diff options
Diffstat (limited to 'drivers/leds')
| -rw-r--r-- | drivers/leds/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/leds/Makefile | 1 | ||||
| -rw-r--r-- | drivers/leds/ledtrig-backlight.c | 110 |
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"); |