[PATCH 4/12] LED: Add LED Timer Trigger

[PATCH 4/12] LED: Add LED Timer Trigger

[Richard Purdie]

Add an example of a complex LED trigger in the form of a generic timer 
which triggers the LED its attached to at a user specified frequency
and duty cycle.

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

Index: linux-2.6.15/drivers/leds/Kconfig
===================================================================
--- linux-2.6.15.orig/drivers/leds/Kconfig	2006-01-29 16:13:48.000000000 +0000
+++ linux-2.6.15/drivers/leds/Kconfig	2006-01-29 20:32:16.000000000 +0000
@@ -22,5 +22,12 @@
 	  These triggers allow kernel events to drive the LEDs and can
 	  be configured via sysfs. If unsure, say Y.
 
+config LEDS_TRIGGER_TIMER
+	tristate "LED Timer Trigger"
+	depends LEDS_TRIGGERS
+	help
+	  This allows LEDs to be controlled by a programmable timer
+	  via sysfs. If unsure, say Y.
+
 endmenu
 
Index: linux-2.6.15/drivers/leds/Makefile
===================================================================
--- linux-2.6.15.orig/drivers/leds/Makefile	2006-01-29 16:13:48.000000000 +0000
+++ linux-2.6.15/drivers/leds/Makefile	2006-01-29 20:32:16.000000000 +0000
@@ -3,3 +3,6 @@
 obj-$(CONFIG_NEW_LEDS)			+= led-core.o
 obj-$(CONFIG_LEDS_CLASS)		+= led-class.o
 obj-$(CONFIG_LEDS_TRIGGERS)		+= led-triggers.o
+
+# LED Triggers
+obj-$(CONFIG_LEDS_TRIGGER_TIMER)	+= ledtrig-timer.o
Index: linux-2.6.15/drivers/leds/ledtrig-timer.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15/drivers/leds/ledtrig-timer.c	2006-01-29 17:40:11.000000000 +0000
@@ -0,0 +1,205 @@
+/*
+ * LED Kernel Timer Trigger
+ *
+ * Copyright 2005-2006 Openedhand Ltd.
+ *
+ * Author: 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/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/sysdev.h>
+#include <linux/timer.h>
+#include <linux/leds.h>
+#include "leds.h"
+
+struct timer_trig_data {
+	unsigned long duty; /* duty cycle, as a percentage */
+	unsigned long frequency; /* frequency of blinking, in Hz */
+	unsigned long delay_on; /* milliseconds on */
+	unsigned long delay_off; /* milliseconds off */
+	struct timer_list timer;
+};
+
+static void led_timer_function(unsigned long data)
+{
+	struct led_classdev *led_cdev = (struct led_classdev *) data;
+	struct timer_trig_data *timer_data = led_cdev->trigger_data;
+	unsigned long brightness = LED_OFF;
+	unsigned long delay = timer_data->delay_off;
+
+	write_lock(&led_cdev->lock);
+
+	if (!timer_data->frequency) {
+		led_set_brightness(led_cdev, LED_OFF);
+		write_unlock(&led_cdev->lock);
+		return;
+	}
+
+	if (!led_cdev->brightness) {
+		brightness = LED_FULL;
+		delay = timer_data->delay_on;
+	}
+
+	led_set_brightness(led_cdev, brightness);
+
+	mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
+	write_unlock(&led_cdev->lock);
+}
+
+/* led_cdev write lock needs to be held */
+static int led_timer_setdata(struct led_classdev *led_cdev, unsigned long duty, unsigned long frequency)
+{
+	struct timer_trig_data *timer_data = led_cdev->trigger_data;
+
+	if (frequency > 500)
+		return -EINVAL;
+
+	if (duty > 100)
+		return -EINVAL;
+
+	timer_data->duty = duty;
+	timer_data->frequency = frequency;
+	if (frequency != 0) {
+		timer_data->delay_on = duty * 1000 / 50 / frequency / 2;
+		timer_data->delay_off = (100 - duty) * 1000 / 50 / frequency / 2;
+	}
+
+	mod_timer(&timer_data->timer, jiffies + 1);
+
+	return 0;
+}
+
+static ssize_t led_duty_show(struct class_device *dev, char *buf)
+{
+	struct led_classdev *led_cdev = dev->class_data;
+	struct timer_trig_data *timer_data;
+
