port100_probe() calls usb_get_dev(), but there is no usb_put_dev()
in port100_disconnect(). The patch adds one.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This implements the target NFC digital operations tg_configure_hw(),
tg_listen(), tg_listen_mdaa(), and tg_send_cmd().

The target mode supports NFC-A technology at 106kbits/s and NFC-F
technologies at 212 and 424kbits/s.
Signed-off-by: NThierry Escande <thierry.escande@linux.intel.com>
Cc: Stephen Tiedemann <stephen.tiedemann@gmail.com>
Tested-by: NCho, Yu-Chen <acho@suse.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This patch implements the initiator NFC operations in_configure_hw()
and in_send_cmd(). It also implements the switch_rf() operation.

The initiator mode supports NFC-A technology at 106kbits/s and NFC-F
technologies at 212 and 424kbits/s.
Signed-off-by: NThierry Escande <thierry.escande@linux.intel.com>
Cc: Stephen Tiedemann <stephen.tiedemann@gmail.com>
Tested-by: NCho, Yu-Chen <acho@suse.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This patch implements the command handling mechanism. The digital stack
serializes all commands sent to the driver. This means that the digital
stack waits for the reply of the current command before sending a new
one. So there is no command queue managed at driver level.

All Port-100 commands are asynchronous. If the command has been sent
successfully to the device, it replies with an ACK frame. Then the
command response is received (or actually no-response in case of
timeout or error) and a command complete work on the system workqueue
is responsible for sending the response (or the error) back to the
digital stack.

The digital stack requires some commands to be synchronous, mainly
hardware configuration ones. These commands use the asynchronous
command path but are made synchronous by using a completion object.
Signed-off-by: NThierry Escande <thierry.escande@linux.intel.com>
Cc: Stephen Tiedemann <stephen.tiedemann@gmail.com>
Tested-by: NCho, Yu-Chen <acho@suse.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

This adds support for the Sony NFC USB dongle RC-S380, based on the
Port-100 chip. This dongle is an analog frontend and does not implement
the digital layer. This driver uses the nfc_digital module which is an
implementation of the NFC Digital Protocol stack.

This patch is a skeleton. It only registers the dongle against the NFC
digital protocol stack. All NFC digital operation functions are stubbed
out.
Signed-off-by: NThierry Escande <thierry.escande@linux.intel.com>
Cc: Stephen Tiedemann <stephen.tiedemann@gmail.com>
Tested-by: NCho, Yu-Chen <acho@suse.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>