drivers/pnp/pnpacpi/core.c - kernel/lockdown - Git at Google

 /*
  * pnpacpi -- PnP ACPI driver
  *
  * Copyright (c) 2004 Matthieu Castet <castet.matthieu@free.fr>
  * Copyright (c) 2004 Li Shaohua <shaohua.li@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, 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/export.h>
 #include <linux/acpi.h>
 #include <linux/pnp.h>
 #include <linux/slab.h>
 #include <linux/mod_devicetable.h>

 #include "../base.h"
 #include "pnpacpi.h"

 static int num;

 /* We need only to blacklist devices that have already an acpi driver that
  * can't use pnp layer. We don't need to blacklist device that are directly
  * used by the kernel (PCI root, ...), as it is harmless and there were
  * already present in pnpbios. But there is an exception for devices that
  * have irqs (PIC, Timer) because we call acpi_register_gsi.
  * Finally, only devices that have a CRS method need to be in this list.
  */
 static struct acpi_device_id excluded_id_list[] __initdata = {
 	{"PNP0C09", 0},		/* EC */
 	{"PNP0C0F", 0},		/* Link device */
 	{"PNP0000", 0},		/* PIC */
 	{"PNP0100", 0},		/* Timer */
 	{"", 0},
 };

 static inline int __init is_exclusive_device(struct acpi_device *dev)
 {
 	return (!acpi_match_device_ids(dev, excluded_id_list));
 }

 /*
  * Compatible Device IDs
  */
 #define TEST_HEX(c) \
 	if (!(('0' <= (c) && (c) <= '9') || ('A' <= (c) && (c) <= 'F'))) \
 		return 0
 #define TEST_ALPHA(c) \
 	if (!('A' <= (c) && (c) <= 'Z')) \
 		return 0
 static int __init ispnpidacpi(const char *id)
 {
 	TEST_ALPHA(id[0]);
 	TEST_ALPHA(id[1]);
 	TEST_ALPHA(id[2]);
 	TEST_HEX(id[3]);
 	TEST_HEX(id[4]);
 	TEST_HEX(id[5]);
 	TEST_HEX(id[6]);
 	if (id[7] != '\0')
 		return 0;
 	return 1;
 }

 static int pnpacpi_get_resources(struct pnp_dev *dev)
 {
 	pnp_dbg(&dev->dev, "get resources\n");
 	return pnpacpi_parse_allocated_resource(dev);
 }

 static int pnpacpi_set_resources(struct pnp_dev *dev)
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle;
 	int ret = 0;

 	pnp_dbg(&dev->dev, "set resources\n");

 	handle = ACPI_HANDLE(&dev->dev);
 	if (!handle || acpi_bus_get_device(handle, &acpi_dev)) {
 		dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
 		return -ENODEV;
 	}

 	if (WARN_ON_ONCE(acpi_dev != dev->data))
 		dev->data = acpi_dev;

 	if (acpi_has_method(handle, METHOD_NAME__SRS)) {
 		struct acpi_buffer buffer;

 		ret = pnpacpi_build_resource_template(dev, &buffer);
 		if (ret)
 			return ret;

 		ret = pnpacpi_encode_resources(dev, &buffer);
 		if (!ret) {
 			acpi_status status;

 			status = acpi_set_current_resources(handle, &buffer);
 			if (ACPI_FAILURE(status))
 				ret = -EIO;
 		}
 		kfree(buffer.pointer);
 	}
 	if (!ret && acpi_bus_power_manageable(handle))
 		ret = acpi_bus_set_power(handle, ACPI_STATE_D0);

 	return ret;
 }

 static int pnpacpi_disable_resources(struct pnp_dev *dev)
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle;
 	acpi_status status;

 	dev_dbg(&dev->dev, "disable resources\n");

 	handle = ACPI_HANDLE(&dev->dev);
 	if (!handle || acpi_bus_get_device(handle, &acpi_dev)) {
 		dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
 		return 0;
 	}

 	/* acpi_unregister_gsi(pnp_irq(dev, 0)); */
 	if (acpi_bus_power_manageable(handle))
 		acpi_bus_set_power(handle, ACPI_STATE_D3_COLD);

