Some LEDs can be programmed to blink without any CPU interaction. To
support this feature, a LED driver can optionally implement the
-blink_set() function (see <linux/leds.h>). If implemented, triggers can
-attempt to use it before falling back to software timers. The blink_set()
-function should return 0 if the blink setting is supported, or -EINVAL
-otherwise, which means that LED blinking will be handled by software.
-
-The blink_set() function should choose a user friendly blinking
-value if it is called with *delay_on==0 && *delay_off==0 parameters. In
-this case the driver should give back the chosen value through delay_on
-and delay_off parameters to the leds subsystem.
+blink_set() function (see <linux/leds.h>). To set an LED to blinking,
+however, it is better to use use the API function led_blink_set(),
+as it will check and implement software fallback if necessary.
+
+To turn off blinking again, use the API function led_brightness_set()
+as that will not just set the LED brightness but also stop any software
+timers that may have been required for blinking.
+
+The blink_set() function should choose a user friendly blinking value
+if it is called with *delay_on==0 && *delay_off==0 parameters. In this
+case the driver should give back the chosen value through delay_on and
+delay_off parameters to the leds subsystem.
Setting the brightness to zero with brightness_set() callback function
should completely turn off the LED and cancel the previously programmed
if NEW_LEDS
config LEDS_CLASS
- tristate "LED Class Support"
+ bool "LED Class Support"
help
This option enables the led sysfs class in /sys/class/leds. You'll
need this to do anything useful with LEDs. If unsure, say N.
__ATTR_NULL,
};
+static void led_timer_function(unsigned long data)
+{
+ struct led_classdev *led_cdev = (void *)data;
+ unsigned long brightness;
+ unsigned long delay;
+
+ if (!led_cdev->blink_delay_on || !led_cdev->blink_delay_off) {
+ led_set_brightness(led_cdev, LED_OFF);
+ return;
+ }
+
+ brightness = led_get_brightness(led_cdev);
+ if (!brightness) {
+ /* Time to switch the LED on. */
+ brightness = led_cdev->blink_brightness;
+ delay = led_cdev->blink_delay_on;
+ } else {
+ /* Store the current brightness value to be able
+ * to restore it when the delay_off period is over.
+ */
+ led_cdev->blink_brightness = brightness;
+ brightness = LED_OFF;
+ delay = led_cdev->blink_delay_off;
+ }
+
+ led_set_brightness(led_cdev, brightness);
+
+ mod_timer(&led_cdev->blink_timer, jiffies + msecs_to_jiffies(delay));
+}
+
+static void led_stop_software_blink(struct led_classdev *led_cdev)
+{
+ /* deactivate previous settings */
+ del_timer_sync(&led_cdev->blink_timer);
+ led_cdev->blink_delay_on = 0;
+ led_cdev->blink_delay_off = 0;
+}
+
+static void led_set_software_blink(struct led_classdev *led_cdev,
+ unsigned long delay_on,
+ unsigned long delay_off)
+{
+ int current_brightness;
+
+ current_brightness = led_get_brightness(led_cdev);
+ if (current_brightness)
+ led_cdev->blink_brightness = current_brightness;
+ if (!led_cdev->blink_brightness)
+ led_cdev->blink_brightness = led_cdev->max_brightness;
+
+ if (delay_on == led_cdev->blink_delay_on &&
+ delay_off == led_cdev->blink_delay_off)
+ return;
+
+ led_stop_software_blink(led_cdev);
+
+ led_cdev->blink_delay_on = delay_on;
+ led_cdev->blink_delay_off = delay_off;
+
+ /* never on - don't blink */
+ if (!delay_on)
+ return;
+
+ /* never off - just set to brightness */
+ if (!delay_off) {
+ led_set_brightness(led_cdev, led_cdev->blink_brightness);
+ return;
+ }
+
+ mod_timer(&led_cdev->blink_timer, jiffies + 1);
+}
+
+
/**
* led_classdev_suspend - suspend an led_classdev.
* @led_cdev: the led_classdev to suspend.
