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Commit 8a00a61b authored by Frederic Danis's avatar Frederic Danis Committed by Samuel Ortiz
Browse files

NFC: Add basic NCI over SPI 



The NFC Forum defines a transport interface based on
Serial Peripheral Interface (SPI) for the NFC Controller
Interface (NCI).

This module implements the SPI transport of NCI, calling SPI module
directly to read/write data to NFC controller (NFCC).

NFCC driver should provide functions performing device open and close.
It should also provide functions asserting/de-asserting interruption
to prevent TX/RX race conditions.
NFCC driver can also fix a delay between transactions if needed by
the hardware.

Signed-off-by: default avatarFrederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
parent a395298c

include/net/nfc/nci_core.h

+49 −0
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
 *  NFC Controller (NFCC) and a Device Host (DH).

 *

 *  Copyright (C) 2011 Texas Instruments, Inc.

 *  Copyright (C) 2013 Intel Corporation. All rights reserved.

 *

 *  Written by Ilan Elias <ilane@ti.com>

 *
@@ -202,4 +203,52 @@ void nci_req_complete(struct nci_dev *ndev, int result); 
/* ----- NCI status code ----- */

int nci_to_errno(__u8 code);



/* ----- NCI over SPI acknowledge modes ----- */

#define NCI_SPI_CRC_DISABLED	0x00

#define NCI_SPI_CRC_ENABLED	0x01



/* ----- NCI SPI structures ----- */

struct nci_spi_dev;



struct nci_spi_ops {

	int (*open)(struct nci_spi_dev *ndev);

	int (*close)(struct nci_spi_dev *ndev);

	void (*assert_int)(struct nci_spi_dev *ndev);

	void (*deassert_int)(struct nci_spi_dev *ndev);

};



struct nci_spi_dev {

	struct nci_dev		*nci_dev;

	struct spi_device	*spi;

	struct nci_spi_ops	*ops;



	unsigned int		xfer_udelay;	/* microseconds delay between

						  transactions */

	u8			acknowledge_mode;



	void			*driver_data;

};



/* ----- NCI SPI Devices ----- */

struct nci_spi_dev *nci_spi_allocate_device(struct spi_device *spi,

						struct nci_spi_ops *ops,

						u32 supported_protocols,

						u32 supported_se,

						u8 acknowledge_mode,

						unsigned int delay);

void nci_spi_free_device(struct nci_spi_dev *ndev);

int nci_spi_register_device(struct nci_spi_dev *ndev);

void nci_spi_unregister_device(struct nci_spi_dev *ndev);



static inline void nci_spi_set_drvdata(struct nci_spi_dev *ndev,

					    void *data)

{

	ndev->driver_data = data;

}



static inline void *nci_spi_get_drvdata(struct nci_spi_dev *ndev)

{

	return ndev->driver_data;

}



#endif /* __NCI_CORE_H */

net/nfc/nci/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -8,3 +8,13 @@ config NFC_NCI 


	  Say Y here to compile NCI support into the kernel or say M to

	  compile it as module (nci).



config NFC_NCI_SPI

	depends on NFC_NCI && SPI

	bool "NCI over SPI protocol support"

	default n

	help

	  NCI (NFC Controller Interface) is a communication protocol between

	  an NFC Controller (NFCC) and a Device Host (DH).



	  Say yes if you use an NCI driver that requires SPI link layer.

net/nfc/nci/Makefile

+3 −1
Original line number Diff line number Diff line
@@ -5,3 +5,5 @@ 
obj-$(CONFIG_NFC_NCI) += nci.o



nci-objs := core.o data.o lib.o ntf.o rsp.o



nci-$(CONFIG_NFC_NCI_SPI) += spi.o

net/nfc/nci/spi.c

0 → 100644
+136 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2013  Intel Corporation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms and conditions of the GNU General Public License,

 * version 2, as published by the Free Software Foundation.

 *

 * This program is distributed in the hope 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.,

 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */



#define pr_fmt(fmt) "nci_spi: %s: " fmt, __func__



#include <linux/export.h>

#include <linux/spi/spi.h>

#include <linux/nfc.h>

#include <net/nfc/nci_core.h>



#define NCI_SPI_HDR_LEN			4

#define NCI_SPI_CRC_LEN			2



static int nci_spi_open(struct nci_dev *nci_dev)

{

	struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);



	return ndev->ops->open(ndev);

}



static int nci_spi_close(struct nci_dev *nci_dev)

{

	struct nci_spi_dev *ndev = nci_get_drvdata(nci_dev);



	return ndev->ops->close(ndev);

}



static int nci_spi_send(struct nci_dev *nci_dev, struct sk_buff *skb)

{

	return 0;

}



static struct nci_ops nci_spi_ops = {

	.open = nci_spi_open,

	.close = nci_spi_close,

	.send = nci_spi_send,

};



/* ---- Interface to NCI SPI drivers ---- */



/**

 * nci_spi_allocate_device - allocate a new nci spi device

 *

 * @spi: SPI device

 * @ops: device operations

 * @supported_protocols: NFC protocols supported by the device

 * @supported_se: NFC Secure Elements supported by the device

 * @acknowledge_mode: Acknowledge mode used by the device

 * @delay: delay between transactions in us

 */

struct nci_spi_dev *nci_spi_allocate_device(struct spi_device *spi,

						struct nci_spi_ops *ops,

						u32 supported_protocols,

						u32 supported_se,

						u8 acknowledge_mode,

						unsigned int delay)

{

	struct nci_spi_dev *ndev;

	int tailroom = 0;



	if (!ops->open || !ops->close || !ops->assert_int || !ops->deassert_int)

		return NULL;



	if (!supported_protocols)

		return NULL;



	ndev = devm_kzalloc(&spi->dev, sizeof(struct nci_dev), GFP_KERNEL);

	if (!ndev)

		return NULL;



	ndev->ops = ops;

	ndev->acknowledge_mode = acknowledge_mode;

	ndev->xfer_udelay = delay;



	if (acknowledge_mode == NCI_SPI_CRC_ENABLED)

		tailroom += NCI_SPI_CRC_LEN;



	ndev->nci_dev = nci_allocate_device(&nci_spi_ops, supported_protocols,

					    supported_se, NCI_SPI_HDR_LEN,

					    tailroom);

	if (!ndev->nci_dev)

		return NULL;



	nci_set_drvdata(ndev->nci_dev, ndev);



	return ndev;

}

EXPORT_SYMBOL_GPL(nci_spi_allocate_device);



/**

 * nci_spi_free_device - deallocate nci spi device

 *

 * @ndev: The nci spi device to deallocate

 */

void nci_spi_free_device(struct nci_spi_dev *ndev)

{

	nci_free_device(ndev->nci_dev);

}

EXPORT_SYMBOL_GPL(nci_spi_free_device);



/**

 * nci_spi_register_device - register a nci spi device in the nfc subsystem

 *

 * @pdev: The nci spi device to register

 */

int nci_spi_register_device(struct nci_spi_dev *ndev)

{

	return nci_register_device(ndev->nci_dev);

}

EXPORT_SYMBOL_GPL(nci_spi_register_device);



/**

 * nci_spi_unregister_device - unregister a nci spi device in the nfc subsystem

 *

 * @dev: The nci spi device to unregister

 */

void nci_spi_unregister_device(struct nci_spi_dev *ndev)

{

	nci_unregister_device(ndev->nci_dev);

}

EXPORT_SYMBOL_GPL(nci_spi_unregister_device);