 	/* continue even if acpi_bus_set_power() fails */
 	status = acpi_evaluate_object(handle, "_DIS", NULL, NULL);
 	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
 		return -ENODEV;

 	return 0;
 }

 #ifdef CONFIG_ACPI_SLEEP
 static bool pnpacpi_can_wakeup(struct pnp_dev *dev)
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle;

 	handle = ACPI_HANDLE(&dev->dev);
 	if (!handle || acpi_bus_get_device(handle, &acpi_dev)) {
 		dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
 		return false;
 	}

 	return acpi_bus_can_wakeup(handle);
 }

 static int pnpacpi_suspend(struct pnp_dev *dev, pm_message_t state)
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle;
 	int error = 0;

 	handle = ACPI_HANDLE(&dev->dev);
 	if (!handle || acpi_bus_get_device(handle, &acpi_dev)) {
 		dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
 		return 0;
 	}

 	if (device_can_wakeup(&dev->dev)) {
 		error = acpi_pm_device_sleep_wake(&dev->dev,
 				device_may_wakeup(&dev->dev));
 		if (error)
 			return error;
 	}

 	if (acpi_bus_power_manageable(handle)) {
 		int power_state = acpi_pm_device_sleep_state(&dev->dev, NULL,
 							ACPI_STATE_D3_COLD);
 		if (power_state < 0)
 			power_state = (state.event == PM_EVENT_ON) ?
 					ACPI_STATE_D0 : ACPI_STATE_D3_COLD;

 		/*
 		 * acpi_bus_set_power() often fails (keyboard port can't be
 		 * powered-down?), and in any case, our return value is ignored
 		 * by pnp_bus_suspend().  Hence we don't revert the wakeup
 		 * setting if the set_power fails.
 		 */
 		error = acpi_bus_set_power(handle, power_state);
 	}

 	return error;
 }

 static int pnpacpi_resume(struct pnp_dev *dev)
 {
 	struct acpi_device *acpi_dev;
 	acpi_handle handle = ACPI_HANDLE(&dev->dev);
 	int error = 0;

 	if (!handle || acpi_bus_get_device(handle, &acpi_dev)) {
 		dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
 		return -ENODEV;
 	}

 	if (device_may_wakeup(&dev->dev))
 		acpi_pm_device_sleep_wake(&dev->dev, false);

 	if (acpi_bus_power_manageable(handle))
 		error = acpi_bus_set_power(handle, ACPI_STATE_D0);

 	return error;
 }
 #endif

 struct pnp_protocol pnpacpi_protocol = {
 	.name	 = "Plug and Play ACPI",
 	.get	 = pnpacpi_get_resources,
 	.set	 = pnpacpi_set_resources,
 	.disable = pnpacpi_disable_resources,
 #ifdef CONFIG_ACPI_SLEEP
 	.can_wakeup = pnpacpi_can_wakeup,
 	.suspend = pnpacpi_suspend,
 	.resume = pnpacpi_resume,
 #endif
 };
 EXPORT_SYMBOL(pnpacpi_protocol);

 static char *__init pnpacpi_get_id(struct acpi_device *device)
 {
 	struct acpi_hardware_id *id;

 	list_for_each_entry(id, &device->pnp.ids, list) {
 		if (ispnpidacpi(id->id))
 			return id->id;
 	}

 	return NULL;
 }

 static int __init pnpacpi_add_device(struct acpi_device *device)
 {
 	struct pnp_dev *dev;
 	char *pnpid;
 	struct acpi_hardware_id *id;
 	int error;

 	/* Skip devices that are already bound */
 	if (device->physical_node_count)
 		return 0;