led_update_brightness(led_cdev);
+ init_timer(&led_cdev->blink_timer);
+ led_cdev->blink_timer.function = led_timer_function;
+ led_cdev->blink_timer.data = (unsigned long)led_cdev;
+
#ifdef CONFIG_LEDS_TRIGGERS
led_trigger_set_default(led_cdev);
#endif
return 0;
}
-
EXPORT_SYMBOL_GPL(led_classdev_register);
/**
up_write(&led_cdev->trigger_lock);
#endif
+ /* Stop blinking */
+ led_brightness_set(led_cdev, LED_OFF);
+
device_unregister(led_cdev->dev);
down_write(&leds_list_lock);
}
EXPORT_SYMBOL_GPL(led_classdev_unregister);
+void led_blink_set(struct led_classdev *led_cdev,
+ unsigned long *delay_on,
+ unsigned long *delay_off)
+{
+ if (led_cdev->blink_set &&
+ led_cdev->blink_set(led_cdev, delay_on, delay_off))
+ return;
+
+ /* blink with 1 Hz as default if nothing specified */
+ if (!*delay_on && !*delay_off)
+ *delay_on = *delay_off = 500;
+
+ led_set_software_blink(led_cdev, *delay_on, *delay_off);
+}
+EXPORT_SYMBOL(led_blink_set);
+
+void led_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ led_stop_software_blink(led_cdev);
+ led_cdev->brightness_set(led_cdev, brightness);
+}
+EXPORT_SYMBOL(led_brightness_set);
+
static int __init leds_init(void)
{
leds_class = class_create(THIS_MODULE, "leds");
if (led_cdev->trigger->deactivate)
led_cdev->trigger->deactivate(led_cdev);
led_cdev->trigger = NULL;
- led_set_brightness(led_cdev, LED_OFF);
+ led_brightness_set(led_cdev, LED_OFF);
}
if (trigger) {
write_lock_irqsave(&trigger->leddev_list_lock, flags);
*/
#include <linux/module.h>
-#include <linux/jiffies.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/ctype.h>
#include <linux/leds.h>
-#include <linux/slab.h>
#include "leds.h"
-struct timer_trig_data {
- int brightness_on; /* LED brightness during "on" period.
- * (LED_OFF < brightness_on <= LED_FULL)
- */
- 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;
- unsigned long delay;
-
- if (!timer_data->delay_on || !timer_data->delay_off) {
- led_set_brightness(led_cdev, LED_OFF);
- return;
- }
-
- brightness = led_get_brightness(led_cdev);
- if (!brightness) {
- /* Time to switch the LED on. */
- brightness = timer_data->brightness_on;
- delay = timer_data->delay_on;
- } else {
- /* Store the current brightness value to be able
- * to restore it when the delay_off period is over.
- */
- timer_data->brightness_on = brightness;
- brightness = LED_OFF;
- delay = timer_data->delay_off;
- }
-
- led_set_brightness(led_cdev, brightness);
-
- mod_timer(&timer_data->timer, jiffies + msecs_to_jiffies(delay));
-}
-
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);
- struct timer_trig_data *timer_data = led_cdev->trigger_data;
- return sprintf(buf, "%lu\n", timer_data->delay_on);
+ 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);
- struct timer_trig_data *timer_data = led_cdev->trigger_data;
int ret = -EINVAL;
char *after;
unsigned long state = simple_strtoul(buf, &after, 10);
count++;
if (count == size) {
- if (timer_data->delay_on != state) {
- /* the new value differs from the previous */
- timer_data->delay_on = state;
-
- /* deactivate previous settings */
- del_timer_sync(&timer_data->timer);
-
- /* try to activate hardware acceleration, if any */
- if (!led_cdev->blink_set ||
- led_cdev->blink_set(led_cdev,
- &timer_data->delay_on, &timer_data->delay_off)) {
- /* no hardware acceleration, blink via timer */
- mod_timer(&timer_data->timer, jiffies + 1);
- }
- }
+ led_blink_set(led_cdev, &state, &led_cdev->blink_delay_off);
ret = count;
}
struct device_attribute *attr, char *buf)
{
struct led_classdev *led_cdev = dev_get_drvdata(dev);
- struct timer_trig_data *timer_data = led_cdev->trigger_data;
- return sprintf(buf, "%lu\n", timer_data->delay_off);
+ 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);
- struct timer_trig_data *timer_data = led_cdev->trigger_data;
int ret = -EINVAL;
char *after;
unsigned long state = simple_strtoul(buf, &after, 10);
count++;
if (count == size) {
- if (timer_data->delay_off != state) {
- /* the new value differs from the previous */
- timer_data->delay_off = state;
-
- /* deactivate previous settings */
- del_timer_sync(&timer_data->timer);
-
- /* try to activate hardware acceleration, if any */
- if (!led_cdev->blink_set ||
- led_cdev->blink_set(led_cdev,
- &timer_data->delay_on, &timer_data->delay_off)) {
- /* no hardware acceleration, blink via timer */
- mod_timer(&timer_data->timer, jiffies + 1);
- }
- }
+ led_blink_set(led_cdev, &led_cdev->blink_delay_on, &state);
ret = count;
}
static void timer_trig_activate(struct led_classdev *led_cdev)
{
- struct timer_trig_data *timer_data;
int rc;
- timer_data = kzalloc(sizeof(struct timer_trig_data), GFP_KERNEL);
- if (!timer_data)
- return;
-
- timer_data->brightness_on = led_get_brightness(led_cdev);
- if (timer_data->brightness_on == LED_OFF)
- timer_data->brightness_on = led_cdev->max_brightness;
- 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;
+ led_cdev->trigger_data = NULL;
rc = device_create_file(led_cdev->dev, &dev_attr_delay_on);
if (rc)
- goto err_out;
+ return;
rc = device_create_file(led_cdev->dev, &dev_attr_delay_off);
if (rc)
goto err_out_delayon;
- /* If there is hardware support for blinking, start one
- * user friendly blink rate chosen by the driver.
