/*
 *  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 <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);

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

#ifdef CONFIG_PM_SLEEP
static int acpi_fan_suspend(struct device *dev);
static int acpi_fan_resume(struct device *dev);
#endif
static SIMPLE_DEV_PM_OPS(acpi_fan_pm, acpi_fan_suspend, acpi_fan_resume);

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,
                },
        .drv.pm = &acpi_fan_pm,
};

/* 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_update_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 const 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,
};

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

static int acpi_fan_add(struct acpi_device *device)
{
        int result = 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_update_power(device->handle, NULL);
        if (result) {
                printk(KERN_ERR PREFIX "Setting initial power state\n");
                goto end;
        }

        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\n", 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'\n");

        result = sysfs_create_link(&cdev->device.kobj,
                                   &device->dev.kobj,
                                   "device");
        if (result)
                dev_err(&device->dev, "Failed to create sysfs link "
                        "'device'\n");

        printk(KERN_INFO PREFIX "%s [%s] (%s)\n",
               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)
{
        struct thermal_cooling_device *cdev = acpi_driver_data(device);

        if (!device || !cdev)
                return -EINVAL;

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

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int acpi_fan_suspend(struct device *dev)
{
        if (!dev)
                return -EINVAL;

        acpi_bus_set_power(to_acpi_device(dev)->handle, ACPI_STATE_D0);

        return AE_OK;
}

static int acpi_fan_resume(struct device *dev)
{
        int result;

        if (!dev)
                return -EINVAL;

        result = acpi_bus_update_power(to_acpi_device(dev)->handle, NULL);
        if (result)
                printk(KERN_ERR PREFIX "Error updating fan power state\n");

        return result;
}
#endif

module_acpi_driver(acpi_fan_driver);