path: root/drivers/nfc/st95hf/core.c

/*
 * --------------------------------------------------------------------
 * Driver for ST NFC Transceiver ST95HF
 * --------------------------------------------------------------------
 * Copyright (C) 2015 STMicroelectronics Pvt. Ltd. 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 that 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, see <http://www.gnu.org/licenses/>.
 */

#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/nfc.h>
#include <linux/of_gpio.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/wait.h>
#include <net/nfc/digital.h>
#include <net/nfc/nfc.h>

#include "spi.h"

/* supported protocols */
#define ST95HF_SUPPORTED_PROT		(NFC_PROTO_ISO14443_MASK | \
					NFC_PROTO_ISO14443_B_MASK | \
					NFC_PROTO_ISO15693_MASK)
/* driver capabilities */
#define ST95HF_CAPABILITIES		NFC_DIGITAL_DRV_CAPS_IN_CRC

/* Command Send Interface */
/* ST95HF_COMMAND_SEND CMD Ids */
#define ECHO_CMD			0x55
#define WRITE_REGISTER_CMD		0x9
#define PROTOCOL_SELECT_CMD		0x2
#define SEND_RECEIVE_CMD		0x4

/* Select protocol codes */
#define ISO15693_PROTOCOL_CODE		0x1
#define ISO14443A_PROTOCOL_CODE		0x2
#define ISO14443B_PROTOCOL_CODE		0x3

/*
 * head room len is 3
 * 1 byte for control byte
 * 1 byte for cmd
 * 1 byte for size
 */
#define ST95HF_HEADROOM_LEN		3

/*
 * tailroom is 1 for ISO14443A
 * and 0 for ISO14443B/ISO15693,
 * hence the max value 1 should be
 * taken.
 */
#define ST95HF_TAILROOM_LEN		1

/* Command Response interface */
#define MAX_RESPONSE_BUFFER_SIZE	280
#define ECHORESPONSE			0x55
#define ST95HF_ERR_MASK			0xF
#define ST95HF_TIMEOUT_ERROR		0x87
#define ST95HF_NFCA_CRC_ERR_MASK	0x20
#define ST95HF_NFCB_CRC_ERR_MASK	0x01

/* ST95HF transmission flag values */
#define TRFLAG_NFCA_SHORT_FRAME		0x07
#define TRFLAG_NFCA_STD_FRAME		0x08
#define TRFLAG_NFCA_STD_FRAME_CRC	0x28

/* Misc defs */
#define HIGH				1
#define LOW				0
#define ISO14443A_RATS_REQ		0xE0
#define RATS_TB1_PRESENT_MASK		0x20
#define RATS_TA1_PRESENT_MASK		0x10
#define TB1_FWI_MASK			0xF0
#define WTX_REQ_FROM_TAG		0xF2

#define MAX_CMD_LEN			0x7

#define MAX_CMD_PARAMS			4
struct cmd {
	int cmd_len;
	unsigned char cmd_id;
	unsigned char no_cmd_params;
	unsigned char cmd_params[MAX_CMD_PARAMS];
	enum req_type req;
};

struct param_list {
	int param_offset;
	int new_param_val;
};

/*
 * List of top-level cmds to be used internally by the driver.
 * All these commands are build on top of ST95HF basic commands
 * such as SEND_RECEIVE_CMD, PROTOCOL_SELECT_CMD, etc.
 * These top level cmds are used internally while implementing various ops of
 * digital layer/driver probe or extending the digital framework layer for
 * features that are not yet implemented there, for example, WTX cmd handling.
 */
enum st95hf_cmd_list {
	CMD_ECHO,
	CMD_ISO14443A_CONFIG,
	CMD_ISO14443A_DEMOGAIN,
	CMD_ISO14443B_DEMOGAIN,
	CMD_ISO14443A_PROTOCOL_SELECT,
	CMD_ISO14443B_PROTOCOL_SELECT,
	CMD_WTX_RESPONSE,
	CMD_FIELD_OFF,
	CMD_ISO15693_PROTOCOL_SELECT,
};

static const struct cmd cmd_array[] = {
	[CMD_ECHO] = {
		.cmd_len = 0x2,
		.cmd_id = ECHO_CMD,
		.no_cmd_params = 0,
		.req = SYNC,
	},
	[CMD_ISO14443A_CONFIG] = {
		.cmd_len = 0x7,
		.cmd_id = WRITE_REGISTER_CMD,
		.no_cmd_params = 0x4,
		.cmd_params = {0x3A, 0x00, 0x5A, 0x04},
		.req = SYNC,
	},
	[CMD_ISO14443A_DEMOGAIN] = {
		.cmd_len = 0x7,
		.cmd_id = WRITE_REGISTER_CMD,
		.no_cmd_params = 0x4,
		.cmd_params = {0x68, 0x01, 0x01, 0xDF},
		.req = SYNC,
	},
	[CMD_ISO14443B_DEMOGAIN] = {
		.cmd_len = 0x7,
		.cmd_id = WRITE_REGISTER_CMD,
		.no_cmd_params = 0x4,
		.cmd_params = {0x68, 0x01, 0x01, 0x51},
		.req = SYNC,
	},
	[CMD_ISO14443A_PROTOCOL_SELECT] = {
		.cmd_len = 0x7,
		.<