drivers/platform/x86/asus-wmi.c

/*
 * Asus PC WMI hotkey driver
 *
 * Copyright(C) 2010 Intel Corporation.
 * Copyright(C) 2010-2011 Corentin Chary <corentin.chary@gmail.com>
 *
 * Portions based on wistron_btns.c:
 * Copyright (C) 2005 Miloslav Trmac <mitr@volny.cz>
 * Copyright (C) 2005 Bernhard Rosenkraenzer <bero@arklinux.org>
 * Copyright (C) 2005 Dmitry Torokhov <dtor@mail.ru>
 *
 *  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
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/input/sparse-keymap.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/leds.h>
#include <linux/rfkill.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/platform_device.h>
#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>

#include "asus-wmi.h"

MODULE_AUTHOR("Corentin Chary <corentincj@iksaif.net>, "
	      "Yong Wang <yong.y.wang@intel.com>");
MODULE_DESCRIPTION("Asus Generic WMI Driver");
MODULE_LICENSE("GPL");

#define to_platform_driver(drv)					\
	(container_of((drv), struct platform_driver, driver))

#define to_asus_wmi_driver(pdrv)					\
	(container_of((pdrv), struct asus_wmi_driver, platform_driver))

#define ASUS_WMI_MGMT_GUID	"97845ED0-4E6D-11DE-8A39-0800200C9A66"

#define NOTIFY_BRNUP_MIN		0x11
#define NOTIFY_BRNUP_MAX		0x1f
#define NOTIFY_BRNDOWN_MIN		0x20
#define NOTIFY_BRNDOWN_MAX		0x2e

/* WMI Methods */
#define ASUS_WMI_METHODID_SPEC	        0x43455053
#define ASUS_WMI_METHODID_SFUN		0x4E554653
#define ASUS_WMI_METHODID_DSTS		0x53544344
#define ASUS_WMI_METHODID_DSTS2		0x53545344
#define ASUS_WMI_METHODID_DEVS		0x53564544
#define ASUS_WMI_METHODID_CFVS		0x53564643
#define ASUS_WMI_METHODID_INIT		0x54494E49

#define ASUS_WMI_UNSUPPORTED_METHOD	0xFFFFFFFE

/* Wireless */
#define ASUS_WMI_DEVID_WLAN		0x00010011
#define ASUS_WMI_DEVID_BLUETOOTH	0x00010013
#define ASUS_WMI_DEVID_WIMAX		0x00010017
#define ASUS_WMI_DEVID_WWAN3G		0x00010019

/* Backlight and Brightness */
#define ASUS_WMI_DEVID_BACKLIGHT	0x00050011
#define ASUS_WMI_DEVID_BRIGHTNESS	0x00050012

/* Misc */
#define ASUS_WMI_DEVID_CAMERA		0x00060013

/* Storage */
#define ASUS_WMI_DEVID_CARDREADER	0x00080013

/* Input */
#define ASUS_WMI_DEVID_TOUCHPAD		0x00100011
#define ASUS_WMI_DEVID_TOUCHPAD_LED	0x00100012

/* DSTS masks */
#define ASUS_WMI_DSTS_STATUS_BIT	0x00000001
#define ASUS_WMI_DSTS_UNKNOWN_BIT	0x00000002
#define ASUS_WMI_DSTS_PRESENCE_BIT	0x00010000
#define ASUS_WMI_DSTS_BRIGHTNESS_MASK	0x000000FF
#define ASUS_WMI_DSTS_MAX_BRIGTH_MASK	0x0000FF00

struct bios_args {
	u32 arg0;
	u32 arg1;
} __packed;

/*
 * <platform>/    - debugfs root directory
 *   dev_id      - current dev_id
 *   ctrl_param  - current ctrl_param
 *   devs        - call DEVS(dev_id, ctrl_param) and print result
 *   dsts        - call DSTS(dev_id)  and print result
 */
struct asus_wmi_debug {
	struct dentry *root;
	u32 dev_id;
	u32 ctrl_param;
};

struct asus_rfkill {
	struct asus_wmi *asus;
	struct rfkill *rfkill;
	u32 dev_id;
};

struct asus_wmi {
	int dsts_id;
	int spec;
	int sfun;

	struct input_dev *inputdev;
	struct backlight_device *backlight_device;
	struct platform_device *platform_device;

	struct led_classdev tpd_led;
	int tpd_led_wk;
	struct workqueue_struct *led_workqueue;
	struct work_struct tpd_led_work;

	struct asus_rfkill wlan;
	struct asus_rfkill bluetooth;
	struct asus_rfkill wimax;
	struct asus_rfkill wwan3g;

	struct hotplug_slot *hotplug_slot;
	struct mutex hotplug_lock;
	struct mutex wmi_lock;
	struct workqueue_struct *hotplug_workqueue;
	struct work_struct hotplug_work;

	struct asus_wmi_debug debug;

	struct asus_wmi_driver *driver;
};

static int asus_wmi_input_init(struct asus_wmi *asus)
{
	int err;

	asus->inputdev = input_allocate_device();
	if (!asus->inputdev)
		return -ENOMEM;

	asus->inputdev->name = asus->driver->input_phys;
	asus->inputdev->phys = asus->driver->input_name;
	asus->inputdev->id.bustype = BUS_HOST;
	asus->inputdev->dev.parent = &asus->platform_device->dev;

	err = sparse_keymap_setup(asus->inputdev, asus->driver->keymap, NULL);
	if (err)
		goto err_free_dev;

	err = input_register_device(asus->inputdev);
	if (err)
		goto err_free_keymap;

	return 0;

