drivers/acpi/bay.c - kernel/msm-4.9 - Gitiles

 /*
  *  bay.c - ACPI removable drive bay driver
  *
  *  Copyright (C) 2006 Kristen Carlson Accardi <kristen.c.accardi@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/notifier.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
 #include <linux/seq_file.h>
 #include <asm/uaccess.h>
 #include <linux/platform_device.h>

 #define ACPI_BAY_DRIVER_NAME "ACPI Removable Drive Bay Driver"

 ACPI_MODULE_NAME("bay")
 MODULE_AUTHOR("Kristen Carlson Accardi");
 MODULE_DESCRIPTION(ACPI_BAY_DRIVER_NAME);
 MODULE_LICENSE("GPL");
 #define ACPI_BAY_CLASS "bay"
 #define ACPI_BAY_COMPONENT	0x10000000
 #define _COMPONENT ACPI_BAY_COMPONENT
 #define bay_dprintk(h,s) {\
 	char prefix[80] = {'\0'};\
 	struct acpi_buffer buffer = {sizeof(prefix), prefix};\
 	acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);\
 	printk(KERN_DEBUG PREFIX "%s: %s\n", prefix, s); }
 static void bay_notify(acpi_handle handle, u32 event, void *data);
 static int acpi_bay_add(struct acpi_device *device);
 static int acpi_bay_remove(struct acpi_device *device, int type);

 static struct acpi_driver acpi_bay_driver = {
 	.name = ACPI_BAY_DRIVER_NAME,
 	.class = ACPI_BAY_CLASS,
 	.ids = ACPI_BAY_HID,
 	.ops = {
 		.add = acpi_bay_add,
 		.remove = acpi_bay_remove,
 		},
 };

 struct bay {
 	acpi_handle handle;
 	char *name;
 	struct list_head list;
 	struct platform_device *pdev;
 };

 static LIST_HEAD(drive_bays);


 /*****************************************************************************
  *                         Drive Bay functions                               *
  *****************************************************************************/
 /**
  * is_ejectable - see if a device is ejectable
  * @handle: acpi handle of the device
  *
  * If an acpi object has a _EJ0 method, then it is ejectable
  */
 static int is_ejectable(acpi_handle handle)
 {
 	acpi_status status;
 	acpi_handle tmp;

 	status = acpi_get_handle(handle, "_EJ0", &tmp);
 	if (ACPI_FAILURE(status))
 		return 0;
 	return 1;
 }

 /**
  * bay_present - see if the bay device is present
  * @bay: the drive bay
  *
  * execute the _STA method.
  */
 static int bay_present(struct bay *bay)
 {
 	unsigned long sta;
 	acpi_status status;

 	if (bay) {
 		status = acpi_evaluate_integer(bay->handle, "_STA", NULL, &sta);
 		if (ACPI_SUCCESS(status) && sta)
 			return 1;
 	}
 	return 0;
 }

 /**
  * eject_device - respond to an eject request
  * @handle - the device to eject
  *
  * Call this devices _EJ0 method.
  */
 static void eject_device(acpi_handle handle)
 {
 	struct acpi_object_list arg_list;
 	union acpi_object arg;

 	bay_dprintk(handle, "Ejecting device");

 	arg_list.count = 1;
 	arg_list.pointer = &arg;
 	arg.type = ACPI_TYPE_INTEGER;
 	arg.integer.value = 1;

 	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_EJ0",
 					      &arg_list, NULL)))
 		pr_debug("Failed to evaluate _EJ0!\n");
 }

 /*
  * show_present - read method for "present" file in sysfs
  */
 static ssize_t show_present(struct device *dev,
 			   struct device_attribute *attr, char *buf)
 {
 	struct bay *bay = dev_get_drvdata(dev);
 	return snprintf(buf, PAGE_SIZE, "%d\n", bay_present(bay));

 }
 DEVICE_ATTR(present, S_IRUGO, show_present, NULL);

