[PATCH] LED: add LED heartbeat trigger
Atsushi Nemoto [Sun, 25 Jun 2006 12:49:15 +0000 (05:49 -0700)]
Add an LED trigger acts like a heart beat.  This can be used as a
replacement of CONFIG_HEARTBEAT code exists in some arch's timer code.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Cc: "Nish Aravamudan" <nish.aravamudan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/leds/Kconfig
drivers/leds/Makefile
drivers/leds/ledtrig-heartbeat.c [new file with mode: 0644]

index f573d5a..9650998 100644 (file)
@@ -93,5 +93,14 @@ config LEDS_TRIGGER_IDE_DISK
          This allows LEDs to be controlled by IDE disk activity.
          If unsure, say Y.
 
+config LEDS_TRIGGER_HEARTBEAT
+       tristate "LED Heartbeat Trigger"
+       depends LEDS_TRIGGERS
+       help
+         This allows LEDs to be controlled by a CPU load average.
+         The flash frequency is a hyperbolic function of the 1-minute
+         load average.
+         If unsure, say Y.
+
 endmenu
 
index dcea100..88d3b6e 100644 (file)
@@ -16,3 +16,4 @@ obj-$(CONFIG_LEDS_AMS_DELTA)          += leds-ams-delta.o
 # LED Triggers
 obj-$(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
diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c
new file mode 100644 (file)
index 0000000..4bf8cec
--- /dev/null
@@ -0,0 +1,118 @@
+/*
+ * LED Heartbeat Trigger
+ *
+ * Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
+ *
+ * Based on Richard Purdie's ledtrig-timer.c and some arch's
+ * CONFIG_HEARTBEAT code.
+ *
+ * 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/timer.h>
+#include <linux/sched.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+struct heartbeat_trig_data {
+       unsigned int phase;
+       unsigned int period;
+       struct timer_list timer;
+};
+
+static void led_heartbeat_function(unsigned long data)
+{
+       struct led_classdev *led_cdev = (struct led_classdev *) data;
+       struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
+       unsigned long brightness = LED_OFF;
+       unsigned long delay = 0;
+
+       /* acts like an actual heart beat -- ie thump-thump-pause... */
+       switch (heartbeat_data->phase) {
+       case 0:
+               /*
+                * The hyperbolic function below modifies the
+                * heartbeat period length in dependency of the
+                * current (1min) load. It goes through the points
+                * f(0)=1260, f(1)=860, f(5)=510, f(inf)->300.
+                */
+               heartbeat_data->period = 300 +
+                       (6720 << FSHIFT) / (5 * avenrun[0] + (7 << FSHIFT));
+               heartbeat_data->period =
+                       msecs_to_jiffies(heartbeat_data->period);
+               delay = msecs_to_jiffies(70);
+               heartbeat_data->phase++;
+               brightness = LED_FULL;
+               break;
+       case 1:
+               delay = heartbeat_data->period / 4 - msecs_to_jiffies(70);
+               heartbeat_data->phase++;
+               break;
+       case 2:
+               delay = msecs_to_jiffies(70);
+               heartbeat_data->phase++;
+               brightness = LED_FULL;
+               break;
+       default:
+               delay = heartbeat_data->period - heartbeat_data->period / 4 -
+                       msecs_to_jiffies(70);
+               heartbeat_data->phase = 0;
+               break;
+       }
+
+       led_set_brightness(led_cdev, brightness);
+       mod_timer(&heartbeat_data->timer, jiffies + delay);
+}
+
+static void heartbeat_trig_activate(struct led_classdev *led_cdev)
+{
+       struct heartbeat_trig_data *heartbeat_data;
+
+       heartbeat_data = kzalloc(sizeof(*heartbeat_data), GFP_KERNEL);
+       if (!heartbeat_data)
+               return;
+
+       led_cdev->trigger_data = heartbeat_data;
+       setup_timer(&heartbeat_data->timer,
+                   led_heartbeat_function, (unsigned long) led_cdev);
+       heartbeat_data->phase = 0;
+       led_heartbeat_function(heartbeat_data->timer.data);
+}
+
+static void heartbeat_trig_deactivate(struct led_classdev *led_cdev)
+{
+       struct heartbeat_trig_data *heartbeat_data = led_cdev->trigger_data;
+
+       if (heartbeat_data) {
+               del_timer_sync(&heartbeat_data->timer);
+               kfree(heartbeat_data);
+       }
+}
+
+static struct led_trigger heartbeat_led_trigger = {
+       .name     = "heartbeat",
+       .activate = heartbeat_trig_activate,
+       .deactivate = heartbeat_trig_deactivate,
+};
+
+static int __init heartbeat_trig_init(void)
+{
+       return led_trigger_register(&heartbeat_led_trigger);
+}
+
+static void __exit heartbeat_trig_exit(void)
+{
+       led_trigger_unregister(&heartbeat_led_trigger);
+}
+
+module_init(heartbeat_trig_init);
+module_exit(heartbeat_trig_exit);
+
+MODULE_AUTHOR("Atsushi Nemoto <anemo@mba.ocn.ne.jp>");
+MODULE_DESCRIPTION("Heartbeat LED trigger");
+MODULE_LICENSE("GPL");