err_free_keymap:
	sparse_keymap_free(asus->inputdev);
err_free_dev:
	input_free_device(asus->inputdev);
	return err;
}

static void asus_wmi_input_exit(struct asus_wmi *asus)
{
	if (asus->inputdev) {
		sparse_keymap_free(asus->inputdev);
		input_unregister_device(asus->inputdev);
	}

	asus->inputdev = NULL;
}

static int asus_wmi_evaluate_method(u32 method_id, u32 arg0, u32 arg1,
				    u32 *retval)
{
	struct bios_args args = {
		.arg0 = arg0,
		.arg1 = arg1,
	};
	struct acpi_buffer input = { (acpi_size) sizeof(args), &args };
	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
	acpi_status status;
	union acpi_object *obj;
	u32 tmp;

	status = wmi_evaluate_method(ASUS_WMI_MGMT_GUID, 1, method_id,
				     &input, &output);

	if (ACPI_FAILURE(status))
		goto exit;

	obj = (union acpi_object *)output.pointer;
	if (obj && obj->type == ACPI_TYPE_INTEGER)
		tmp = (u32) obj->integer.value;
	else
		tmp = 0;

	if (retval)
		*retval = tmp;

	kfree(obj);

exit:
	if (ACPI_FAILURE(status))
		return -EIO;

	if (tmp == ASUS_WMI_UNSUPPORTED_METHOD)
		return -ENODEV;

	return 0;
}

static int asus_wmi_get_devstate(struct asus_wmi *asus, u32 dev_id, u32 *retval)
{
	return asus_wmi_evaluate_method(asus->dsts_id, dev_id, 0, retval);
}

static int asus_wmi_set_devstate(u32 dev_id, u32 ctrl_param,
				 u32 *retval)
{
	return asus_wmi_evaluate_method(ASUS_WMI_METHODID_DEVS, dev_id,
					ctrl_param, retval);
}

/* Helper for special devices with magic return codes */
static int asus_wmi_get_devstate_bits(struct asus_wmi *asus,
				      u32 dev_id, u32 mask)
{
	u32 retval = 0;
	int err;

	err = asus_wmi_get_devstate(asus, dev_id, &retval);

	if (err < 0)
		return err;

	if (!(retval & ASUS_WMI_DSTS_PRESENCE_BIT))
		return -ENODEV;

	if (mask == ASUS_WMI_DSTS_STATUS_BIT) {
		if (retval & ASUS_WMI_DSTS_UNKNOWN_BIT)
			return -ENODEV;
	}

	return retval & mask;
}

static int asus_wmi_get_devstate_simple(struct asus_wmi *asus, u32 dev_id)
{
	return asus_wmi_get_devstate_bits(asus, dev_id,
					  ASUS_WMI_DSTS_STATUS_BIT);
}

/*
 * LEDs
 */
/*
 * These functions actually update the LED's, and are called from a
 * workqueue. By doing this as separate work rather than when the LED
 * subsystem asks, we avoid messing with the Asus ACPI stuff during a
 * potentially bad time, such as a timer interrupt.
 */
static void tpd_led_update(struct work_struct *work)
{
	int ctrl_param;
	struct asus_wmi *asus;

	asus = container_of(work, struct asus_wmi, tpd_led_work);

	ctrl_param = asus->tpd_led_wk;
	asus_wmi_set_devstate(ASUS_WMI_DEVID_TOUCHPAD_LED, ctrl_param, NULL);
}

static void tpd_led_set(struct led_classdev *led_cdev,
			enum led_brightness value)
{
	struct asus_wmi *asus;

	asus = container_of(led_cdev, struct asus_wmi, tpd_led);

	asus->tpd_led_wk = !!value;
	queue_work(asus->led_workqueue, &asus->tpd_led_work);
}

static int read_tpd_led_state(struct asus_wmi *asus)
{
	return asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_TOUCHPAD_LED);
}

static enum led_brightness tpd_led_get(struct led_classdev *led_cdev)
{
	struct asus_wmi *asus;

	asus = container_of(led_cdev, struct asus_wmi, tpd_led);

	return read_tpd_led_state(asus);
}

static int asus_wmi_led_init(struct asus_wmi *asus)
{
	int rv;

	if (read_tpd_led_state(asus) < 0)
		return 0;

	asus->led_workqueue = create_singlethread_workqueue("led_workqueue");
	if (!asus->led_workqueue)
		return -ENOMEM;
	INIT_WORK(&asus->tpd_led_work, tpd_led_update);

	asus->tpd_led.name = "asus::touchpad";
	asus->tpd_led.brightness_set = tpd_led_set;
	asus->tpd_led.brightness_get = tpd_led_get;
	asus->tpd_led.max_brightness = 1;

	rv = led_classdev_register(&asus->platform_device->dev, &asus->tpd_led);
	if (rv) {
		destroy_workqueue(asus->led_workqueue);
		return rv;
	}

	return 0;
}

static void asus_wmi_led_exit(struct asus_wmi *asus)
{
	if (asus->tpd_led.dev)
		led_classdev_unregister(&asus->tpd_led);
	if (asus->led_workqueue)
		destroy_workqueue(asus->led_workqueue);
}

