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Commit 0dcd8073 authored by Dmitry Torokhov's avatar Dmitry Torokhov
Browse files

Input: add skeleton for simple polled devices 



input-polldev provides a skeleton for supporting simple input
devices that need to be periodically scanned or polled to
detect changes in their state.

Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 85796e7d

drivers/input/misc/Kconfig

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Original line number Diff line number Diff line
@@ -90,6 +90,17 @@ config INPUT_UINPUT 
	  To compile this driver as a module, choose M here: the

	  module will be called uinput.



config INPUT_POLLDEV

	tristate "Polled input device skeleton"

	help

	  Say Y here if you are using a driver for an input

	  device that periodically polls hardware state. This

	  option is only useful for out-of-tree drivers since

	  in-tree drivers select it automatically.



	  To compile this driver as a module, choose M here: the

	  module will be called input-polldev.



config HP_SDC_RTC

	tristate "HP SDC Real Time Clock"

	depends on GSC || HP300

drivers/input/misc/Makefile

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Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


# Each configuration option enables a list of files.



obj-$(CONFIG_INPUT_POLLDEV)		+= input-polldev.o

obj-$(CONFIG_INPUT_SPARCSPKR)		+= sparcspkr.o

obj-$(CONFIG_INPUT_PCSPKR)		+= pcspkr.o

obj-$(CONFIG_INPUT_M68K_BEEP)		+= m68kspkr.o

drivers/input/misc/input-polldev.c

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/*

 * Generic implementation of a polled input device



 * Copyright (c) 2007 Dmitry Torokhov

 *

 * 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/jiffies.h>

#include <linux/mutex.h>

#include <linux/input-polldev.h>



static DEFINE_MUTEX(polldev_mutex);

static int polldev_users;

static struct workqueue_struct *polldev_wq;



static int input_polldev_start_workqueue(void)

{

	int retval;



	retval = mutex_lock_interruptible(&polldev_mutex);

	if (retval)

		return retval;



	if (!polldev_users) {

		polldev_wq = create_singlethread_workqueue("ipolldevd");

		if (!polldev_wq) {

			printk(KERN_ERR "input-polldev: failed to create "

				"ipolldevd workqueue\n");

			retval = -ENOMEM;

			goto out;

		}

	}



	polldev_users++;



 out:

	mutex_unlock(&polldev_mutex);

	return retval;

}



static void input_polldev_stop_workqueue(void)

{

	mutex_lock(&polldev_mutex);



	if (!--polldev_users)

		destroy_workqueue(polldev_wq);



	mutex_unlock(&polldev_mutex);

}



static void input_polled_device_work(struct work_struct *work)

{

	struct input_polled_dev *dev =

		container_of(work, struct input_polled_dev, work.work);



	dev->poll(dev);

	queue_delayed_work(polldev_wq, &dev->work,

			   msecs_to_jiffies(dev->poll_interval));

}



static int input_open_polled_device(struct input_dev *input)

{

	struct input_polled_dev *dev = input->private;

	int error;



	error = input_polldev_start_workqueue();

	if (error)

		return error;



	if (dev->flush)

		dev->flush(dev);



	queue_delayed_work(polldev_wq, &dev->work,

			   msecs_to_jiffies(dev->poll_interval));



	return 0;

}



static void input_close_polled_device(struct input_dev *input)

{

	struct input_polled_dev *dev = input->private;



	cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);

	input_polldev_stop_workqueue();

}



/**

 * input_allocate_polled_device - allocated memory polled device

 *

 * The function allocates memory for a polled device and also

 * for an input device associated with this polled device.

 */

struct input_polled_dev *input_allocate_polled_device(void)

{

	struct input_polled_dev *dev;



	dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);

	if (!dev)

		return NULL;



	dev->input = input_allocate_device();

	if (!dev->input) {

		kfree(dev);

		return NULL;

	}



	return dev;

}

EXPORT_SYMBOL(input_allocate_polled_device);



/**

 * input_free_polled_device - free memory allocated for polled device

 * @dev: device to free

 *

 * The function frees memory allocated for polling device and drops

 * reference to the associated input device (if present).

 */

void input_free_polled_device(struct input_polled_dev *dev)

{

	if (dev) {

		input_free_device(dev->input);

		kfree(dev);

	}

}

EXPORT_SYMBOL(input_free_polled_device);



/**

 * input_register_polled_device - register polled device

 * @dev: device to register

 *

 * The function registers previously initialized polled input device

 * with input layer. The device should be allocated with call to

 * input_allocate_polled_device(). Callers should also set up poll()

 * method and set up capabilities (id, name, phys, bits) of the

 * corresponing input_dev structure.

 */

int input_register_polled_device(struct input_polled_dev *dev)

{

	struct input_dev *input = dev->input;



	INIT_DELAYED_WORK(&dev->work, input_polled_device_work);

	if (!dev->poll_interval)

		dev->poll_interval = 500;

	input->private = dev;

	input->open = input_open_polled_device;

	input->close = input_close_polled_device;



	return input_register_device(input);

}

EXPORT_SYMBOL(input_register_polled_device);



/**

 * input_unregister_polled_device - unregister polled device

 * @dev: device to unregister

 *

 * The function unregisters previously registered polled input

 * device from input layer. Polling is stopped and device is

 * ready to be freed with call to input_free_polled_device().

 * Callers should not attempt to access dev->input pointer

 * after calling this function.

 */

void input_unregister_polled_device(struct input_polled_dev *dev)

{

	input_unregister_device(dev->input);

	dev->input = NULL;

}

EXPORT_SYMBOL(input_unregister_polled_device);

include/linux/input-polldev.h

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#ifndef _INPUT_POLLDEV_H

#define _INPUT_POLLDEV_H



/*

 * Copyright (c) 2007 Dmitry Torokhov

 *

 * 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/input.h>

#include <linux/workqueue.h>



/**

 * struct input_polled_dev - simple polled input device

 * @private: private driver data

 * @flush: driver-supplied method that flushes device's state upon

 *	opening (optional)

 * @poll: driver-supplied method that polls the device and posts

 *	input events (mandatory).

 * @poll_interval: specifies how often the poll() method shoudl be called.

 * @input: input device structire associated with the polled device.

 *	Must be properly initialized by the driver (id, name, phys, bits).

 *

 * Polled input device provides a skeleton for supporting simple input

 * devices that do not raise interrupts but have to be periodically

 * scanned or polled to detect changes in their state.

 */

struct input_polled_dev {

	void *private;



	void (*flush)(struct input_polled_dev *dev);

	void (*poll)(struct input_polled_dev *dev);

	unsigned int poll_interval; /* msec */



	struct input_dev *input;

	struct delayed_work work;

};



struct input_polled_dev *input_allocate_polled_device(void);

void input_free_polled_device(struct input_polled_dev *dev);

int input_register_polled_device(struct input_polled_dev *dev);

void input_unregister_polled_device(struct input_polled_dev *dev);



#endif