drivers/input/input-leds.c

   1 /*
   2  * LED support for the input layer
   3  *
   4  * Copyright 2010-2015 Samuel Thibault <samuel.thibault@ens-lyon.org>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/slab.h>
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/leds.h>
  16 #include <linux/input.h>
  17
  18 #if IS_ENABLED(CONFIG_VT)
  19 #define VT_TRIGGER(_name)       .trigger = _name
  20 #else
  21 #define VT_TRIGGER(_name)       .trigger = NULL
  22 #endif
  23
  24 static const struct {
  25         const char *name;
  26         const char *trigger;
  27 } input_led_info[LED_CNT] = {
  28         [LED_NUML]      = { "numlock", VT_TRIGGER("kbd-numlock") },
  29         [LED_CAPSL]     = { "capslock", VT_TRIGGER("kbd-capslock") },
  30         [LED_SCROLLL]   = { "scrolllock", VT_TRIGGER("kbd-scrolllock") },
  31         [LED_COMPOSE]   = { "compose" },
  32         [LED_KANA]      = { "kana", VT_TRIGGER("kbd-kanalock") },
  33         [LED_SLEEP]     = { "sleep" } ,
  34         [LED_SUSPEND]   = { "suspend" },
  35         [LED_MUTE]      = { "mute" },
  36         [LED_MISC]      = { "misc" },
  37         [LED_MAIL]      = { "mail" },
  38         [LED_CHARGING]  = { "charging" },
  39 };
  40
  41 struct input_led {
  42         struct led_classdev cdev;
  43         struct input_handle *handle;
  44         unsigned int code; /* One of LED_* constants */
  45 };
  46
  47 struct input_leds {
  48         struct input_handle handle;
  49         unsigned int num_leds;
  50         struct input_led leds[];
  51 };
  52
  53 static enum led_brightness input_leds_brightness_get(struct led_classdev *cdev)
  54 {
  55         struct input_led *led = container_of(cdev, struct input_led, cdev);
  56         struct input_dev *input = led->handle->dev;
  57
  58         return test_bit(led->code, input->led) ? cdev->max_brightness : 0;
  59 }
  60
  61 static void input_leds_brightness_set(struct led_classdev *cdev,
  62                                       enum led_brightness brightness)
  63 {
  64         struct input_led *led = container_of(cdev, struct input_led, cdev);
  65
  66         input_inject_event(led->handle, EV_LED, led->code, !!brightness);
  67 }
  68
  69 static void input_leds_event(struct input_handle *handle, unsigned int type,
  70                              unsigned int code, int value)
  71 {
  72 }
  73
  74 static int input_leds_connect(struct input_handler *handler,
  75                               struct input_dev *dev,
  76                               const struct input_device_id *id)
  77 {
  78         struct input_leds *leds;
  79         unsigned int num_leds;
  80         unsigned int led_code;
  81         int led_no;
  82         int error;
  83
  84         num_leds = bitmap_weight(dev->ledbit, LED_CNT);
  85         if (!num_leds)
  86                 return -ENXIO;
  87
  88         leds = kzalloc(sizeof(*leds) + num_leds * sizeof(*leds->leds),
  89                        GFP_KERNEL);
  90         if (!leds)
  91                 return -ENOMEM;
  92
  93         leds->num_leds = num_leds;
  94
  95         leds->handle.dev = dev;
  96         leds->handle.handler = handler;
  97         leds->handle.name = "leds";
  98         leds->handle.private = leds;
  99
 100         error = input_register_handle(&leds->handle);
 101         if (error)
 102                 goto err_free_mem;
 103
 104         error = input_open_device(&leds->handle);
 105         if (error)
 106                 goto err_unregister_handle;
 107
 108         led_no = 0;
 109         for_each_set_bit(led_code, dev->ledbit, LED_CNT) {
 110                 struct input_led *led = &leds->leds[led_no];
 111
 112                 led->handle = &leds->handle;
 113                 led->code = led_code;
 114
 115                 if (WARN_ON(!input_led_info[led_code].name))
 116                         continue;
 117
 118                 led->cdev.name = kasprintf(GFP_KERNEL, "%s::%s",
 119                                            dev_name(&dev->dev),
 120                                            input_led_info[led_code].name);
 121                 if (!led->cdev.name) {
 122                         error = -ENOMEM;
 123                         goto err_unregister_leds;
 124                 }
 125
 126                 led->cdev.max_brightness = 1;
 127                 led->cdev.brightness_get = input_leds_brightness_get;
 128                 led->cdev.brightness_set = input_leds_brightness_set;
 129                 led->cdev.default_trigger = input_led_info[led_code].trigger;
 130
 131                 error = led_classdev_register(&dev->dev, &led->cdev);
 132                 if (error) {
 133                         dev_err(&dev->dev, "failed to register LED %s: %d\n",
 134                                 led->cdev.name, error);
 135                         kfree(led->cdev.name);
 136                         goto err_unregister_leds;
 137                 }
 138
 139                 led_no++;
 140         }
 141
 142         return 0;
 143
 144 err_unregister_leds:
 145         while (--led_no >= 0) {
 146                 struct input_led *led = &leds->leds[led_no];
 147
 148                 led_classdev_unregister(&led->cdev);
 149                 kfree(led->cdev.name);
 150         }
 151
 152         input_close_device(&leds->handle);
 153
 154 err_unregister_handle:
 155         input_unregister_handle(&leds->handle);
 156
 157 err_free_mem:
 158         kfree(leds);
 159         return error;
 160 }
 161
 162 static void input_leds_disconnect(struct input_handle *handle)
 163 {
 164         struct input_leds *leds = handle->private;
 165         int i;
 166
 167         for (i = 0; i < leds->num_leds; i++) {
 168                 struct input_led *led = &leds->leds[i];
 169
 170                 led_classdev_unregister(&led->cdev);
 171                 kfree(led->cdev.name);
 172         }
 173
 174         input_close_device(handle);
 175         input_unregister_handle(handle);
 176
 177         kfree(leds);
 178 }
 179
 180 static const struct input_device_id input_leds_ids[] = {
 181         {
 182                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
 183                 .evbit = { BIT_MASK(EV_LED) },
 184         },
 185         { },
 186 };
 187 MODULE_DEVICE_TABLE(input, input_leds_ids);
 188
 189 static struct input_handler input_leds_handler = {
 190         .event =        input_leds_event,
 191         .connect =      input_leds_connect,
 192         .disconnect =   input_leds_disconnect,
 193         .name =         "leds",
 194         .id_table =     input_leds_ids,
 195 };
 196
 197 static int __init input_leds_init(void)
 198 {
 199         return input_register_handler(&input_leds_handler);
 200 }
 201 module_init(input_leds_init);
 202
 203 static void __exit input_leds_exit(void)
 204 {
 205         input_unregister_handler(&input_leds_handler);
 206 }
 207 module_exit(input_leds_exit);
 208
 209 MODULE_AUTHOR("Samuel Thibault <samuel.thibault@ens-lyon.org>");
 210 MODULE_AUTHOR("Dmitry Torokhov <dmitry.torokhov@gmail.com>");
 211 MODULE_DESCRIPTION("Input -> LEDs Bridge");
 212 MODULE_LICENSE("GPL v2");