/*
 * PCI hotplug (for wlan rfkill)
 */
static bool asus_wlan_rfkill_blocked(struct asus_wmi *asus)
{
	int result = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_WLAN);

	if (result < 0)
		return false;
	return !result;
}

static void asus_rfkill_hotplug(struct asus_wmi *asus)
{
	struct pci_dev *dev;
	struct pci_bus *bus;
	bool blocked;
	bool absent;
	u32 l;

	mutex_lock(&asus->wmi_lock);
	blocked = asus_wlan_rfkill_blocked(asus);
	mutex_unlock(&asus->wmi_lock);

	mutex_lock(&asus->hotplug_lock);

	if (asus->wlan.rfkill)
		rfkill_set_sw_state(asus->wlan.rfkill, blocked);

	if (asus->hotplug_slot) {
		bus = pci_find_bus(0, 1);
		if (!bus) {
			pr_warning("Unable to find PCI bus 1?\n");
			goto out_unlock;
		}

		if (pci_bus_read_config_dword(bus, 0, PCI_VENDOR_ID, &l)) {
			pr_err("Unable to read PCI config space?\n");
			goto out_unlock;
		}
		absent = (l == 0xffffffff);

		if (blocked != absent) {
			pr_warning("BIOS says wireless lan is %s, "
				   "but the pci device is %s\n",
				   blocked ? "blocked" : "unblocked",
				   absent ? "absent" : "present");
			pr_warning("skipped wireless hotplug as probably "
				   "inappropriate for this model\n");
			goto out_unlock;
		}

		if (!blocked) {
			dev = pci_get_slot(bus, 0);
			if (dev) {
				/* Device already present */
				pci_dev_put(dev);
				goto out_unlock;
			}
			dev = pci_scan_single_device(bus, 0);
			if (dev) {
				pci_bus_assign_resources(bus);
				if (pci_bus_add_device(dev))
					pr_err("Unable to hotplug wifi\n");
			}
		} else {
			dev = pci_get_slot(bus, 0);
			if (dev) {
				pci_remove_bus_device(dev);
				pci_dev_put(dev);
			}
		}
	}

out_unlock:
	mutex_unlock(&asus->hotplug_lock);
}

static void asus_rfkill_notify(acpi_handle handle, u32 event, void *data)
{
	struct asus_wmi *asus = data;

	if (event != ACPI_NOTIFY_BUS_CHECK)
		return;

	/*
	 * We can't call directly asus_rfkill_hotplug because most
	 * of the time WMBC is still being executed and not reetrant.
	 * There is currently no way to tell ACPICA that  we want this
	 * method to be serialized, we schedule a asus_rfkill_hotplug
	 * call later, in a safer context.
	 */
	queue_work(asus->hotplug_workqueue, &asus->hotplug_work);
}

static int asus_register_rfkill_notifier(struct asus_wmi *asus, char *node)
{
	acpi_status status;
	acpi_handle handle;

	status = acpi_get_handle(NULL, node, &handle);

	if (ACPI_SUCCESS(status)) {
		status = acpi_install_notify_handler(handle,
						     ACPI_SYSTEM_NOTIFY,
						     asus_rfkill_notify, asus);
		if (ACPI_FAILURE(status))
			pr_warning("Failed to register notify on %s\n", node);
	} else
		return -ENODEV;

	return 0;
}

static void asus_unregister_rfkill_notifier(struct asus_wmi *asus, char *node)
{
	acpi_status status = AE_OK;
	acpi_handle handle;

	status = acpi_get_handle(NULL, node, &handle);

	if (ACPI_SUCCESS(status)) {
		status = acpi_remove_notify_handler(handle,
						    ACPI_SYSTEM_NOTIFY,
						    asus_rfkill_notify);
		if (ACPI_FAILURE(status))
			pr_err("Error removing rfkill notify handler %s\n",
			       node);
	}
}

static int asus_get_adapter_status(struct hotplug_slot *hotplug_slot,
				   u8 *value)
{
	struct asus_wmi *asus = hotplug_slot->private;
	int result = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_WLAN);

	if (result < 0)
		return result;

	*value = !!result;
	return 0;
}

static void asus_cleanup_pci_hotplug(struct hotplug_slot *hotplug_slot)
{
	kfree(hotplug_slot->info);
	kfree(hotplug_slot);
}

static struct hotplug_slot_ops asus_hotplug_slot_ops = {
	.owner = THIS_MODULE,
	.get_adapter_status = asus_get_adapter_status,
	.get_power_status = asus_get_adapter_status,
};

static void asus_hotplug_work(struct work_struct *work)
{
	struct asus_wmi *asus;

	asus = container_of(work, struct asus_wmi, hotplug_work);
	asus_rfkill_hotplug(asus);
}

static int asus_setup_pci_hotplug(struct asus_wmi *asus)
{
	int ret = -ENOMEM;
	struct pci_bus *bus = pci_find_bus(0, 1);

	if (!bus) {
		pr_err("Unable to find wifi PCI bus\n");
		return -ENODEV;
	}

	asus->hotplug_workqueue =
	    create_singlethread_workqueue("hotplug_workqueue");
	if (!asus->hotplug_workqueue)
		goto error_workqueue;

	INIT_WORK(&asus->hotplug_work, asus_hotplug_work);

	asus->hotplug_slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
	if (!asus->hotplug_slot)
		goto error_slot;

	asus->hotplug_slot->info = kzalloc(sizeof(struct hotplug_slot_info),
					   GFP_KERNEL);
	if (!asus->hotplug_slot->info)
		goto error_info;

	asus->hotplug_slot->private = asus;
	asus->hotplug_slot->release = &asus_cleanup_pci_hotplug;
	asus->hotplug_slot->ops = &asus_hotplug_slot_ops;
	asus_get_adapter_status(asus->hotplug_slot,
				&asus->hotplug_slot->info->adapter_status);

	ret = pci_hp_register(asus->hotplug_slot, bus, 0, "asus-wifi");
	if (ret) {
		pr_err("Unable to register hotplug slot - %d\n", ret);
		goto error_register;
	}

	return 0;

error_register:
	kfree(asus->hotplug_slot->info);
error_info:
	kfree(asus->hotplug_slot);
	asus->hotplug_slot = NULL;
error_slot:
	destroy_workqueue(asus->hotplug_workqueue);
error_workqueue:
	return ret;
}