 /*
  * write_eject - write method for "eject" file in sysfs
  */
 static ssize_t write_eject(struct device *dev, struct device_attribute *attr,
 			   const char *buf, size_t count)
 {
 	struct bay *bay = dev_get_drvdata(dev);

 	if (!count)
 		return -EINVAL;

 	eject_device(bay->handle);
 	return count;
 }
 DEVICE_ATTR(eject, S_IWUSR, NULL, write_eject);

 /**
  * is_ata - see if a device is an ata device
  * @handle: acpi handle of the device
  *
  * If an acpi object has one of 4 ATA ACPI methods defined,
  * then it is an ATA device
  */
 static int is_ata(acpi_handle handle)
 {
 	acpi_handle tmp;

 	if ((ACPI_SUCCESS(acpi_get_handle(handle, "_GTF", &tmp))) ||
 	   (ACPI_SUCCESS(acpi_get_handle(handle, "_GTM", &tmp))) ||
 	   (ACPI_SUCCESS(acpi_get_handle(handle, "_STM", &tmp))) ||
 	   (ACPI_SUCCESS(acpi_get_handle(handle, "_SDD", &tmp))))
 		return 1;

 	return 0;
 }

 /**
  * parent_is_ata(acpi_handle handle)
  *
  */
 static int parent_is_ata(acpi_handle handle)
 {
 	acpi_handle phandle;

 	if (acpi_get_parent(handle, &phandle))
 		return 0;

 	return is_ata(phandle);
 }

 /**
  * is_ejectable_bay - see if a device is an ejectable drive bay
  * @handle: acpi handle of the device
  *
  * If an acpi object is ejectable and has one of the ACPI ATA
  * methods defined, then we can safely call it an ejectable
  * drive bay
  */
 static int is_ejectable_bay(acpi_handle handle)
 {
 	if ((is_ata(handle) || parent_is_ata(handle)) && is_ejectable(handle))
 		return 1;
 	return 0;
 }

 /**
  * eject_removable_drive - try to eject this drive
  * @dev : the device structure of the drive
  *
  * If a device is a removable drive that requires an _EJ0 method
  * to be executed in order to safely remove from the system, do
  * it.  ATM - always returns success
  */
 int eject_removable_drive(struct device *dev)
 {
 	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);

 	if (handle) {
 		bay_dprintk(handle, "Got device handle");
 		if (is_ejectable_bay(handle))
 			eject_device(handle);
 	} else {
 		printk("No acpi handle for device\n");
 	}

 	/* should I return an error code? */
 	return 0;
 }
 EXPORT_SYMBOL_GPL(eject_removable_drive);

 static int acpi_bay_add(struct acpi_device *device)
 {
 	bay_dprintk(device->handle, "adding bay device");
 	strcpy(acpi_device_name(device), "Dockable Bay");
 	strcpy(acpi_device_class(device), "bay");
 	return 0;
 }

 static int acpi_bay_add_fs(struct bay *bay)
 {
 	int ret;
 	struct device *dev = &bay->pdev->dev;

 	ret = device_create_file(dev, &dev_attr_present);
 	if (ret)
 		goto add_fs_err;
 	ret = device_create_file(dev, &dev_attr_eject);
 	if (ret) {
 		device_remove_file(dev, &dev_attr_present);
 		goto add_fs_err;
 	}
 	return 0;

  add_fs_err:
 	bay_dprintk(bay->handle, "Error adding sysfs files\n");
 	return ret;
 }

 static void acpi_bay_remove_fs(struct bay *bay)
 {
 	struct device *dev = &bay->pdev->dev;

 	/* cleanup sysfs */
 	device_remove_file(dev, &dev_attr_present);
 	device_remove_file(dev, &dev_attr_eject);
 }

 static int bay_is_dock_device(acpi_handle handle)
 {
 	acpi_handle parent;

 	acpi_get_parent(handle, &parent);

 	/* if the device or it's parent is dependent on the
 	 * dock, then we are a dock device
 	 */
 	return (is_dock_device(handle) || is_dock_device(parent));
 }

 static int bay_add(acpi_handle handle, int id)
 {
 	acpi_status status;
 	struct bay *new_bay;
 	struct platform_device *pdev;
 	struct acpi_buffer nbuffer = {ACPI_ALLOCATE_BUFFER, NULL};
 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &nbuffer);

 	bay_dprintk(handle, "Adding notify handler");

