Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6
[linux-2.6.git] / drivers / input / misc / input-polldev.c
1 /*
2  * Generic implementation of a polled input device
3
4  * Copyright (c) 2007 Dmitry Torokhov
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License version 2 as published by
8  * the Free Software Foundation.
9  */
10
11 #include <linux/jiffies.h>
12 #include <linux/mutex.h>
13 #include <linux/input-polldev.h>
14
15 static DEFINE_MUTEX(polldev_mutex);
16 static int polldev_users;
17 static struct workqueue_struct *polldev_wq;
18
19 static int input_polldev_start_workqueue(void)
20 {
21         int retval;
22
23         retval = mutex_lock_interruptible(&polldev_mutex);
24         if (retval)
25                 return retval;
26
27         if (!polldev_users) {
28                 polldev_wq = create_singlethread_workqueue("ipolldevd");
29                 if (!polldev_wq) {
30                         printk(KERN_ERR "input-polldev: failed to create "
31                                 "ipolldevd workqueue\n");
32                         retval = -ENOMEM;
33                         goto out;
34                 }
35         }
36
37         polldev_users++;
38
39  out:
40         mutex_unlock(&polldev_mutex);
41         return retval;
42 }
43
44 static void input_polldev_stop_workqueue(void)
45 {
46         mutex_lock(&polldev_mutex);
47
48         if (!--polldev_users)
49                 destroy_workqueue(polldev_wq);
50
51         mutex_unlock(&polldev_mutex);
52 }
53
54 static void input_polled_device_work(struct work_struct *work)
55 {
56         struct input_polled_dev *dev =
57                 container_of(work, struct input_polled_dev, work.work);
58
59         dev->poll(dev);
60         queue_delayed_work(polldev_wq, &dev->work,
61                            msecs_to_jiffies(dev->poll_interval));
62 }
63
64 static int input_open_polled_device(struct input_dev *input)
65 {
66         struct input_polled_dev *dev = input->private;
67         int error;
68
69         error = input_polldev_start_workqueue();
70         if (error)
71                 return error;
72
73         if (dev->flush)
74                 dev->flush(dev);
75
76         queue_delayed_work(polldev_wq, &dev->work,
77                            msecs_to_jiffies(dev->poll_interval));
78
79         return 0;
80 }
81
82 static void input_close_polled_device(struct input_dev *input)
83 {
84         struct input_polled_dev *dev = input->private;
85
86         cancel_rearming_delayed_workqueue(polldev_wq, &dev->work);
87         input_polldev_stop_workqueue();
88 }
89
90 /**
91  * input_allocate_polled_device - allocated memory polled device
92  *
93  * The function allocates memory for a polled device and also
94  * for an input device associated with this polled device.
95  */
96 struct input_polled_dev *input_allocate_polled_device(void)
97 {
98         struct input_polled_dev *dev;
99
100         dev = kzalloc(sizeof(struct input_polled_dev), GFP_KERNEL);
101         if (!dev)
102                 return NULL;
103
104         dev->input = input_allocate_device();
105         if (!dev->input) {
106                 kfree(dev);
107                 return NULL;
108         }
109
110         return dev;
111 }
112 EXPORT_SYMBOL(input_allocate_polled_device);
113
114 /**
115  * input_free_polled_device - free memory allocated for polled device
116  * @dev: device to free
117  *
118  * The function frees memory allocated for polling device and drops
119  * reference to the associated input device (if present).
120  */
121 void input_free_polled_device(struct input_polled_dev *dev)
122 {
123         if (dev) {
124                 input_free_device(dev->input);
125                 kfree(dev);
126         }
127 }
128 EXPORT_SYMBOL(input_free_polled_device);
129
130 /**
131  * input_register_polled_device - register polled device
132  * @dev: device to register
133  *
134  * The function registers previously initialized polled input device
135  * with input layer. The device should be allocated with call to
136  * input_allocate_polled_device(). Callers should also set up poll()
137  * method and set up capabilities (id, name, phys, bits) of the
138  * corresponing input_dev structure.
139  */
140 int input_register_polled_device(struct input_polled_dev *dev)
141 {
142         struct input_dev *input = dev->input;
143
144         INIT_DELAYED_WORK(&dev->work, input_polled_device_work);
145         if (!dev->poll_interval)
146                 dev->poll_interval = 500;
147         input->private = dev;
148         input->open = input_open_polled_device;
149         input->close = input_close_polled_device;
150
151         return input_register_device(input);
152 }
153 EXPORT_SYMBOL(input_register_polled_device);
154
155 /**
156  * input_unregister_polled_device - unregister polled device
157  * @dev: device to unregister
158  *
159  * The function unregisters previously registered polled input
160  * device from input layer. Polling is stopped and device is
161  * ready to be freed with call to input_free_polled_device().
162  * Callers should not attempt to access dev->input pointer
163  * after calling this function.
164  */
165 void input_unregister_polled_device(struct input_polled_dev *dev)
166 {
167         input_unregister_device(dev->input);
168         dev->input = NULL;
169 }
170 EXPORT_SYMBOL(input_unregister_polled_device);
171