/*
 * Rfkill devices
 */
static int asus_rfkill_set(void *data, bool blocked)
{
	struct asus_rfkill *priv = data;
	u32 ctrl_param = !blocked;

	return asus_wmi_set_devstate(priv->dev_id, ctrl_param, NULL);
}

static void asus_rfkill_query(struct rfkill *rfkill, void *data)
{
	struct asus_rfkill *priv = data;
	int result;

	result = asus_wmi_get_devstate_simple(priv->asus, priv->dev_id);

	if (result < 0)
		return;

	rfkill_set_sw_state(priv->rfkill, !result);
}

static int asus_rfkill_wlan_set(void *data, bool blocked)
{
	struct asus_rfkill *priv = data;
	struct asus_wmi *asus = priv->asus;
	int ret;

	/*
	 * This handler is enabled only if hotplug is enabled.
	 * In this case, the asus_wmi_set_devstate() will
	 * trigger a wmi notification and we need to wait
	 * this call to finish before being able to call
	 * any wmi method
	 */
	mutex_lock(&asus->wmi_lock);
	ret = asus_rfkill_set(data, blocked);
	mutex_unlock(&asus->wmi_lock);
	return ret;
}

static const struct rfkill_ops asus_rfkill_wlan_ops = {
	.set_block = asus_rfkill_wlan_set,
	.query = asus_rfkill_query,
};

static const struct rfkill_ops asus_rfkill_ops = {
	.set_block = asus_rfkill_set,
	.query = asus_rfkill_query,
};

static int asus_new_rfkill(struct asus_wmi *asus,
			   struct asus_rfkill *arfkill,
			   const char *name, enum rfkill_type type, int dev_id)
{
	int result = asus_wmi_get_devstate_simple(asus, dev_id);
	struct rfkill **rfkill = &arfkill->rfkill;

	if (result < 0)
		return result;

	arfkill->dev_id = dev_id;
	arfkill->asus = asus;

	if (dev_id == ASUS_WMI_DEVID_WLAN && asus->driver->hotplug_wireless)
		*rfkill = rfkill_alloc(name, &asus->platform_device->dev, type,
				       &asus_rfkill_wlan_ops, arfkill);
	else
		*rfkill = rfkill_alloc(name, &asus->platform_device->dev, type,
				       &asus_rfkill_ops, arfkill);

	if (!*rfkill)
		return -EINVAL;

	rfkill_init_sw_state(*rfkill, !result);
	result = rfkill_register(*rfkill);
	if (result) {
		rfkill_destroy(*rfkill);
		*rfkill = NULL;
		return result;
	}
	return 0;
}

static void asus_wmi_rfkill_exit(struct asus_wmi *asus)
{
	asus_unregister_rfkill_notifier(asus, "\\_SB.PCI0.P0P5");
	asus_unregister_rfkill_notifier(asus, "\\_SB.PCI0.P0P6");
	asus_unregister_rfkill_notifier(asus, "\\_SB.PCI0.P0P7");
	if (asus->wlan.rfkill) {
		rfkill_unregister(asus->wlan.rfkill);
		rfkill_destroy(asus->wlan.rfkill);
		asus->wlan.rfkill = NULL;
	}
	/*
	 * Refresh pci hotplug in case the rfkill state was changed after
	 * asus_unregister_rfkill_notifier()
	 */
	asus_rfkill_hotplug(asus);
	if (asus->hotplug_slot)
		pci_hp_deregister(asus->hotplug_slot);
	if (asus->hotplug_workqueue)
		destroy_workqueue(asus->hotplug_workqueue);

	if (asus->bluetooth.rfkill) {
		rfkill_unregister(asus->bluetooth.rfkill);
		rfkill_destroy(asus->bluetooth.rfkill);
		asus->bluetooth.rfkill = NULL;
	}
	if (asus->wimax.rfkill) {
		rfkill_unregister(asus->wimax.rfkill);
		rfkill_destroy(asus->wimax.rfkill);
		asus->wimax.rfkill = NULL;
	}
	if (asus->wwan3g.rfkill) {
		rfkill_unregister(asus->wwan3g.rfkill);
		rfkill_destroy(asus->wwan3g.rfkill);
		asus->wwan3g.rfkill = NULL;
	}
}

static int asus_wmi_rfkill_init(struct asus_wmi *asus)
{
	int result = 0;

	mutex_init(&asus->hotplug_lock);
	mutex_init(&asus->wmi_lock);

	result = asus_new_rfkill(asus, &asus->wlan, "asus-wlan",
				 RFKILL_TYPE_WLAN, ASUS_WMI_DEVID_WLAN);

	if (result && result != -ENODEV)
		goto exit;

	result = asus_new_rfkill(asus, &asus->bluetooth,
				 "asus-bluetooth", RFKILL_TYPE_BLUETOOTH,
				 ASUS_WMI_DEVID_BLUETOOTH);

	if (result && result != -ENODEV)
		goto exit;

	result = asus_new_rfkill(asus, &asus->wimax, "asus-wimax",
				 RFKILL_TYPE_WIMAX, ASUS_WMI_DEVID_WIMAX);

	if (result && result != -ENODEV)
		goto exit;