 	/*
 	 * If a PnPacpi device is not present , the device
 	 * driver should not be loaded.
 	 */
 	if (!acpi_has_method(device->handle, "_CRS"))
 		return 0;

 	pnpid = pnpacpi_get_id(device);
 	if (!pnpid)
 		return 0;

 	if (is_exclusive_device(device) || !device->status.present)
 		return 0;

 	dev = pnp_alloc_dev(&pnpacpi_protocol, num, pnpid);
 	if (!dev)
 		return -ENOMEM;

 	dev->data = device;
 	/* .enabled means the device can decode the resources */
 	dev->active = device->status.enabled;
 	if (acpi_has_method(device->handle, "_SRS"))
 		dev->capabilities |= PNP_CONFIGURABLE;
 	dev->capabilities |= PNP_READ;
 	if (device->flags.dynamic_status && (dev->capabilities & PNP_CONFIGURABLE))
 		dev->capabilities |= PNP_WRITE;
 	if (device->flags.removable)
 		dev->capabilities |= PNP_REMOVABLE;
 	if (acpi_has_method(device->handle, "_DIS"))
 		dev->capabilities |= PNP_DISABLE;

 	if (strlen(acpi_device_name(device)))
 		strncpy(dev->name, acpi_device_name(device), sizeof(dev->name));
 	else
 		strncpy(dev->name, acpi_device_bid(device), sizeof(dev->name));

 	if (dev->active)
 		pnpacpi_parse_allocated_resource(dev);

 	if (dev->capabilities & PNP_CONFIGURABLE)
 		pnpacpi_parse_resource_option_data(dev);

 	list_for_each_entry(id, &device->pnp.ids, list) {
 		if (!strcmp(id->id, pnpid))
 			continue;
 		if (!ispnpidacpi(id->id))
 			continue;
 		pnp_add_id(dev, id->id);
 	}

 	/* clear out the damaged flags */
 	if (!dev->active)
 		pnp_init_resources(dev);

 	error = pnp_add_device(dev);
 	if (error) {
 		put_device(&dev->dev);
 		return error;
 	}

 	num++;

 	return 0;
 }

 static acpi_status __init pnpacpi_add_device_handler(acpi_handle handle,
 						     u32 lvl, void *context,
 						     void **rv)
 {
 	struct acpi_device *device;

 	if (!acpi_bus_get_device(handle, &device))
 		pnpacpi_add_device(device);
 	else
 		return AE_CTRL_DEPTH;
 	return AE_OK;
 }

 static int __init acpi_pnp_match(struct device *dev, void *_pnp)
 {
 	struct acpi_device *acpi = to_acpi_device(dev);
 	struct pnp_dev *pnp = _pnp;

 	/* true means it matched */
 	return pnp->data == acpi;
 }

 static struct acpi_device * __init acpi_pnp_find_companion(struct device *dev)
 {
 	dev = bus_find_device(&acpi_bus_type, NULL, to_pnp_dev(dev),
 			      acpi_pnp_match);
 	if (!dev)
 		return NULL;

 	put_device(dev);
 	return to_acpi_device(dev);
 }

 /* complete initialization of a PNPACPI device includes having
  * pnpdev->dev.archdata.acpi_handle point to its ACPI sibling.
  */
 static bool acpi_pnp_bus_match(struct device *dev)
 {
 	return dev->bus == &pnp_bus_type;
 }

 static struct acpi_bus_type __initdata acpi_pnp_bus = {
 	.name	     = "PNP",
 	.match	     = acpi_pnp_bus_match,
 	.find_companion = acpi_pnp_find_companion,
 };

 int pnpacpi_disabled __initdata;
 static int __init pnpacpi_init(void)
 {
 	if (acpi_disabled || pnpacpi_disabled) {
 		printk(KERN_INFO "pnp: PnP ACPI: disabled\n");
 		return 0;
 	}
 	printk(KERN_INFO "pnp: PnP ACPI init\n");
 	pnp_register_protocol(&pnpacpi_protocol);
 	register_acpi_bus_type(&acpi_pnp_bus);
 	acpi_get_devices(NULL, pnpacpi_add_device_handler, NULL, NULL);
 	printk(KERN_INFO "pnp: PnP ACPI: found %d devices\n", num);
 	unregister_acpi_bus_type(&acpi_pnp_bus);
 	pnp_platform_devices = 1;
 	return 0;
 }

 fs_initcall(pnpacpi_init);

 static int __init pnpacpi_setup(char *str)
 {
 	if (str == NULL)
 		return 1;
 	if (!strncmp(str, "off", 3))
 		pnpacpi_disabled = 1;
 	return 1;
 }

