From: Joe Xue <lgxue@xxxxxxxxxxx>
Allow LEDs blink in burst mode. Three parameters are exported to
sysfs: freq, delay_off and times.
new file: Documentation/leds/ledtrig-burst.txt
modified: drivers/leds/trigger/Kconfig
modified: drivers/leds/trigger/Makefile
new file: drivers/leds/trigger/ledtrig-burst.c
Signed-off-by: Joe Xue <lgxue@xxxxxxxxxxx>
---
Documentation/leds/ledtrig-burst.txt | 58 ++++++++
drivers/leds/trigger/Kconfig | 10 ++
drivers/leds/trigger/Makefile | 1 +
drivers/leds/trigger/ledtrig-burst.c | 250 +++++++++++++++++++++++++++++++++++
4 files changed, 319 insertions(+)
create mode 100644 Documentation/leds/ledtrig-burst.txt
create mode 100644 drivers/leds/trigger/ledtrig-burst.c
diff --git a/Documentation/leds/ledtrig-burst.txt b/Documentation/leds/ledtrig-burst.txt
new file mode 100644
index 0000000..50a7955
--- /dev/null
+++ b/Documentation/leds/ledtrig-burst.txt
@@ -0,0 +1,58 @@
+LED Burst Trigger
+=================
+
+0. Introduction
+
+Sometimes, the system has only one no-color led to indicate different stats.
+The LED timer trigger can let LEDs to blink in different frequency, but most
+people maybe just can discriminate two states, slow and fast.
+
+In this case, Morse code maybe is a good choice :-), but who can bear it.
+
+Besides the Morse code, another way is using burst mode. People can easily tell
+how many times the LED blinks in one cycle.
+
+Burst trigger is designed for this purpose.
+
+1. How to use
+
+Burst trigger can be enabled and disabled from user space on led class
+devices that support this trigger as shown below:
+
+ echo burst > trigger
+
+Three properties are exported. They are freq, times and delay_off.
+
+ freq - the blink frequency, default value is 3 means 3HZ
+ times - burst blink times in one cycle, no default value
+ delay_off - off time between two burst blinks, default value is 500 ms
+
+2. Case studies
+
+ Example 1
+
+ echo burst > trigger
+ echo 2 > times
+
+ The behaviour is like below:
+
+ on(1/6s)off(1/6s)on(1/6s)off(1/6m)
+ ...off 500ms...
+ on(1/6s)off(1/6s)on(1/3s)off(1/6m)
+ ...off 500ms
+ ...
+
+ Example 2
+
+ echo burst > trigger
+ echo 4 > freq
+ echo 3 > times
+ echo 1000 > delay_off
+
+ The behaviour is like below:
+
+ on(1/8s)off(1/8s)on(1/8s)off(1/8m)on(1/8s)off(1/8m)
+ ...off 1s...
+ on(1/8s)off(1/8s)on(1/8s)off(1/8m)on(1/8s)off(1/8m)
+ ...off 1s
+ ...
diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 49794b4..8f4ebbf 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -108,4 +108,14 @@ config LEDS_TRIGGER_CAMERA
This enables direct flash/torch on/off by the driver, kernel space.
If unsure, say Y.
+config LEDS_TRIGGER_BURST
+ tristate "LED Burst Trigger"
+ depends on LEDS_TRIGGERS
+ help
+ This allows LEDs to blink in burst mode with parameters
+ controlled via sysfs. It's useful to notify different states
+ by using one led.
+ For more details read Documentation/leds/leds-burst.txt.
+ If unsure, say Y.
+
endif # LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 1abf48d..6c48517 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_LEDS_TRIGGER_CPU) += ledtrig-cpu.o
obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON) += ledtrig-default-on.o
obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT) += ledtrig-transient.o
obj-$(CONFIG_LEDS_TRIGGER_CAMERA) += ledtrig-camera.o
+obj-$(CONFIG_LEDS_TRIGGER_BURST) += ledtrig-burst.o
diff --git a/drivers/leds/trigger/ledtrig-burst.c b/drivers/leds/trigger/ledtrig-burst.c
new file mode 100644
index 0000000..95eda2a
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-burst.c
@@ -0,0 +1,250 @@
+/*
+ * LED Kernel Burst Trigger
+ *
+ * Copyright (C) 2013 Joe Xue <lgxue@xxxxxxxxxxx>
+ *
+ * Based on Richard Purdie's ledtrig-timer.c and Atsushi Nemoto's
+ * ledtrig-heartbeat.c and Shuah Khan's ledtrig-burst.c
+ *
+ * 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.
+ *
+ */
+/*
+ * Burst trigger allows LEDs to blink in burst mode. The difference
+ * between burst trigger and timer trigger is timer trigger makes the
+ * LEDs blink continually in a frequency while burst trigger makes the
+ * LEDs blink some times in a special frequency then have a stop.
+ * Burst trigger allows LEDs to indicate different stats. Users can easy
+ * to describe it to support engineers by saying 3/4/5/X times burst
+ * blink.
