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_get_count(struct input_dev *dev)
  75 {
  76         unsigned int led_code;
  77         int count = 0;
  78
  79         for_each_set_bit(led_code, dev->ledbit, LED_CNT)
  80                 if (input_led_info[led_code].name)
  81                         count++;
  82
  83         return count;
  84 }
  85
  86 static int input_leds_connect(struct input_handler *handler,
  87                               struct input_dev *dev,
  88                               const struct input_device_id *id)
  89 {
  90         struct input_leds *leds;
  91         struct input_led *led;
  92         unsigned int num_leds;
  93         unsigned int led_code;
  94         int led_no;
  95         int error;
  96
  97         num_leds = input_leds_get_count(dev);
  98         if (!num_leds)
  99                 return -ENXIO;
 100
 101         leds = kzalloc(sizeof(*leds) + num_leds * sizeof(*leds->leds),
 102                        GFP_KERNEL);
 103         if (!leds)
 104                 return -ENOMEM;
 105
 106         leds->num_leds = num_leds;
 107
 108         leds->handle.dev = dev;
 109         leds->handle.handler = handler;
 110         leds->handle.name = "leds";
 111         leds->handle.private = leds;
 112
 113         error = input_register_handle(&leds->handle);
 114         if (error)
 115                 goto err_free_mem;
 116
 117         error = input_open_device(&leds->handle);
 118         if (error)
 119                 goto err_unregister_handle;
 120
 121         led_no = 0;
 122         for_each_set_bit(led_code, dev->ledbit, LED_CNT) {
 123                 if (!input_led_info[led_code].name)
 124                         continue;
 125
 126                 led = &leds->leds[led_no];
 127                 led->handle = &leds->handle;
 128                 led->code = led_code;
 129
 130                 led->cdev.name = kasprintf(GFP_KERNEL, "%s::%s",
 131                                            dev_name(&dev->dev),
 132                                            input_led_info[led_code].name);
 133                 if (!led->cdev.name) {
 134                         error = -ENOMEM;
 135                         goto err_unregister_leds;
 136                 }
 137
 138                 led->cdev.max_brightness = 1;
 139                 led->cdev.brightness_get = input_leds_brightness_get;
 140                 led->cdev.brightness_set = input_leds_brightness_set;
 141                 led->cdev.default_trigger = input_led_info[led_code].trigger;
 142
 143                 error = led_classdev_register(&dev->dev, &led->cdev);
 144                 if (error) {
 145                         dev_err(&dev->dev, "failed to register LED %s: %d\n",
 146                                 led->cdev.name, error);
 147                         kfree(led->cdev.name);
 148                         goto err_unregister_leds;
 149                 }
 150
 151                 led_no++;
 152         }
 153
 154         return 0;
 155
 156 err_unregister_leds:
 157         while (--led_no >= 0) {
 158                 struct input_led *led = &leds->leds[led_no];
 159
 160                 led_classdev_unregister(&led->cdev);
 161                 kfree(led->cdev.name);
 162         }
 163
 164         input_close_device(&leds->handle);
 165
 166 err_unregister_handle:
 167         input_unregister_handle(&leds->handle);
 168
 169 err_free_mem:
 170         kfree(leds);
 171         return error;
 172 }
 173
 174 static void input_leds_disconnect(struct input_handle *handle)
 175 {
 176         struct input_leds *leds = handle->private;
 177         int i;
 178
 179         for (i = 0; i < leds->num_leds; i++) {
 180                 struct input_led *led = &leds->leds[i];
 181
 182                 led_classdev_unregister(&led->cdev);
 183                 kfree(led->cdev.name);
 184         }
 185
 186         input_close_device(handle);
 187         input_unregister_handle(handle);
 188
 189         kfree(leds);
 190 }
 191
 192 static const struct input_device_id input_leds_ids[] = {
 193         {
 194                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
 195                 .evbit = { BIT_MASK(EV_LED) },
 196         },
 197         { },
 198 };
 199 MODULE_DEVICE_TABLE(input, input_leds_ids);
 200
 201 static struct input_handler input_leds_handler = {
 202         .event =        input_leds_event,
 203         .connect =      input_leds_connect,
 204         .disconnect =   input_leds_disconnect,
 205         .name =         "leds",
 206         .id_table =     input_leds_ids,
 207 };
 208
 209 static int __init input_leds_init(void)
 210 {
 211         return input_register_handler(&input_leds_handler);
 212 }
 213 module_init(input_leds_init);
 214
 215 static void __exit input_leds_exit(void)
 216 {
 217         input_unregister_handler(&input_leds_handler);
 218 }
 219 module_exit(input_leds_exit);
 220
 221 MODULE_AUTHOR("Samuel Thibault <samuel.thibault@ens-lyon.org>");
 222 MODULE_AUTHOR("Dmitry Torokhov <dmitry.torokhov@gmail.com>");
 223 MODULE_DESCRIPTION("Input -> LEDs Bridge");
 224 MODULE_LICENSE("GPL v2");