- */
- if (led_cdev->blink_set)
- led_cdev->blink_set(led_cdev,
- &timer_data->delay_on, &timer_data->delay_off);
+ led_cdev->trigger_data = (void *)1;
return;
err_out_delayon:
device_remove_file(led_cdev->dev, &dev_attr_delay_on);
-err_out:
- led_cdev->trigger_data = NULL;
- kfree(timer_data);
}
static void timer_trig_deactivate(struct led_classdev *led_cdev)
{
- struct timer_trig_data *timer_data = led_cdev->trigger_data;
- unsigned long on = 0, off = 0;
-
- if (timer_data) {
+ if (led_cdev->trigger_data) {
device_remove_file(led_cdev->dev, &dev_attr_delay_on);
device_remove_file(led_cdev->dev, &dev_attr_delay_off);
- del_timer_sync(&timer_data->timer);
- kfree(timer_data);
}
- /* If there is hardware support for blinking, stop it */
- if (led_cdev->blink_set)
- led_cdev->blink_set(led_cdev, &on, &off);
+ /* Stop blinking */
+ led_brightness_set(led_cdev, LED_OFF);
}
static struct led_trigger timer_led_trigger = {
boolean
default y if (RT2X00_LIB=y && LEDS_CLASS=y) || (RT2X00_LIB=m && LEDS_CLASS!=n)
-comment "rt2x00 leds support disabled due to modularized LEDS_CLASS and built-in rt2x00"
- depends on RT2X00_LIB=y && LEDS_CLASS=m
-
config RT2X00_LIB_DEBUGFS
bool "Ralink debugfs support"
depends on RT2X00_LIB && MAC80211_DEBUGFS
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rwsem.h>
+#include <linux/timer.h>
struct device;
/*
/* Get LED brightness level */
enum led_brightness (*brightness_get)(struct led_classdev *led_cdev);
- /* Activate hardware accelerated blink, delays are in
- * miliseconds and if none is provided then a sensible default
- * should be chosen. The call can adjust the timings if it can't
- * match the values specified exactly. */
+ /*
+ * Activate hardware accelerated blink, delays are in milliseconds
+ * and if both are zero then a sensible default should be chosen.
+ * The call should adjust the timings in that case and if it can't
+ * match the values specified exactly.
+ * Deactivate blinking again when the brightness is set to a fixed
+ * value via the brightness_set() callback.
+ */
int (*blink_set)(struct led_classdev *led_cdev,
unsigned long *delay_on,
unsigned long *delay_off);
struct list_head node; /* LED Device list */
const char *default_trigger; /* Trigger to use */
+ unsigned long blink_delay_on, blink_delay_off;
+ struct timer_list blink_timer;
+ int blink_brightness;
+
#ifdef CONFIG_LEDS_TRIGGERS
/* Protects the trigger data below */
struct rw_semaphore trigger_lock;
extern void led_classdev_suspend(struct led_classdev *led_cdev);
extern void led_classdev_resume(struct led_classdev *led_cdev);
+/**
+ * led_blink_set - set blinking with software fallback
+ * @led_cdev: the LED to start blinking
+ * @delay_on: the time it should be on (in ms)
+ * @delay_off: the time it should ble off (in ms)
+ *
+ * This function makes the LED blink, attempting to use the
+ * hardware acceleration if possible, but falling back to
+ * software blinking if there is no hardware blinking or if
+ * the LED refuses the passed values.
+ *
+ * Note that if software blinking is active, simply calling
+ * led_cdev->brightness_set() will not stop the blinking,
+ * use led_classdev_brightness_set() instead.
+ */
+extern void led_blink_set(struct led_classdev *led_cdev,
+ unsigned long *delay_on,
+ unsigned long *delay_off);
+/**
+ * led_brightness_set - set LED brightness
+ * @led_cdev: the LED to set
+ * @brightness: the brightness to set it to
+ *
+ * Set an LED's brightness, and, if necessary, cancel the
+ * software blink timer that implements blinking when the
+ * hardware doesn't.
+ */
+extern void led_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness);
+
/*
* LED Triggers
*/
projects / users / hch / configfs.git / commitdiff