leds: add oneshot trigger

Add oneshot trigger to blink a led with configurale parameters via
sysfs.

Signed-off-by: Fabio Baltieri <fabio.baltieri@gmail.com>
Cc: Shuah Khan <shuahkhan@gmail.com>
Signed-off-by: Bryan Wu <bryan.wu@canonical.com>

3 files changed, 219 insertions, 0 deletions

diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index 12b2b55c519..54dd1a396fa 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -443,6 +443,20 @@ config LEDS_TRIGGER_TIMER
 
 	  If unsure, say Y.
 
+config LEDS_TRIGGER_ONESHOT
+	tristate "LED One-shot Trigger"
+	depends on LEDS_TRIGGERS
+	help
+	  This allows LEDs to blink in one-shot pulses with parameters
+	  controlled via sysfs.  It's useful to notify the user on
+	  sporadic events, when there are no clear begin and end trap points,
+	  or on dense events, where this blinks the LED at constant rate if
+	  rearmed continuously.
+
+	  It also shows how to use the led_blink_set_oneshot() function.
+
+	  If unsure, say Y.
+
 config LEDS_TRIGGER_IDE_DISK
 	bool "LED IDE Disk Trigger"
 	depends on IDE_GD_ATA
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index f8958cd6cf6..9112d518f9d 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_LEDS_DAC124S085)		+= leds-dac124s085.o
 
 # LED Triggers
 obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o
+obj-$(CONFIG_LEDS_TRIGGER_ONESHOT)	+= ledtrig-oneshot.o
 obj-$(CONFIG_LEDS_TRIGGER_IDE_DISK)	+= ledtrig-ide-disk.o
 obj-$(CONFIG_LEDS_TRIGGER_HEARTBEAT)	+= ledtrig-heartbeat.o
 obj-$(CONFIG_LEDS_TRIGGER_BACKLIGHT)	+= ledtrig-backlight.o
diff --git a/drivers/leds/ledtrig-oneshot.c b/drivers/leds/ledtrig-oneshot.c
new file mode 100644
index 00000000000..5c9edf7f489
--- /dev/null
+++ b/drivers/leds/ledtrig-oneshot.c
@@ -0,0 +1,204 @@
+/*
+ * One-shot LED Trigger
+ *
+ * Copyright 2012, Fabio Baltieri <fabio.baltieri@gmail.com>
+ *
+ * Based on ledtrig-timer.c by 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/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+#define DEFAULT_DELAY 100
+
+struct oneshot_trig_data {
+	unsigned int invert;
+};
+
+static ssize_t led_shot(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
+
+	led_blink_set_oneshot(led_cdev,
+			&led_cdev->blink_delay_on, &led_cdev->blink_delay_off,
+			oneshot_data->invert);
+
+	/* content is ignored */
+	return size;
+}
+static ssize_t led_invert_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
+
+	return sprintf(buf, "%u\n", oneshot_data->invert);
+}
+
+static ssize_t led_invert_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
+	unsigned long state;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &state);
+	if (ret)
+		return ret;
+
+	oneshot_data->invert = !!state;
+
+	if (oneshot_data->invert)
+		led_set_brightness(led_cdev, LED_FULL);
+	else
+		led_set_brightness(led_cdev, LED_OFF);
+
+	return size;
+}
+
+static ssize_t led_delay_on_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%lu\n", led_cdev->blink_delay_on);
+}
+
+static ssize_t led_delay_on_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	unsigned long state;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &state);
+	if (ret)
+		return ret;
+
+	led_cdev->blink_delay_on = state;
+
+	return size;
+}
+static ssize_t led_delay_off_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%lu\n", led_cdev->blink_delay_off);
+}
+
+static ssize_t led_delay_off_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev_get_drvdata(dev);
+	unsigned long state;
+	int ret;
+
+	ret = kstrtoul(buf, 0, &state);
+	if (ret)
+		return ret;
+
+	led_cdev->blink_delay_off = state;
+
+	return size;
+}
+
+static DEVICE_ATTR(delay_on, 0644, led_delay_on_show, led_delay_on_store);
+static DEVICE_ATTR(delay_off, 0644, led_delay_off_show, led_delay_off_store);
+static DEVICE_ATTR(invert, 0644, led_invert_show, led_invert_store);
+static DEVICE_ATTR(shot, 0200, NULL, led_shot);
+
+static void oneshot_trig_activate(struct led_classdev *led_cdev)
+{
+	struct oneshot_trig_data *oneshot_data;
+	int rc;
+
+	oneshot_data = kzalloc(sizeof(*oneshot_data), GFP_KERNEL);
+	if (!oneshot_data)
+		return;
+
+	led_cdev->trigger_data = oneshot_data;
+
+	rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
+	if (rc)
+		goto err_out_trig_data;
+	rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
+	if (rc)
+		goto err_out_delayon;
+	rc = device_create_file(led_cdev->dev, &dev_attr_invert);
+	if (rc)
+		goto err_out_delayoff;
+	rc = device_create_file(led_cdev->dev, &dev_attr_shot);
+	if (rc)
+		goto err_out_invert;
+
+	led_cdev->blink_delay_on = DEFAULT_DELAY;
+	led_cdev->blink_delay_off = DEFAULT_DELAY;
+
+	led_cdev->activated = true;
+
+	return;
+
+err_out_invert:
+	device_remove_file(led_cdev->dev, &dev_attr_invert);
+err_out_delayoff:
+	device_remove_file(led_cdev->dev, &dev_attr_delay_off);
+err_out_delayon:
+	device_remove_file(led_cdev->dev, &dev_attr_delay_on);
+err_out_trig_data:
+	kfree(led_cdev->trigger_data);
+}
+
+static void oneshot_trig_deactivate(struct led_classdev *led_cdev)
+{
+	struct oneshot_trig_data *oneshot_data = led_cdev->trigger_data;
+
+	if (led_cdev->activated) {
+		device_remove_file(led_cdev->dev, &dev_attr_delay_on);
+		device_remove_file(led_cdev->dev, &dev_attr_delay_off);
+		device_remove_file(led_cdev->dev, &dev_attr_invert);
+		device_remove_file(led_cdev->dev, &dev_attr_shot);
+		kfree(oneshot_data);
+		led_cdev->activated = false;
+	}
+
+	/* Stop blinking */
+	led_brightness_set(led_cdev, LED_OFF);
+}
+
+static struct led_trigger oneshot_led_trigger = {
+	.name     = "oneshot",
+	.activate = oneshot_trig_activate,
+	.deactivate = oneshot_trig_deactivate,
+};
+
+static int __init oneshot_trig_init(void)
+{
+	return led_trigger_register(&oneshot_led_trigger);
+}
+
+static void __exit oneshot_trig_exit(void)
+{
+	led_trigger_unregister(&oneshot_led_trigger);
+}
+
+module_init(oneshot_trig_init);
+module_exit(oneshot_trig_exit);
+
+MODULE_AUTHOR("Fabio Baltieri <fabio.baltieri@gmail.com>");
+MODULE_DESCRIPTION("One-shot LED trigger");
+MODULE_LICENSE("GPL");