drivers/input/input-leds.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LED support for the input layer
   4  *
   5  * Copyright 2010-2015 Samuel Thibault <samuel.thibault@ens-lyon.org>
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/slab.h>
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/leds.h>
  13 #include <linux/input.h>
  14
  15 #if IS_ENABLED(CONFIG_VT)
  16 #define VT_TRIGGER(_name)       .trigger = _name
  17 #else
  18 #define VT_TRIGGER(_name)       .trigger = NULL
  19 #endif
  20
  21 #if IS_ENABLED(CONFIG_SND_CTL_LED)
  22 #define AUDIO_TRIGGER(_name)    .trigger = _name
  23 #else
  24 #define AUDIO_TRIGGER(_name)    .trigger = NULL
  25 #endif
  26
  27 static const struct {
  28         const char *name;
  29         const char *trigger;
  30 } input_led_info[LED_CNT] = {
  31         [LED_NUML]      = { "numlock", VT_TRIGGER("kbd-numlock") },
  32         [LED_CAPSL]     = { "capslock", VT_TRIGGER("kbd-capslock") },
  33         [LED_SCROLLL]   = { "scrolllock", VT_TRIGGER("kbd-scrolllock") },
  34         [LED_COMPOSE]   = { "compose" },
  35         [LED_KANA]      = { "kana", VT_TRIGGER("kbd-kanalock") },
  36         [LED_SLEEP]     = { "sleep" } ,
  37         [LED_SUSPEND]   = { "suspend" },
  38         [LED_MUTE]      = { "mute", AUDIO_TRIGGER("audio-mute") },
  39         [LED_MISC]      = { "misc" },
  40         [LED_MAIL]      = { "mail" },
  41         [LED_CHARGING]  = { "charging" },
  42 };
  43
  44 struct input_led {
  45         struct led_classdev cdev;
  46         struct input_handle *handle;
  47         unsigned int code; /* One of LED_* constants */
  48 };
  49
  50 struct input_leds {
  51         struct input_handle handle;
  52         unsigned int num_leds;
  53         struct input_led leds[] __counted_by(num_leds);
  54 };
  55
  56 static enum led_brightness input_leds_brightness_get(struct led_classdev *cdev)
  57 {
  58         struct input_led *led = container_of(cdev, struct input_led, cdev);
  59         struct input_dev *input = led->handle->dev;
  60
  61         return test_bit(led->code, input->led) ? cdev->max_brightness : 0;
  62 }
  63
  64 static void input_leds_brightness_set(struct led_classdev *cdev,
  65                                       enum led_brightness brightness)
  66 {
  67         struct input_led *led = container_of(cdev, struct input_led, cdev);
  68
  69         input_inject_event(led->handle, EV_LED, led->code, !!brightness);
  70 }
  71
  72 static void input_leds_event(struct input_handle *handle, unsigned int type,
  73                              unsigned int code, int value)
  74 {
  75 }
  76
  77 static int input_leds_get_count(struct input_dev *dev)
  78 {
  79         unsigned int led_code;
  80         int count = 0;
  81
  82         for_each_set_bit(led_code, dev->ledbit, LED_CNT)
  83                 if (input_led_info[led_code].name)
  84                         count++;
  85
  86         return count;
  87 }
  88
  89 static int input_leds_connect(struct input_handler *handler,
  90                               struct input_dev *dev,
  91                               const struct input_device_id *id)
  92 {
  93         struct input_leds *leds;
  94         struct input_led *led;
  95         unsigned int num_leds;
  96         unsigned int led_code;
  97         int led_no;
  98         int error;
  99
 100         num_leds = input_leds_get_count(dev);
 101         if (!num_leds)
 102                 return -ENXIO;
 103
 104         leds = kzalloc(struct_size(leds, leds, num_leds), GFP_KERNEL);
 105         if (!leds)
 106                 return -ENOMEM;
 107
 108         leds->num_leds = num_leds;
 109
 110         leds->handle.dev = dev;
 111         leds->handle.handler = handler;
 112         leds->handle.name = "leds";
 113         leds->handle.private = leds;
 114
