leds: Add backlight LED trigger (132e9306) · Commits · 戴 / test

drivers/leds/Kconfig

+9 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/leds/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/leds/ledtrig-backlight.c

0 → 100644

+110 −0

Original line number	Diff line number	Diff line
		/*
		* 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");

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