 	/*
 	 * Initialize bay device structure
 	 */
 	new_bay = kzalloc(sizeof(*new_bay), GFP_ATOMIC);
 	INIT_LIST_HEAD(&new_bay->list);
 	new_bay->handle = handle;
 	new_bay->name = (char *)nbuffer.pointer;

 	/* initialize platform device stuff */
 	pdev = platform_device_register_simple(ACPI_BAY_CLASS, id, NULL, 0);
 	if (pdev == NULL) {
 		printk(KERN_ERR PREFIX "Error registering bay device\n");
 		goto bay_add_err;
 	}
 	new_bay->pdev = pdev;
 	platform_set_drvdata(pdev, new_bay);

 	if (acpi_bay_add_fs(new_bay)) {
 		platform_device_unregister(new_bay->pdev);
 		goto bay_add_err;
 	}

 	/* register for events on this device */
 	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 			bay_notify, new_bay);
 	if (ACPI_FAILURE(status)) {
 		printk(KERN_ERR PREFIX "Error installing bay notify handler\n");
 	}

 	/* if we are on a dock station, we should register for dock
 	 * notifications.
 	 */
 	if (bay_is_dock_device(handle)) {
 		bay_dprintk(handle, "Is dependent on dock\n");
 		register_hotplug_dock_device(handle, bay_notify, new_bay);
 	}
 	list_add(&new_bay->list, &drive_bays);
 	printk(KERN_INFO PREFIX "Bay [%s] Added\n", new_bay->name);
 	return 0;

 bay_add_err:
 	kfree(new_bay->name);
 	kfree(new_bay);
 	return -ENODEV;
 }

 static int acpi_bay_remove(struct acpi_device *device, int type)
 {
 	/*** FIXME: do something here */
 	return 0;
 }

 /**
  * bay_create_acpi_device - add new devices to acpi
  * @handle - handle of the device to add
  *
  *  This function will create a new acpi_device for the given
  *  handle if one does not exist already.  This should cause
  *  acpi to scan for drivers for the given devices, and call
  *  matching driver's add routine.
  *
  *  Returns a pointer to the acpi_device corresponding to the handle.
  */
 static struct acpi_device * bay_create_acpi_device(acpi_handle handle)
 {
 	struct acpi_device *device = NULL;
 	struct acpi_device *parent_device;
 	acpi_handle parent;
 	int ret;

 	bay_dprintk(handle, "Trying to get device");
 	if (acpi_bus_get_device(handle, &device)) {
 		/*
 		 * no device created for this object,
 		 * so we should create one.
 		 */
 		bay_dprintk(handle, "No device for handle");
 		acpi_get_parent(handle, &parent);
 		if (acpi_bus_get_device(parent, &parent_device))
 			parent_device = NULL;

 		ret = acpi_bus_add(&device, parent_device, handle,
 			ACPI_BUS_TYPE_DEVICE);
 		if (ret) {
 			pr_debug("error adding bus, %x\n",
 				-ret);
 			return NULL;
 		}
 	}
 	return device;
 }

 /**
  * bay_notify - act upon an acpi bay notification
  * @handle: the bay handle
  * @event: the acpi event
  * @data: our driver data struct
  *
  */
 static void bay_notify(acpi_handle handle, u32 event, void *data)
 {
 	struct acpi_device *dev;

 	bay_dprintk(handle, "Bay event");

 	switch(event) {
 	case ACPI_NOTIFY_BUS_CHECK:
 		printk("Bus Check\n");
 	case ACPI_NOTIFY_DEVICE_CHECK:
 		printk("Device Check\n");
 		dev = bay_create_acpi_device(handle);
 		if (dev)
 			acpi_bus_generate_event(dev, event, 0);
 		else
 			printk("No device for generating event\n");
 		/* wouldn't it be a good idea to just rescan SATA
 		 * right here?
 		 */
 		break;
 	case ACPI_NOTIFY_EJECT_REQUEST:
 		printk("Eject request\n");
 		dev = bay_create_acpi_device(handle);
 		if (dev)
 			acpi_bus_generate_event(dev, event, 0);
 		else
 			printk("No device for generating eventn");

