driver core: prune docs about device_interface

drivers/base/intf.c was removed before the beginning of (git) time but
its Documentation stuck around.  Remove it.
Signed-off-by: Brandon Philips <brandon@ifup.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Documentation/driver-model/interface.txt

-
-Device Interfaces
-
-Introduction
-~~~~~~~~~~~~
-
-Device interfaces are the logical interfaces of device classes that correlate
-directly to userspace interfaces, like device nodes. 
-   
-Each device class may have multiple interfaces through which you can 
-access the same device. An input device may support the mouse interface, 
-the 'evdev' interface, and the touchscreen interface. A SCSI disk would 
-support the disk interface, the SCSI generic interface, and possibly a raw 
-device interface. 
-
-Device interfaces are registered with the class they belong to. As devices
-are added to the class, they are added to each interface registered with
-the class. The interface is responsible for determining whether the device
-supports the interface or not. 
-
-
-Programming Interface
-~~~~~~~~~~~~~~~~~~~~~
-
-struct device_interface {
-	char			* name;
-	rwlock_t		lock;
-	u32			devnum;
-	struct device_class	* devclass;
-
-	struct list_head	node;
-	struct driver_dir_entry	dir;
-
-	int (*add_device)(struct device *);
-	int (*add_device)(struct intf_data *);
-};
-
-int interface_register(struct device_interface *);
-void interface_unregister(struct device_interface *);
-
-
-An interface must specify the device class it belongs to. It is added
-to that class's list of interfaces on registration.
-
-
-Interfaces can be added to a device class at any time. Whenever it is
-added, each device in the class is passed to the interface's
-add_device callback. When an interface is removed, each device is
-removed from the interface.
-
-
-Devices
-~~~~~~~
-Once a device is added to a device class, it is added to each
-interface that is registered with the device class. The class
-is expected to place a class-specific data structure in 
-struct device::class_data. The interface can use that (along with
-other fields of struct device) to determine whether or not the driver
-and/or device support that particular interface.
-
-
-Data
-~~~~
-
-struct intf_data {
-	struct list_head	node;
-	struct device_interface	* intf;
-	struct device 		* dev;
-	u32			intf_num;
-};
-
-int interface_add_data(struct interface_data *);
-
-The interface is responsible for allocating and initializing a struct 
-intf_data and calling interface_add_data() to add it to the device's list
-of interfaces it belongs to. This list will be iterated over when the device
-is removed from the class (instead of all possible interfaces for a class).
-This structure should probably be embedded in whatever per-device data 
-structure the interface is allocating anyway.
-   
-Devices are enumerated within the interface. This happens in interface_add_data()
-and the enumerated value is stored in the struct intf_data for that device. 
-
-sysfs
-~~~~~
-Each interface is given a directory in the directory of the device
-class it belongs to:
-
-Interfaces get a directory in the class's directory as well:
-
-   class/
-   `-- input
-       |-- devices
-       |-- drivers
-       |-- mouse
-       `-- evdev
-
-When a device is added to the interface, a symlink is created that points 
-to the device's directory in the physical hierarchy:
-
-   class/
-   `-- input
-       |-- devices
-       |   `-- 1 -> ../../../root/pci0/00:1f.0/usb_bus/00:1f.2-1:0/
-       |-- drivers
-       |   `-- usb:usb_mouse -> ../../../bus/drivers/usb_mouse/
-       |-- mouse
-       |   `-- 1 -> ../../../root/pci0/00:1f.0/usb_bus/00:1f.2-1:0/
-       `-- evdev
-           `-- 1 -> ../../../root/pci0/00:1f.0/usb_bus/00:1f.2-1:0/
-
-
-Future Plans
-~~~~~~~~~~~~
-A device interface is correlated directly with a userspace interface
-for a device, specifically a device node. For instance, a SCSI disk
-exposes at least two interfaces to userspace: the standard SCSI disk
-interface and the SCSI generic interface. It might also export a raw
-device interface. 
-
-Many interfaces have a major number associated with them and each
-device gets a minor number. Or, multiple interfaces might share one
-major number, and each will receive a range of minor numbers (like in
-the case of input devices).
-
-These major and minor numbers could be stored in the interface
-structure. Major and minor allocations could happen when the interface
-is registered with the class, or via a helper function. 
-

include/linux/cpu.h

@@ -10,11 +10,6 @@
  *
  * CPUs are exported via sysfs in the class/cpu/devices/
  * directory. 
- *
- * Per-cpu interfaces can be implemented using a struct device_interface. 
- * See the following for how to do this: 
- * - drivers/base/intf.c 
- * - Documentation/driver-model/interface.txt
  */
 #ifndef _LINUX_CPU_H_
 #define _LINUX_CPU_H_

include/linux/node.h

@@ -10,11 +10,6 @@
  *
  * Nodes are exported via driverfs in the class/node/devices/
  * directory. 
- *
- * Per-node interfaces can be implemented using a struct device_interface. 
- * See the following for how to do this: 
- * - drivers/base/intf.c 
- * - Documentation/driver-model/interface.txt
  */
 #ifndef _LINUX_NODE_H_
 #define _LINUX_NODE_H_