+	read_lock(&led_cdev->lock);
+	timer_data = led_cdev->trigger_data;
+	sprintf(buf, "%lu\n", timer_data->duty);
+	read_unlock(&led_cdev->lock);
+
+	return strlen(buf) + 1;
+}
+
+static ssize_t led_duty_store(struct class_device *dev, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev->class_data;
+	struct timer_trig_data *timer_data;
+	int ret = -EINVAL;
+	char *after;
+
+	unsigned long state = simple_strtoul(buf, &after, 10);
+	if (after - buf > 0) {
+		write_lock(&led_cdev->lock);
+		timer_data = led_cdev->trigger_data;
+		ret = led_timer_setdata(led_cdev, state, timer_data->frequency);
+		if (!ret)
+			ret = after - buf;			
+		write_unlock(&led_cdev->lock);
+	}
+
+	return ret;
+}
+
+
+static ssize_t led_frequency_show(struct class_device *dev, char *buf)
+{
+	struct led_classdev *led_cdev = dev->class_data;
+	struct timer_trig_data *timer_data;
+
+	read_lock(&led_cdev->lock);
+	timer_data = led_cdev->trigger_data;
+	sprintf(buf, "%lu\n", timer_data->frequency);
+	read_unlock(&led_cdev->lock);
+
+	return strlen(buf) + 1;
+}
+
+static ssize_t led_frequency_store(struct class_device *dev, const char *buf, size_t size)
+{
+	struct led_classdev *led_cdev = dev->class_data;
+	struct timer_trig_data *timer_data;
+	int ret = -EINVAL;
+	char *after;
+
+	unsigned long state = simple_strtoul(buf, &after, 10);
+	if (after - buf > 0) {
+		write_lock(&led_cdev->lock);
+		timer_data = led_cdev->trigger_data;
+		ret = led_timer_setdata(led_cdev, timer_data->duty, state);
+		if (!ret)
+			ret = after - buf;			
+		write_unlock(&led_cdev->lock);
+	}
+
+	return ret;
+}
+
+static CLASS_DEVICE_ATTR(duty, 0644, led_duty_show, led_duty_store);
+static CLASS_DEVICE_ATTR(frequency, 0644, led_frequency_show, led_frequency_store);
+
+static void timer_trig_activate(struct led_classdev *led_cdev)
+{
+	struct timer_trig_data *timer_data;
+
+	timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
+	if (!timer_data)
+		return;
+
+	led_cdev->trigger_data = timer_data;
+
+	init_timer(&timer_data->timer);
+	timer_data->timer.function = led_timer_function;
+	timer_data->timer.data = (unsigned long) led_cdev;
+
+	timer_data->duty = 50;
+
+	class_device_create_file(led_cdev->class_dev, &class_device_attr_duty);
+	class_device_create_file(led_cdev->class_dev, &class_device_attr_frequency);
+}
+
+static void timer_trig_deactivate(struct led_classdev *led_cdev)
+{
+	struct timer_trig_data *timer_data = led_cdev->trigger_data;
+	if (timer_data) {
+		class_device_remove_file(led_cdev->class_dev, &class_device_attr_duty);
+		class_device_remove_file(led_cdev->class_dev, &class_device_attr_frequency);
+		del_timer_sync(&timer_data->timer);
+		kfree(timer_data);
+	}
+}
+
+static struct led_trigger timer_led_trigger = {
+	.name     = "timer",
+	.activate = timer_trig_activate,
+	.deactivate = timer_trig_deactivate,
+};
+
+static int __init timer_trig_init(void)
+{
+	return led_trigger_register(&timer_led_trigger);
+}
+
+static void __exit timer_trig_exit (void)
+{
+	led_trigger_unregister(&timer_led_trigger);
+}
+
+module_init(timer_trig_init);
+module_exit(timer_trig_exit);
+
+MODULE_AUTHOR("Richard Purdie <rpurdie@openedhand.com>");
+MODULE_DESCRIPTION("Timer LED trigger");
+MODULE_LICENSE("GPL");

RE: [PATCH 4/12] LED: Add LED Timer Trigger

[Richard Purdie]

As mentioned on LKML by John Bowler, using frequency and duty as
attributes is a bad idea as it restricts the potential usage of this
trigger. Therefore, instead export the two delay parameters directly.
Also remove unneeded locking and use class_get_devdata().

