/*
   *  acpi_fan.c - ACPI Fan Driver ($Revision: 29 $)
   *
   *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   *  This program is free software; you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation; either version 2 of the License, or (at
   *  your option) any later version.
   *
   *  This program is distributed in the hope that it will be useful, but
   *  WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   *  General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License along
   *  with this program; if not, write to the Free Software Foundation, Inc.,
   *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
   *
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>
  #include <asm/uaccess.h>

  #include <linux/thermal.h>

  #include <acpi/acpi_bus.h>
  #include <acpi/acpi_drivers.h>

  #define PREFIX "ACPI: "

  #define ACPI_FAN_CLASS			"fan"

  #define ACPI_FAN_FILE_STATE		"state"

  
  #define _COMPONENT		ACPI_FAN_COMPONENT

  ACPI_MODULE_NAME("fan");

  MODULE_AUTHOR("Paul Diefenbaugh");

  MODULE_DESCRIPTION("ACPI Fan Driver");

  MODULE_LICENSE("GPL");

  static int acpi_fan_add(struct acpi_device *device);
  static int acpi_fan_remove(struct acpi_device *device, int type);

  static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state);
  static int acpi_fan_resume(struct acpi_device *device);

  static const struct acpi_device_id fan_device_ids[] = {
  	{"PNP0C0B", 0},
  	{"", 0},
  };
  MODULE_DEVICE_TABLE(acpi, fan_device_ids);

  static struct acpi_driver acpi_fan_driver = {

  	.name = "fan",

  	.class = ACPI_FAN_CLASS,

  	.ids = fan_device_ids,

  	.ops = {
  		.add = acpi_fan_add,
  		.remove = acpi_fan_remove,

  		.suspend = acpi_fan_suspend,
  		.resume = acpi_fan_resume,

  		},

  };

  /* thermal cooling device callbacks */

  static int fan_get_max_state(struct thermal_cooling_device *cdev, unsigned long
  			     *state)

  {
  	/* ACPI fan device only support two states: ON/OFF */

  	*state = 1;
  	return 0;

  }

  static int fan_get_cur_state(struct thermal_cooling_device *cdev, unsigned long
  			     *state)

  {
  	struct acpi_device *device = cdev->devdata;

  	int result;

  	int acpi_state;

  
  	if (!device)
  		return -EINVAL;

  	result = acpi_bus_get_power(device->handle, &acpi_state);

  	if (result)
  		return result;

  	*state = (acpi_state == ACPI_STATE_D3 ? 0 :
  		 (acpi_state == ACPI_STATE_D0 ? 1 : -1));
  	return 0;

  }
  
  static int

  fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)

  {
  	struct acpi_device *device = cdev->devdata;
  	int result;
  
  	if (!device || (state != 0 && state != 1))
  		return -EINVAL;
  
  	result = acpi_bus_set_power(device->handle,
  				state ? ACPI_STATE_D0 : ACPI_STATE_D3);
  
  	return result;
  }
  
  static struct thermal_cooling_device_ops fan_cooling_ops = {
  	.get_max_state = fan_get_max_state,
  	.get_cur_state = fan_get_cur_state,
  	.set_cur_state = fan_set_cur_state,
  };

  /* --------------------------------------------------------------------------
                                FS Interface (/proc)
     -------------------------------------------------------------------------- */

  #ifdef CONFIG_ACPI_PROCFS

  static struct proc_dir_entry *acpi_fan_dir;

  static int acpi_fan_read_state(struct seq_file *seq, void *offset)

  {

  	struct acpi_device *device = seq->private;

  	int state = 0;

  	if (device) {
  		if (acpi_bus_get_power(device->handle, &state))

  			seq_printf(seq, "status:                  ERROR
  ");
  		else
  			seq_printf(seq, "status:                  %s
  ",

  				   !state ? "on" : "off");

  	}

  	return 0;

  }
  
  static int acpi_fan_state_open_fs(struct inode *inode, struct file *file)
  {
  	return single_open(file, acpi_fan_read_state, PDE(inode)->data);
  }
  
  static ssize_t

  acpi_fan_write_state(struct file *file, const char __user * buffer,
  		     size_t count, loff_t * ppos)

  {

  	int result = 0;

  	struct seq_file *m = file->private_data;

  	struct acpi_device *device = m->private;

  	char state_string[3] = { '\0' };

  	if (count > sizeof(state_string) - 1)

  		return -EINVAL;

  	if (copy_from_user(state_string, buffer, count))

  		return -EFAULT;

  	state_string[count] = '\0';

  	if ((state_string[0] < '0') || (state_string[0] > '3'))
  		return -EINVAL;
  	if (state_string[1] == '
  ')
  		state_string[1] = '\0';
  	if (state_string[1] != '\0')
  		return -EINVAL;

  	result = acpi_bus_set_power(device->handle,

  				    simple_strtoul(state_string, NULL, 0));

  	if (result)

  		return result;

  	return count;

  }

  static const struct file_operations acpi_fan_state_ops = {

  	.open = acpi_fan_state_open_fs,
  	.read = seq_read,
  	.write = acpi_fan_write_state,
  	.llseek = seq_lseek,
  	.release = single_release,

  	.owner = THIS_MODULE,
  };

  static int acpi_fan_add_fs(struct acpi_device *device)

