net/rfkill/rfkill-input.c

   1 /*
   2  * Input layer to RF Kill interface connector
   3  *
   4  * Copyright (c) 2007 Dmitry Torokhov
   5  */
   6
   7 /*
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License version 2 as published
  10  * by the Free Software Foundation.
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/input.h>
  15 #include <linux/slab.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/init.h>
  18 #include <linux/rfkill.h>
  19
  20 MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
  21 MODULE_DESCRIPTION("Input layer to RF switch connector");
  22 MODULE_LICENSE("GPL");
  23
  24 struct rfkill_task {
  25         struct work_struct work;
  26         enum rfkill_type type;
  27         struct mutex mutex; /* ensures that task is serialized */
  28         spinlock_t lock; /* for accessing last and desired state */
  29         unsigned long last; /* last schedule */
  30         enum rfkill_state desired_state; /* on/off */
  31         enum rfkill_state current_state; /* on/off */
  32 };
  33
  34 static void rfkill_task_handler(struct work_struct *work)
  35 {
  36         struct rfkill_task *task = container_of(work, struct rfkill_task, work);
  37         enum rfkill_state state;
  38
  39         mutex_lock(&task->mutex);
  40
  41         /*
  42          * Use temp variable to fetch desired state to keep it
  43          * consistent even if rfkill_schedule_toggle() runs in
  44          * another thread or interrupts us.
  45          */
  46         state = task->desired_state;
  47
  48         if (state != task->current_state) {
  49                 rfkill_switch_all(task->type, state);
  50                 task->current_state = state;
  51         }
  52
  53         mutex_unlock(&task->mutex);
  54 }
  55
  56 static void rfkill_schedule_toggle(struct rfkill_task *task)
  57 {
  58         unsigned int flags;
  59
  60         spin_lock_irqsave(&task->lock, flags);
  61
  62         if (time_after(jiffies, task->last + msecs_to_jiffies(200))) {
  63                 task->desired_state = !task->desired_state;
  64                 task->last = jiffies;
  65                 schedule_work(&task->work);
  66         }
  67
  68         spin_unlock_irqrestore(&task->lock, flags);
  69 }
  70
  71 #define DEFINE_RFKILL_TASK(n, t)                        \
  72         struct rfkill_task n = {                        \
  73                 .work = __WORK_INITIALIZER(n.work,      \
  74                                 rfkill_task_handler),   \
  75                 .type = t,                              \
  76                 .mutex = __MUTEX_INITIALIZER(n.mutex),  \
  77                 .lock = __SPIN_LOCK_UNLOCKED(n.lock),   \
  78                 .desired_state = RFKILL_STATE_ON,       \
  79                 .current_state = RFKILL_STATE_ON,       \
  80         }
  81
  82 static DEFINE_RFKILL_TASK(rfkill_wlan, RFKILL_TYPE_WLAN);
  83 static DEFINE_RFKILL_TASK(rfkill_bt, RFKILL_TYPE_BLUETOOTH);
  84
  85 static void rfkill_event(struct input_handle *handle, unsigned int type,
  86                         unsigned int code, int down)
  87 {
  88         if (type == EV_KEY && down == 1) {
  89                 switch (code) {
  90                 case KEY_WLAN:
  91                         rfkill_schedule_toggle(&rfkill_wlan);
  92                         break;
  93                 case KEY_BLUETOOTH:
  94                         rfkill_schedule_toggle(&rfkill_bt);
  95                         break;
  96                 default:
  97                         break;
  98                 }
  99         }
 100 }
 101
 102 static int rfkill_connect(struct input_handler *handler, struct input_dev *dev,
 103                           const struct input_device_id *id)
 104 {
 105         struct input_handle *handle;
 106         int error;
 107
 108         handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
 109         if (!handle)
 110                 return -ENOMEM;
 111
 112         handle->dev = dev;
 113         handle->handler = handler;
 114         handle->name = "rfkill";
 115
 116         error = input_register_handle(handle);
 117         if (error)
 118                 goto err_free_handle;
 119
 120         error = input_open_device(handle);
 121         if (error)
 122                 goto err_unregister_handle;
 123
 124         return 0;
 125
 126  err_unregister_handle:
 127         input_unregister_handle(handle);
 128  err_free_handle:
 129         kfree(handle);
 130         return error;
 131 }
 132
 133 static void rfkill_disconnect(struct input_handle *handle)
 134 {
 135         input_close_device(handle);
 136         input_unregister_handle(handle);
 137         kfree(handle);
 138 }
 139
 140 static const struct input_device_id rfkill_ids[] = {
 141         {
 142                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
 143                 .evbit = { BIT(EV_KEY) },
 144                 .keybit = { [LONG(KEY_WLAN)] = BIT(KEY_WLAN) },
 145         },
 146         {
 147                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
 148                 .evbit = { BIT(EV_KEY) },
 149                 .keybit = { [LONG(KEY_BLUETOOTH)] = BIT(KEY_BLUETOOTH) },
 150         },
 151         { }
 152 };
 153
 154 static struct input_handler rfkill_handler = {
 155         .event =        rfkill_event,
 156         .connect =      rfkill_connect,
 157         .disconnect =   rfkill_disconnect,
 158         .name =         "rfkill",
 159         .id_table =     rfkill_ids,
 160 };
 161
 162 static int __init rfkill_handler_init(void)
 163 {
 164         return input_register_handler(&rfkill_handler);
 165 }
 166
 167 static void __exit rfkill_handler_exit(void)
 168 {
 169         input_unregister_handler(&rfkill_handler);
 170         flush_scheduled_work();
 171 }
 172
 173 module_init(rfkill_handler_init);
 174 module_exit(rfkill_handler_exit);