 __setup("pnpacpi=", pnpacpi_setup);
	/*
	* pnpacpi -- PnP ACPI driver
	*
	* Copyright (c) 2004 Matthieu Castet <castet.matthieu@free.fr>
	* Copyright (c) 2004 Li Shaohua <shaohua.li@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, 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/export.h>
	#include <linux/acpi.h>
	#include <linux/pnp.h>
	#include <linux/slab.h>
	#include <linux/mod_devicetable.h>

	#include "../base.h"
	#include "pnpacpi.h"

	static int num;

	/* We need only to blacklist devices that have already an acpi driver that
	* can't use pnp layer. We don't need to blacklist device that are directly
	* used by the kernel (PCI root, ...), as it is harmless and there were
	* already present in pnpbios. But there is an exception for devices that
	* have irqs (PIC, Timer) because we call acpi_register_gsi.
	* Finally, only devices that have a CRS method need to be in this list.
	*/
	static struct acpi_device_id excluded_id_list[] __initdata = {
	{"PNP0C09", 0}, /* EC */
	{"PNP0C0F", 0}, /* Link device */
	{"PNP0000", 0}, /* PIC */
	{"PNP0100", 0}, /* Timer */
	{"", 0},
	};

	static inline int __init is_exclusive_device(struct acpi_device *dev)
	{
	return (!acpi_match_device_ids(dev, excluded_id_list));
	}

	/*
	* Compatible Device IDs
	*/
	#define TEST_HEX(c) \
	if (!(('0' <= (c) && (c) <= '9') \|\| ('A' <= (c) && (c) <= 'F'))) \
	return 0
	#define TEST_ALPHA(c) \
	if (!('A' <= (c) && (c) <= 'Z')) \
	return 0
	static int __init ispnpidacpi(const char *id)
	{
	TEST_ALPHA(id[0]);
	TEST_ALPHA(id[1]);
	TEST_ALPHA(id[2]);
	TEST_HEX(id[3]);
	TEST_HEX(id[4]);
	TEST_HEX(id[5]);
	TEST_HEX(id[6]);
	if (id[7] != '\0')
	return 0;
	return 1;
	}

	static int pnpacpi_get_resources(struct pnp_dev *dev)
	{
	pnp_dbg(&dev->dev, "get resources\n");
	return pnpacpi_parse_allocated_resource(dev);
	}

	static int pnpacpi_set_resources(struct pnp_dev *dev)
	{
	struct acpi_device *acpi_dev;
	acpi_handle handle;
	int ret = 0;

	pnp_dbg(&dev->dev, "set resources\n");

	handle = ACPI_HANDLE(&dev->dev);
	if (!handle \|\| acpi_bus_get_device(handle, &acpi_dev)) {
	dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
	return -ENODEV;
	}

	if (WARN_ON_ONCE(acpi_dev != dev->data))
	dev->data = acpi_dev;

	if (acpi_has_method(handle, METHOD_NAME__SRS)) {
	struct acpi_buffer buffer;

	ret = pnpacpi_build_resource_template(dev, &buffer);
	if (ret)
	return ret;

	ret = pnpacpi_encode_resources(dev, &buffer);
	if (!ret) {
	acpi_status status;

	status = acpi_set_current_resources(handle, &buffer);
	if (ACPI_FAILURE(status))
	ret = -EIO;
	}
	kfree(buffer.pointer);
	}
	if (!ret && acpi_bus_power_manageable(handle))
	ret = acpi_bus_set_power(handle, ACPI_STATE_D0);

	return ret;
	}

	static int pnpacpi_disable_resources(struct pnp_dev *dev)
	{
	struct acpi_device *acpi_dev;
	acpi_handle handle;
	acpi_status status;

	dev_dbg(&dev->dev, "disable resources\n");

	handle = ACPI_HANDLE(&dev->dev);
	if (!handle \|\| acpi_bus_get_device(handle, &acpi_dev)) {
	dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
	return 0;
	}

	/* acpi_unregister_gsi(pnp_irq(dev, 0)); */
	if (acpi_bus_power_manageable(handle))
	acpi_bus_set_power(handle, ACPI_STATE_D3_COLD);