 		/* wouldn't it be a good idea to just call the
 		 * eject_device here if we were a SATA device?
 		 */
 		break;
 	default:
 		printk("unknown event %d\n", event);
 	}
 }

 static acpi_status
 find_bay(acpi_handle handle, u32 lvl, void *context, void **rv)
 {
 	int *count = (int *)context;

 	/*
 	 * there could be more than one ejectable bay.
 	 * so, just return AE_OK always so that every object
 	 * will be checked.
 	 */
 	if (is_ejectable_bay(handle)) {
 		bay_dprintk(handle, "found ejectable bay");
 		if (!bay_add(handle, *count))
 			(*count)++;
 	}
 	return AE_OK;
 }

 static int __init bay_init(void)
 {
 	int bays = 0;

 	INIT_LIST_HEAD(&drive_bays);

 	/* look for dockable drive bays */
 	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 		ACPI_UINT32_MAX, find_bay, &bays, NULL);

 	if (bays)
 		if ((acpi_bus_register_driver(&acpi_bay_driver) < 0))
 			printk(KERN_ERR "Unable to register bay driver\n");

 	if (!bays)
 		return -ENODEV;

 	return 0;
 }

 static void __exit bay_exit(void)
 {
 	struct bay *bay, *tmp;

 	list_for_each_entry_safe(bay, tmp, &drive_bays, list) {
 		if (is_dock_device(bay->handle))
 			unregister_hotplug_dock_device(bay->handle);
 		acpi_bay_remove_fs(bay);
 		acpi_remove_notify_handler(bay->handle, ACPI_SYSTEM_NOTIFY,
 			bay_notify);
 		platform_device_unregister(bay->pdev);
 		kfree(bay->name);
 		kfree(bay);
 	}

 	acpi_bus_unregister_driver(&acpi_bay_driver);
 }

 postcore_initcall(bay_init);
 module_exit(bay_exit);
	/*
	* bay.c - ACPI removable drive bay driver
	*
	* Copyright (C) 2006 Kristen Carlson Accardi <kristen.c.accardi@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/notifier.h>
	#include <acpi/acpi_bus.h>
	#include <acpi/acpi_drivers.h>
	#include <linux/seq_file.h>
	#include <asm/uaccess.h>
	#include <linux/platform_device.h>

	#define ACPI_BAY_DRIVER_NAME "ACPI Removable Drive Bay Driver"

	ACPI_MODULE_NAME("bay")
	MODULE_AUTHOR("Kristen Carlson Accardi");
	MODULE_DESCRIPTION(ACPI_BAY_DRIVER_NAME);
	MODULE_LICENSE("GPL");
	#define ACPI_BAY_CLASS "bay"
	#define ACPI_BAY_COMPONENT 0x10000000
	#define _COMPONENT ACPI_BAY_COMPONENT
	#define bay_dprintk(h,s) {\
	char prefix[80] = {'\0'};\
	struct acpi_buffer buffer = {sizeof(prefix), prefix};\
	acpi_get_name(h, ACPI_FULL_PATHNAME, &buffer);\
	printk(KERN_DEBUG PREFIX "%s: %s\n", prefix, s); }
	static void bay_notify(acpi_handle handle, u32 event, void *data);
	static int acpi_bay_add(struct acpi_device *device);
	static int acpi_bay_remove(struct acpi_device *device, int type);

	static struct acpi_driver acpi_bay_driver = {
	.name = ACPI_BAY_DRIVER_NAME,
	.class = ACPI_BAY_CLASS,
	.ids = ACPI_BAY_HID,
	.ops = {
	.add = acpi_bay_add,
	.remove = acpi_bay_remove,
	},
	};

	struct bay {
	acpi_handle handle;
	char *name;
	struct list_head list;
	struct platform_device *pdev;
	};

	static LIST_HEAD(drive_bays);