  {

  	struct proc_dir_entry *entry = NULL;

  
  	if (!device)

  		return -EINVAL;

  
  	if (!acpi_device_dir(device)) {
  		acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),

  						     acpi_fan_dir);

  		if (!acpi_device_dir(device))

  			return -ENODEV;

  	}
  
  	/* 'status' [R/W] */

  	entry = proc_create_data(ACPI_FAN_FILE_STATE,
  				 S_IFREG | S_IRUGO | S_IWUSR,
  				 acpi_device_dir(device),
  				 &acpi_fan_state_ops,
  				 device);

  	if (!entry)

  		return -ENODEV;

  	return 0;

  }

  static int acpi_fan_remove_fs(struct acpi_device *device)

  {

  
  	if (acpi_device_dir(device)) {

  		remove_proc_entry(ACPI_FAN_FILE_STATE, acpi_device_dir(device));

  		remove_proc_entry(acpi_device_bid(device), acpi_fan_dir);
  		acpi_device_dir(device) = NULL;
  	}

  	return 0;

  }

  #else
  static int acpi_fan_add_fs(struct acpi_device *device)
  {
  	return 0;
  }

  static int acpi_fan_remove_fs(struct acpi_device *device)
  {
  	return 0;
  }
  #endif

  /* --------------------------------------------------------------------------
                                   Driver Interface
     -------------------------------------------------------------------------- */

  static int acpi_fan_add(struct acpi_device *device)

  {

  	int result = 0;

  	int state = 0;

  	struct thermal_cooling_device *cdev;

  
  	if (!device)

  		return -EINVAL;

  	strcpy(acpi_device_name(device), "Fan");

  	strcpy(acpi_device_class(device), ACPI_FAN_CLASS);

  	result = acpi_bus_get_power(device->handle, &state);

  	if (result) {

  		printk(KERN_ERR PREFIX "Reading power state
  ");

  		goto end;
  	}

  	device->flags.force_power_state = 1;
  	acpi_bus_set_power(device->handle, state);
  	device->flags.force_power_state = 0;

  	cdev = thermal_cooling_device_register("Fan", device,
  						&fan_cooling_ops);

  	if (IS_ERR(cdev)) {
  		result = PTR_ERR(cdev);
  		goto end;
  	}

  	dev_dbg(&device->dev, "registered as cooling_device%d
  ", cdev->id);

  	device->driver_data = cdev;

  	result = sysfs_create_link(&device->dev.kobj,
  				   &cdev->device.kobj,
  				   "thermal_cooling");
  	if (result)

  		dev_err(&device->dev, "Failed to create sysfs link "
  			"'thermal_cooling'
  ");

  
  	result = sysfs_create_link(&cdev->device.kobj,
  				   &device->dev.kobj,
  				   "device");
  	if (result)

  		dev_err(&device->dev, "Failed to create sysfs link "
  			"'device'
  ");

  	result = acpi_fan_add_fs(device);
  	if (result)
  		goto end;
  
  	printk(KERN_INFO PREFIX "%s [%s] (%s)
  ",

  	       acpi_device_name(device), acpi_device_bid(device),
  	       !device->power.state ? "on" : "off");

        end:

  	return result;

  }

  static int acpi_fan_remove(struct acpi_device *device, int type)

  {

  	struct thermal_cooling_device *cdev = acpi_driver_data(device);
  
  	if (!device || !cdev)

  		return -EINVAL;

  	acpi_fan_remove_fs(device);

  	sysfs_remove_link(&device->dev.kobj, "thermal_cooling");
  	sysfs_remove_link(&cdev->device.kobj, "device");
  	thermal_cooling_device_unregister(cdev);

  	return 0;

  }

  static int acpi_fan_suspend(struct acpi_device *device, pm_message_t state)
  {
  	if (!device)
  		return -EINVAL;
  
  	acpi_bus_set_power(device->handle, ACPI_STATE_D0);
  
  	return AE_OK;
  }
  
  static int acpi_fan_resume(struct acpi_device *device)
  {
  	int result = 0;
  	int power_state = 0;
  
  	if (!device)
  		return -EINVAL;
  
  	result = acpi_bus_get_power(device->handle, &power_state);
  	if (result) {

  		printk(KERN_ERR PREFIX
  				  "Error reading fan power state
  ");

  		return result;
  	}
  
  	device->flags.force_power_state = 1;
  	acpi_bus_set_power(device->handle, power_state);
  	device->flags.force_power_state = 0;
  
  	return result;
  }

  static int __init acpi_fan_init(void)

  {

  	int result = 0;

  #ifdef CONFIG_ACPI_PROCFS

  	acpi_fan_dir = proc_mkdir(ACPI_FAN_CLASS, acpi_root_dir);
  	if (!acpi_fan_dir)

  		return -ENODEV;

  #endif

  
  	result = acpi_bus_register_driver(&acpi_fan_driver);
  	if (result < 0) {

  #ifdef CONFIG_ACPI_PROCFS

  		remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);

  #endif

  		return -ENODEV;

  	}

  	return 0;

  }

  static void __exit acpi_fan_exit(void)

  {

  
  	acpi_bus_unregister_driver(&acpi_fan_driver);
  
  	remove_proc_entry(ACPI_FAN_CLASS, acpi_root_dir);

  	return;

  }

  module_init(acpi_fan_init);
  module_exit(acpi_fan_exit);