	result = asus_new_rfkill(asus, &asus->wwan3g, "asus-wwan3g",
				 RFKILL_TYPE_WWAN, ASUS_WMI_DEVID_WWAN3G);

	if (result && result != -ENODEV)
		goto exit;

	if (!asus->driver->hotplug_wireless)
		goto exit;

	result = asus_setup_pci_hotplug(asus);
	/*
	 * If we get -EBUSY then something else is handling the PCI hotplug -
	 * don't fail in this case
	 */
	if (result == -EBUSY)
		result = 0;

	asus_register_rfkill_notifier(asus, "\\_SB.PCI0.P0P5");
	asus_register_rfkill_notifier(asus, "\\_SB.PCI0.P0P6");
	asus_register_rfkill_notifier(asus, "\\_SB.PCI0.P0P7");
	/*
	 * Refresh pci hotplug in case the rfkill state was changed during
	 * setup.
	 */
	asus_rfkill_hotplug(asus);

exit:
	if (result && result != -ENODEV)
		asus_wmi_rfkill_exit(asus);

	if (result == -ENODEV)
		result = 0;

	return result;
}

/*
 * Backlight
 */
static int read_backlight_power(struct asus_wmi *asus)
{
	int ret = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_BACKLIGHT);

	if (ret < 0)
		return ret;

	return ret ? FB_BLANK_UNBLANK : FB_BLANK_POWERDOWN;
}

static int read_brightness_max(struct asus_wmi *asus)
{
	u32 retval;
	int err;

	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_BRIGHTNESS, &retval);

	if (err < 0)
		return err;

	retval = retval & ASUS_WMI_DSTS_MAX_BRIGTH_MASK;
	retval >>= 8;

	if (!retval)
		return -ENODEV;

	return retval;
}

static int read_brightness(struct backlight_device *bd)
{
	struct asus_wmi *asus = bl_get_data(bd);
	u32 retval, err;

	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_BRIGHTNESS, &retval);

	if (err < 0)
		return err;

	return retval & ASUS_WMI_DSTS_BRIGHTNESS_MASK;
}

static int update_bl_status(struct backlight_device *bd)
{
	struct asus_wmi *asus = bl_get_data(bd);
	u32 ctrl_param;
	int power, err;

	ctrl_param = bd->props.brightness;

	err = asus_wmi_set_devstate(ASUS_WMI_DEVID_BRIGHTNESS,
				    ctrl_param, NULL);

	if (err < 0)
		return err;

	power = read_backlight_power(asus);
	if (power != -ENODEV && bd->props.power != power) {
		ctrl_param = !!(bd->props.power == FB_BLANK_UNBLANK);
		err = asus_wmi_set_devstate(ASUS_WMI_DEVID_BACKLIGHT,
					    ctrl_param, NULL);
	}
	return err;
}

static const struct backlight_ops asus_wmi_bl_ops = {
	.get_brightness = read_brightness,
	.update_status = update_bl_status,
};

static int asus_wmi_backlight_notify(struct asus_wmi *asus, int code)
{
	struct backlight_device *bd = asus->backlight_device;
	int old = bd->props.brightness;
	int new = old;

	if (code >= NOTIFY_BRNUP_MIN && code <= NOTIFY_BRNUP_MAX)
		new = code - NOTIFY_BRNUP_MIN + 1;
	else if (code >= NOTIFY_BRNDOWN_MIN && code <= NOTIFY_BRNDOWN_MAX)
		new = code - NOTIFY_BRNDOWN_MIN;

	bd->props.brightness = new;
	backlight_update_status(bd);
	backlight_force_update(bd, BACKLIGHT_UPDATE_HOTKEY);

	return old;
}

static int asus_wmi_backlight_init(struct asus_wmi *asus)
{
	struct backlight_device *bd;
	struct backlight_properties props;
	int max;
	int power;

	max = read_brightness_max(asus);

	if (max == -ENODEV)
		max = 0;
	else if (max < 0)
		return max;

	power = read_backlight_power(asus);

	if (power == -ENODEV)
		power = FB_BLANK_UNBLANK;
	else if (power < 0)
		return power;

	memset(&props, 0, sizeof(struct backlight_properties));
	props.max_brightness = max;
	bd = backlight_device_register(asus->driver->name,
				       &asus->platform_device->dev, asus,
				       &asus_wmi_bl_ops, &props);
	if (IS_ERR(bd)) {
		pr_err("Could not register backlight device\n");
		return PTR_ERR(bd);
	}

	asus->backlight_device = bd;

	bd->props.brightness = read_brightness(bd);
	bd->props.power = power;
	backlight_update_status(bd);

	return 0;
}

static void asus_wmi_backlight_exit(struct asus_wmi *asus)
{
	if (asus->backlight_device)
		backlight_device_unregister(asus->backlight_device);

	asus->backlight_device = NULL;
}

static void asus_wmi_notify(u32 value, void *context)
{
	struct asus_wmi *asus = context;
	struct acpi_buffer response = { ACPI_ALLOCATE_BUFFER, NULL };
	union acpi_object *obj;
	acpi_status status;
	int code;
	int orig_code;

	status = wmi_get_event_data(value, &response);
	if (status != AE_OK) {
		pr_err("bad event status 0x%x\n", status);
		return;
	}

	obj = (union acpi_object *)response.pointer;

	if (!obj || obj->type != ACPI_TYPE_INTEGER)
		goto exit;

	code = obj->integer.value;
	orig_code = code;

	if (code >= NOTIFY_BRNUP_MIN && code <= NOTIFY_BRNUP_MAX)
		code = NOTIFY_BRNUP_MIN;
	else if (code >= NOTIFY_BRNDOWN_MIN &&
		 code <= NOTIFY_BRNDOWN_MAX)
		code = NOTIFY_BRNDOWN_MIN;