	/*****************************************************************************
	* Drive Bay functions *
	*****************************************************************************/
	/**
	* is_ejectable - see if a device is ejectable
	* @handle: acpi handle of the device
	*
	* If an acpi object has a _EJ0 method, then it is ejectable
	*/
	static int is_ejectable(acpi_handle handle)
	{
	acpi_status status;
	acpi_handle tmp;

	status = acpi_get_handle(handle, "_EJ0", &tmp);
	if (ACPI_FAILURE(status))
	return 0;
	return 1;
	}

	/**
	* bay_present - see if the bay device is present
	* @bay: the drive bay
	*
	* execute the _STA method.
	*/
	static int bay_present(struct bay *bay)
	{
	unsigned long sta;
	acpi_status status;

	if (bay) {
	status = acpi_evaluate_integer(bay->handle, "_STA", NULL, &sta);
	if (ACPI_SUCCESS(status) && sta)
	return 1;
	}
	return 0;
	}

	/**
	* eject_device - respond to an eject request
	* @handle - the device to eject
	*
	* Call this devices _EJ0 method.
	*/
	static void eject_device(acpi_handle handle)
	{
	struct acpi_object_list arg_list;
	union acpi_object arg;

	bay_dprintk(handle, "Ejecting device");

	arg_list.count = 1;
	arg_list.pointer = &arg;
	arg.type = ACPI_TYPE_INTEGER;
	arg.integer.value = 1;

	if (ACPI_FAILURE(acpi_evaluate_object(handle, "_EJ0",
	&arg_list, NULL)))
	pr_debug("Failed to evaluate _EJ0!\n");
	}

	/*
	* show_present - read method for "present" file in sysfs
	*/
	static ssize_t show_present(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct bay *bay = dev_get_drvdata(dev);
	return snprintf(buf, PAGE_SIZE, "%d\n", bay_present(bay));

	}
	DEVICE_ATTR(present, S_IRUGO, show_present, NULL);

	/*
	* write_eject - write method for "eject" file in sysfs
	*/
	static ssize_t write_eject(struct device dev, struct device_attribute attr,
	const char *buf, size_t count)
	{
	struct bay *bay = dev_get_drvdata(dev);

	if (!count)
	return -EINVAL;

	eject_device(bay->handle);
	return count;
	}
	DEVICE_ATTR(eject, S_IWUSR, NULL, write_eject);

	/**
	* is_ata - see if a device is an ata device
	* @handle: acpi handle of the device
	*
	* If an acpi object has one of 4 ATA ACPI methods defined,
	* then it is an ATA device
	*/
	static int is_ata(acpi_handle handle)
	{
	acpi_handle tmp;

	if ((ACPI_SUCCESS(acpi_get_handle(handle, "_GTF", &tmp))) \|\|
	(ACPI_SUCCESS(acpi_get_handle(handle, "_GTM", &tmp))) \|\|
	(ACPI_SUCCESS(acpi_get_handle(handle, "_STM", &tmp))) \|\|
	(ACPI_SUCCESS(acpi_get_handle(handle, "_SDD", &tmp))))
	return 1;

	return 0;
	}

	/**
	* parent_is_ata(acpi_handle handle)
	*
	*/
	static int parent_is_ata(acpi_handle handle)
	{
	acpi_handle phandle;

	if (acpi_get_parent(handle, &phandle))
	return 0;

	return is_ata(phandle);
	}

	/**
	* is_ejectable_bay - see if a device is an ejectable drive bay
	* @handle: acpi handle of the device
	*
	* If an acpi object is ejectable and has one of the ACPI ATA
	* methods defined, then we can safely call it an ejectable
	* drive bay
	*/
	static int is_ejectable_bay(acpi_handle handle)
	{
	if ((is_ata(handle) \|\| parent_is_ata(handle)) && is_ejectable(handle))
	return 1;
	return 0;
	}

