Dmitry Torokhov | 0dcd807 | 2007-04-29 23:42:45 -0400 | [diff] [blame^] | 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 | |