5 files changed, 281 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 106f9aeca04f..a4d12ecaf6a5 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -14,5 +14,13 @@ config LEDS_CLASS
           This option enables the led sysfs class in /sys/class/leds.  You'll
           need this to do anything useful with LEDs.  If unsure, say N.
 
+config LEDS_TRIGGERS
+        bool "LED Trigger support"
+        depends NEW_LEDS
+        help
+          This option enables trigger support for the leds class.
+          These triggers allow kernel events to drive the LEDs and can
+          be configured via sysfs. If unsure, say Y.
+
 endmenu
 
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 8a62871437fa..a9d8becd6189 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -2,3 +2,4 @@
 # LED Core
 obj-$(CONFIG_NEW_LEDS)                  += led-core.o
 obj-$(CONFIG_LEDS_CLASS)                += led-class.o
+obj-$(CONFIG_LEDS_TRIGGERS)             += led-triggers.o
diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c
index 0292df4101ba..b0b5d05fadd6 100644
--- a/drivers/leds/led-class.c
+++ b/drivers/leds/led-class.c
@@ -54,6 +54,9 @@ static ssize_t led_brightness_store(struct class_device *dev,
 
 static CLASS_DEVICE_ATTR(brightness, 0644, led_brightness_show,
                         led_brightness_store);
+#ifdef CONFIG_LEDS_TRIGGERS
+static CLASS_DEVICE_ATTR(trigger, 0644, led_trigger_show, led_trigger_store);
+#endif
 
 /**
  * led_classdev_suspend - suspend an led_classdev.
@@ -100,6 +103,15 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev)
         list_add_tail(&led_cdev->node, &leds_list);
         write_unlock(&leds_list_lock);
 
+#ifdef CONFIG_LEDS_TRIGGERS
+        rwlock_init(&led_cdev->trigger_lock);
+
+        led_trigger_set_default(led_cdev);
+
+        class_device_create_file(led_cdev->class_dev,
+                                &class_device_attr_trigger);
+#endif
+
         printk(KERN_INFO "Registered led device: %s\n",
                         led_cdev->class_dev->class_id);
 
@@ -117,6 +129,14 @@ void led_classdev_unregister(struct led_classdev *led_cdev)
 {
         class_device_remove_file(led_cdev->class_dev,
                                 &class_device_attr_brightness);
+#ifdef CONFIG_LEDS_TRIGGERS
+        class_device_remove_file(led_cdev->class_dev,
+                                &class_device_attr_trigger);
+        write_lock(&led_cdev->trigger_lock);
+        if (led_cdev->trigger)
+                led_trigger_set(led_cdev, NULL);
+        write_unlock(&led_cdev->trigger_lock);
+#endif
 
         class_device_unregister(led_cdev->class_dev);
 