+*/
+
+#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 burst_trig_data {
+ int state;
+ unsigned long freq;
+ unsigned long times;
+ unsigned long count;
+ unsigned long delay_off;
+ int brightness_on;
+ struct timer_list timer;
+};
+
+static void burst_timer_function(unsigned long data)
+{
+ struct led_classdev *led_cdev = (struct led_classdev *) data;
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+
+ if (burst_data->count > 0) {
+ /* revert the light state */
+ burst_data->state = 1 - burst_data->state;
+ __led_set_brightness(led_cdev,
+ burst_data->state*burst_data->brightness_on);
+ burst_data->count--;
+ /* the delay time for on and off are 1000/(freq*2) = 500/freq */
+ mod_timer(&burst_data->timer,
+ jiffies + msecs_to_jiffies(500/burst_data->freq));
+ } else {
+ burst_data->count = burst_data->times * 2;
+ mod_timer(&burst_data->timer,
+ jiffies + msecs_to_jiffies(burst_data->delay_off));
+ }
+}
+
+static ssize_t burst_delay_off_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+
+ return sprintf(buf, "%lu\n", burst_data->delay_off);
+}
+
+static ssize_t burst_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);
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+ unsigned long state;
+ ssize_t ret = -EINVAL;
+
+ ret = kstrtoul(buf, 10, &state);
+ if (ret)
+ return ret;
+
+ burst_data->delay_off = state;
+
+ return size;
+}
+
+static ssize_t burst_times_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+
+ return sprintf(buf, "%lu\n", burst_data->times);
+}
+
+static ssize_t burst_times_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+ unsigned long state;
+ ssize_t ret = -EINVAL;
+
+ ret = kstrtoul(buf, 10, &state);
+ if (ret)
+ return ret;
+
+ /* if the times is larger then 0 then use it else stop burst */
+ if (state > 0) {
+ burst_data->times = state;
+ burst_data->count = state*2;
+ del_timer_sync(&burst_data->timer);
+ mod_timer(&burst_data->timer, jiffies + 1);
+ } else {
+ del_timer_sync(&burst_data->timer);
+ }
+
+ return size;
+}
+
+static ssize_t burst_freq_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+
+ return sprintf(buf, "%lu\n", burst_data->freq);
+}
+
+static ssize_t burst_freq_store(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t size)
+{
+ struct led_classdev *led_cdev = dev_get_drvdata(dev);
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+ unsigned long state;
+ ssize_t ret = -EINVAL;
+
+ ret = kstrtoul(buf, 10, &state);
+ if (ret)
+ return ret;
+
+ /* the frequency can not be 0 */
+ if (state == 0)
+ return -EINVAL;
+
+ burst_data->freq = state;
+
+ return size;
+}
+
+static DEVICE_ATTR(freq, 0644, burst_freq_show, burst_freq_store);
+static DEVICE_ATTR(times, 0644, burst_times_show, burst_times_store);
+static DEVICE_ATTR(delay_off, 0644,
+ burst_delay_off_show, burst_delay_off_store);
+
+static void burst_trig_activate(struct led_classdev *led_cdev)
+{
+ int rc;
+ struct burst_trig_data *tdata;
+
+ tdata = kzalloc(sizeof(struct burst_trig_data), GFP_KERNEL);
+ if (!tdata) {
+ dev_err(led_cdev->dev,
+ "unable to allocate burst trigger\n");
+ return;
+ }
+ /* default frequency 3HZ */
+ tdata->freq = 3;
+ /* default delay_off 500ms */
+ tdata->delay_off = 500;
+
+ tdata->state = 0;
+
+ led_cdev->trigger_data = tdata;
+
+ rc = device_create_file(led_cdev->dev, &dev_attr_freq);
+ if (rc)
+ goto err_out;
+
+ rc = device_create_file(led_cdev->dev, &dev_attr_times);
+ if (rc)
+ goto err_out_times;
+
+ rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
+ if (rc)
+ goto err_out_delay_off;
+
+ setup_timer(&tdata->timer, burst_timer_function,
+ (unsigned long) led_cdev);
+
+ tdata->brightness_on = led_get_brightness(led_cdev);
+ if (tdata->brightness_on == LED_OFF)
+ tdata->brightness_on = led_cdev->max_brightness;
+
+ __led_set_brightness(led_cdev, LED_OFF);
+ led_cdev->activated = true;
+
+ return;
+
+err_out_delay_off:
+ device_remove_file(led_cdev->dev, &dev_attr_times);
+err_out_times:
+ device_remove_file(led_cdev->dev, &dev_attr_freq);
+err_out:
+ dev_err(led_cdev->dev, "unable to register burst trigger\n");
+ led_cdev->trigger_data = NULL;
+ kfree(tdata);
+}
+
+static void burst_trig_deactivate(struct led_classdev *led_cdev)
+{
+ struct burst_trig_data *burst_data = led_cdev->trigger_data;
+
+ if (led_cdev->activated) {
+ del_timer_sync(&burst_data->timer);
+ device_remove_file(led_cdev->dev, &dev_attr_freq);
+ device_remove_file(led_cdev->dev, &dev_attr_times);
+ device_remove_file(led_cdev->dev, &dev_attr_delay_off);
+ led_cdev->trigger_data = NULL;
+ led_cdev->activated = false;
+ kfree(burst_data);
+ }
+ __led_set_brightness(led_cdev, LED_OFF);
+}
+
+static struct led_trigger burst_trigger = {
+ .name = "burst",
+ .activate = burst_trig_activate,
+ .deactivate = burst_trig_deactivate,
+};
+
+static int __init burst_trig_init(void)
+{
+ return led_trigger_register(&burst_trigger);
+}
+
+static void __exit burst_trig_exit(void)
+{
+ led_trigger_unregister(&burst_trigger);
+}
+
+module_init(burst_trig_init);
+module_exit(burst_trig_exit);
+
+MODULE_AUTHOR("Joe Xue <lgxue@xxxxxxxxxxx");
+MODULE_DESCRIPTION("Burst LED trigger");
+MODULE_LICENSE("GPL");
--
1.8.1.2
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