/*
   * LED support for the input layer
   *
   * Copyright 2010-2015 Samuel Thibault <samuel.thibault@ens-lyon.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 as
   * published by the Free Software Foundation.
   */
  
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/leds.h>
  #include <linux/input.h>
  
  #if IS_ENABLED(CONFIG_VT)
  #define VT_TRIGGER(_name)	.trigger = _name
  #else
  #define VT_TRIGGER(_name)	.trigger = NULL
  #endif
  
  static const struct {
  	const char *name;
  	const char *trigger;
  } input_led_info[LED_CNT] = {
  	[LED_NUML]	= { "numlock", VT_TRIGGER("kbd-numlock") },
  	[LED_CAPSL]	= { "capslock", VT_TRIGGER("kbd-capslock") },
  	[LED_SCROLLL]	= { "scrolllock", VT_TRIGGER("kbd-scrolllock") },
  	[LED_COMPOSE]	= { "compose" },
  	[LED_KANA]	= { "kana", VT_TRIGGER("kbd-kanalock") },
  	[LED_SLEEP]	= { "sleep" } ,
  	[LED_SUSPEND]	= { "suspend" },
  	[LED_MUTE]	= { "mute" },
  	[LED_MISC]	= { "misc" },
  	[LED_MAIL]	= { "mail" },
  	[LED_CHARGING]	= { "charging" },
  };
  
  struct input_led {
  	struct led_classdev cdev;
  	struct input_handle *handle;
  	unsigned int code; /* One of LED_* constants */
  };
  
  struct input_leds {
  	struct input_handle handle;
  	unsigned int num_leds;
  	struct input_led leds[];
  };
  
  static enum led_brightness input_leds_brightness_get(struct led_classdev *cdev)
  {
  	struct input_led *led = container_of(cdev, struct input_led, cdev);
  	struct input_dev *input = led->handle->dev;
  
  	return test_bit(led->code, input->led) ? cdev->max_brightness : 0;
  }
  
  static void input_leds_brightness_set(struct led_classdev *cdev,
  				      enum led_brightness brightness)
  {
  	struct input_led *led = container_of(cdev, struct input_led, cdev);
  
  	input_inject_event(led->handle, EV_LED, led->code, !!brightness);
  }
  
  static void input_leds_event(struct input_handle *handle, unsigned int type,
  			     unsigned int code, int value)
  {
  }

  static int input_leds_get_count(struct input_dev *dev)
  {
  	unsigned int led_code;
  	int count = 0;
  
  	for_each_set_bit(led_code, dev->ledbit, LED_CNT)
  		if (input_led_info[led_code].name)
  			count++;
  
  	return count;
  }

  static int input_leds_connect(struct input_handler *handler,
  			      struct input_dev *dev,
  			      const struct input_device_id *id)
  {
  	struct input_leds *leds;

  	struct input_led *led;

  	unsigned int num_leds;
  	unsigned int led_code;
  	int led_no;
  	int error;

  	num_leds = input_leds_get_count(dev);

  	if (!num_leds)
  		return -ENXIO;
  
  	leds = kzalloc(sizeof(*leds) + num_leds * sizeof(*leds->leds),
  		       GFP_KERNEL);
  	if (!leds)
  		return -ENOMEM;
  
  	leds->num_leds = num_leds;
  
  	leds->handle.dev = dev;
  	leds->handle.handler = handler;
  	leds->handle.name = "leds";
  	leds->handle.private = leds;
  
  	error = input_register_handle(&leds->handle);
  	if (error)
  		goto err_free_mem;
  
  	error = input_open_device(&leds->handle);
  	if (error)
  		goto err_unregister_handle;
  
  	led_no = 0;
  	for_each_set_bit(led_code, dev->ledbit, LED_CNT) {

  		if (!input_led_info[led_code].name)
  			continue;

  		led = &leds->leds[led_no];

  		led->handle = &leds->handle;
  		led->code = led_code;

  		led->cdev.name = kasprintf(GFP_KERNEL, "%s::%s",
  					   dev_name(&dev->dev),
  					   input_led_info[led_code].name);
  		if (!led->cdev.name) {
  			error = -ENOMEM;
  			goto err_unregister_leds;
  		}
  
  		led->cdev.max_brightness = 1;
  		led->cdev.brightness_get = input_leds_brightness_get;
  		led->cdev.brightness_set = input_leds_brightness_set;
  		led->cdev.default_trigger = input_led_info[led_code].trigger;
  
  		error = led_classdev_register(&dev->dev, &led->cdev);
  		if (error) {
  			dev_err(&dev->dev, "failed to register LED %s: %d
  ",
  				led->cdev.name, error);
  			kfree(led->cdev.name);
  			goto err_unregister_leds;
  		}
  
  		led_no++;
  	}
  
  	return 0;
  
  err_unregister_leds:
  	while (--led_no >= 0) {
  		struct input_led *led = &leds->leds[led_no];
  
  		led_classdev_unregister(&led->cdev);
  		kfree(led->cdev.name);
  	}
  
  	input_close_device(&leds->handle);
  
  err_unregister_handle:
  	input_unregister_handle(&leds->handle);
  
  err_free_mem:
  	kfree(leds);
  	return error;
  }
  
  static void input_leds_disconnect(struct input_handle *handle)
  {
  	struct input_leds *leds = handle->private;
  	int i;
  
  	for (i = 0; i < leds->num_leds; i++) {
  		struct input_led *led = &leds->leds[i];
  
  		led_classdev_unregister(&led->cdev);
  		kfree(led->cdev.name);
  	}
  
  	input_close_device(handle);
  	input_unregister_handle(handle);
  
  	kfree(leds);
  }
  
  static const struct input_device_id input_leds_ids[] = {
  	{
  		.flags = INPUT_DEVICE_ID_MATCH_EVBIT,
  		.evbit = { BIT_MASK(EV_LED) },
  	},
  	{ },
  };
  MODULE_DEVICE_TABLE(input, input_leds_ids);
  
  static struct input_handler input_leds_handler = {
  	.event =	input_leds_event,
  	.connect =	input_leds_connect,
  	.disconnect =	input_leds_disconnect,
  	.name =		"leds",
  	.id_table =	input_leds_ids,
  };
  
  static int __init input_leds_init(void)
  {
  	return input_register_handler(&input_leds_handler);
  }
  module_init(input_leds_init);
  
  static void __exit input_leds_exit(void)
  {
  	input_unregister_handler(&input_leds_handler);
  }
  module_exit(input_leds_exit);
  
  MODULE_AUTHOR("Samuel Thibault <samuel.thibault@ens-lyon.org>");
  MODULE_AUTHOR("Dmitry Torokhov <dmitry.torokhov@gmail.com>");
  MODULE_DESCRIPTION("Input -> LEDs Bridge");
  MODULE_LICENSE("GPL v2");