Signed-off-by: Richard Purdie <rpurdie@rpsys.net>

Index: linux-2.6.15/drivers/leds/ledtrig-timer.c
===================================================================
--- linux-2.6.15.orig/drivers/leds/ledtrig-timer.c	2006-02-08 01:42:26.000000000 +0000
+++ linux-2.6.15/drivers/leds/ledtrig-timer.c	2006-02-08 02:03:20.000000000 +0000
@@ -24,8 +24,6 @@
 #include "leds.h"
 
 struct timer_trig_data {
-	unsigned long duty;		/* duty cycle, as a percentage */
-	unsigned long frequency;	/* frequency of blinking, in Hz */
 	unsigned long delay_on;		/* milliseconds on */
 	unsigned long delay_off;	/* milliseconds off */
 	struct timer_list timer;
@@ -38,9 +36,8 @@
 	unsigned long brightness = LED_OFF;
 	unsigned long delay = timer_data->delay_off;
 
-	write_lock(&led_cdev->lock);
-
-	if (!timer_data->frequency) {
+	if (!timer_data->delay_on || !timer_data->delay_off) {
+		write_lock(&led_cdev->lock);
 		led_set_brightness(led_cdev, LED_OFF);
 		write_unlock(&led_cdev->lock);
 		return;
@@ -51,107 +48,73 @@
 		delay = timer_data->delay_on;
 	}
 
+	write_lock(&led_cdev->lock);
 	led_set_brightness(led_cdev, brightness);
+	write_unlock(&led_cdev->lock);
 
 	mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
-	write_unlock(&led_cdev->lock);
 }
 
-/* led_cdev write lock needs to be held */
-static int led_timer_setdata(struct led_classdev *led_cdev, unsigned long duty,
-				unsigned long frequency)
+static ssize_t led_delay_on_show(struct class_device *dev, char *buf)
 {
+	struct led_classdev *led_cdev = class_get_devdata(dev);
 	struct timer_trig_data *timer_data = led_cdev->trigger_data;
 
-	if (frequency > 500)
-		return -EINVAL;
-
-	if (duty > 100)
-		return -EINVAL;
-
-	timer_data->duty = duty;
-	timer_data->frequency = frequency;
-	if (frequency != 0) {
-		timer_data->delay_on = duty * 1000 / 50 / frequency / 2;
-		timer_data->delay_off = (100 - duty)*1000 / 50 / frequency / 2;
-	}
-
-	mod_timer(&timer_data->timer, jiffies + 1);
-
-	return 0;
-}
-
-static ssize_t led_duty_show(struct class_device *dev, char *buf)
-{
-	struct led_classdev *led_cdev = dev->class_data;
-	struct timer_trig_data *timer_data;
-
-	read_lock(&led_cdev->lock);
-	timer_data = led_cdev->trigger_data;
-	sprintf(buf, "%lu\n", timer_data->duty);
-	read_unlock(&led_cdev->lock);
+	sprintf(buf, "%lu\n", timer_data->delay_on);
 
 	return strlen(buf) + 1;
 }
 
-static ssize_t led_duty_store(struct class_device *dev, const char *buf,
+static ssize_t led_delay_on_store(struct class_device *dev, const char *buf,
 				size_t size)
 {
-	struct led_classdev *led_cdev = dev->class_data;
-	struct timer_trig_data *timer_data;
+	struct led_classdev *led_cdev = class_get_devdata(dev);
+	struct timer_trig_data *timer_data = led_cdev->trigger_data;
 	int ret = -EINVAL;
 	char *after;
-
 	unsigned long state = simple_strtoul(buf, &after, 10);
+
 	if (after - buf > 0) {
-		write_lock(&led_cdev->lock);
-		timer_data = led_cdev->trigger_data;
-		ret = led_timer_setdata(led_cdev, state, timer_data->frequency);
-		if (!ret)
-			ret = after - buf;			
-		write_unlock(&led_cdev->lock);
+		timer_data->delay_on = state;
+		mod_timer(&timer_data->timer, jiffies + 1);
+		ret = after - buf;
 	}
 
