summaryrefslogtreecommitdiff
path: root/drivers/leds/ledtrig-heartbeat.c
diff options
context:
space:
mode:
authorAtsushi Nemoto <anemo@mba.ocn.ne.jp>2006-06-25 05:49:15 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-25 10:01:23 -0700
commit891c668b90ded38cec36f0852c4983573597170d (patch)
tree50bd91c6a8afab05cf974d5abe100b69b2bb3fd4 /drivers/leds/ledtrig-heartbeat.c
parentfa9799e33d362aeca4555cd6318735bab1c04d16 (diff)
[PATCH] LED: add LED heartbeat trigger
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>
Diffstat (limited to 'drivers/leds/ledtrig-heartbeat.c')
-rw-r--r--drivers/leds/ledtrig-heartbeat.c118
1 files changed, 118 insertions, 0 deletions
diff --git a/drivers/leds/ledtrig-heartbeat.c b/drivers/leds/ledtrig-heartbeat.c
new file mode 100644
index 000000000000..4bf8cec8b8c1
--- /dev/null
+++ b/drivers/leds/ledtrig-heartbeat.c
@@ -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");