	/**
	* eject_removable_drive - try to eject this drive
	* @dev : the device structure of the drive
	*
	* If a device is a removable drive that requires an _EJ0 method
	* to be executed in order to safely remove from the system, do
	* it. ATM - always returns success
	*/
	int eject_removable_drive(struct device *dev)
	{
	acpi_handle handle = DEVICE_ACPI_HANDLE(dev);

	if (handle) {
	bay_dprintk(handle, "Got device handle");
	if (is_ejectable_bay(handle))
	eject_device(handle);
	} else {
	printk("No acpi handle for device\n");
	}

	/* should I return an error code? */
	return 0;
	}
	EXPORT_SYMBOL_GPL(eject_removable_drive);

	static int acpi_bay_add(struct acpi_device *device)
	{
	bay_dprintk(device->handle, "adding bay device");
	strcpy(acpi_device_name(device), "Dockable Bay");
	strcpy(acpi_device_class(device), "bay");
	return 0;
	}

	static int acpi_bay_add_fs(struct bay *bay)
	{
	int ret;
	struct device *dev = &bay->pdev->dev;

	ret = device_create_file(dev, &dev_attr_present);
	if (ret)
	goto add_fs_err;
	ret = device_create_file(dev, &dev_attr_eject);
	if (ret) {
	device_remove_file(dev, &dev_attr_present);
	goto add_fs_err;
	}
	return 0;

	add_fs_err:
	bay_dprintk(bay->handle, "Error adding sysfs files\n");
	return ret;
	}

	static void acpi_bay_remove_fs(struct bay *bay)
	{
	struct device *dev = &bay->pdev->dev;

	/* cleanup sysfs */
	device_remove_file(dev, &dev_attr_present);
	device_remove_file(dev, &dev_attr_eject);
	}

	static int bay_is_dock_device(acpi_handle handle)
	{
	acpi_handle parent;

	acpi_get_parent(handle, &parent);

	/* if the device or it's parent is dependent on the
	* dock, then we are a dock device
	*/
	return (is_dock_device(handle) \|\| is_dock_device(parent));
	}

	static int bay_add(acpi_handle handle, int id)
	{
	acpi_status status;
	struct bay *new_bay;
	struct platform_device *pdev;
	struct acpi_buffer nbuffer = {ACPI_ALLOCATE_BUFFER, NULL};
	acpi_get_name(handle, ACPI_FULL_PATHNAME, &nbuffer);

	bay_dprintk(handle, "Adding notify handler");

	/*
	* Initialize bay device structure
	*/
	new_bay = kzalloc(sizeof(*new_bay), GFP_ATOMIC);
	INIT_LIST_HEAD(&new_bay->list);
	new_bay->handle = handle;
	new_bay->name = (char *)nbuffer.pointer;

	/* initialize platform device stuff */
	pdev = platform_device_register_simple(ACPI_BAY_CLASS, id, NULL, 0);
	if (pdev == NULL) {
	printk(KERN_ERR PREFIX "Error registering bay device\n");
	goto bay_add_err;
	}
	new_bay->pdev = pdev;
	platform_set_drvdata(pdev, new_bay);

	if (acpi_bay_add_fs(new_bay)) {
	platform_device_unregister(new_bay->pdev);
	goto bay_add_err;
	}

	/* register for events on this device */
	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
	bay_notify, new_bay);
	if (ACPI_FAILURE(status)) {
	printk(KERN_ERR PREFIX "Error installing bay notify handler\n");
	}

	/* if we are on a dock station, we should register for dock
	* notifications.
	*/
	if (bay_is_dock_device(handle)) {
	bay_dprintk(handle, "Is dependent on dock\n");
	register_hotplug_dock_device(handle, bay_notify, new_bay);
	}
	list_add(&new_bay->list, &drive_bays);
	printk(KERN_INFO PREFIX "Bay [%s] Added\n", new_bay->name);
	return 0;

	bay_add_err:
	kfree(new_bay->name);
	kfree(new_bay);
	return -ENODEV;
	}

	static int acpi_bay_remove(struct acpi_device *device, int type)
	{
	/*** FIXME: do something here */
	return 0;
	}