 	return ret;
 }
 
-static ssize_t led_frequency_show(struct class_device *dev, char *buf)
+static ssize_t led_delay_off_show(struct class_device *dev, char *buf)
 {
-	struct led_classdev *led_cdev = dev->class_data;
-	struct timer_trig_data *timer_data;
+	struct led_classdev *led_cdev = class_get_devdata(dev);
+	struct timer_trig_data *timer_data = led_cdev->trigger_data;
 
-	read_lock(&led_cdev->lock);
-	timer_data = led_cdev->trigger_data;
-	sprintf(buf, "%lu\n", timer_data->frequency);
-	read_unlock(&led_cdev->lock);
+	sprintf(buf, "%lu\n", timer_data->delay_off);
 
 	return strlen(buf) + 1;
 }
 
-static ssize_t led_frequency_store(struct class_device *dev, const char *buf,
+static ssize_t led_delay_off_store(struct class_device *dev, const char *buf,
 				size_t size)
 {
-	struct led_classdev *led_cdev = dev->class_data;
-	struct timer_trig_data *timer_data;
+	struct led_classdev *led_cdev = class_get_devdata(dev);
+	struct timer_trig_data *timer_data = led_cdev->trigger_data;
 	int ret = -EINVAL;
 	char *after;
 	unsigned long state = simple_strtoul(buf, &after, 10);
 
 	if (after - buf > 0) {
-		write_lock(&led_cdev->lock);
-		timer_data = led_cdev->trigger_data;
-		ret = led_timer_setdata(led_cdev, timer_data->duty, state);
-		if (!ret)
-			ret = after - buf;			
-		write_unlock(&led_cdev->lock);
+		timer_data->delay_off = state;
+		mod_timer(&timer_data->timer, jiffies + 1);
+		ret = after - buf;
 	}
 
 	return ret;
 }
 
-static CLASS_DEVICE_ATTR(duty, 0644, led_duty_show, led_duty_store);
-static CLASS_DEVICE_ATTR(frequency, 0644, led_frequency_show,
-			led_frequency_store);
+static CLASS_DEVICE_ATTR(delay_on, 0644, led_delay_on_show, 
+			led_delay_on_store);
+static CLASS_DEVICE_ATTR(delay_off, 0644, led_delay_off_show,
+			led_delay_off_store);
 
 static void timer_trig_activate(struct led_classdev *led_cdev)
 {
@@ -167,11 +130,10 @@
 	timer_data->timer.function = led_timer_function;
 	timer_data->timer.data = (unsigned long) led_cdev;
 
-	timer_data->duty = 50;
-
-	class_device_create_file(led_cdev->class_dev, &class_device_attr_duty);
+	class_device_create_file(led_cdev->class_dev, 
+				&class_device_attr_delay_on);
 	class_device_create_file(led_cdev->class_dev,
-				&class_device_attr_frequency);
+				&class_device_attr_delay_off);
 }
 
 static void timer_trig_deactivate(struct led_classdev *led_cdev)
@@ -180,9 +142,9 @@
 
 	if (timer_data) {
 		class_device_remove_file(led_cdev->class_dev,
-					&class_device_attr_duty);
+					&class_device_attr_delay_on);
 		class_device_remove_file(led_cdev->class_dev,
-					&class_device_attr_frequency);
+					&class_device_attr_delay_off);
 		del_timer_sync(&timer_data->timer);
 		kfree(timer_data);
 	}
@@ -199,7 +161,7 @@
 	return led_trigger_register(&timer_led_trigger);
 }
 
-static void __exit timer_trig_exit (void)
+static void __exit timer_trig_exit(void)
 {
 	led_trigger_unregister(&timer_led_trigger);
 }