	if (code == NOTIFY_BRNUP_MIN || code == NOTIFY_BRNDOWN_MIN) {
		if (!acpi_video_backlight_support())
			asus_wmi_backlight_notify(asus, orig_code);
	} else if (!sparse_keymap_report_event(asus->inputdev, code, 1, true))
		pr_info("Unknown key %x pressed\n", code);

exit:
	kfree(obj);
}

/*
 * Sys helpers
 */
static int parse_arg(const char *buf, unsigned long count, int *val)
{
	if (!count)
		return 0;
	if (sscanf(buf, "%i", val) != 1)
		return -EINVAL;
	return count;
}

static ssize_t store_sys_wmi(struct asus_wmi *asus, int devid,
			     const char *buf, size_t count)
{
	u32 retval;
	int rv, err, value;

	value = asus_wmi_get_devstate_simple(asus, devid);
	if (value == -ENODEV)	/* Check device presence */
		return value;

	rv = parse_arg(buf, count, &value);
	err = asus_wmi_set_devstate(devid, value, &retval);

	if (err < 0)
		return err;

	return rv;
}

static ssize_t show_sys_wmi(struct asus_wmi *asus, int devid, char *buf)
{
	int value = asus_wmi_get_devstate_simple(asus, devid);

	if (value < 0)
		return value;

	return sprintf(buf, "%d\n", value);
}

#define ASUS_WMI_CREATE_DEVICE_ATTR(_name, _mode, _cm)			\
	static ssize_t show_##_name(struct device *dev,			\
				    struct device_attribute *attr,	\
				    char *buf)				\
	{								\
		struct asus_wmi *asus = dev_get_drvdata(dev);		\
									\
		return show_sys_wmi(asus, _cm, buf);			\
	}								\
	static ssize_t store_##_name(struct device *dev,		\
				     struct device_attribute *attr,	\
				     const char *buf, size_t count)	\
	{								\
		struct asus_wmi *asus = dev_get_drvdata(dev);		\
									\
		return store_sys_wmi(asus, _cm, buf, count);		\
	}								\
	static struct device_attribute dev_attr_##_name = {		\
		.attr = {						\
			.name = __stringify(_name),			\
			.mode = _mode },				\
		.show   = show_##_name,					\
		.store  = store_##_name,				\
	}

ASUS_WMI_CREATE_DEVICE_ATTR(touchpad, 0644, ASUS_WMI_DEVID_TOUCHPAD);
ASUS_WMI_CREATE_DEVICE_ATTR(camera, 0644, ASUS_WMI_DEVID_CAMERA);
ASUS_WMI_CREATE_DEVICE_ATTR(cardr, 0644, ASUS_WMI_DEVID_CARDREADER);

static ssize_t store_cpufv(struct device *dev, struct device_attribute *attr,
			   const char *buf, size_t count)
{
	int value;

	if (!count || sscanf(buf, "%i", &value) != 1)
		return -EINVAL;
	if (value < 0 || value > 2)
		return -EINVAL;

	return asus_wmi_evaluate_method(ASUS_WMI_METHODID_CFVS, value, 0, NULL);
}

static DEVICE_ATTR(cpufv, S_IRUGO | S_IWUSR, NULL, store_cpufv);

static struct attribute *platform_attributes[] = {
	&dev_attr_cpufv.attr,
	&dev_attr_camera.attr,
	&dev_attr_cardr.attr,
	&dev_attr_touchpad.attr,
	NULL
};

static mode_t asus_sysfs_is_visible(struct kobject *kobj,
				    struct attribute *attr, int idx)
{
	struct device *dev = container_of(kobj, struct device, kobj);
	struct platform_device *pdev = to_platform_device(dev);
	struct asus_wmi *asus = platform_get_drvdata(pdev);
	bool ok = true;
	int devid = -1;

	if (attr == &dev_attr_camera.attr)
		devid = ASUS_WMI_DEVID_CAMERA;
	else if (attr == &dev_attr_cardr.attr)
		devid = ASUS_WMI_DEVID_CARDREADER;
	else if (attr == &dev_attr_touchpad.attr)
		devid = ASUS_WMI_DEVID_TOUCHPAD;

	if (devid != -1)
		ok = !(asus_wmi_get_devstate_simple(asus, devid) < 0);

	return ok ? attr->mode : 0;
}

static struct attribute_group platform_attribute_group = {
	.is_visible = asus_sysfs_is_visible,
	.attrs = platform_attributes
};

static void asus_wmi_sysfs_exit(struct platform_device *device)
{
	sysfs_remove_group(&device->dev.kobj, &platform_attribute_group);
}

static int asus_wmi_sysfs_init(struct platform_device *device)
{
	return sysfs_create_group(&device->dev.kobj, &platform_attribute_group);
}

/*
 * Platform device
 */
static int __init asus_wmi_platform_init(struct asus_wmi *asus)
{
	int rv;

	/* INIT enable hotkeys on some models */
	if (!asus_wmi_evaluate_method(ASUS_WMI_METHODID_INIT, 0, 0, &rv))
		pr_info("Initialization: %#x", rv);

	/* We don't know yet what to do with this version... */
	if (!asus_wmi_evaluate_method(ASUS_WMI_METHODID_SPEC, 0, 0x9, &rv)) {
		pr_info("BIOS WMI version: %d.%d", rv >> 8, rv & 0xFF);
		asus->spec = rv;
	}

