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authorBrandon Philips <brandon@ifup.org>2010-11-07 01:28:24 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2010-11-10 16:57:11 -0800
commitb17cd8d69a75f921d9d444cc3ac9b5b1d0b66ca0 (patch)
tree0bf40bde5e39ef855b4d0afe74fb0a61cf7590f3 /Documentation/driver-model
parente658e9fe65306346e827676a121eca3534ad75ff (diff)
downloadlinux-linaro-stable-b17cd8d69a75f921d9d444cc3ac9b5b1d0b66ca0.tar.gz
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>
Diffstat (limited to 'Documentation/driver-model')
-rw-r--r--Documentation/driver-model/interface.txt129
1 files changed, 0 insertions, 129 deletions
diff --git a/Documentation/driver-model/interface.txt b/Documentation/driver-model/interface.txt
deleted file mode 100644
index c66912bfe866..000000000000
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-
-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.
-