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0dcd8073 DT |
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 |