	/*
	 * The SFUN method probably allows the original driver to get the list
	 * of features supported by a given model. For now, 0x0100 or 0x0800
	 * bit signifies that the laptop is equipped with a Wi-Fi MiniPCI card.
	 * The significance of others is yet to be found.
	 */
	if (!asus_wmi_evaluate_method(ASUS_WMI_METHODID_SFUN, 0, 0, &rv)) {
		pr_info("SFUN value: %#x", rv);
		asus->sfun = rv;
	}

	/*
	 * Eee PC and Notebooks seems to have different method_id for DSTS,
	 * but it may also be related to the BIOS's SPEC.
	 * Note, on most Eeepc, there is no way to check if a method exist
	 * or note, while on notebooks, they returns 0xFFFFFFFE on failure,
	 * but once again, SPEC may probably be used for that kind of things.
	 */
	if (!asus_wmi_evaluate_method(ASUS_WMI_METHODID_DSTS, 0, 0, NULL))
		asus->dsts_id = ASUS_WMI_METHODID_DSTS;
	else if (!asus_wmi_evaluate_method(ASUS_WMI_METHODID_DSTS2, 0, 0, NULL))
		asus->dsts_id = ASUS_WMI_METHODID_DSTS2;

	if (!asus->dsts_id) {
		pr_err("Can't find DSTS");
		return -ENODEV;
	}

	return asus_wmi_sysfs_init(asus->platform_device);
}

static void asus_wmi_platform_exit(struct asus_wmi *asus)
{
	asus_wmi_sysfs_exit(asus->platform_device);
}

/*
 * debugfs
 */
struct asus_wmi_debugfs_node {
	struct asus_wmi *asus;
	char *name;
	int (*show) (struct seq_file *m, void *data);
};

static int show_dsts(struct seq_file *m, void *data)
{
	struct asus_wmi *asus = m->private;
	int err;
	u32 retval = -1;

	err = asus_wmi_get_devstate(asus, asus->debug.dev_id, &retval);

	if (err < 0)
		return err;

	seq_printf(m, "DSTS(%x) = %x\n", asus->debug.dev_id, retval);

	return 0;
}

static int show_devs(struct seq_file *m, void *data)
{
	struct asus_wmi *asus = m->private;
	int err;
	u32 retval = -1;

	err = asus_wmi_set_devstate(asus->debug.dev_id, asus->debug.ctrl_param,
				    &retval);

	if (err < 0)
		return err;

	seq_printf(m, "DEVS(%x, %x) = %x\n", asus->debug.dev_id,
		   asus->debug.ctrl_param, retval);

	return 0;
}

static struct asus_wmi_debugfs_node asus_wmi_debug_files[] = {
	{NULL, "devs", show_devs},
	{NULL, "dsts", show_dsts},
};

static int asus_wmi_debugfs_open(struct inode *inode, struct file *file)
{
	struct asus_wmi_debugfs_node *node = inode->i_private;

	return single_open(file, node->show, node->asus);
}

static const struct file_operations asus_wmi_debugfs_io_ops = {
	.owner = THIS_MODULE,
	.open = asus_wmi_debugfs_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
};

static void asus_wmi_debugfs_exit(struct asus_wmi *asus)
{
	debugfs_remove_recursive(asus->debug.root);
}

static int asus_wmi_debugfs_init(struct asus_wmi *asus)
{
	struct dentry *dent;
	int i;

	asus->debug.root = debugfs_create_dir(asus->driver->name, NULL);
	if (!asus->debug.root) {
		pr_err("failed to create debugfs directory");
		goto error_debugfs;
	}

	dent = debugfs_create_x32("dev_id", S_IRUGO | S_IWUSR,
				  asus->debug.root, &asus->debug.dev_id);
	if (!dent)
		goto error_debugfs;

	dent = debugfs_create_x32("ctrl_param", S_IRUGO | S_IWUSR,
				  asus->debug.root, &asus->debug.ctrl_param);
	if (!dent)
		goto error_debugfs;

	for (i = 0; i < ARRAY_SIZE(asus_wmi_debug_files); i++) {
		struct asus_wmi_debugfs_node *node = &asus_wmi_debug_files[i];

		node->asus = asus;
		dent = debugfs_create_file(node->name, S_IFREG | S_IRUGO,
					   asus->debug.root, node,
					   &asus_wmi_debugfs_io_ops);
		if (!dent) {
			pr_err("failed to create debug file: %s\n", node->name);
			goto error_debugfs;
		}
	}

	return 0;

error_debugfs:
	asus_wmi_debugfs_exit(asus);
	return -ENOMEM;
}

/*
 * WMI Driver
 */
static int asus_wmi_add(struct platform_device *pdev)
{
	struct platform_driver *pdrv = to_platform_driver(pdev->dev.driver);
	struct asus_wmi_driver *wdrv = to_asus_wmi_driver(pdrv);
	struct asus_wmi *asus;
	acpi_status status;
	int err;

	asus = kzalloc(sizeof(struct asus_wmi), GFP_KERNEL);
	if (!asus)
		return -ENOMEM;

	asus->driver = wdrv;
	asus->platform_device = pdev;
	wdrv->platform_device = pdev;
	platform_set_drvdata(asus->platform_device, asus);

	if (wdrv->quirks)
		wdrv->quirks(asus->driver);

	err = asus_wmi_platform_init(asus);
	if (err)
		goto fail_platform;

	err = asus_wmi_input_init(asus);
	if (err)
		goto fail_input;

	err = asus_wmi_led_init(asus);
	if (err)
		goto fail_leds;

	err = asus_wmi_rfkill_init(asus);
	if (err)
		goto fail_rfkill;