 115         error = input_register_handle(&leds->handle);
 116         if (error)
 117                 goto err_free_mem;
 118
 119         error = input_open_device(&leds->handle);
 120         if (error)
 121                 goto err_unregister_handle;
 122
 123         led_no = 0;
 124         for_each_set_bit(led_code, dev->ledbit, LED_CNT) {
 125                 if (!input_led_info[led_code].name)
 126                         continue;
 127
 128                 led = &leds->leds[led_no];
 129                 led->handle = &leds->handle;
 130                 led->code = led_code;
 131
 132                 led->cdev.name = kasprintf(GFP_KERNEL, "%s::%s",
 133                                            dev_name(&dev->dev),
 134                                            input_led_info[led_code].name);
 135                 if (!led->cdev.name) {
 136                         error = -ENOMEM;
 137                         goto err_unregister_leds;
 138                 }
 139
 140                 led->cdev.max_brightness = 1;
 141                 led->cdev.brightness_get = input_leds_brightness_get;
 142                 led->cdev.brightness_set = input_leds_brightness_set;
 143                 led->cdev.default_trigger = input_led_info[led_code].trigger;
 144
 145                 error = led_classdev_register(&dev->dev, &led->cdev);
 146                 if (error) {
 147                         dev_err(&dev->dev, "failed to register LED %s: %d\n",
 148                                 led->cdev.name, error);
 149                         kfree(led->cdev.name);
 150                         goto err_unregister_leds;
 151                 }
 152
 153                 led_no++;
 154         }
 155
 156         return 0;
 157
 158 err_unregister_leds:
 159         while (--led_no >= 0) {
 160                 struct input_led *led = &leds->leds[led_no];
 161
 162                 led_classdev_unregister(&led->cdev);
 163                 kfree(led->cdev.name);
 164         }
 165
 166         input_close_device(&leds->handle);
 167
 168 err_unregister_handle:
 169         input_unregister_handle(&leds->handle);
 170
 171 err_free_mem:
 172         kfree(leds);
 173         return error;
 174 }
 175
 176 static void input_leds_disconnect(struct input_handle *handle)
 177 {
 178         struct input_leds *leds = handle->private;
 179         int i;
 180
 181         for (i = 0; i < leds->num_leds; i++) {
 182                 struct input_led *led = &leds->leds[i];
 183
 184                 led_classdev_unregister(&led->cdev);
 185                 kfree(led->cdev.name);
 186         }
 187
 188         input_close_device(handle);
 189         input_unregister_handle(handle);
 190
 191         kfree(leds);
 192 }
 193
 194 static const struct input_device_id input_leds_ids[] = {
 195         {
 196                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT,
 197                 .evbit = { BIT_MASK(EV_LED) },
 198         },
 199         { },
 200 };
 201 MODULE_DEVICE_TABLE(input, input_leds_ids);
 202
 203 static struct input_handler input_leds_handler = {
 204         .event =        input_leds_event,
 205         .connect =      input_leds_connect,
 206         .disconnect =   input_leds_disconnect,
 207         .name =         "leds",
 208         .id_table =     input_leds_ids,
 209 };
 210
 211 static int __init input_leds_init(void)
 212 {
 213         return input_register_handler(&input_leds_handler);
 214 }
 215 module_init(input_leds_init);
 216
 217 static void __exit input_leds_exit(void)
 218 {
 219         input_unregister_handler(&input_leds_handler);
 220 }
 221 module_exit(input_leds_exit);
 222
 223 MODULE_AUTHOR("Samuel Thibault <samuel.thibault@ens-lyon.org>");
 224 MODULE_AUTHOR("Dmitry Torokhov <dmitry.torokhov@gmail.com>");
 225 MODULE_DESCRIPTION("Input -> LEDs Bridge");
 226 MODULE_LICENSE("GPL v2");