diff options
author | John W. Linville <linville@tuxdriver.com> | 2011-07-08 11:03:36 -0400 |
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committer | John W. Linville <linville@tuxdriver.com> | 2011-07-08 11:03:36 -0400 |
commit | 204d1641d200709c759d8c269458cbc7de378c40 (patch) | |
tree | ce88690b4422078883f1651537ccd1f5d8ed7258 | |
parent | 31817df025e24559a01d33ddd68bd11b21bf9d7b (diff) | |
parent | 5f0dd296a01c8173fcc05a8b262a1168ae90bc74 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 into for-davem
124 files changed, 6268 insertions, 1033 deletions
diff --git a/Documentation/networking/nfc.txt b/Documentation/networking/nfc.txt new file mode 100644 index 00000000000..b24c29bdae2 --- /dev/null +++ b/Documentation/networking/nfc.txt @@ -0,0 +1,128 @@ +Linux NFC subsystem +=================== + +The Near Field Communication (NFC) subsystem is required to standardize the +NFC device drivers development and to create an unified userspace interface. + +This document covers the architecture overview, the device driver interface +description and the userspace interface description. + +Architecture overview +--------------------- + +The NFC subsystem is responsible for: + - NFC adapters management; + - Polling for targets; + - Low-level data exchange; + +The subsystem is divided in some parts. The 'core' is responsible for +providing the device driver interface. On the other side, it is also +responsible for providing an interface to control operations and low-level +data exchange. + +The control operations are available to userspace via generic netlink. + +The low-level data exchange interface is provided by the new socket family +PF_NFC. The NFC_SOCKPROTO_RAW performs raw communication with NFC targets. + + + +--------------------------------------+ + | USER SPACE | + +--------------------------------------+ + ^ ^ + | low-level | control + | data exchange | operations + | | + | v + | +-----------+ + | AF_NFC | netlink | + | socket +-----------+ + | raw ^ + | | + v v + +---------+ +-----------+ + | rawsock | <--------> | core | + +---------+ +-----------+ + ^ + | + v + +-----------+ + | driver | + +-----------+ + +Device Driver Interface +----------------------- + +When registering on the NFC subsystem, the device driver must inform the core +of the set of supported NFC protocols and the set of ops callbacks. The ops +callbacks that must be implemented are the following: + +* start_poll - setup the device to poll for targets +* stop_poll - stop on progress polling operation +* activate_target - select and initialize one of the targets found +* deactivate_target - deselect and deinitialize the selected target +* data_exchange - send data and receive the response (transceive operation) + +Userspace interface +-------------------- + +The userspace interface is divided in control operations and low-level data +exchange operation. + +CONTROL OPERATIONS: + +Generic netlink is used to implement the interface to the control operations. +The operations are composed by commands and events, all listed below: + +* NFC_CMD_GET_DEVICE - get specific device info or dump the device list +* NFC_CMD_START_POLL - setup a specific device to polling for targets +* NFC_CMD_STOP_POLL - stop the polling operation in a specific device +* NFC_CMD_GET_TARGET - dump the list of targets found by a specific device + +* NFC_EVENT_DEVICE_ADDED - reports an NFC device addition +* NFC_EVENT_DEVICE_REMOVED - reports an NFC device removal +* NFC_EVENT_TARGETS_FOUND - reports START_POLL results when 1 or more targets +are found + +The user must call START_POLL to |