	/**
	* bay_create_acpi_device - add new devices to acpi
	* @handle - handle of the device to add
	*
	* This function will create a new acpi_device for the given
	* handle if one does not exist already. This should cause
	* acpi to scan for drivers for the given devices, and call
	* matching driver's add routine.
	*
	* Returns a pointer to the acpi_device corresponding to the handle.
	*/
	static struct acpi_device * bay_create_acpi_device(acpi_handle handle)
	{
	struct acpi_device *device = NULL;
	struct acpi_device *parent_device;
	acpi_handle parent;
	int ret;

	bay_dprintk(handle, "Trying to get device");
	if (acpi_bus_get_device(handle, &device)) {
	/*
	* no device created for this object,
	* so we should create one.
	*/
	bay_dprintk(handle, "No device for handle");
	acpi_get_parent(handle, &parent);
	if (acpi_bus_get_device(parent, &parent_device))
	parent_device = NULL;

	ret = acpi_bus_add(&device, parent_device, handle,
	ACPI_BUS_TYPE_DEVICE);
	if (ret) {
	pr_debug("error adding bus, %x\n",
	-ret);
	return NULL;
	}
	}
	return device;
	}

	/**
	* bay_notify - act upon an acpi bay notification
	* @handle: the bay handle
	* @event: the acpi event
	* @data: our driver data struct
	*
	*/
	static void bay_notify(acpi_handle handle, u32 event, void *data)
	{
	struct acpi_device *dev;

	bay_dprintk(handle, "Bay event");

	switch(event) {
	case ACPI_NOTIFY_BUS_CHECK:
	printk("Bus Check\n");
	case ACPI_NOTIFY_DEVICE_CHECK:
	printk("Device Check\n");
	dev = bay_create_acpi_device(handle);
	if (dev)
	acpi_bus_generate_event(dev, event, 0);
	else
	printk("No device for generating event\n");
	/* wouldn't it be a good idea to just rescan SATA
	* right here?
	*/
	break;
	case ACPI_NOTIFY_EJECT_REQUEST:
	printk("Eject request\n");
	dev = bay_create_acpi_device(handle);
	if (dev)
	acpi_bus_generate_event(dev, event, 0);
	else
	printk("No device for generating eventn");

	/* wouldn't it be a good idea to just call the
	* eject_device here if we were a SATA device?
	*/
	break;
	default:
	printk("unknown event %d\n", event);
	}
	}

	static acpi_status
	find_bay(acpi_handle handle, u32 lvl, void context, void *rv)
	{
	int count = (int )context;

	/*
	* there could be more than one ejectable bay.
	* so, just return AE_OK always so that every object
	* will be checked.
	*/
	if (is_ejectable_bay(handle)) {
	bay_dprintk(handle, "found ejectable bay");
	if (!bay_add(handle, *count))
	(*count)++;
	}
	return AE_OK;
	}

	static int __init bay_init(void)
	{
	int bays = 0;

	INIT_LIST_HEAD(&drive_bays);

	/* look for dockable drive bays */
	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
	ACPI_UINT32_MAX, find_bay, &bays, NULL);

	if (bays)
	if ((acpi_bus_register_driver(&acpi_bay_driver) < 0))
	printk(KERN_ERR "Unable to register bay driver\n");

	if (!bays)
	return -ENODEV;

	return 0;
	}

	static void __exit bay_exit(void)
	{
	struct bay bay, tmp;

	list_for_each_entry_safe(bay, tmp, &drive_bays, list) {
	if (is_dock_device(bay->handle))
	unregister_hotplug_dock_device(bay->handle);
	acpi_bay_remove_fs(bay);
	acpi_remove_notify_handler(bay->handle, ACPI_SYSTEM_NOTIFY,
	bay_notify);
	platform_device_unregister(bay->pdev);
	kfree(bay->name);
	kfree(bay);
	}

	acpi_bus_unregister_driver(&acpi_bay_driver);
	}

	postcore_initcall(bay_init);
	module_exit(bay_exit);