drivers/leds/trigger/ledtrig-transient.c

Source file repositories/reference/linux-study-clean/drivers/leds/trigger/ledtrig-transient.c

File Facts

System
Linux kernel
Corpus path
drivers/leds/trigger/ledtrig-transient.c
Extension
.c
Size
5377 bytes
Lines
199
Domain
Driver Families
Bucket
drivers/leds
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct transient_trig_data {
	int activate;
	int state;
	int restore_state;
	unsigned long duration;
	struct timer_list timer;
	struct led_classdev *led_cdev;
};

static void transient_timer_function(struct timer_list *t)
{
	struct transient_trig_data *transient_data =
		timer_container_of(transient_data, t, timer);
	struct led_classdev *led_cdev = transient_data->led_cdev;

	transient_data->activate = 0;
	led_set_brightness_nosleep(led_cdev, transient_data->restore_state);
}

static ssize_t transient_activate_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct transient_trig_data *transient_data =
		led_trigger_get_drvdata(dev);

	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 = led_trigger_get_led(dev);
	struct transient_trig_data *transient_data =
		led_trigger_get_drvdata(dev);
	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) {
		timer_delete(&transient_data->timer);
		transient_data->activate = state;
		led_set_brightness_nosleep(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_nosleep(led_cdev, transient_data->state);
		transient_data->restore_state =
		    (transient_data->state == LED_FULL) ? LED_OFF : LED_FULL;
		mod_timer(&transient_data->timer,
			  jiffies + msecs_to_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 transient_trig_data *transient_data = led_trigger_get_drvdata(dev);

	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 transient_trig_data *transient_data =
		led_trigger_get_drvdata(dev);
	unsigned long state;
	ssize_t ret;

	ret = kstrtoul(buf, 10, &state);
	if (ret)

Annotation

Implementation Notes