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authorLinus Torvalds <torvalds@linux-foundation.org>2008-10-23 16:07:32 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-23 16:07:32 -0700
commitea541686d8454efac4f2b5c0767affb12d4b6a52 (patch)
treeef0812fcc3e07c067042add6388146b3485c793e /drivers/leds/ledtrig-backlight.c
parent0d876c6a96e2cabf8632e8066b617d9c2dec9518 (diff)
parent601a1b92ed3ce0025f7bec6fc591cceaef8d9d69 (diff)
downloadlinux-linaro-ea541686d8454efac4f2b5c0767affb12d4b6a52.tar.gz
Merge branch 'for-linus' of git://git.o-hand.com/linux-rpurdie-leds
* 'for-linus' of git://git.o-hand.com/linux-rpurdie-leds: leds/acpi: Fix merge fallout from acpi_driver_data change leds: Simplify logic in leds-ams-delta leds: Fix trigger registration race leds: Fix leds-class.c comment leds: Add driver for HP harddisk protection LEDs leds: leds-pca955x - Mark pca955x_led_set() static leds: Remove uneeded leds-cm-x270 driver leds: Remove uneeded strlen calls leds: Add leds-wrap default-trigger leds: Make default trigger fields const leds: Add backlight LED trigger leds: da903x: Add support for LEDs found on DA9030/DA9034
Diffstat (limited to 'drivers/leds/ledtrig-backlight.c')
-rw-r--r--drivers/leds/ledtrig-backlight.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/leds/ledtrig-backlight.c b/drivers/leds/ledtrig-backlight.c
new file mode 100644
index 00000000000..d3dfcfb417b
--- /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");