	/* continue even if acpi_bus_set_power() fails */
	status = acpi_evaluate_object(handle, "_DIS", NULL, NULL);
	if (ACPI_FAILURE(status) && status != AE_NOT_FOUND)
	return -ENODEV;

	return 0;
	}

	#ifdef CONFIG_ACPI_SLEEP
	static bool pnpacpi_can_wakeup(struct pnp_dev *dev)
	{
	struct acpi_device *acpi_dev;
	acpi_handle handle;

	handle = ACPI_HANDLE(&dev->dev);
	if (!handle \|\| acpi_bus_get_device(handle, &acpi_dev)) {
	dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
	return false;
	}

	return acpi_bus_can_wakeup(handle);
	}

	static int pnpacpi_suspend(struct pnp_dev *dev, pm_message_t state)
	{
	struct acpi_device *acpi_dev;
	acpi_handle handle;
	int error = 0;

	handle = ACPI_HANDLE(&dev->dev);
	if (!handle \|\| acpi_bus_get_device(handle, &acpi_dev)) {
	dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
	return 0;
	}

	if (device_can_wakeup(&dev->dev)) {
	error = acpi_pm_device_sleep_wake(&dev->dev,
	device_may_wakeup(&dev->dev));
	if (error)
	return error;
	}

	if (acpi_bus_power_manageable(handle)) {
	int power_state = acpi_pm_device_sleep_state(&dev->dev, NULL,
	ACPI_STATE_D3_COLD);
	if (power_state < 0)
	power_state = (state.event == PM_EVENT_ON) ?
	ACPI_STATE_D0 : ACPI_STATE_D3_COLD;

	/*
	* acpi_bus_set_power() often fails (keyboard port can't be
	* powered-down?), and in any case, our return value is ignored
	* by pnp_bus_suspend(). Hence we don't revert the wakeup
	* setting if the set_power fails.
	*/
	error = acpi_bus_set_power(handle, power_state);
	}

	return error;
	}

	static int pnpacpi_resume(struct pnp_dev *dev)
	{
	struct acpi_device *acpi_dev;
	acpi_handle handle = ACPI_HANDLE(&dev->dev);
	int error = 0;

	if (!handle \|\| acpi_bus_get_device(handle, &acpi_dev)) {
	dev_dbg(&dev->dev, "ACPI device not found in %s!\n", __func__);
	return -ENODEV;
	}

	if (device_may_wakeup(&dev->dev))
	acpi_pm_device_sleep_wake(&dev->dev, false);

	if (acpi_bus_power_manageable(handle))
	error = acpi_bus_set_power(handle, ACPI_STATE_D0);

	return error;
	}
	#endif

	struct pnp_protocol pnpacpi_protocol = {
	.name = "Plug and Play ACPI",
	.get = pnpacpi_get_resources,
	.set = pnpacpi_set_resources,
	.disable = pnpacpi_disable_resources,
	#ifdef CONFIG_ACPI_SLEEP
	.can_wakeup = pnpacpi_can_wakeup,
	.suspend = pnpacpi_suspend,
	.resume = pnpacpi_resume,
	#endif
	};
	EXPORT_SYMBOL(pnpacpi_protocol);

	static char __init pnpacpi_get_id(struct acpi_device device)
	{
	struct acpi_hardware_id *id;

	list_for_each_entry(id, &device->pnp.ids, list) {
	if (ispnpidacpi(id->id))
	return id->id;
	}

	return NULL;
	}

	static int __init pnpacpi_add_device(struct acpi_device *device)
	{
	struct pnp_dev *dev;
	char *pnpid;
	struct acpi_hardware_id *id;
	int error;

	/* Skip devices that are already bound */
	if (device->physical_node_count)
	return 0;

