drivers/input/input-poller.c

Source file repositories/reference/linux-study-clean/drivers/input/input-poller.c

File Facts

System
Linux kernel
Corpus path
drivers/input/input-poller.c
Extension
.c
Size
5382 bytes
Lines
222
Domain
Driver Families
Bucket
drivers/input
Inferred role
Driver Families: exported/initcall integration point
Status
integration 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 input_dev_poller {
	void (*poll)(struct input_dev *dev);

	unsigned int poll_interval; /* msec */
	unsigned int poll_interval_max; /* msec */
	unsigned int poll_interval_min; /* msec */

	struct input_dev *input;
	struct delayed_work work;
};

static void input_dev_poller_queue_work(struct input_dev_poller *poller)
{
	unsigned long delay;

	delay = msecs_to_jiffies(poller->poll_interval);
	if (delay >= HZ)
		delay = round_jiffies_relative(delay);

	queue_delayed_work(system_freezable_wq, &poller->work, delay);
}

static void input_dev_poller_work(struct work_struct *work)
{
	struct input_dev_poller *poller =
		container_of(work, struct input_dev_poller, work.work);

	poller->poll(poller->input);
	input_dev_poller_queue_work(poller);
}

void input_dev_poller_finalize(struct input_dev_poller *poller)
{
	if (!poller->poll_interval)
		poller->poll_interval = 500;
	if (!poller->poll_interval_max)
		poller->poll_interval_max = poller->poll_interval;
}

void input_dev_poller_start(struct input_dev_poller *poller)
{
	/* Only start polling if polling is enabled */
	if (poller->poll_interval > 0) {
		poller->poll(poller->input);
		input_dev_poller_queue_work(poller);
	}
}

void input_dev_poller_stop(struct input_dev_poller *poller)
{
	cancel_delayed_work_sync(&poller->work);
}

int input_setup_polling(struct input_dev *dev,
			void (*poll_fn)(struct input_dev *dev))
{
	struct input_dev_poller *poller;

	poller = kzalloc_obj(*poller);
	if (!poller) {
		/*
		 * We want to show message even though kzalloc() may have
		 * printed backtrace as knowing what instance of input
		 * device we were dealing with is helpful.
		 */
		dev_err(dev->dev.parent ?: &dev->dev,
			"%s: unable to allocate poller structure\n", __func__);
		return -ENOMEM;
	}

	INIT_DELAYED_WORK(&poller->work, input_dev_poller_work);
	poller->input = dev;
	poller->poll = poll_fn;

	dev->poller = poller;
	return 0;
}
EXPORT_SYMBOL(input_setup_polling);

static bool input_dev_ensure_poller(struct input_dev *dev)
{
	if (!dev->poller) {
		dev_err(dev->dev.parent ?: &dev->dev,
			"poller structure has not been set up\n");
		return false;
	}

	return true;
}

Annotation

Implementation Notes