret = fb_register_client(&n->notifier);
+        if (ret)
+                dev_err(led->dev, "unable to register backlight trigger\n");
+}
+
+static void bl_trig_deactivate(struct led_classdev *led)
+{
+        struct bl_trig_notifier *n =
+                (struct bl_trig_notifier *) led->trigger_data;
+
+        if (n) {
+                fb_unregister_client(&n->notifier);
+                kfree(n);
+        }
+}
+
+static struct led_trigger bl_led_trigger = {
+        .name           = "backlight",
+        .activate       = bl_trig_activate,
+        .deactivate     = bl_trig_deactivate
+};
+
+static int __init bl_trig_init(void)
+{
+        return led_trigger_register(&bl_led_trigger);
+}
+
+static void __exit bl_trig_exit(void)
+{
+        led_trigger_unregister(&bl_led_trigger);
+}
+
+module_init(bl_trig_init);
+module_exit(bl_trig_exit);
+
+MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
+MODULE_DESCRIPTION("Backlight emulation LED trigger");
+MODULE_LICENSE("GPL v2");