	/*
	* If a PnPacpi device is not present , the device
	* driver should not be loaded.
	*/
	if (!acpi_has_method(device->handle, "_CRS"))
	return 0;

	pnpid = pnpacpi_get_id(device);
	if (!pnpid)
	return 0;

	if (is_exclusive_device(device) \|\| !device->status.present)
	return 0;

	dev = pnp_alloc_dev(&pnpacpi_protocol, num, pnpid);
	if (!dev)
	return -ENOMEM;

	dev->data = device;
	/* .enabled means the device can decode the resources */
	dev->active = device->status.enabled;
	if (acpi_has_method(device->handle, "_SRS"))
	dev->capabilities \|= PNP_CONFIGURABLE;
	dev->capabilities \|= PNP_READ;
	if (device->flags.dynamic_status && (dev->capabilities & PNP_CONFIGURABLE))
	dev->capabilities \|= PNP_WRITE;
	if (device->flags.removable)
	dev->capabilities \|= PNP_REMOVABLE;
	if (acpi_has_method(device->handle, "_DIS"))
	dev->capabilities \|= PNP_DISABLE;

	if (strlen(acpi_device_name(device)))
	strncpy(dev->name, acpi_device_name(device), sizeof(dev->name));
	else
	strncpy(dev->name, acpi_device_bid(device), sizeof(dev->name));

	if (dev->active)
	pnpacpi_parse_allocated_resource(dev);

	if (dev->capabilities & PNP_CONFIGURABLE)
	pnpacpi_parse_resource_option_data(dev);

	list_for_each_entry(id, &device->pnp.ids, list) {
	if (!strcmp(id->id, pnpid))
	continue;
	if (!ispnpidacpi(id->id))
	continue;
	pnp_add_id(dev, id->id);
	}

	/* clear out the damaged flags */
	if (!dev->active)
	pnp_init_resources(dev);

	error = pnp_add_device(dev);
	if (error) {
	put_device(&dev->dev);
	return error;
	}

	num++;

	return 0;
	}

	static acpi_status __init pnpacpi_add_device_handler(acpi_handle handle,
	u32 lvl, void *context,
	void **rv)
	{
	struct acpi_device *device;

	if (!acpi_bus_get_device(handle, &device))
	pnpacpi_add_device(device);
	else
	return AE_CTRL_DEPTH;
	return AE_OK;
	}

	static int __init acpi_pnp_match(struct device dev, void _pnp)
	{
	struct acpi_device *acpi = to_acpi_device(dev);
	struct pnp_dev *pnp = _pnp;

	/* true means it matched */
	return pnp->data == acpi;
	}

	static struct acpi_device * __init acpi_pnp_find_companion(struct device *dev)
	{
	dev = bus_find_device(&acpi_bus_type, NULL, to_pnp_dev(dev),
	acpi_pnp_match);
	if (!dev)
	return NULL;

	put_device(dev);
	return to_acpi_device(dev);
	}

	/* complete initialization of a PNPACPI device includes having
	* pnpdev->dev.archdata.acpi_handle point to its ACPI sibling.
	*/
	static bool acpi_pnp_bus_match(struct device *dev)
	{
	return dev->bus == &pnp_bus_type;
	}

	static struct acpi_bus_type __initdata acpi_pnp_bus = {
	.name = "PNP",
	.match = acpi_pnp_bus_match,
	.find_companion = acpi_pnp_find_companion,
	};

	int pnpacpi_disabled __initdata;
	static int __init pnpacpi_init(void)
	{
	if (acpi_disabled \|\| pnpacpi_disabled) {
	printk(KERN_INFO "pnp: PnP ACPI: disabled\n");
	return 0;
	}
	printk(KERN_INFO "pnp: PnP ACPI init\n");
	pnp_register_protocol(&pnpacpi_protocol);
	register_acpi_bus_type(&acpi_pnp_bus);
	acpi_get_devices(NULL, pnpacpi_add_device_handler, NULL, NULL);
	printk(KERN_INFO "pnp: PnP ACPI: found %d devices\n", num);
	unregister_acpi_bus_type(&acpi_pnp_bus);
	pnp_platform_devices = 1;
	return 0;
	}

	fs_initcall(pnpacpi_init);

	static int __init pnpacpi_setup(char *str)
	{
	if (str == NULL)
	return 1;
	if (!strncmp(str, "off", 3))
	pnpacpi_disabled = 1;
	return 1;
	}

	__setup("pnpacpi=", pnpacpi_setup);