diff --git a/drivers/leds/led-triggers.c b/drivers/leds/led-triggers.c
new file mode 100644
index 000000000000..5e2cd8be1191
--- /dev/null
+++ b/drivers/leds/led-triggers.c
@@ -0,0 +1,239 @@
+/*
+ * LED Triggers Core
+ *
+ * Copyright 2005-2006 Openedhand Ltd.
+ *
+ * Author: Richard Purdie <rpurdie@openedhand.com>
+ *
+ * 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/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/sysdev.h>
+#include <linux/timer.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+/*
+ * Nests outside led_cdev->trigger_lock
+ */
+static rwlock_t triggers_list_lock = RW_LOCK_UNLOCKED;
+static LIST_HEAD(trigger_list);
+
+ssize_t led_trigger_store(struct class_device *dev, const char *buf,
+                        size_t count)
+{
+        struct led_classdev *led_cdev = class_get_devdata(dev);
+        char trigger_name[TRIG_NAME_MAX];
+        struct led_trigger *trig;
+        size_t len;
+
+        trigger_name[sizeof(trigger_name) - 1] = '\0';
+        strncpy(trigger_name, buf, sizeof(trigger_name) - 1);
+        len = strlen(trigger_name);
+
+        if (len && trigger_name[len - 1] == '\n')
+                trigger_name[len - 1] = '\0';
+
+        if (!strcmp(trigger_name, "none")) {
+                write_lock(&led_cdev->trigger_lock);
+                led_trigger_set(led_cdev, NULL);
+                write_unlock(&led_cdev->trigger_lock);
+                return count;
+        }
+
+        read_lock(&triggers_list_lock);
+        list_for_each_entry(trig, &trigger_list, next_trig) {
+                if (!strcmp(trigger_name, trig->name)) {
+                        write_lock(&led_cdev->trigger_lock);
+                        led_trigger_set(led_cdev, trig);
+                        write_unlock(&led_cdev->trigger_lock);
+
+                        read_unlock(&triggers_list_lock);
+                        return count;
+                }
+        }
+        read_unlock(&triggers_list_lock);
+
+        return -EINVAL;
+}
+
+
+ssize_t led_trigger_show(struct class_device *dev, char *buf)
+{
+        struct led_classdev *led_cdev = class_get_devdata(dev);
+        struct led_trigger *trig;
+        int len = 0;
+
+        read_lock(&triggers_list_lock);
+        read_lock(&led_cdev->trigger_lock);
+
+        if (!led_cdev->trigger)
+                len += sprintf(buf+len, "[none] ");
+        else
+                len += sprintf(buf+len, "none ");
+
+        list_for_each_entry(trig, &trigger_list, next_trig) {
+                if (led_cdev->trigger && !strcmp(led_cdev->trigger->name,
+                                                        trig->name))
+                        len += sprintf(buf+len, "[%s] ", trig->name);
+                else
+                        len += sprintf(buf+len, "%s ", trig->name);
+        }
+        read_unlock(&led_cdev->trigger_lock);
+        read_unlock(&triggers_list_lock);
+
+        len += sprintf(len+buf, "\n");
+        return len;
+}
+
+void led_trigger_event(struct led_trigger *trigger,
+                        enum led_brightness brightness)
+{
+        struct list_head *entry;
+
+        if (!trigger)
+                return;
+
+        read_lock(&trigger->leddev_list_lock);
+        list_for_each(entry, &trigger->led_cdevs) {
+                struct led_classdev *led_cdev;
+
+                led_cdev = list_entry(entry, struct led_classdev, trig_list);
+                led_set_brightness(led_cdev, brightness);
+        }
+        read_unlock(&trigger->leddev_list_lock);
+}
+
+/* Caller must ensure led_cdev->trigger_lock held */
+void led_trigger_set(struct led_classdev *led_cdev, struct led_trigger *trigger)
+{
+        unsigned long flags;
+
+        /* Remove any existing trigger */
+        if (led_cdev->trigger) {
+                write_lock_irqsave(&led_cdev->trigger->leddev_list_lock, flags);
+                list_del(&led_cdev->trig_list);
+                write_unlock_irqrestore(&led_cdev->trigger->leddev_list_lock, flags);
+                if (led_cdev->trigger->deactivate)
+                        led_cdev->trigger->deactivate(led_cdev);
+        }
+        if (trigger) {
+                write_lock_irqsave(&trigger->leddev_list_lock, flags);
+                list_add_tail(&led_cdev->trig_list, &trigger->led_cdevs);
