1 files changed, 237 insertions, 0 deletions

diff --git a/drivers/leds/ledtrig-transient.c b/drivers/leds/ledtrig-transient.c
new file mode 100644
index 000000000000..83179f435e1e
--- /dev/null
+++ b/drivers/leds/ledtrig-transient.c
@@ -0,0 +1,237 @@
+/*
+ * LED Kernel Transient Trigger
+ *
+ * Copyright (C) 2012 Shuah Khan <shuahkhan@gmail.com>
+ *
+ * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's
+ * ledtrig-heartbeat.c
+ * Design and use-case input from Jonas Bonn <jonas@southpole.se> and
+ * Neil Brown <neilb@suse.de>
+ *
+ * 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.
+ *
+ */
+/*
+ * Transient trigger allows one shot timer activation. Please refer to
+ * Documentation/leds/ledtrig-transient.txt for details
+*/
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/timer.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+struct transient_trig_data {
+	int activate;
+	int state;
+	int restore_state;
+	unsigned long duration;
+	struct timer_list timer;
+};
+
+static void transient_timer_function(unsigned long data)
+{
+	struct led_classdev *led_cdev = (struct led_classdev *) data;
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+
+	transient_data->activate = 0;
+	led_set_brightness(led_cdev, transient_data->restore_state);
+}
+
+static ssize_t transient_activate_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+
+	return sprintf(buf, "%d\n", transient_data->activate);
+}
+
+static ssize_t transient_activate_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+	unsigned long state;
+	ssize_t ret;
+
+	ret = kstrtoul(buf, 10, &state);
+	if (ret)
+		return ret;
+
+	if (state != 1 && state != 0)
+		return -EINVAL;
+
+	/* cancel the running timer */
+	if (state == 0 && transient_data->activate == 1) {
+		del_timer(&transient_data->timer);
+		transient_data->activate = state;
+		led_set_brightness(led_cdev, transient_data->restore_state);
+		return size;
+	}
+
+	/* start timer if there is no active timer */
+	if (state == 1 && transient_data->activate == 0 &&
+	    transient_data->duration != 0) {
+		transient_data->activate = state;
+		led_set_brightness(led_cdev, transient_data->state);
+		transient_data->restore_state =
+		    (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
+		mod_timer(&transient_data->timer,
+			  jiffies + transient_data->duration);
+	}
+
+	/* state == 0 && transient_data->activate == 0
+		timer is not active - just return */
+	/* state == 1 && transient_data->activate == 1
+		timer is already active - just return */
+
+	return size;
+}
+
+static ssize_t transient_duration_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+
+	return sprintf(buf, "%lu\n", transient_data->duration);
+}
+
+static ssize_t transient_duration_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+	unsigned long state;
+	ssize_t ret;
+
+	ret = kstrtoul(buf, 10, &state);
+	if (ret)
+		return ret;
+
+	transient_data->duration = state;
+	return size;
+}
+
+static ssize_t transient_state_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+	int state;
+
+	state = (transient_data->state == LED_FULL) ? 1 : 0;
+	return sprintf(buf, "%d\n", state);
+}
+
+static ssize_t transient_state_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+	unsigned long state;
+	ssize_t ret;
+
+	ret = kstrtoul(buf, 10, &state);
+	if (ret)
+		return ret;
+
+	if (state != 1 && state != 0)
+		return -EINVAL;
+
+	transient_data->state = (state == 1) ? LED_FULL : LED_OFF;
+	return size;
+}
+
+static DEVICE_ATTR(activate, 0644, transient_activate_show,
+		   transient_activate_store);
+static DEVICE_ATTR(duration, 0644, transient_duration_show,
+		   transient_duration_store);
+static DEVICE_ATTR(state, 0644, transient_state_show, transient_state_store);
+
+static void transient_trig_activate(struct led_classdev *led_cdev)
+{
+	int rc;
+	struct transient_trig_data *tdata;
+
+	tdata = kzalloc(sizeof(struct transient_trig_data), GFP_KERNEL);
+	if (!tdata) {
+		dev_err(led_cdev->dev,
+			"unable to allocate transient trigger\n");
+		return;
+	}
+	led_cdev->trigger_data = tdata;
+
+	rc = device_create_file(led_cdev->dev, &dev_attr_activate);
+	if (rc)
+		goto err_out;
+
+	rc = device_create_file(led_cdev->dev, &dev_attr_duration);
+	if (rc)
+		goto err_out_duration;
+
+	rc = device_create_file(led_cdev->dev, &dev_attr_state);
+	if (rc)
+		goto err_out_state;
+
+	setup_timer(&tdata->timer, transient_timer_function,
+		    (unsigned long) led_cdev);
+	led_cdev->activated = true;
+
+	return;
+
+err_out_state:
+	device_remove_file(led_cdev->dev, &dev_attr_duration);
+err_out_duration:
+	device_remove_file(led_cdev->dev, &dev_attr_activate);
+err_out:
+	dev_err(led_cdev->dev, "unable to register transient trigger\n");
+	led_cdev->trigger_data = NULL;
+	kfree(tdata);
+}
+
+static void transient_trig_deactivate(struct led_classdev *led_cdev)
+{
+	struct transient_trig_data *transient_data = led_cdev->trigger_data;
+
+	if (led_cdev->activated) {
+		del_timer_sync(&transient_data->timer);
+		led_set_brightness(led_cdev, transient_data->restore_state);
+		device_remove_file(led_cdev->dev, &dev_attr_activate);
+		device_remove_file(led_cdev->dev, &dev_attr_duration);
+		device_remove_file(led_cdev->dev, &dev_attr_state);
+		led_cdev->trigger_data = NULL;
+		led_cdev->activated = false;
+		kfree(transient_data);
+	}
+}
+
+static struct led_trigger transient_trigger = {
+	.name     = "transient",
+	.activate = transient_trig_activate,
+	.deactivate = transient_trig_deactivate,
+};
+
+static int __init transient_trig_init(void)
+{
+	return led_trigger_register(&transient_trigger);
+}
+
+static void __exit transient_trig_exit(void)
+{
+	led_trigger_unregister(&transient_trigger);
+}
+
+module_init(transient_trig_init);
+module_exit(transient_trig_exit);
+
+MODULE_AUTHOR("Shuah Khan <shuahkhan@gmail.com>");
+MODULE_DESCRIPTION("Transient LED trigger");
+MODULE_LICENSE("GPL");