[PATCH] LED: add LED timer trigger

Add an example of a complex LED trigger in the form of a generic timer which
triggers the LED its attached to at a user specified frequency and duty cycle.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 180 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index a4d12ecaf6a5..fda44df5921f 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -22,5 +22,12 @@ config LEDS_TRIGGERS
           These triggers allow kernel events to drive the LEDs and can
           be configured via sysfs. If unsure, say Y.
 
+config LEDS_TRIGGER_TIMER
+        tristate "LED Timer Trigger"
+        depends LEDS_TRIGGERS
+        help
+          This allows LEDs to be controlled by a programmable timer
+          via sysfs. If unsure, say Y.
+
 endmenu
 
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index a9d8becd6189..81e4abb9dcb0 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -3,3 +3,6 @@
 obj-$(CONFIG_NEW_LEDS)                  += led-core.o
 obj-$(CONFIG_LEDS_CLASS)                += led-class.o
 obj-$(CONFIG_LEDS_TRIGGERS)             += led-triggers.o
+
+# LED Triggers
+obj-$(CONFIG_LEDS_TRIGGER_TIMER)        += ledtrig-timer.o
diff --git a/drivers/leds/ledtrig-timer.c b/drivers/leds/ledtrig-timer.c
new file mode 100644
index 000000000000..f484b5d6dbf8
--- /dev/null
+++ b/drivers/leds/ledtrig-timer.c
@@ -0,0 +1,170 @@
+/*
+ * LED Kernel Timer Trigger
+ *
+ * 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"
+
+struct timer_trig_data {
+        unsigned long delay_on;         /* milliseconds on */
+        unsigned long delay_off;        /* milliseconds off */
+        struct timer_list timer;
+};
+
+static void led_timer_function(unsigned long data)
+{
+        struct led_classdev *led_cdev = (struct led_classdev *) data;
+        struct timer_trig_data *timer_data = led_cdev->trigger_data;
+        unsigned long brightness = LED_OFF;
+        unsigned long delay = timer_data->delay_off;
+
+        if (!timer_data->delay_on || !timer_data->delay_off) {
+                led_set_brightness(led_cdev, LED_OFF);
+                return;
+        }
+
+        if (!led_cdev->brightness) {
+                brightness = LED_FULL;
+                delay = timer_data->delay_on;
+        }
+
+        led_set_brightness(led_cdev, brightness);
+
+        mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
+}
+
+static ssize_t led_delay_on_show(struct class_device *dev, char *buf)
+{
+        struct led_classdev *led_cdev = class_get_devdata(dev);
+        struct timer_trig_data *timer_data = led_cdev->trigger_data;
+
+        sprintf(buf, "%lu\n", timer_data->delay_on);
+
+        return strlen(buf) + 1;
+}
+
+static ssize_t led_delay_on_store(struct class_device *dev, const char *buf,
+                                size_t size)
+{
+        struct led_classdev *led_cdev = class_get_devdata(dev);
+        struct timer_trig_data *timer_data = led_cdev->trigger_data;
+        int ret = -EINVAL;
+        char *after;
+        unsigned long state = simple_strtoul(buf, &after, 10);
+
+        if (after - buf > 0) {
+                timer_data->delay_on = state;
+                mod_timer(&timer_data->timer, jiffies + 1);
+                ret = after - buf;
+        }
+
+        return ret;
+}
+
+static ssize_t led_delay_off_show(struct class_device *dev, char *buf)
+{
+        struct led_classdev *led_cdev = class_get_devdata(dev);
+        struct timer_trig_data *timer_data = led_cdev->trigger_data;
+
+        sprintf(buf, "%lu\n", timer_data->delay_off);
+
+        return strlen(buf) + 1;
+}
+
+static ssize_t led_delay_off_store(struct class_device *dev, const char *buf,
+                                size_t size)
+{
+        struct led_classdev *led_cdev = class_get_devdata(dev);
+        struct timer_trig_data *timer_data = led_cdev->trigger_data;
+        int ret = -EINVAL;
+        char *after;
+        unsigned long state = simple_strtoul(buf, &after, 10);
+
+        if (after - buf > 0) {
+                timer_data->delay_off = state;
+                mod_timer(&timer_data->timer, jiffies + 1);
+                ret = after - buf;
+        }
+
+        return ret;
+}
+
+static CLASS_DEVICE_ATTR(delay_on, 0644, led_delay_on_show,
+                        led_delay_on_store);
+static CLASS_DEVICE_ATTR(delay_off, 0644, led_delay_off_show,
+                        led_delay_off_store);
+
+static void timer_trig_activate(struct led_classdev *led_cdev)
+{
+        struct timer_trig_data *timer_data;
+
+        timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
+        if (!timer_data)
+                return;
+
+        led_cdev->trigger_data = timer_data;
+
+        init_timer(&timer_data->timer);
+        timer_data->timer.function = led_timer_function;
+        timer_data->timer.data = (unsigned long) led_cdev;
+
+        class_device_create_file(led_cdev->class_dev,
+                                &class_device_attr_delay_on);
+        class_device_create_file(led_cdev->class_dev,
+                                &class_device_attr_delay_off);
+}
+
+static void timer_trig_deactivate(struct led_classdev *led_cdev)
+{
+        struct timer_trig_data *timer_data = led_cdev->trigger_data;
+
+        if (timer_data) {
+                class_device_remove_file(led_cdev->class_dev,
+                                        &class_device_attr_delay_on);
+                class_device_remove_file(led_cdev->class_dev,
+                                        &class_device_attr_delay_off);
+                del_timer_sync(&timer_data->timer);
+                kfree(timer_data);
+        }
+}
+
+static struct led_trigger timer_led_trigger = {
+        .name     = "timer",
+        .activate = timer_trig_activate,
+        .deactivate = timer_trig_deactivate,
+};
+
+static int __init timer_trig_init(void)
+{
+        return led_trigger_register(&timer_led_trigger);
+}
+
+static void __exit timer_trig_exit(void)
+{
+        led_trigger_unregister(&timer_led_trigger);
+}
+
+module_init(timer_trig_init);
+module_exit(timer_trig_exit);
+
+MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
+MODULE_DESCRIPTION("Timer LED trigger");
+MODULE_LICENSE("GPL");