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: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Dmitry Torokhov 2007-04-29 23:42:45 -04:00
parent 85796e7d93
commit 0dcd807367
4 changed files with 229 additions and 0 deletions

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@ -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

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@ -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

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@ -0,0 +1,171 @@
/*
* 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);

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@ -0,0 +1,46 @@
#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