	if (!acpi_video_backlight_support()) {
		err = asus_wmi_backlight_init(asus);
		if (err && err != -ENODEV)
			goto fail_backlight;
	} else
		pr_info("Backlight controlled by ACPI video driver\n");

	status = wmi_install_notify_handler(asus->driver->event_guid,
					    asus_wmi_notify, asus);
	if (ACPI_FAILURE(status)) {
		pr_err("Unable to register notify handler - %d\n", status);
		err = -ENODEV;
		goto fail_wmi_handler;
	}

	err = asus_wmi_debugfs_init(asus);
	if (err)
		goto fail_debugfs;

	return 0;

fail_debugfs:
	wmi_remove_notify_handler(asus->driver->event_guid);
fail_wmi_handler:
	asus_wmi_backlight_exit(asus);
fail_backlight:
	asus_wmi_rfkill_exit(asus);
fail_rfkill:
	asus_wmi_led_exit(asus);
fail_leds:
	asus_wmi_input_exit(asus);
fail_input:
	asus_wmi_platform_exit(asus);
fail_platform:
	kfree(asus);
	return err;
}

static int asus_wmi_remove(struct platform_device *device)
{
	struct asus_wmi *asus;

	asus = platform_get_drvdata(device);
	wmi_remove_notify_handler(asus->driver->event_guid);
	asus_wmi_backlight_exit(asus);
	asus_wmi_input_exit(asus);
	asus_wmi_led_exit(asus);
	asus_wmi_rfkill_exit(asus);
	asus_wmi_debugfs_exit(asus);
	asus_wmi_platform_exit(asus);

	kfree(asus);
	return 0;
}

/*
 * Platform driver - hibernate/resume callbacks
 */
static int asus_hotk_thaw(struct device *device)
{
	struct asus_wmi *asus = dev_get_drvdata(device);

	if (asus->wlan.rfkill) {
		bool wlan;

		/*
		 * Work around bios bug - acpi _PTS turns off the wireless led
		 * during suspend.  Normally it restores it on resume, but
		 * we should kick it ourselves in case hibernation is aborted.
		 */
		wlan = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_WLAN);
		asus_wmi_set_devstate(ASUS_WMI_DEVID_WLAN, wlan, NULL);
	}

	return 0;
}

static int asus_hotk_restore(struct device *device)
{
	struct asus_wmi *asus = dev_get_drvdata(device);
	int bl;

	/* Refresh both wlan rfkill state and pci hotplug */
	if (asus->wlan.rfkill)
		asus_rfkill_hotplug(asus);

	if (asus->bluetooth.rfkill) {
		bl = !asus_wmi_get_devstate_simple(asus,
						   ASUS_WMI_DEVID_BLUETOOTH);
		rfkill_set_sw_state(asus->bluetooth.rfkill, bl);
	}
	if (asus->wimax.rfkill) {
		bl = !asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_WIMAX);
		rfkill_set_sw_state(asus->wimax.rfkill, bl);
	}
	if (asus->wwan3g.rfkill) {
		bl = !asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_WWAN3G);
		rfkill_set_sw_state(asus->wwan3g.rfkill, bl);
	}

	return 0;
}

static const struct dev_pm_ops asus_pm_ops = {
	.thaw = asus_hotk_thaw,
	.restore = asus_hotk_restore,
};

static int asus_wmi_probe(struct platform_device *pdev)
{
	struct platform_driver *pdrv = to_platform_driver(pdev->dev.driver);
	struct asus_wmi_driver *wdrv = to_asus_wmi_driver(pdrv);
	int ret;

	if (!wmi_has_guid(ASUS_WMI_MGMT_GUID)) {
		pr_warning("Management GUID not found\n");
		return -ENODEV;
	}

	if (wdrv->event_guid && !wmi_has_guid(wdrv->event_guid)) {
		pr_warning("Event GUID not found\n");
		return -ENODEV;
	}

	if (wdrv->probe) {
		ret = wdrv->probe(pdev);
		if (ret)
			return ret;
	}

	return asus_wmi_add(pdev);
}

static bool used;

int asus_wmi_register_driver(struct asus_wmi_driver *driver)
{
	struct platform_driver *platform_driver;
	struct platform_device *platform_device;

	if (used)
		return -EBUSY;

	platform_driver = &driver->platform_driver;
	platform_driver->remove = asus_wmi_remove;
	platform_driver->driver.owner = driver->owner;
	platform_driver->driver.name = driver->name;
	platform_driver->driver.pm = &asus_pm_ops;

	platform_device = platform_create_bundle(platform_driver,
						 asus_wmi_probe,
						 NULL, 0, NULL, 0);
	if (IS_ERR(platform_device))
		return PTR_ERR(platform_device);

	used = true;
	return 0;
}
EXPORT_SYMBOL_GPL(asus_wmi_register_driver);

void asus_wmi_unregister_driver(struct asus_wmi_driver *driver)
{
	platform_device_unregister(driver->platform_device);
	platform_driver_unregister(&driver->platform_driver);
	used = false;
}
EXPORT_SYMBOL_GPL(asus_wmi_unregister_driver);

static int __init asus_wmi_init(void)
{
	if (!wmi_has_guid(ASUS_WMI_MGMT_GUID)) {
		pr_info("Asus Management GUID not found");
		return -ENODEV;
	}

	pr_info("ASUS WMI generic driver loaded");
	return 0;
}

static void __exit asus_wmi_exit(void)
{
	pr_info("ASUS WMI generic driver unloaded");
}

module_init(asus_wmi_init);
module_exit(asus_wmi_exit);