+                write_unlock_irqrestore(&trigger->leddev_list_lock, flags);
+                if (trigger->activate)
+                        trigger->activate(led_cdev);
+        }
+        led_cdev->trigger = trigger;
+}
+
+void led_trigger_set_default(struct led_classdev *led_cdev)
+{
+        struct led_trigger *trig;
+
+        if (!led_cdev->default_trigger)
+                return;
+
+        read_lock(&triggers_list_lock);
+        write_lock(&led_cdev->trigger_lock);
+        list_for_each_entry(trig, &trigger_list, next_trig) {
+                if (!strcmp(led_cdev->default_trigger, trig->name))
+                        led_trigger_set(led_cdev, trig);
+        }
+        write_unlock(&led_cdev->trigger_lock);
+        read_unlock(&triggers_list_lock);
+}
+
+int led_trigger_register(struct led_trigger *trigger)
+{
+        struct led_classdev *led_cdev;
+
+        rwlock_init(&trigger->leddev_list_lock);
+        INIT_LIST_HEAD(&trigger->led_cdevs);
+
+        /* Add to the list of led triggers */
+        write_lock(&triggers_list_lock);
+        list_add_tail(&trigger->next_trig, &trigger_list);
+        write_unlock(&triggers_list_lock);
+
+        /* Register with any LEDs that have this as a default trigger */
+        read_lock(&leds_list_lock);
+        list_for_each_entry(led_cdev, &leds_list, node) {
+                write_lock(&led_cdev->trigger_lock);
+                if (!led_cdev->trigger && led_cdev->default_trigger &&
+                            !strcmp(led_cdev->default_trigger, trigger->name))
+                        led_trigger_set(led_cdev, trigger);
+                write_unlock(&led_cdev->trigger_lock);
+        }
+        read_unlock(&leds_list_lock);
+
+        return 0;
+}
+
+void led_trigger_register_simple(const char *name, struct led_trigger **tp)
+{
+        struct led_trigger *trigger;
+
+        trigger = kzalloc(sizeof(struct led_trigger), GFP_KERNEL);
+
+        if (trigger) {
+                trigger->name = name;
+                led_trigger_register(trigger);
+        }
+        *tp = trigger;
+}
+
+void led_trigger_unregister(struct led_trigger *trigger)
+{
+        struct led_classdev *led_cdev;
+
+        /* Remove from the list of led triggers */
+        write_lock(&triggers_list_lock);
+        list_del(&trigger->next_trig);
+        write_unlock(&triggers_list_lock);
+
+        /* Remove anyone actively using this trigger */
+        read_lock(&leds_list_lock);
+        list_for_each_entry(led_cdev, &leds_list, node) {
+                write_lock(&led_cdev->trigger_lock);
+                if (led_cdev->trigger == trigger)
+                        led_trigger_set(led_cdev, NULL);
+                write_unlock(&led_cdev->trigger_lock);
+        }
+        read_unlock(&leds_list_lock);
+}
+
+void led_trigger_unregister_simple(struct led_trigger *trigger)
+{
+        led_trigger_unregister(trigger);
+        kfree(trigger);
+}
+
+/* Used by LED Class */
+EXPORT_SYMBOL_GPL(led_trigger_set);
+EXPORT_SYMBOL_GPL(led_trigger_set_default);
+EXPORT_SYMBOL_GPL(led_trigger_show);
+EXPORT_SYMBOL_GPL(led_trigger_store);
+
+/* LED Trigger Interface */
+EXPORT_SYMBOL_GPL(led_trigger_register);
+EXPORT_SYMBOL_GPL(led_trigger_unregister);
+
+/* Simple LED Tigger Interface */
+EXPORT_SYMBOL_GPL(led_trigger_register_simple);
+EXPORT_SYMBOL_GPL(led_trigger_unregister_simple);
+EXPORT_SYMBOL_GPL(led_trigger_event);
+
+MODULE_AUTHOR("Richard Purdie");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LED Triggers Core");
diff --git a/drivers/leds/leds.h b/drivers/leds/leds.h
index d26ca2f7e722..a715c4ed93ff 100644
--- a/drivers/leds/leds.h
+++ b/drivers/leds/leds.h
@@ -28,4 +28,17 @@ static inline void led_set_brightness(struct led_classdev *led_cdev,
 extern rwlock_t leds_list_lock;
 extern struct list_head leds_list;
 
+#ifdef CONFIG_LEDS_TRIGGERS
+void led_trigger_set_default(struct led_classdev *led_cdev);
+void led_trigger_set(struct led_classdev *led_cdev,
+                        struct led_trigger *trigger);
+#else
+#define led_trigger_set_default(x) do {} while(0)
+#define led_trigger_set(x, y) do {} while(0)
+#endif
+
+ssize_t led_trigger_store(struct class_device *dev, const char *buf,
+                        size_t count);
+ssize_t led_trigger_show(struct class_device *dev, char *buf);
+
 #endif  /* __LEDS_H_INCLUDED */